/**
 * SideQuests — the job board's model: the contracts posted on every
 * system EXCEPT the player's home (safe space — the Explore drawer's
 * own gate, data/actionbar.json → surface.explore.items), and the run's
 * ledger of the contracts it has taken.
 *
 * LAYERING — the board is a VIEW over this (js/ui/JobBoardWindow.js):
 *   - the WINDOW renders sideQuestPostingsFor(seed, record, galaxy) (the
 *     current system's postings) and hands the player's intent to the
 *     scene (ACCEPT / SET ACTIVE / CLAIM REWARD);
 *   - the SCENE (GameScene.acceptSideQuest / setActiveSideQuest /
 *     claimSideQuest — the claimSurfaceQuest precedent: state + effects
 *     there, the note on the surface) lands them on the SideQuestState
 *     ledger (registry 'sidequests' — rides the saves like the quest
 *     ledger, SaveData capture/prepareLoad);
 *   - this module owns the CONTRACTS: which ones stand, what they say,
 *     what they pay, the PATROL's route (buildPatrolRoute +
 *     patrolTargetSystem), and the accepted/active/completed/claimed
 *     record — pure, seeded, Node-testable (dev/sidequests.test.mjs).
 *
 * CATEGORIES — the four job types (data/sidequests.json → categories):
 * patrol / delivery / bounty / escort. Every category is ACCOUNTED FOR —
 * its slot machinery here, its description pool + reward band in the
 * data, the window's row + contract readout, the ledger, the accept
 * seam — behind its OWN `enabled` gate, and the gate is the contract:
 * a category's jobs appear on the board ONLY when its rules land and
 * its flag flips. PATROL is the first live type (enabled:true) — a
 * patrol's objective is its ROUTE (below); the other three stay
 * OFFLINE until their rule sets land.
 *
 * PATROL — the route the player flies (data/sidequests.json → patrol):
 *   - TARGET — patrolTargetSystem: the route's system. Default the
 *     posting's own system; in a FACTION system at or beyond the
 *     diagonal mark (neighborMinD — the '40% from home' rule), a seeded
 *     draw (neighborChance) may stand a NEIGHBOR — a system the
 *     posting's jump gates reach (galaxy.jumpGatesFor) controlled by
 *     ANOTHER faction (the push-the-factions-out voice made a route).
 *   - ROUTE — buildPatrolRoute: N isolated waypoints ([min,max] in the
 *     data) as plain world coordinates, inside the caller's REGION (the
 *     player's unlocked tether regions when the target is the system
 *     they stand in; one tether region around each anchor when it is a
 *     system not yet unlocked — the scene's job to assemble), keeping
 *     anchorClearance from every anchor (planet / station / gate)
 *     and minSeparation apart (relaxed, never the region — a patrol
 *     must always be completable). Seeded on (seed, 'sidequests',
 *     <targetSystemId>, 'patrol', <jobId>, 'route') — same contract +
 *     region ⇒ same route, across re-accepts, scene restarts, saves.
 *   - ENCOUNTERS — the patrol's hostile CONTACTS (data →
 *     patrol.encounters): how many stand (counts — the odds: 1 on 20%
 *     of patrols, 2 on 20%, 3 on 60%), WHERE they stand (patrolEncounterPositions — the max-spread subset of the route's waypoints — the
 *     contacts spread across the route, never clustered), WHAT they fly
 *     (the band's roster — the player's LEVEL × the target's HOPS from
 *     home; today the low band, levels 1–5 at 1–2 hops, the established
 *     type only), and the fight's shape (the wave — one rolling wave of
 *     six, three at a time). derivePatrolEncounters rolls it all seeded
 *     at the accept (the labelled fork (seed, 'sidequests',
 *     <targetSystemId>, 'patrol', <jobId>, 'encounters')) and fixes it
 *     on the route record — a signed contract is a signed contract;
 *     patrolEncounterScript shapes the contact's wave script for
 *     CombatSystem.startWaves; the scene's updatePatrol fires the wave
 *     at the contact's waypoint and marks it cleared on the run's
 *     completion (the witness is the completion, not the attempt — the
 *     combatDone precedent), and patrolRouteComplete stands the
 *     contract: every waypoint logged AND every contact cleared.
 *   - LEDGER — SideQuestState carries the accepted order, the ONE
 *     active contract (reconcileActive: the top accepted contract
 *     stands active until it is done and claimed), the route record
 *     (waypoints + visited + the contract's payout — credits AND the
 *     XP reward, patrolEncounterXp), and the claimed marks. The
 *     scene's updatePatrol checks the ship in (visitRadius, any
 *     order), completes the contract, and pays the reward exactly
 *     once on claim (the credits + the XP, the claim's two payouts).
 *
 * DETERMINISM (the worldgen contract, PROJECT_NOTES → "World model") —
 * postings derive from the galaxy seed + the system record through
 * LABELLED forks: Rng.derive(seed, 'sidequests', <sysId>, …). The same
 * contract stands on the same system for the whole run — across visits,
 * scene restarts, and saves — and a different system draws its own (the
 * variant pool keeps the galaxy's boards from reading as one repeated
 * ad). Nothing here depends on call order.
 *
 * FLAVOR — the variant pools split by SYSTEM CONTEXT
 * (data/sidequests.json → descriptions): NEUTRAL systems post about
 * keeping their system safe from PIRATES; a FACTION's systems post about
 * pushing the OTHER factions out of their space. The faction pools carry
 * placeholders, resolved at generation (never stored): {system} = the
 * system's name, {faction} = the system's faction label
 * (data/factions.json), {issuer} = that faction's board name
 * (data/sidequests.json → factions), {enemies} = the other two
 * factions' labels ("MindWeave and Zenith").
 */
import { config } from '../config/Config.js';
import { Rng } from '../utils/Rng.js';
import { Tether } from '../tether/Tether.js';
import { enemyTypeConfig, enemyTypeIds } from '../combat/EnemyTypes.js';

/** The four job types, canonical slot order (the data's category keys). */
export const SIDE_QUEST_CATEGORIES = ['patrol', 'delivery', 'bounty', 'escort'];

/** The three player factions (data/factions.json minus 'neutral'). */
const FACTIONS = ['apex', 'mindweave', 'zenith'];

const clamp01 = (v) => Math.min(1, Math.max(0, Number.isFinite(v) ? v : 0));

/** The feature's master switch (data/sidequests.json → enabled). */
export function sideQuestsEnabled() {
  return config.get('sidequests.enabled', true) !== false;
}

/**
 * The postings-per-system roll range (data/sidequests.json →
 * board.perSystem). A malformed range falls back to the design's 3–4.
 * @returns {[number, number]} [min, max] (integers, min ≤ max)
 */
export function sideQuestCountRange() {
  const raw = config.get('sidequests.board.perSystem', null);
  if (!Array.isArray(raw) || raw.length < 2) return [3, 4];
  let lo = Math.floor(Number(raw[0]));
  let hi = Math.floor(Number(raw[1]));
  if (!Number.isFinite(lo) || !Number.isFinite(hi)) return [3, 4];
  lo = Math.max(1, lo);
  hi = Math.max(lo, hi);
  return [lo, hi];
}

/** The Rng fork label under the galaxy seed (data/sidequests.json → board.seedLabel). */
function seedLabel() {
  const s = String(config.get('sidequests.board.seedLabel', 'sidequests') || 'sidequests').trim();
  return s || 'sidequests';
}

/**
 * A category's meta (data/sidequests.json → categories.<id>).
 *
 * `minLevel` (the BOUNTY HUNT's gate — data → categories.bounty.minLevel)
 * is the combat LEVEL the board demands (js/combat/XpManager.js): under
 * it the posting still STANDS (its slot is seeded — a board that
 * reshuffled as the player leveled would never settle), but the row
 * renders LOCKED and the scene's accept refuses it. 1 = no gate
 * (patrol's, and every category's, default). `contexts` (the BOUNTY
 * HUNT's neutral-only posting) lists which boards post it — ['neutral'],
 * ['faction'], or both (the default when a category says nothing).
 *
 * @returns {{id:string, enabled:boolean, label:string, accent:string, minLevel:number, contexts:string[]}|null} null when unknown
 */
export function sideQuestCategoryMeta(id) {
  if (!SIDE_QUEST_CATEGORIES.includes(id)) return null;
  const c = config.get(`sidequests.categories.${id}`, null);
  if (!c || typeof c !== 'object') return null;
  // An omitted minLevel demands NOTHING (0) — that is every legacy category,
  // which stood open long before the hunt's gate existed. A fresh run's combat
  // level is 0 (js/combat/XpManager.js), so a default of 1 would have rendered
  // the standing PATROLS locked; only a category that SAYS so asks for a level.
  const minLevel = Math.max(0, Math.floor(numOr(c.minLevel, 0)));
  const contexts = (Array.isArray(c.contexts) ? c.contexts : [])
    .map((v) => String(v).trim().toLowerCase())
    .filter((v) => v === 'neutral' || v === 'faction');
  return {
    id,
    enabled: c.enabled === true, // strict — a missing flag is OFFLINE (never fabricate jobs)
    label: String(c.label ?? id.toUpperCase()),
    accent: String(c.accent ?? '#00e5ff'),
    minLevel,
    contexts: contexts.length > 0 ? contexts : ['neutral', 'faction'],
  };
}

/**
 * The LIVE categories (enabled:true, canonical order). The board's gate:
 * only these ever generate a posting — a category is accounted for but
 * unavailable until its rules are built and its flag flipped.
 *
 * @param {string} [context] 'neutral' | 'faction' — when given, the
 *   category's own `contexts` list also gates it (a BOUNTY HUNT never
 *   stands on a faction board; omitting the argument is every category
 *   that says nothing about contexts, i.e. patrol unchanged)
 * @returns {string[]}
 */
export function enabledSideQuestCategories(context = null) {
  const ctx = context === 'neutral' || context === 'faction' ? context : null;
  return SIDE_QUEST_CATEGORIES.filter((id) => {
    const meta = sideQuestCategoryMeta(id);
    if (!meta || meta.enabled !== true) return false;
    return ctx === null || meta.contexts.includes(ctx);
  });
}

/**
 * Can this posting be ACCEPTED at this combat level? The gate is the
 * category's `minLevel` (the scene's accept refuses with the data's deny
 * toast, and the board renders the row LOCKED); a posting without a
 * known level (a test, an old call) stands open.
 * @param {object} posting sideQuestPostingsFor's shape
 * @param {number|null} level the player's combat level
 * @returns {{ok:boolean, locked:boolean, minLevel:number}}
 */
export function sideQuestAcceptable(posting, level = null) {
  const meta = sideQuestCategoryMeta(posting?.category);
  const minLevel = meta ? meta.minLevel : 0;
  // UNKNOWN is not LEVEL 0. `null` / `undefined` (no XP bank in the boot, an
  // older caller that never reads one) stands the contract OPEN — Number(null)
  // is 0, which would otherwise lock every gated category on a missing read.
  if (level === null || level === undefined || !Number.isFinite(Number(level))) {
    return { ok: true, locked: false, minLevel };
  }
  const lvl = Math.floor(Number(level));
  return { ok: lvl >= minLevel, locked: lvl < minLevel, minLevel };
}

