// Headless verification for Colorado Defense.
//   node tools/verifyColoradoDefense.js
// Exits non-zero on any failure.
//
// 1. Ground-layout invariants (9 slots, 3 bases + 6 cities, symmetric spacing).
// 2. City-pool draw correctness + malformed-pool fallback.
// 3. Difficulty escalation monotonicity across waves 1-40 (bounded).
// 4. MIRV step-unlock threshold.
// 5. Scripted explosion/collision fixture.
// 6. Palette-progression monotonicity.
// 7. Monte-carlo "always fire at nearest incoming missile" bot run.

import {
  BASE_SLOTS, CITY_SLOTS, GROUND_SLOTS, slotX, mulberry32, pickCities,
  DEFAULT_CITIES, TUNE, spawnInterval, fallSpeed, waveQuota, mirvChance,
  PALETTES, paletteIndexForWave, createGame, step, pickFiringBase,
  fireInterceptor, lerpPos, explosionRadius,
} from '../src/games/coloradodefense/ColoradoDefenseLogic.js';

let failures = 0;
function check(name, cond, detail = '') {
  if (cond) { console.log(`  ok   ${name}`); return; }
  failures += 1;
  console.error(`  FAIL ${name}${detail ? ` — ${detail}` : ''}`);
}

// ── 1. Ground layout ─────────────────────────────────────────────────────────

console.log('Ground layout');
{
  check('9 slots total', GROUND_SLOTS === 9);
  check('3 base slots', BASE_SLOTS.length === 3);
  check('6 city slots', CITY_SLOTS.length === 6);
  const allSlots = [...BASE_SLOTS, ...CITY_SLOTS].sort((a, b) => a - b);
  check('slots partition 0..8 exactly', allSlots.join(',') === '0,1,2,3,4,5,6,7,8');
  check('classic arrangement Base,City,City,City,Base,City,City,City,Base',
    BASE_SLOTS.join(',') === '0,4,8' && CITY_SLOTS.join(',') === '1,2,3,5,6,7');

  const xs = Array.from({ length: GROUND_SLOTS }, (_, i) => slotX(i));
  let increasing = true;
  for (let i = 1; i < xs.length; i += 1) if (xs[i] <= xs[i - 1]) increasing = false;
  check('slot positions strictly increasing left to right', increasing);
  const mid = (xs[0] + xs[8]) / 2;
  check('layout symmetric around center', Math.abs((xs[4]) - mid) < 1, `slot4=${xs[4]} mid=${mid}`);
}

// ── 2. City pool ──────────────────────────────────────────────────────────────

console.log('City pool');
{
  const rng = mulberry32(42);
  for (const seed of [1, 2, 3, 999, 123456]) {
    const r = mulberry32(seed);
    const picked = pickCities(DEFAULT_CITIES, r);
    check(`seed ${seed}: exactly 6 cities`, picked.length === 6);
    check(`seed ${seed}: unique cities`, new Set(picked).size === 6, picked.join(','));
    check(`seed ${seed}: all from pool`, picked.every((n) => DEFAULT_CITIES.includes(n)));
  }
  const empty = pickCities([], rng);
  check('empty pool falls back safely (no throw, bounded length)', empty.length === 6);
  const small = pickCities(['A', 'B'], rng);
  check('pool smaller than 6 cycles without throwing', small.length === 6);
}

// ── 3. Escalation monotonicity ────────────────────────────────────────────────

console.log('Escalation monotonicity (waves 1-40)');
{
  let spawnOk = true; let fallOk = true; let quotaOk = true;
  let spawnBounded = true; let fallBounded = true; let quotaBounded = true;
  for (let w = 2; w <= 40; w += 1) {
    if (spawnInterval(w) > spawnInterval(w - 1)) spawnOk = false;
    if (fallSpeed(w) < fallSpeed(w - 1)) fallOk = false;
    if (waveQuota(w) < waveQuota(w - 1)) quotaOk = false;
  }
  for (let w = 1; w <= 40; w += 1) {
    if (spawnInterval(w) < TUNE.SPAWN_MS_MIN) spawnBounded = false;
    if (fallSpeed(w) > TUNE.FALL_SPEED_MAX) fallBounded = false;
    if (waveQuota(w) > TUNE.WAVE_QUOTA_MAX) quotaBounded = false;
  }
  check('spawn interval never increases with wave', spawnOk);
  check('fall speed never decreases with wave', fallOk);
  check('wave quota never decreases with wave', quotaOk);
  check('spawn interval bounded at floor', spawnBounded);
  check('fall speed bounded at cap', fallBounded);
  check('wave quota bounded at cap', quotaBounded);
}

// ── 4. MIRV step-unlock ────────────────────────────────────────────────────────

console.log('MIRV step-unlock');
{
  let belowZero = true;
  for (let w = 1; w < TUNE.MIRV_WAVE; w += 1) if (mirvChance(w) !== 0) belowZero = false;
  check(`mirvChance is 0 before wave ${TUNE.MIRV_WAVE}`, belowZero);
  check(`mirvChance > 0 at wave ${TUNE.MIRV_WAVE}`, mirvChance(TUNE.MIRV_WAVE) > 0);
  check('mirvChance bounded at max', mirvChance(999) <= TUNE.MIRV_CHANCE_MAX);
}

// ── 5. Explosion/collision fixture ────────────────────────────────────────────

console.log('Explosion/collision fixture');
{
  const sim = createGame(DEFAULT_CITIES, 7);
  const target = sim.cities[0];
  // A slow-descending missile (long dur) barely drifts during the
  // interceptor's flight time, so a shot at its current position still lands.
  sim.enemyMissiles.push({
    id: sim.nextId++, fromX: target.x, fromY: 0, toX: target.x, toY: target.y,
    targetSlot: target.slot, targetKind: 'city', t: 0.5, dur: 60000, kind: 'single', splitAt: 2, splitDone: true,
  });
  const missilePos = lerpPos(sim.enemyMissiles[0]);
  const base = pickFiringBase(sim, missilePos.x, missilePos.y);
  fireInterceptor(sim, base, missilePos.x, missilePos.y);
  let destroyed = false;
  let steps = 0;
  while (!destroyed && steps < 200) {
    const events = step(sim, 16);
    if (events.some((e) => e.type === 'missileDestroyed')) destroyed = true;
    steps += 1;
  }
  check('interceptor blast destroys missile within radius', destroyed, `steps=${steps}`);
  check('score increased on kill', sim.score > 0, `score=${sim.score}`);

  const sim2 = createGame(DEFAULT_CITIES, 