/**
 * Faction id → label (data/factions.json → factions), the three player
 * factions only. A missing entry falls back to the id's own casing so a
 * hand-edited table can't blank the board's copy.
 * @returns {Record<string,string>}
 */
export function sideQuestFactionLabels() {
  const table = config.get('factions.factions', null);
  const out = {};
  for (const id of FACTIONS) {
    const entry = table && typeof table === 'object' ? table[id] : null;
    const label = entry && typeof entry.label === 'string' && entry.label ? entry.label : id;
    out[id] = label.charAt(0).toUpperCase() + label.slice(1);
  }
  return out;
}

/**
 * Resolve the pool's placeholders in a line of copy (resolveSideQuestText's
 * input context). {system} / {faction} / {issuer} / {enemies} — the
 * neutral context leaves the faction-side keys empty (its pools don't
 * carry them).
 * @param {object} rec a system record ({ id, name, faction, … })
 */
function postingContext(rec) {
  const system = String(rec?.name ?? rec?.id ?? 'this system');
  const faction = typeof rec?.faction === 'string' && rec.faction !== '' ? rec.faction : null;
  if (!faction) return { context: 'neutral', system, faction: '', issuer: '', enemies: '' };
  const labels = sideQuestFactionLabels();
  const label = labels[faction] ?? faction;
  const issuer =
    String(config.get(`sidequests.factions.${faction}`, '') || '').trim() || `${label} Authority`;
  const others = FACTIONS.filter((f) => f !== faction).map((f) => labels[f] ?? f);
  const enemies =
    others.length === 2 ? `${others[0]} and ${others[1]}` : others.join(', ');
  return { context: 'faction', system, faction: label, issuer, enemies };
}

/**
 * The pool's placeholder resolution (the data's contract): {system},
 * {faction}, {issuer}, {enemies} → the context's values. split/join (no
 * $-quirks). A placeholder with no value in the context (a {faction} in
 * a neutral pool — a data bug) resolves to '' rather than leaking its
 * braces.
 * @param {string} text the pool line
 * @param {object} ctx the postingContext() shape
 * @returns {string}
 */
export function resolveSideQuestText(text, ctx = null) {
  if (typeof text !== 'string' || text === '') return '';
  ctx = ctx && typeof ctx === 'object' ? ctx : {};
  const map = {
    system: ctx.system ?? '',
    faction: ctx.faction ?? '',
    issuer: ctx.issuer ?? '',
    enemies: ctx.enemies ?? '',
  };
  let out = text;
  for (const [key, value] of Object.entries(map)) {
    if (!value) continue;
    out = out.split(`{${key}}`).join(String(value));
  }
  // Any placeholder that still stands (no value for this context) is
  // blanked — the board never ships a brace pair to the player.
  out = out.replace(/\{system\}|\{faction\}|\{issuer\}|\{enemies\}/g, '');
  return out;
}

/**
 * The posting's CREDITS payout (data/sidequests.json → rewards): the
 * category's band [min,max] rolled seeded per posting, scaled OUT with
 * the system's home→far diagonal d as (1 + d * distanceScale) — the
 * far systems' boards pay more for the same risk (the economy's 'a hop
 * is a hop' rule). A missing band falls back to [40,80]; the result is
 * rounded to 5 CR, floored at 5 CR.
 * @param {string} cat the category id
 * @param {number} d the system's home→far diagonal (0..1)
 * @param {Rng} r the posting's seeded stream
 * @returns {{credits:number}}
 */
export function rollSideQuestReward(cat, d, r) {
  let band = config.get(`sidequests.rewards.${cat}`, null);
  if (!Array.isArray(band) || band.length < 2 || !Number.isFinite(Number(band[0])) || !Number.isFinite(Number(band[1]))) {
    band = [40, 80];
  }
  const scale = 1 + clamp01(d) * (Number(config.get('sidequests.rewards.distanceScale', 0.75)) || 0);
  const lo = Math.min(Number(band[0]), Number(band[1]));
  const hi = Math.max(Number(band[0]), Number(band[1]));
  const credits = Math.max(5, Math.round((r.range(lo, hi) * scale) / 5) * 5);
  return { credits };
}

/**
 * The patrol's TARGET system — the system the route will be built in.
 * Default (returns null): the posting's own system. The NEIGHBOR rule
 * (data/sidequests.json → patrol): in a FACTION system at or beyond the
 * diagonal mark (neighborMinD — the design's '40% from home'), a seeded
 * draw (neighborChance) may stand a system the posting's jump gates
 * reach (galaxy.jumpGatesFor) controlled by ANOTHER faction — the
 * push-them-out voice made a route. The draw rides the posting's own
 * seeded stream, so the same posting stands with the same target for
 * the whole run (visits, scene restarts, saves); no galaxy, or no
 * other-faction link, falls back to the posting system — never a null
 * target.
 *
 * @param {object} rec the posting's system record ({ id, faction, d, … })
 * @param {Rng} r the posting's seeded stream
 * @param {object|null} [galaxy] the galaxy (jumpGatesFor + byId) — null in tests
 * @returns {{id:string, name:string}|null} null = the posting system stands
 */
export function patrolTargetSystem(rec, r, galaxy = null) {
  const faction = typeof rec?.faction === 'string' ? rec.faction : '';
  if (faction === '' || faction === 'neutral') return null; // neutral space patrols its own system
  const minD = Number(config.get('sidequests.patrol.neighborMinD', 0.4));
  if (!Number.isFinite(minD) || clamp01(Number(rec?.d)) < minD) return null; // the '40% from home' mark
  const chance = Number(config.get('sidequests.patrol.neighborChance', 0.5));
  if (!r.chance(clamp01(Number.isFinite(chance) ? chance : 0.5))) return null; // the seeded draw (the posting system stands)
  if (!galaxy || typeof galaxy.jumpGatesFor !== 'function') return null; // no galaxy (a test) — the posting system stands
  const cands = [];
  let links = null;
  try {
    links = galaxy.jumpGatesFor(rec.id);
  } catch {
    links = null; // an unknown id (a hand-built test record) — the posting system stands
  }
  for (const nb of links ?? []) {
    if (!nb || typeof nb.id !== 'string' || nb.id === rec.id) continue;
    const nf = typeof nb.faction === 'string' ? nb.faction : '';
    if (nf !== '' && nf !== 'neutral' && nf !== faction) cands.push(nb); // a NEIGHBOR controlled by ANOTHER faction
  }
  if (cands.length === 0) return null; // no other-faction link — the posting system stands
  const nb = r.pick(cands);
  return nb ? { id: nb.id, name: String(nb.name ?? nb.id) } : null;
}

/**
 * The patrol's ROUTE — N isolated waypoints (data/sidequests.json →
 * patrol.waypoints [min,max]) as plain world coordinates inside the
 * target system. The REGION argument is the contract's flight envelope
 * (the scene assembles it: the player's UNLOCKED tether regions when
 * the target is the system they stand in; one tether region — a level-1
 * radius — around each of the target's planets / stations / gates when
 * it is a system not yet unlocked). Waypoints stay inside the region
 * (a rim inset off the tether line), anchorClearance px clear of every
 * ANCHOR (a planet / station / gate center — the scene's list) and
 * minSeparation px apart; a tight field relaxes the clearance and
 * separation (never the region) until it gives, and a field that gives
 * nowhere stands the point at its region's heart — a patrol must always
 * be completable.
 *
 * Seeded on its own labelled fork (seed, 'sidequests',
 * <targetSystemId>, 'patrol', <jobId>, 'route') — the worldgen
 * determinism contract: same seed + contract + region ⇒ same route,
 * across re-accepts, scene restarts, and saves; nothing here depends on
 * call order.
 *
 * @param {string|number} seed the galaxy's seed
 * @param {string} jobId the accepted contract's id (the fork's key)
 * @param {string} targetSystemId the route's system (the posting's target)
 * @param {object[]} region [{ x, y, radius }] the flight envelope
 * @param {object[]} [anchors] [{ x, y }] the keep-out centers (planets / stations / gates)
 * @returns {{targetSystemId:string, waypoints:number[][], visited:number[]}}
 */
export function buildPatrolRoute(seed, jobId, targetSystemId, region, anchors = [], opts = {}) {
  // The placement LAW is shared (region inset, anchor clearance, separation);
  // `opts` lets another contract type stand its OWN leg count + fork label on
  // top of it — a BOUNTY HUNT asks for the plan's exact leg count under its
  // 'bounty' fork (GameScene._establishBountyHunt). No opts = patrol exactly
  // as it always was.
  const rawRange = Array.isArray(opts?.waypoints) && opts.waypoints.length > 0
    ? opts.waypoints
    : config.get('sidequests.patrol.waypoints', [3, 5]);
  let lo = Math.floor(Number(Array.isArray(rawRange) ? rawRange[0] : 3));
  let hi = Math.floor(Number(Array.isArray(rawRange) ? rawRange[1] : 5));
  if (!Number.isFinite(lo) || !Number.isFinite(hi)) {
    lo = 3;
    hi = 5;
  }
  lo = Math.max(1, lo);
  hi = Math.max(lo, hi);
  const anchorClearance = Math.max(0, Number(config.get('sidequests.patrol.anchorClearance', 1100)) || 0);
  const minSeparation = Math.max(0, Number(config.get('sidequests.patrol.minSeparation', 1500)) || 0);
  const inset = Math.max(0, Number(config.get('sidequests.patrol.regionInset', 96)) || 0);

  const regions = (Array.isArray(region) ? region : [])
    .map((t) => ({ x: Number(t?.x), y: Number(t?.y), radius: Number(t?.radius) }))
    .filter((t) => Number.isFinite(t.x) && Number.isFinite(t.y) && Number.isFinite(t.radius) && t.radius > 0);
  if (regions.length === 0) {
    // No usable region (a caller without tether data — a test, or a
    // degenerate system): the system's heart at one tether's width, so
    // the route still stands (a patrol must always be completable).
    regions.push({ x: 0, y: 0, radius: Tether.radiusForLevel(1) });
  }
  const anchorPts = (Array.isArray(anchors) ? anchors : [])
    .map((a) => ({ x: Number(a?.x), y: Number(a?.y) }))
    .filter((a) => Number.isFinite(a.x) && Number.isFinite(a.y));

  // The effective envelope: each region inset by the rim margin (a
  // waypoint never sits on a tether's line). A region smaller than its
  // inset gives up the inset rather than the region (kept at a 4 px
  // floor so the sampler never weights a zero-disc).
  const eff = regions.map((t) => ({ x: t.x, y: t.y, r: Math.max(4, t.radius - inset) }));
  const areas = eff.map((t) => t.r * t.r); // the sampler's weights (disc area)
  const inside = (x, y) => eff.some((t) => (x - t.x) ** 2 + (y - t.y) ** 2 <= t.r * t.r);

  const fork = String(opts?.fork ?? 'patrol');
  const r = Rng.derive(seed, seedLabel(), targetSystemId, fork, jobId, 'route');
  const n = r.int(lo, hi);
  const pickRegion = () => {
    const total = areas.reduce((a, b) => a + b, 0);
    let u = r.next() * total;
    for (let i = 0; i < eff.length; i++) {
      u -= areas[i];
      if (u <= 0) return eff[i];
    }
    return eff[eff.length - 1];
  };

  const placed = [];
  for (let i = 0; i < n; i++) {
    let clear = anchorClearance;
    let sep = minSeparation;
    let pt = null;
    for (let attempt = 0; attempt < 900 && !pt; attempt++) {
      const t = pickRegion();
      const rad = Math.sqrt(r.next()) * t.r; // uniform in the disc (the sqrt)
      const ang = r.next() * Math.PI * 2;
      const x = t.x + Math.cos(ang) * rad;
      const y = t.y + Math.sin(ang) * rad;
      if (!inside(x, y)) continue;
      const okA = clear <= 0 || anchorPts.every((a) => Math.hypot(x - a.x, y - a.y) >= clear);
      const okS = sep <= 0 || placed.every((p) => Math.hypot(x - p.x, y - p.y) >= sep);
      if (okA && okS) pt = { x, y };
      else if (attempt === 299 || attempt === 699) {
        clear *= 0.5; // the field's giving — ease the clearance…
        sep *= 0.5; // …and the separation (never the region)
      }
    }
    if (!pt) {
      // The field gave nowhere (a system of one crowded anchor): stand
      // the point at the region's heart, half an inset off center on a
      // seeded bearing — inside the envelope, best-effort isolated.
      const t = pickRegion();
      const ang = r.next() * Math.PI * 2;
      const rad = Math.min(t.r * 0.5, Math.max(4, anchorClearance * 0.5));
      pt = { x: t.x + Math.cos(ang) * rad, y: t.y + Math.sin(ang) * rad };
    }
    placed.push(pt);
  }

  return {
    targetSystemId: String(targetSystemId),
    waypoints: placed.map((p) => [Math.round(p.x), Math.round(p.y)]),
    visited: [],
  };
}

// ------------------------------------------------- the patrol's ENCOUNTERS
// The contract's hostile CONTACTS (data/sidequests.json → patrol.encounters):
// how many stand (counts), where they stand (positions — the max-spread
// subset of the route's waypoints), what they fly (the band's roster —
// the player's level × the target's hops from home), and the fight's shape
// (the wave — one rolling wave of six, three at a time). All pure and
// seeded — the scene's _establishPatrol rolls the spec at the accept and
// fixes it on the route record; the scene's updatePatrol fires it at the
// contact's waypoint and marks the clearance on the wave run's completion.

/** The established type (the base craft's named id) — the low band's roster and the bandless fallback alike. */
const ESTABLISHED_ENEMY_TYPES = ['raider'];

/** A finite number, else the fallback. */
function numOr(v, fb) {
  const n = Number(v);
  return Number.isFinite(n) ? n : fb;
}

/**
 * The contact COUNT's odds (data/sidequests.json → patrol.encounters.counts
 * — [count, odds] pairs; the design: 1 contact on 20% of patrols, 2 on
 * 20%, 3 on 60%). A malformed table falls back to the design's own.
 * @returns {Array<[number, number]>} sorted by count, positive weights
 */
export function patrolEncounterCounts() {
  const raw = config.get('sidequests.patrol.encounters.counts', null);
  const pairs = [];
  if (Array.isArray(raw)) {
    for (const [c, w] of raw) {
      const count = Math.floor(numOr(c, NaN));
      const weight = numOr(w, NaN);
      if (Number.isFinite(count) && count >= 1 && Number.isFinite(weight) && weight > 0) pairs.push([count, weight]);
    }
  }
  if (pairs.length === 0) return [[1, 0.2], [2, 0.2], [3, 0.6]];
  return pairs.sort((a, b) => a[0] - b[0]);
}

/**
 * A contact's WAVE shape (data/sidequests.json → patrol.encounters.wave —
 * the design: one ROLLING wave of six, three at a time, each kill
 * replaced — the combat.waves rolling mechanic, js/combat/Waves.js).
 * @returns {{kind:string, total:number, maxConcurrent:number, replacePerKill:number}}
 */
export function patrolEncounterWave() {
  const raw = config.get('sidequests.patrol.encounters.wave', null);
  const w = raw && typeof raw === 'object' && !Array.isArray(raw) ? raw : {};
  const kind = w.kind === 'fixed' ? 'fixed' : 'rolling';
  const total = Math.max(1, Math.floor(numOr(w.total, 6)));
  return {
    kind,
    total,
    maxConcurrent: Math.min(total, Math.max(1, Math.floor(numOr(w.maxConcurrent, 3)))),
    replacePerKill: kind === 'rolling' ? Math.max(0, Math.floor(numOr(w.replacePerKill, 1))) : 0,
  };
}

/**
 * The standing band's ROSTER — the enemy types a patrol's contacts fly
 * (data/sidequests.json → patrol.encounters.bands): the FIRST band in
 * list order whose `levels` AND `hops` windows both contain the
 * player's state — the difficulty's first axis (the player's COMBAT
 * level × the target system's HOPS from home — the jump network's tree
 * depth, the 'systems 1–2 hops out' rule). Today the low band — levels
 * 1–5 at 1–2 hops from home — flies the ESTABLISHED type only (raider);
 * the farther/higher bands — with the enemy types they introduce —
 * append to the list when those types land. A roster's type ids are
 * validated against combat.enemyTypes (js/combat/EnemyTypes.js) — an
 * unknown id (a data typo) never ships; a roster that empties — or no
 * band standing at all — takes the fallback (the established type).
 *
 * @param {number} level the player's combat level (data/progression.json — js/combat/XpManager.js)
 * @param {number} hops the target system's jump-network depth from home (0 = home)
 * @returns {string[]} the roster's type ids (never empty)
 */
export function patrolEnemyRoster(level, hops) {
  const valid = new Set(enemyTypeIds());
  const lvl = numOr(level, 0);
  const hop = numOr(hops, 0);
  const bands = config.get('sidequests.patrol.encounters.bands', null);
  let pick = null;
  if (Array.isArray(bands)) {
    for (const b of bands) {
      if (!b || typeof b !== 'object' || Array.isArray(b)) continue;
      if (!Array.isArray(b.levels) || b.levels.length < 2 || !Array.isArray(b.hops) || b.hops.length < 2) continue;
      const [lo, hi] = [numOr(b.levels[0], NaN), numOr(b.levels[1], NaN)];
      const [ho, hh] = [numOr(b.hops[0], NaN), numOr(b.hops[1], NaN)];
      if (![lo, hi, ho, hh].every(Number.isFinite)) continue;
      if (lvl >= Math.min(lo, hi) && lvl <= Math.max(lo, hi) && hop >= Math.min(ho, hh) && hop <= Math.max(ho, hh)) {
        pick = b.enemyTypes; // the first standing band wins (list order)
        break;
      }
    }
  }
  let raw = pick;
  if (raw == null) raw = config.get('sidequests.patrol.encounters.fallbackEnemyTypes', null);
  if (raw == null) raw = ESTABLISHED_ENEMY_TYPES;
  const out = (Array.isArray(raw) ? raw : [raw])
    .map((t) => String(t).trim())
    .filter((t) => t !== '' && valid.has(t));
  if (out.length > 0) return out;
  return ESTABLISHED_ENEMY_TYPES.filter((t) => valid.has(t));
}

/**
 * The contact's WAYPOINTS — the `count` of the route's `waypoints`
 * (finite [x,y] pairs) the contacts stand on, SPREAD across the route
 * (data/sidequests.json → patrol.encounters — POSITIONING): for count ≥
 * 2, the most EVENLY SPREAD subset of the route's waypoints (scored by
 * its MINIMUM pairwise separation — maximin — then its total: on a
 * near-linear route that's the ends and the middle; a 3–5-point
 * route's contacts never cluster); a single contact stands on the
 * waypoint nearest the route's centroid (the patrol's
 * middle). Pure in (waypoints, count) — deterministic, ties keep the
 * lowest index order (the route itself is seeded, so the pair is stable
 * for the run).
 *
 * @param {Array<[number, number]>} waypoints the route's waypoints
 * @param {number} count the contacts' number (clamped to the route's length)
 * @returns {number[]} the waypoint indices (distinct, ascending; [] for an empty route)
 */
export function patrolEncounterPositions(waypoints, count) {
  const n = Array.isArray(waypoints) ? waypoints.length : 0;
  if (n === 0) return [];
  const k = Math.max(1, Math.min(Math.floor(numOr(count, 1)), n));
  if (k === n) return waypoints.map((_, i) => i);
  if (k === 1) {
    // One contact: the patrol's MIDDLE — the waypoint nearest the
    // route's centroid (the points' center of mass — the route is a set
    // of points, not a path, so the centroid is its only 'middle').
    let cx = 0, cy = 0, m = 0;
    for (const w of waypoints) {
      if (Array.isArray(w) && w.length >= 2 && Number.isFinite(w[0]) && Number.isFinite(w[1])) {
        cx += w[0];
        cy += w[1];
        m++;
      }
    }
    if (m === 0) return [0];
    cx /= m;
    cy /= m;
    let best = 0;
    let bestD = Infinity;
    for (let i = 0; i < n; i++) {
      const w = waypoints[i];
      if (!Array.isArray(w) || w.length < 2) continue;
      const d = (w[0] - cx) ** 2 + (w[1] - cy) ** 2;
      if (d < bestD) {
        bestD = d;
        best = i;
      }
    }
    return [best];
  }
  // k ≥ 2: every C(n, k) subset (n ≤ the route's 5 — a trivial space),
  // scored for EVEN SPREAD: first the MINIMUM pairwise separation
  // (maximin — the contacts are as far apart from each other as the
  // route allows: on a near-linear route that's the ends and the middle,
  // never a cluster), then the total pairwise separation, ties the
  // lowest index order (the subsets enumerate in index order).
  const dist = (a, b) => Math.hypot(waypoints[a][0] - waypoints[b][0], waypoints[a][1] - waypoints[b][1]);
  const score = (idxs) => {
    let min = Infinity;
    let sum = 0;
    for (let a = 0; a < idxs.length; a++) {
      for (let b = a + 1; b < idxs.length; b++) {
        const d = dist(idxs[a], idxs[b]);
        if (d < min) min = d;
        sum += d;
      }
    }
    return { min, sum };
  };
  const combos = [];
  const rec = (start, cur) => {
    if (cur.length === k) {
      combos.push(cur.slice());
      return;
    }
    for (let i = start; i <= n - (k - cur.length); i++) rec(i + 1, [...cur, i]);
  };
  rec(0, []);
  let best = null;
  let bestMin = -1;
  let bestSum = -1;
  for (const c of combos) {
    const s = score(c);
    if (s.min > bestMin + 1e-9 || (Math.abs(s.min - bestMin) <= 1e-9 && s.sum > bestSum + 1e-9)) {
      bestMin = s.min;
      bestSum = s.sum;
      best = c;
    }
  }
  return best ?? [0];
}

/**
 * The patrol's ENCOUNTERS — the contract's contact spec, rolled/derived
 * at the accept (the scene's _establishPatrol) from the data's rules:
 * the COUNT by its odds (patrolEncounterCounts — 1 on 20%, 2 on 20%, 3
 * on 60%), the POSITIONS on the route's waypoints (patrolEncounter
 * Positions — the max-spread subset, the single contact at the route's
 * middle), the ROSTER from the standing band (patrolEnemyRoster — the
 * player's level × the target's hops from home; today the low band's
 * established type only), and the WAVE shape (patrolEncounterWave — one
 * rolling wave of six, three at a time).
 *
 * Seeded on its own labelled fork (seed, 'sidequests',
 * <targetSystemId>, 'patrol', <jobId>, 'encounters') — the worldgen
 * contract: same seed + contract ⇒ the same encounters, across
 * re-accepts, scene restarts, and saves — and the result is FIXED on
 * the route record (SideQuestState.setRoute), so a later re-tune of
 * the data's odds or bands can't re-roll a standing contract's combat.
 *
 * @param {string|number} seed the galaxy's seed
 * @param {string} jobId the accepted contract's id (the fork's key)
 * @param {string} targetSystemId the route's system (the fork's key)
 * @param {Array<[number, number]>} waypoints the route's waypoints
 * @param {number} level the player's combat level at the accept
 * @param {number} hops the target system's jump-network depth from home
 * @returns {?{at:number[], cleared:number[], roster:string[], wave:object}} null when the feature is off or the route is empty
 */
export function derivePatrolEncounters(seed, jobId, targetSystemId, waypoints, level, hops) {
  if (config.get('sidequests.patrol.encounters.enabled', true) === false) return null;
  if (!Array.isArray(waypoints) || waypoints.length === 0) return null;
  const r = Rng.derive(seed, seedLabel(), targetSystemId, 'patrol', String(jobId), 'encounters');
  const count = Math.max(1, Math.floor(numOr(r.weighted(patrolEncounterCounts(), 3), 3)));
  return {
    at: patrolEncounterPositions(waypoints, count),
    cleared: [],
    roster: patrolEnemyRoster(level, hops),
    wave: patrolEncounterWave(),
  };
}

/**
 * A contact's WAVE SCRIPT (the shape for CombatSystem.startWaves —
 * js/combat/CombatSystem.js; the same `{ waves: [...] }` shape the named
 * scripts normalize to, js/combat/Waves.js): one wave of the contact's
 * roster (equal weights — a single-type band is a pure type + total),
 * the spec's wave shape (the data's: rolling six, three at a time). Pure
 * — the scene's _firePatrolContact hands it to startWaves.
 * @param {object} encounters the route record's encounters spec
 * @returns {{waves: object[]}}
 */
export function patrolEncounterScript(encounters) {
  const e = encounters && typeof encounters === 'object' && !Array.isArray(encounters) ? encounters : null;
  const roster = (e?.roster && Array.isArray(e.roster) && e.roster.length > 0 ? e.roster : ESTABLISHED_ENEMY_TYPES)
    .map((t) => String(t).trim())
    .filter((t) => t !== '');
  const w = { ...patrolEncounterWave(), ...(e?.wave && typeof e.wave === 'object' && !Array.isArray(e.wave) ? e.wave : {}) };
  const kind = w.kind === 'fixed' ? 'fixed' : 'rolling';
  const total = Math.max(1, Math.floor(numOr(w.total, 6)));
  const wave = {
    kind,
    roster: Object.fromEntries(roster.map((t) => [t, 1])),
    total,
    maxConcurrent: Math.min(total, Math.max(1, Math.floor(numOr(w.maxConcurrent, 3)))),
  };
  if (kind === 'rolling') wave.replacePerKill = Math.max(0, Math.floor(numOr(w.replacePerKill, 1)));
  return { waves: [wave] };
}

/**
 * The XP REWARD — the contract's SECOND payout (the claim pays it
 * beside the credits): the experience WORTH of the patrol's defeated
 * contacts. Completing the route requires every contact's wave to run
 * to completion, so the enemies the player defeats during the quest
 * ARE the contacts' waves — `at.length` × the wave's `total` — each
 * enemy worth its type's `xp` (data/combat.json — the roster's weighted
 * average; today's equal-weight specs are a plain average). Zero when
 * the route carries no encounters (old saves, the feature off) — the
 * reward degrades to credits-only, the route's waypoints alone
 * completing it. Pure in the spec — it reads the SAME wave shape +
 * roster patrolEncounterScript hands to the fight, so the reward and
 * the combat can't drift apart (a re-tune of the bands re-tunes both).
 *
 * @param {object|null} encounters the route record's encounters spec
 * @returns {number} the payout's XP (0 for a route without encounters)
 */
export function patrolEncounterXp(encounters) {
  const e = encounters && typeof encounters === 'object' && !Array.isArray(encounters) ? encounters : null;
  const at = e && Array.isArray(e.at) ? e.at.length : 0;
  if (at === 0) return 0;
  const wave = patrolEncounterScript(e).waves[0];
  const total = Math.max(0, Math.floor(numOr(wave?.total, 0)));
  if (total === 0) return 0;
  const roster =
    wave?.roster && typeof wave.roster === 'object' && !Array.isArray(wave.roster) ? wave.roster : null;
  let weightSum = 0;
  let xpWeighted = 0;
  if (roster) {
    for (const [typeId, w] of Object.entries(roster)) {
      const weight = Math.max(0, Number(w) || 0);
      if (weight === 0) continue;
      weightSum += weight;
      xpWeighted += weight * Math.max(0, Number(enemyTypeConfig(String(typeId))?.xp) || 0);
    }
  }
  if (weightSum === 0) return 0;
  return Math.round(at * total * (xpWeighted / weightSum));
}

/**
 * A patrol's ROUTE is COMPLETE when every waypoint is LOGGED and every
 * contact CLEARED (the contract's combat is part of the job — the
 * reward's door opens on the last of the two). A route without
 * encounters (a save predating the contacts — old saves load) completes
 * on its waypoints alone.
 * @param {object} route the route record (sideQuestState.routeFor's shape)
 * @returns {boolean}
 */
export function patrolRouteComplete(route) {
  if (!route || typeof route !== 'object') return false;
  const wpCount = Array.isArray(route.waypoints) ? route.waypoints.length : 0;
  const visited = Array.isArray(route.visited) ? route.visited.length : 0;
  if (wpCount === 0 || visited < wpCount) return false;
  const enc = route.encounters;
  if (!enc || typeof enc !== 'object') return true;
  const at = Array.isArray(enc.at) ? enc.at : [];
  if (at.length === 0) return true;
  const cleared = new Set(Array.isArray(enc.cleared) ? enc.cleared : []);
  return at.every((i) => cleared.has(i));
}

// --------------------------------------------- the BOUNTY HUNT (category 'bounty')
// The contract with a NAME ON IT (data/sidequests.json → bounty). A hunt is
// a patrol with its ending hidden: three legs along one pirate leader's
// travel lanes, flown STRICTLY IN ORDER, and the mark stands on ONE of them
// (20% on the first leg, else 20% of what is left on the second, else the
// third at 100%). The rolls happen ONCE at the accept on their own labelled
// fork and ride the route record — a signed contract is a signed contract —
// and NOTHING here is spoken to the player before it fires (the plan object
// is model-side only; the board, the compass, and the beacons never read
// `bountyAt`).
//
// The scene's share (js/scenes/GameScene.js → _establishBountyHunt /
// updateBountyHunt) uses these pure pieces:
//   bountyRules(level)          — the standing band's numbers (the data's,
//                                 with `inherits` resolved and fallbacks)
//   deriveBountyPlan(…)         — the rolled chain (bountyAt + per-leg pickets)
//   bountySkirmishScript / bountyEngagementScript — CombatSystem.startWaves shapes
//   bountyHuntXp(plan)          — the claim's XP beside the credits
//   nextBountyWaypoint(route)   — the SEQUENTIAL check-in rule (one leg at a time)
//   bountyRouteComplete(route)  — the kill is the whole job

/** The elite's fallback frames (a dossier naming a craft that isn't in combat.enemyTypes). */
const BOUNTY_FALLBACK_FRAMES = [
  'bomber',
  'spitter',
  'stinger',
  'hunter',
  'gunner',
  'barrage',
  'warden',
];

/**
 * The wanted leader's OWN identity, carried on the plan (the dossier's name +
 * epithet). The comms name the mark only once its fight stands in front of the
 * ship — the plan itself never reads out where it hides — and because the mark
 * rides the route record it survives a save. Empty strings when the board had
 * no dossier (a hand-edited pool): the hunt still flies, silent.
 */
function bountyMark(raw) {
  const m = raw && typeof raw === 'object' ? raw : {};
  return {
    name: String(m.name ?? '').trim(),
    epithet: String(m.epithet ?? '').trim(),
  };
}

/** One wave shape, clamped (a hunt's fight is never smaller than one hostile). */
function bountyWaveShape(raw, fb) {
  const w = raw && typeof raw === 'object' && !Array.isArray(raw) ? raw : {};
  const kind = (w.kind ?? fb.kind) === 'fixed' ? 'fixed' : 'rolling';
  const total = Math.max(1, Math.floor(numOr(w.total, fb.total)));
  const out = {
    kind,
    total,
    maxConcurrent: Math.min(total, Math.max(1, Math.floor(numOr(w.maxConcurrent, fb.maxConcurrent)))),
    replacePerKill:
      kind === 'rolling' ? Math.max(0, Math.floor(numOr(w.replacePerKill, fb.replacePerKill))) : 0,
  };
  if (Array.isArray(w.roster) && w.roster.length > 0) out.roster = w.roster.map(String);
  if (w.raiderType != null) out.raiderType = String(w.raiderType);
  if (w.raiders != null) out.raiders = Math.max(0, Math.floor(numOr(w.raiders, fb.raiders ?? 0)));
  if (Array.isArray(w.eliteFrames) && w.eliteFrames.length > 0) out.eliteFrames = w.eliteFrames.map(String);
  return out;
}

/**
 * The standing band's RULES (data/sidequests.json → bounty + bounty.encounters).
 * A BAND is a level window's tuning: the live 'hunter' band (levels 2–5) and
 * the stubbed 'marksman' band (6+), which `inherits` the hunter's numbers so a
 * player who outruns level 5 keeps getting hunts instead of losing the content
 * mid-run. Resolution: the first band whose `levels` window holds the player's
 * combat level, else the fallbackBand, else the first band; the chosen band's
 * own overrides (bountyChance / skirmishChance / waypoints / skirmishWave /
 * bountyWave) sit on top of the shared encounter block, and `inherits` pulls
 * that band's numbers underneath them.
 *
 * @param {number} level the player's combat level (js/combat/XpManager.js)
 * @returns {{id:string, legs:[number,number], visitRadius:number, bountyChance:number, skirmishChance:number, skirmishWave:object, bountyWave:object}}
 */
export function bountyRules(level = 0) {
  const enc = config.get('sidequests.bounty.encounters', null);
  const e = enc && typeof enc === 'object' && !Array.isArray(enc) ? enc : {};
  const legRange = (() => {
    const raw = config.get('sidequests.bounty.waypoints', [3, 3]);
    let lo = Math.floor(numOr(Array.isArray(raw) ? raw[0] : 3, 3));
    let hi = Math.floor(numOr(Array.isArray(raw) ? raw[1] : 3, 3));
    if (!Number.isFinite(lo) || !Number.isFinite(hi)) return [3, 3];
    lo = Math.max(1, lo);
    hi = Math.max(lo, hi);
    return [lo, hi];
  })();
  const base = {
    id: 'hunter',
    legs: legRange,
    visitRadius: Math.max(60, numOr(config.get('sidequests.bounty.visitRadius', 420), 420)),
    bountyChance: Math.min(1, Math.max(0, numOr(e.bountyChance, 0.2))),
    skirmishChance: Math.min(1, Math.max(0, numOr(e.skirmishChance, 0.5))),
    skirmishWave: bountyWaveShape(e.skirmishWave, {
      kind: 'rolling',
      total: 6,
      maxConcurrent: 3,
      replacePerKill: 1,
      roster: ['raider'],
    }),
    bountyWave: bountyWaveShape(e.bountyWave, {
      kind: 'rolling',
      total: 9,
      raiders: 8,
      maxConcurrent: 3,
      replacePerKill: 1,
      raiderType: 'raider',
      eliteFrames: BOUNTY_FALLBACK_FRAMES.slice(),
    }),
    elite: {
      healthScale: Math.max(1, numOr(e.bountyWave?.elite?.healthScale, 2)),
      damageScale: Math.max(1, numOr(e.bountyWave?.elite?.damageScale, 2)),
    },
    enabled: e.enabled !== false,
  };
  // The elite's own scales ride the wave shape (the runner reads one object).
  base.bountyWave.elite = { ...base.elite };

  const bands = Array.isArray(e.bands) ? e.bands : [];
  const byId = new Map();
  for (const b of bands) {
    if (b && typeof b === 'object' && !Array.isArray(b) && b.id != null) byId.set(String(b.id), b);
  }
  const lvl = numOr(level, 0);
  let band = null;
  for (const b of bands) {
    if (!b || typeof b !== 'object' || Array.isArray(b)) continue;
    const w = Array.isArray(b.levels) ? b.levels : null;
    if (!w) continue;
    const lo = numOr(w[0], NaN);
    const hi = numOr(w[1] ?? w[0], lo);
    if (!Number.isFinite(lo) || !Number.isFinite(hi)) continue;
    if (lvl >= Math.min(lo, hi) && lvl <= Math.max(lo, hi)) {
      band = b; // the first window holding the level wins (list order)
      break;
    }
  }
  if (!band) band = byId.get(String(e.fallbackBand ?? '')) ?? bands[0] ?? null;
  if (!band || typeof band !== 'object' || Array.isArray(band)) return base;

  // The band's overrides, with `inherits` standing underneath them.
  const layers = [];
  const seen = new Set();
  let cur = band;
  while (cur && !seen.has(String(cur.id ?? ''))) {
    seen.add(String(cur.id ?? ''));
    layers.unshift(cur);
    cur = cur.inherits != null ? byId.get(String(cur.inherits)) : null;
  }
  const out = { ...base, id: String(band.id ?? base.id) };
  for (const layer of layers) {
    if (Array.isArray(layer.waypoints)) {
      const lo = Math.max(1, Math.floor(numOr(layer.waypoints[0], base.legs[0])));
      const hi = Math.max(lo, Math.floor(numOr(layer.waypoints[1] ?? layer.waypoints[0], base.legs[1])));
      out.legs = [lo, hi];
    }
    if (Number.isFinite(Number(layer.bountyChance))) out.bountyChance = Math.min(1, Math.max(0, Number(layer.bountyChance)));
    if (Number.isFinite(Number(layer.skirmishChance))) out.skirmishChance = Math.min(1, Math.max(0, Number(layer.skirmishChance)));
    if (Number.isFinite(Number(layer.visitRadius))) out.visitRadius = Math.max(60, Number(layer.visitRadius));
    if (layer.skirmishWave) out.skirmishWave = bountyWaveShape(layer.skirmishWave, out.skirmishWave);
    if (layer.bountyWave) {
      out.bountyWave = bountyWaveShape(layer.bountyWave, out.bountyWave);
      const sc = layer.bountyWave.elite || {};
      out.bountyWave.elite = {
        healthScale: Math.max(1, numOr(sc.healthScale, base.elite.healthScale)),
        damageScale: Math.max(1, numOr(sc.damageScale, base.elite.damageScale)),
      };
    }
  }
  return out;
}

/**
 * The hunt's PLAN — the hidden shape of one contract, rolled at the accept
 * and FIXED on the route record (never re-drawn; never shown).
 *
 * The chain rides its own labelled fork (seed,'sidequests',
 * <targetSystemId>,'bounty',<jobId>,'chain'): legs 1..N-1 each roll
 * `bountyChance` for the mark and the LAST leg stands it at 100% — with the
 * data's 0.2 and three legs that reads 20% / 16% / 64%. Each leg BEFORE the
 * mark independently rolls `skirmishChance` for the leader's pickets (the
 * bounty leg never does — the mark IS that fight, and no leg after it owes
 * anything).
 *
 * @param {string|number} seed the galaxy's seed
 * @param {string} jobId the accepted contract's id (the fork's key)
 * @param {string} targetSystemId the hunt's system (the fork's key)
 * @param {number} level the player's combat level at the accept (the band)
 * @param {object} [opts] { craft, mark } — the dossier's declared craft (its own
 *   story's frame id); an id outside combat.enemyTypes falls back to a SEEDED
 *   pick from the band's eliteFrames, so a data typo stands a fight instead of
 *   breaking one. `mark` ({ name, epithet }) is the wanted leader's OWN name —
 *   carried on the plan so the fight's comms can say who it was AFTER the fact
 *   (never before: the plan itself stays invisible), and it rides the save.
 * @returns {{legs:number, bountyAt:number, pickets:boolean[], band:string, raiders:number, eliteType:string, skirmishWave:object, bountyWave:object}}
 */
export function deriveBountyPlan(seed, jobId, targetSystemId, level = 0, opts = {}) {
  const rules = bountyRules(level);
  const r = Rng.derive(seed, seedLabel(), targetSystemId, 'bounty', String(jobId), 'chain');
  const legs = Math.max(1, r.int(rules.legs[0], rules.legs[1]));
  let bountyAt = legs - 1; // the LAST leg stands the mark (the chain's guarantee)
  for (let i = 0; i < legs - 1; i++) {
    if (r.chance(rules.bountyChance)) {
      bountyAt = i;
      break;
    }
  }
  const pickets = [];
  for (let i = 0; i < legs - 1; i++) {
    if (i >= bountyAt) {
      pickets.push(false); // the mark's own leg, and anything after it, never rolls
      continue;
    }
    pickets.push(r.chance(rules.skirmishChance));
  }
  const valid = new Set(enemyTypeIds());
  const declared = String(opts?.craft ?? '').trim();
  const frames = (Array.isArray(rules.bountyWave.eliteFrames) ? rules.bountyWave.eliteFrames : BOUNTY_FALLBACK_FRAMES)
    .map((t) => String(t).trim())
    .filter((t) => valid.has(t));
  let eliteType = declared !== '' && valid.has(declared) ? declared : null;
  if (!eliteType) {
    const pool = frames.length > 0 ? frames : BOUNTY_FALLBACK_FRAMES.filter((t) => valid.has(t));
    eliteType = pool.length > 0 ? String(r.pick(pool)) : ESTABLISHED_ENEMY_TYPES[0];
  }
  const raiderType = valid.has(String(rules.bountyWave.raiderType ?? ''))
    ? String(rules.bountyWave.raiderType)
    : ESTABLISHED_ENEMY_TYPES[0];
  const raiders = Math.max(0, Math.floor(numOr(rules.bountyWave.raiders, rules.bountyWave.total - 1)));
  return {
    legs,
    bountyAt,
    pickets,
    band: rules.id,
    raiders,
    raiderType,
    eliteType,
    mark: bountyMark(opts?.mark),
    skirmishWave: { ...rules.skirmishWave },
    bountyWave: { ...rules.bountyWave, total: Math.max(1, raiders + 1) },
    visitRadius: rules.visitRadius,
  };
}

/** A hunt's picket wave — one rolling wave of the established type, three at a time. */
export function bountySkirmishScript(plan = {}) {
  const w = plan?.skirmishWave || bountyRules(0).skirmishWave;
  const kind = w.kind === 'fixed' ? 'fixed' : 'rolling';
  const total = Math.max(1, Math.floor(numOr(w.total, 6)));
  const type = ESTABLISHED_ENEMY_TYPES[0];
  const wave = {
    kind,
    roster: { [type]: 1 },
    total,
    maxConcurrent: Math.min(total, Math.max(1, Math.floor(numOr(w.maxConcurrent, 3)))),
  };
  if (kind === 'rolling') wave.replacePerKill = Math.max(0, Math.floor(numOr(w.replacePerKill, 1)));
  return { waves: [wave] };
}

/**
 * The BOUNTY's wave — one rolling wave of `raiders + 1`: the escort plus the
 * mark itself, declared on the wave as `elite` so js/combat/Waves.js deploys
 * it with the OPENING group and js/combat/EnemyShip.js doubles its hull /
 * shields and weapon damage (the data's healthScale / damageScale). The kill
 * is the contract: the scene halts the run (CombatSystem.haltWaves) and waits
 * out the survivors.
 */
export function bountyEngagementScript(plan = {}) {
  const rules = bountyRules(0);
  const w = plan?.bountyWave || rules.bountyWave;
  const kind = w.kind === 'fixed' ? 'fixed' : 'rolling';
  const eliteType = String(plan?.eliteType ?? 'raider');
  const raiders = Math.max(0, Math.floor(numOr(plan?.raiders, Math.max(0, numOr(w.total, 9) - 1))));
  const raiderType = String(w.raiderType ?? ESTABLISHED_ENEMY_TYPES[0]);
  const total = Math.max(1, raiders + 1); // the escort + exactly one mark
  const roster = {};
  if (raiders > 0) roster[raiderType] = raiders;
  roster[eliteType] = (roster[eliteType] ?? 0) + 1;
  const wave = {
    kind,
    roster,
    total,
    maxConcurrent: Math.min(total, Math.max(1, Math.floor(numOr(w.maxConcurrent, 3)))),
    elite: {
      type: eliteType,
      healthScale: numOr(w.elite?.healthScale, rules.elite.healthScale),
      damageScale: numOr(w.elite?.damageScale, rules.elite.damageScale),
      // The name the KILL reads out (js/combat/Waves.js keeps it; EnemyShip
      // tags it; GameScene's witness puts it in the comms line).
      name: String(plan?.mark?.name ?? '').trim(),
    },
  };
  if (kind === 'rolling') wave.replacePerKill = Math.max(0, Math.floor(numOr(w.replacePerKill, 1)));
  return { waves: [wave] };
}

/**
 * The hunt's XP payout — the worth of everything it throws at the ship: the
 * mark (its own type's worth × its scale-up) plus the escort plus every
 * rolled picket wave. Fixed at the accept beside the credits, so the claim
 * pays what the plan promised even if the data is re-tuned mid-run.
 */
export function bountyHuntXp(plan = {}) {
  const p = plan && typeof plan === 'object' ? plan : {};
  const xpOf = (t) => Math.max(0, Number(enemyTypeConfig(String(t))?.xp) || 0);
  const rules = bountyRules(0);
  const raiders = Math.max(0, Math.floor(numOr(p.raiders, numOr(rules.bountyWave.raiders, 8))));
  const raiderType = p.raiderType != null ? String(p.raiderType) : String(rules.bountyWave.raiderType ?? 'raider');
  const eliteType = String(p.eliteType ?? ESTABLISHED_ENEMY_TYPES[0]);
  const scale = numOr(p.bountyWave?.elite?.healthScale, rules.bountyWave.elite?.healthScale ?? 2);
  let xp = raiders * xpOf(raiderType) + xpOf(eliteType) * Math.max(1, scale);
  const skirmishTotal = Math.max(0, Math.floor(numOr(p.skirmishWave?.total, rules.skirmishWave.total)));
  const pickets = (Array.isArray(p.pickets) ? p.pickets : []).filter(Boolean).length;
  xp += pickets * skirmishTotal * xpOf(ESTABLISHED_ENEMY_TYPES[0]);
  return Math.round(xp);
}

/**
 * The SEQUENTIAL check-in rule — the hunt's one departure from patrol law.
 * The chain's odds read an ORDER, so a hunt logs its legs one at a time: the
 * NEXT leg is the lowest index not yet logged, and only that leg's beacon and
 * compass point anywhere. `null` when every leg stands logged.
 *
 * @param {object} route the route record
 * @returns {?{index:number, x:number, y:number, leg:number, of:number}}
 */
export function nextBountyWaypoint(route) {
  if (!route || typeof route !== 'object') return null;
  const wp = Array.isArray(route.waypoints) ? route.waypoints : [];
  if (wp.length === 0) return null;
  const visited = new Set(Array.isArray(route.visited) ? route.visited : []);
  for (let i = 0; i < wp.length; i++) {
    const w = wp[i];
    if (!Array.isArray(w) || w.length < 2) continue;
    if (visited.has(i)) continue;
    return { index: i, x: Number(w[0]), y: Number(w[1]), leg: i + 1, of: wp.length };
  }
  return null;
}

/**
 * The hunt is COMPLETE when the mark is DOWN (the contract's only witness —
 * the legs are a formality the kill checks off at once). A malformed or
 * missing bounty record falls back to the patrol law (every leg logged) so a
 * degraded save can still finish.
 */
export function bountyRouteComplete(route) {
  if (!route || typeof route !== 'object') return false;
  const b = route.bounty && typeof route.bounty === 'object' ? route.bounty : null;
  if (b?.down === true) return true;
  if (!b) return patrolRouteComplete(route);
  return false;
}

/**
 * A bounty posting's DOSSIER (the wanted list's fields — data →
 * descriptions.neutral.bounty[]). Resolved for the readout, with the craft
 * VALIDATED against combat.enemyTypes and the copy placeholder-free. Returns
 * null when the pool entry isn't a dossier (a hand-edited pool) — the posting
 * still stands on its title/description alone.
 */
function buildBountyDossier(v, ctx) {
  if (!v || typeof v !== 'object' || Array.isArray(v)) return null;
  const name = resolveSideQuestText(String(v.name ?? ''), ctx).trim();
  if (name === '') return null;
  const valid = new Set(enemyTypeIds());
  const craft = String(v.craft ?? '').trim();
  return {
    name,
    epithet: resolveSideQuestText(String(v.epithet ?? ''), ctx).trim(),
    crime: resolveSideQuestText(String(v.crime ?? ''), ctx).trim(),
    craft: valid.has(craft) ? craft : null, // null = the plan picks a frame (seeded)
    craftLabel: resolveSideQuestText(String(v.craftLabel ?? ''), ctx).trim(),
  };
}

/**
 * One line of the hunt's UI copy (data/sidequests.json → ui.<key>) with its
 * `{placeholders}` filled. A key can stand as a plain string or as
 * `{ glyph, color, text }` (the toasts carry their own glyph + color); an
 * unknown key falls back to `fb` so a data typo degrades to the design's own
 * words instead of blanking a toast. Placeholders with no value blank out.
 * @returns {{glyph:string,color:string,text:string}|null} null when neither the key nor a fallback stands
 */
function bountyUiLine(key, vars = {}, fb = '') {
  const raw = config.get(`sidequests.ui.${key}`, null);
  const obj = raw && typeof raw === 'object' && !Array.isArray(raw) ? raw : null;
  const text = obj ? String(obj.text ?? '') : typeof raw === 'string' ? raw : '';
  if (text === '' && fb === '') return null;
  let out = text === '' ? String(fb) : text;
  for (const [k, value] of Object.entries(vars)) out = out.split(`{${k}}`).join(String(value));
  out = out.replace(/\{[a-zA-Z]+\}/g, ''); // an unfilled placeholder never ships
  return {
    glyph: obj ? String(obj.glyph ?? '') : '',
    color: obj ? String(obj.color ?? '') : '',
    text: out,
  };
}

/** The bounty gate's combat level (data → categories.bounty.minLevel; the design's 2). */
export function bountyMinLevel() {
  return sideQuestCategoryMeta('bounty')?.minLevel ?? 2;
}

/** A locked row's badge (“LOCKED — REQUIRES LEVEL 2”); `sub` = the detail line under it. */
export function bountyLockCopy(sub = false) {
  const level = bountyMinLevel();
  return sub
    ? bountyUiLine('bountyLockSub', { level }, 'BRING YOUR RECORD UP TO LEVEL {level}')
    : bountyUiLine('bountyLockBadge', { level }, 'LOCKED — REQUIRES LEVEL {level}');
}

/** The scene's refusal when a locked contract is pressed anyway. */
export function bountyDenyCopy() {
  return bountyUiLine('bountyAcceptDenyToast', { level: bountyMinLevel() }, 'COMMISSION REFUSED — LEVEL {level} REQUIRED');
}

/** A hunt line's copy (a leg logged / pickets inbound / the mark sighted / down / complete). */
export function bountyText(key, vars = {}) {
  return bountyUiLine(key, vars, '');
}

/** The readout's progress line (logged legs only — never what waits on them). */
export function bountyProgressCopy(route) {
  const wp = Array.isArray(route?.waypoints) ? route.waypoints : [];
  const visited = Array.isArray(route?.visited) ? new Set(route.visited).size : 0;
  return bountyUiLine('bountyRouteProgress', { visited, total: wp.length }, 'WAYPOINT {visited} OF {total} LOGGED');
}

/** The contract readout's dossier lines (wanted / epithet / charges / craft). */
export function bountyDossierCopy(dossier) {
  const d = dossier && typeof dossier === 'object' ? dossier : null;
  if (!d || !d.name) return [];
  const craftLine = bountyUiLine('dossierCraft', { craft: d.craftLabel ?? '' }, 'CRAFT — {craft}');
  const lines = [
    bountyUiLine('dossierWanted', { name: d.name }, 'WANTED — {name}'),
    d.epithet ? bountyUiLine('dossierEpithet', { epithet: d.epithet }, '{epithet}') : null,
    bountyUiLine('dossierCrime', { crime: d.crime ?? '' }, 'CHARGES — {crime}'),
    d.craftLabel ? craftLine : null,
  ];
  return lines.filter((l) => l && l.text !== '');
}

/**
 * A bounty route record's PLAN, normalized (SideQuestState.setRoute's pass).
 * The rolled shape is VALIDATED, never re-drawn: `bountyAt` inside the leg
 * count, one `pickets` mark per leg with nothing standing on the mark's own
 * leg or behind it, the elite a real combat.enemyTypes id, the wave shapes
 * finite, and the runtime marks (`down`, the cleared picket legs) kept. A
 * malformed record degrades to null — the route's waypoints still stand, the
 * hunt simply never fires (a hand-edited save must not manufacture a fight).
 *
 * @param {*} raw deriveBountyPlan's result (or a save's)
 * @param {number} wpCount the route's waypoint count
 * @returns {?object}
 */
function normalizeBountyPlan(raw, wpCount) {
  if (!raw || typeof raw !== 'object' || Array.isArray(raw)) return null;
  const legs = Math.max(1, Math.floor(numOr(raw.legs, wpCount)));
  const bountyAt = Math.floor(numOr(raw.bountyAt, NaN));
  if (!Number.isInteger(bountyAt) || bountyAt < 0 || bountyAt >= legs) return null;
  const valid = new Set(enemyTypeIds());
  const eliteType = String(raw.eliteType ?? '').trim();
  if (!valid.has(eliteType)) return null;
  // The pickets: one mark per leg BEFORE the mark (the chain's rule — the leg
  // that holds the hunt, and every leg behind it, never rolls).
  const pickets = [];
  for (let i = 0; i < legs - 1; i++) {
    pickets.push(i < bountyAt && raw.pickets?.[i] === true);
  }
  const raiders = Math.max(0, Math.floor(numOr(raw.raiders, 8)));
  const raiderType = valid.has(String(raw.raiderType ?? '').trim())
    ? String(raw.raiderType).trim()
    : ESTABLISHED_ENEMY_TYPES[0];
  const rules = bountyRules(0);
  const mark = bountyMark(raw.mark);
  const sw = raw.skirmishWave && typeof raw.skirmishWave === 'object' ? raw.skirmishWave : {};
  const bw = raw.bountyWave && typeof raw.bountyWave === 'object' ? raw.bountyWave : {};
  const el = bw.elite && typeof bw.elite === 'object' ? bw.elite : {};
  return {
    legs,
    bountyAt,
    pickets,
    band: String(raw.band ?? 'hunter'),
    raiders,
    raiderType,
    eliteType,
    mark,
    skirmishWave: bountyWaveShape(sw, rules.skirmishWave),
    bountyWave: {
      ...bountyWaveShape({ ...bw, total: Math.max(1, raiders + 1) }, rules.bountyWave),
      raiderType,
      raiders,
      elite: {
        healthScale: Math.max(1, numOr(el.healthScale, 2)),
        damageScale: Math.max(1, numOr(el.damageScale, 2)),
      },
    },
    visitRadius: Math.max(60, numOr(raw.visitRadius, rules.visitRadius)),
    // The runtime marks (the scene's witness marks — a fresh plan carries none).
    down: raw.down === true,
    skirmishCleared: [...new Set(
      (Array.isArray(raw.skirmishCleared) ? raw.skirmishCleared : []).filter(
        (i) => Number.isInteger(i) && i >= 0 && i < bountyAt && raw.pickets?.[i] === true,
      ),
    )].sort((a, b) => a - b),
  };
}

/**
 * The system's LIVE postings (the board's list) — 3–4 by design
 * (sideQuestCountRange), drawn from the LIVE categories only
 * (enabledSideQuestCategories): distinct categories while they last,
 * then repeats into the variant pools (the same category can hold more
 * than one posting once the count outruns the live set).
 *
 * Deterministic in (seed, record[, galaxy]) — the labelled forks under
 * Rng.derive(seed, seedLabel, <sysId>) make the roll, the category
 * order, and every per-posting draw (the patrol's target included) independent
 * of call order, so the board stands the same across visits, scene
 * restarts, and saves.
 *
 * A posting's shape (the window's row + detail + the scene's accept):
 *   { id, systemId, systemName, faction (null = neutral), category,
 *     label, accent, title, issuer, description, reward: { credits },
 *     objective: { type } }  — objective is the typed socket the
 * category's completion rules fill in when the type lands. A PATROL
 * posting additionally carries targetSystemId / targetSystemName (the
 * route's system — patrolTargetSystem; default the posting's own
 * system).
 *
 * @param {string|number} seed the galaxy's seed
 * @param {object} rec a system record ({ id, name, faction, d, … })
 * @param {object|null} [galaxy] the galaxy (the patrol's neighbor rule's jumpGatesFor) — null in tests
 * @returns {object[]} [] when the feature is off or no category is live
 */
export function sideQuestPostingsFor(seed, rec, galaxy = null, level = null) {
  if (!sideQuestsEnabled()) return [];
  if (!rec || typeof rec.id !== 'string' || rec.id === '') return [];
  const ctx = postingContext(rec);
  const cats = enabledSideQuestCategories(ctx.context); // a faction board never draws a neutral-only type
  if (cats.length === 0) return [];

  const [lo, hi] = sideQuestCountRange();
  const base = Rng.derive(seed, seedLabel(), rec.id);
  const count = base.int(lo, hi);
  const order = base.shuffle(cats); // the system's slot order (seeded, stable)

  const out = [];
  const usedDossier = new Set(); // one board never posts the SAME wanted leader twice
  for (let slot = 0; slot < count; slot++) {
    const cat = order[slot % order.length];
    const r = Rng.derive(seed, seedLabel(), rec.id, cat, slot); // per-posting stream
    const posting = buildPosting(seed, rec, ctx, cat, slot, r, galaxy, usedDossier);
    if (!posting) continue;
    if (cat === 'bounty' && posting.dossier?.name) usedDossier.add(posting.dossier.name);
    // The level gate is PRESENTATION + ACCEPT, never generation: the
    // posting stands in its seeded slot below the gate too (a locked
    // row is still the same row), and the scene refuses the accept.
    const gate = sideQuestAcceptable(posting, level);
    posting.locked = gate.locked === true;
    posting.minLevel = gate.minLevel;
    out.push(posting);
  }
  return out;
}

/** One posting from its pool variant + reward roll (null on a bad pool entry). */
function buildPosting(seed, rec, ctx, cat, slot, r, galaxy = null, usedDossier = null) {
  const meta = sideQuestCategoryMeta(cat);
  if (!meta) return null;

  const poolPath = `sidequests.descriptions.${ctx.context}.${cat}`;
  let pool = config.get(poolPath, null);
  if (!Array.isArray(pool)) pool = config.get(`sidequests.descriptions.neutral.${cat}`, null); // the neutral voice as fallback
  pool = Array.isArray(pool) ? pool : [];
  let v = pool.length > 0 ? pool[r.int(0, pool.length - 1)] : null;
  // A WANTED LIST never posts the same leader twice on one board: the seeded
  // draw stands when it is fresh, otherwise the next entry forward (wrapping)
  // takes it. Deterministic — the slots are visited in a fixed order and the
  // used set is built by this loop alone, so a system's board never depends on
  // call order or on any other system.
  if (cat === 'bounty' && pool.length > 0 && usedDossier && usedDossier.size > 0) {
    for (let step = 0; step < pool.length; step++) {
      const cand = pool[(pool.indexOf(v) + step + pool.length) % pool.length];
      if (!cand?.name || !usedDossier.has(cand.name)) {
        v = cand;
        break;
      }
    }
  }

  const title = resolveSideQuestText(v?.title ?? `${meta.label} Contract`, ctx);
  // The row's issuer line: the pool's own name (the neutral pools' —
  // “The Harbormaster”), or the faction's board name (the faction pools'
  // {issuer} placeholder — the data's sidequests.factions table), so a
  // faction's postings read “ISSUER — ZENITH CONCORD”, not “The Board”.
  const issuerRaw = v?.issuer ?? (ctx.issuer || 'The Board');
  const issuer = resolveSideQuestText(issuerRaw, ctx) || 'The Board';
  const description = resolveSideQuestText(v?.body ?? '', ctx);

  return {
    id: `sq-${rec.id}-${cat}-${slot}`, // stable for the run (save-safe ledger key)
    systemId: rec.id,
    systemName: String(rec.name ?? rec.id),
    faction: ctx.context === 'faction' ? rec.faction : null,
    category: cat,
    label: meta.label,
    accent: meta.accent,
    title,
    issuer,
    description,
    reward: rollSideQuestReward(cat, rec.d, r),
    // The completion socket: the type's objective spec (its steps, its
    // witness, its payout rule) is built WITH the type and rides here —
    // the UI already renders objective.text when one stands.
    objective: { type: cat },
    // The PATROL's target system — the route's system (patrolTargetSystem:
    // the posting system, or a NEIGHBOR the jump gates reach when the
    // system's faction, diagonal, and seeded draw agree). Patrol-only —
    // the other categories' routes (when they land) carry their own
    // shape.
    ...(cat === 'patrol' ? patrolTargetFields(rec, r, galaxy) : {}),
    // The BOUNTY HUNT's DOSSIER (data → descriptions.neutral.bounty[]) — the
    // wanted leader's name/epithet/charges and the CRAFT its own story names
    // (`craft`, validated against combat.enemyTypes; null on a pool entry that
    // doesn't declare one, where the plan picks a frame seeded). The hunt's
    // plan (which leg holds the mark) is NOT here — it rolls at the accept and
    // rides the route record, never the board.
    ...(cat === 'bounty' ? { dossier: buildBountyDossier(v, ctx), targetSystemId: rec.id, targetSystemName: String(rec.name ?? rec.id) } : {}),
  };
}

/** The patrol posting's target fields (its own system, or the neighbor's). */
function patrolTargetFields(rec, r, galaxy) {
  const t = patrolTargetSystem(rec, r, galaxy);
  return t
    ? { targetSystemId: t.id, targetSystemName: t.name }
    : { targetSystemId: rec.id, targetSystemName: String(rec.name ?? rec.id) };
}

/**
 * The seed's JOB SPACE — every id the ledger could lawfully hold: each
 * system × the full slot range (the range's max — a superset of what any
 * enabled set can post) × all four categories. Used by SideQuestState.
 * fromJSON to drop ledger ids the save's galaxy never posted (a
 * hand-edited or foreign ledger degrades instead of sticking).
 *
 * @param {object[]} records the galaxy's system records (Galaxy.records)
 * @returns {Set<string>}
 */
export function allSideQuestJobIds(records) {
  const set = new Set();
  if (!Array.isArray(records)) return set;
  const [, hi] = sideQuestCountRange();
  for (const rec of records) {
    if (!rec || typeof rec.id !== 'string' || rec.id === '') continue;
    for (let slot = 0; slot < hi; slot++) {
      for (const cat of SIDE_QUEST_CATEGORIES) {
        set.add(`sq-${rec.id}-${cat}-${slot}`);
      }
    }
  }
  return set;
}

/**
 * The run's SIDE QUEST ledger (pure; save-ready): which posted contracts
 * the player has ACCEPTED (in the order taken), which is the ONE ACTIVE
 * contract being flown, which of the taken contracts have COMPLETED,
 * which of those have been CLAIMED, and the PATROL route record (its
 * target system, its waypoints, its visited marks). The ids are
 * postings' ids (sq-<sysId>-<cat>-<slot>) — the postings themselves
 * regenerate from the seed, so the save carries only the marks (a save =
 * seed + player state).
 *
 * Invariants (the scene's flows lean on them):
 *   - completed ⊆ accepted, claimed ⊆ completed;
 *   - accept / complete / claim are idempotent (a double-press or a
 *     re-open can't double-take, double-pay, or re-open a contract);
 *   - ONE active contract at a time (activeId) — reconcileActive keeps
 *     a standing active valid, and otherwise stands the TOP accepted
 *     contract (acceptedOrder's head) that is not done + claimed; null
 *     when no contract is out;
 *   - a save predating the feature (no field) loads an empty ledger
 *     (old saves load); ids the save's galaxy never posted are dropped,
 *     not propagated; a route record only for a contract this ledger
 *     holds (a route for a foreign id degrades away).
 */
/**
 * A route record's ENCOUNTERS spec, normalized (SideQuestState.setRoute's
 * pass): the at/cleared indices valid for the route (distinct, sorted;
 * cleared ⊆ at), the roster's type ids (combat.enemyTypes — unknown ids
 * dropped, the established type standing when the roster empties), the
 * wave shape finite. A malformed or missing spec degrades to null (an
 * encounter-free route — the waypoints still stand the contract), so a
 * hand-edited save or a future data shape can't break the patrol.
 * @param {*} raw the raw spec (derivePatrolEncounters' result, or a save's)
 * @param {number} wpCount the route's waypoint count
 * @returns {?{at:number[], cleared:number[], roster:string[], wave:object}}
 */
function normalizePatrolEncounters(raw, wpCount) {
  if (!raw || typeof raw !== 'object' || Array.isArray(raw)) return null;
  const at = [...new Set(
    (Array.isArray(raw.at) ? raw.at : []).filter(
      (i) => Number.isInteger(i) && i >= 0 && i < wpCount,
    ),
  )].sort((a, b) => a - b);
  if (at.length === 0) return null; // no contact stands (the route's waypoints do)
  const cleared = [...new Set(
    (Array.isArray(raw.cleared) ? raw.cleared : []).filter(
      (i) => Number.isInteger(i) && at.includes(i),
    ),
  )].sort((a, b) => a - b);
  const validTypes = new Set(enemyTypeIds());
  const roster = (Array.isArray(raw.roster) ? raw.roster : [])
    .map((t) => String(t).trim())
    .filter((t) => t !== '' && validTypes.has(t));
  const wave = patrolEncounterWave();
  const w = raw.wave && typeof raw.wave === 'object' && !Array.isArray(raw.wave) ? raw.wave : {};
  const kind = w.kind === 'fixed' ? 'fixed' : wave.kind;
  const total = Math.max(1, Math.floor(numOr(w.total, wave.total)));
  const out = {
    at,
    cleared,
    roster: roster.length > 0 ? roster : ESTABLISHED_ENEMY_TYPES.slice(),
    wave: {
      kind,
      total,
      maxConcurrent: Math.min(total, Math.max(1, Math.floor(numOr(w.maxConcurrent, wave.maxConcurrent)))),
    },
  };
  if (kind === 'rolling') out.wave.replacePerKill = Math.max(0, Math.floor(numOr(w.replacePerKill, wave.replacePerKill)));
  return out;
}

export class SideQuestState {
  constructor() {
    this.accepted = new Set();
    this.acceptedOrder = []; // the order taken (the active slot's "top")
    this.completed = new Set(); // completed ⊆ accepted
    this.claimed = new Set(); // claimed ⊆ completed
    this.activeId = null; // the ONE contract being flown (taken, not done, not claimed)
    this.routes = new Map(); // id → { targetSystemId, credits, xp, waypoints, visited, encounters }
  }

  /**
   * Take the contract (idempotent — re-accepting is a no-op).
   * @returns {boolean} true when NEWLY accepted
   */
  accept(id) {
    if (typeof id !== 'string' || id === '') return false;
    if (this.accepted.has(id)) return false;
    this.accepted.add(id);
    this.acceptedOrder.push(id);
    return true;
  }

  isAccepted(id) {
    return this.accepted.has(id);
  }

  /** The taken order (the ledger's "top" is index 0). */
  acceptedList() {
    return [...this.acceptedOrder];
  }

  /**
   * Mark a taken contract COMPLETE (the type's objective stood — the
   * scene's call when a category lands; only ACCEPTED contracts can
   * complete — completed ⊆ accepted). A done contract drops out of the
   * ACTIVE slot (reconcileActive — the next top one stands).
   * @returns {boolean} true when NEWLY completed
   */
  complete(id) {
    if (typeof id !== 'string' || id === '') return false;
    if (!this.accepted.has(id)) return false;
    if (this.completed.has(id)) return false;
    this.completed.add(id);
    this.reconcileActive();
    return true;
  }

  isCompleted(id) {
    return this.completed.has(id);
  }

  /**
   * Mark a completed contract CLAIMED (the reward is paid exactly once —
   * idempotent; claimed ⊆ completed, so an uncompleted contract can't
   * be claimed). A claimed contract drops out of the ACTIVE slot.
   * @returns {boolean} true when NEWLY claimed
   */
  claim(id) {
    if (typeof id !== 'string' || id === '') return false;
    if (!this.completed.has(id)) return false;
    if (this.claimed.has(id)) return false;
    this.claimed.add(id);
    this.reconcileActive();
    return true;
  }

  isClaimed(id) {
    return this.claimed.has(id);
  }

  isActive(id) {
    return this.activeId === id;
  }

  /**
   * Stand the ACTIVE contract — the ONE being flown. It must be taken,
   * not done, not claimed (the board's door only offers it in that state
   * anyway — this is the belt-and-braces pass).
   * @returns {boolean} true when it stands
   */
  setActive(id) {
    if (typeof id !== 'string' || id === '') return false;
    if (!this.accepted.has(id) || this.completed.has(id) || this.claimed.has(id)) return false;
    this.activeId = id;
    return true;
  }

  /**
   * The ACTIVE slot's truth: a standing active (taken, not done, not
   * claimed) is kept; otherwise the TOP accepted contract (acceptedOrder's
   * head — "if no quest is active and the player has accepted quests, the
   * top accepted stands") that is not done + claimed takes the slot; null
   * when no contract is out.
   * @returns {string|null}
   */
  reconcileActive() {
    if (
      this.activeId &&
      this.accepted.has(this.activeId) &&
      !this.completed.has(this.activeId) &&
      !this.claimed.has(this.activeId)
    ) {
      return this.activeId;
    }
    this.activeId =
      this.acceptedOrder.find((id) => !this.completed.has(id) && !this.claimed.has(id)) ?? null;
    return this.activeId;
  }

  // ------------------------------------------------- the patrol's ROUTE

  /**
   * Stand a contract's ROUTE record (the patrol's waypoints + the
   * contract's ENCOUNTERS — the scene's buildPatrolRoute +
   * derivePatrolEncounters results, at the accept). Only a TAKEN
   * contract can carry a route (a route for a foreign id degrades away);
   * the record is validated + normalized (finite waypoint pairs, visited
   * indices in range, no duplicates; the encounters' at/cleared indices
   * valid for the route, the roster the data's type ids, the wave shape
   * finite — a malformed spec degrades to an encounter-free route rather
   * than a broken one). @returns {boolean} true when it stands
   */
  setRoute(id, route) {
    if (typeof id !== 'string' || id === '') return false;
    if (!this.accepted.has(id)) return false;
    if (!route || typeof route !== 'object') return false;
    const waypoints = (Array.isArray(route.waypoints) ? route.waypoints : [])
      .filter((w) => Array.isArray(w) && w.length >= 2 && Number.isFinite(w[0]) && Number.isFinite(w[1]))
      .map((w) => [Math.round(w[0]), Math.round(w[1])]);
    const visited = [...new Set(
      (Array.isArray(route.visited) ? route.visited : []).filter(
        (i) => Number.isInteger(i) && i >= 0 && i < waypoints.length,
      ),
    )];
    const kind = route.kind === 'bounty' ? 'bounty' : 'patrol';
    const encounters = normalizePatrolEncounters(route.encounters, waypoints.length);
    const bounty = kind === 'bounty' ? normalizeBountyPlan(route.bounty, waypoints.length) : null;
    this.routes.set(id, {
      // The route's TYPE — 'patrol' (the default: every patrol, and every
      // save written before the hunts existed) or 'bounty' (a hunt: SEQUENTIAL
      // legs + the hidden plan). The type is what branches the scene's update;
      // a patrol record normalizes exactly as it always did.
      kind,
      targetSystemId: String(route.targetSystemId ?? ''),
      credits: Number.isFinite(Number(route.credits)) ? Number(route.credits) : 0, // the contract's CREDITS payout — fixed at the accept
      // The contract's XP payout (the claim's second reward — beside the
      // credits): the accept fixes it on the record (patrolEncounterXp,
      // the scene's _establishPatrol); a route that stands without one
      // (an old save) derives it from its own spec — the same contract,
      // a signed contract is a signed contract.
      xp:
        Number.isFinite(Number(route.xp)) && Number(route.xp) >= 0
          ? Number(route.xp)
          : kind === 'bounty'
            ? bountyHuntXp(bounty)
            : patrolEncounterXp(encounters),
      waypoints,
      visited,
      encounters,
      bounty,
    });
    return true;
  }

  /**
   * Mark a contract's contact CLEARED (the wave run completed — the
   * scene's _firePatrolContact's onComplete). Idempotent — the run's
   * completion fires once; a re-fire (a mid-fight quit re-arms the
   * contact — the witness is the completion, not the attempt) marks it
   * again without a second effect. A cleared contact's index is always a
   * route waypoint index (validated). @returns {boolean} true when NEWLY cleared
   */
  encounterCleared(id, idx) {
    const route = this.routes.get(id);
    if (!route || !route.encounters) return false;
    if (!Number.isInteger(idx) || !route.encounters.at.includes(idx)) return false;
    if (route.encounters.cleared.includes(idx)) return false;
    route.encounters.cleared.push(idx);
    return true;
  }

  /**
   * A contract's route record (the scene's check-ins + the board's route
   * line + the claim's payout read it).
   * @returns {{kind:string, targetSystemId:string, credits:number, xp:number, waypoints:number[][], visited:number[], encounters:?object, bounty:?object}|null}
   */
  routeFor(id) {
    return this.routes.get(id) ?? null;
  }

  /**
   * Check off a waypoint (idempotent — the scene's per-frame pass may
   * see the ship inside the radius on several frames; only the FIRST
   * logs). @returns {boolean} true when NEWLY logged
   */
  visitWaypoint(id, idx, opts = {}) {
    const route = this.routes.get(id);
    if (!route) return false;
    if (!Number.isInteger(idx) || idx < 0 || idx >= route.waypoints.length) return false;
    if (route.visited.includes(idx)) return false;
    // A HUNT flies its legs IN ORDER — the chain's odds read a first, second
    // and third leg — so only the NEXT leg logs, unless the caller is the
    // kill's own check-off (`opts.anyOrder`: the mark came down and what is
    // left of the lane is signed off with it). A patrol keeps its any-order law.
    if (route.kind === 'bounty' && opts.anyOrder !== true) {
      const next = nextBountyWaypoint(route);
      if (!next || next.index !== idx) return false;
    }
    route.visited.push(idx);
    return true;
  }

  /**
   * A hunt's PICKET wave cleared (the leg's raid wave ran to completion — the
   * witness is the completion, not the attempt, exactly as a patrol contact).
   * Only a leg that ROLLED a picket can clear. @returns {boolean} true when NEWLY cleared
   */
  bountySkirmishCleared(id, idx) {
    const route = this.routes.get(id);
    const b = route?.bounty;
    if (!b || !Number.isInteger(idx) || idx < 0 || idx >= (b.pickets?.length ?? 0)) return false;
    if (b.pickets[idx] !== true) return false;
    if (b.skirmishCleared.includes(idx)) return false;
    b.skirmishCleared.push(idx);
    return true;
  }

  /**
   * THE MARK IS DOWN — the hunt's completion witness (the kill, then every
   * survivor of its escort put down). It sets the plan's `down` mark and
   * checks off EVERY remaining leg in the same breath (a hunt ends on the
   * kill, not on the flying), so bountyRouteComplete stands from here and no
   * further leg fires. Idempotent — a double witness marks once.
   * @returns {boolean} true when NEWLY witnessed
   */
  bountyDown(id) {
    const route = this.routes.get(id);
    const b = route?.bounty;
    if (!b) return false;
    for (let i = 0; i < route.waypoints.length; i++) {
      if (!route.visited.includes(i)) route.visited.push(i);
    }
    if (b.down === true) return false;
    b.down = true;
    return true;
  }

  toJSON() {
    return {
      accepted: [...this.acceptedOrder],
      completed: [...this.completed],
      claimed: [...this.claimed],
      activeId: this.activeId,
      routes: Object.fromEntries(this.routes),
    };
  }

  /**
   * Restore a ledger from a save record. A malformed record yields an
   * empty ledger rather than a throw (contracts are a progression
   * nicety, not a crash vector — the QuestState precedent). With a
   * `known` job space (allSideQuestJobIds of the restored galaxy) only
   * ids inside it survive — a foreign or hand-edited id degrades. The
   * active slot is restored through reconcileActive: a standing saved
   * active is kept, else the top accepted stands (the save's order).
   * @param {object} data the record.sidequests shape
   * @param {Set<string>|null} [known] the save's galaxy job space
   */
  static fromJSON(data, known = null) {
    const st = new SideQuestState();
    if (!data || typeof data !== 'object') return st;
    const list = (arr) => (Array.isArray(arr) ? arr.filter((x) => typeof x === 'string' && x !== '') : []);
    const ok = (id) => (known ? known.has(id) : true);
    for (const id of list(data.accepted)) {
      if (!ok(id) || st.accepted.has(id)) continue;
      st.accepted.add(id);
      st.acceptedOrder.push(id);
    }
    for (const id of list(data.completed)) {
      if (!ok(id) || !st.accepted.has(id) || st.completed.has(id)) continue; // completed ⊆ accepted
      st.completed.add(id);
    }
    for (const id of list(data.claimed)) {
      if (!ok(id) || !st.completed.has(id) || st.claimed.has(id)) continue; // claimed ⊆ completed
      st.claimed.add(id);
    }
    const routes = data.routes && typeof data.routes === 'object' && !Array.isArray(data.routes) ? data.routes : null;
    if (routes) {
      for (const [id, raw] of Object.entries(routes)) {
        if (!ok(id) || !st.accepted.has(id)) continue; // a route only for a contract this ledger holds
        st.setRoute(id, raw);
      }
    }
    if (typeof data.activeId === 'string' && data.activeId !== '') st.activeId = data.activeId;
    st.reconcileActive(); // a standing saved active is kept; else the top accepted stands; else null
    return st;
  }
}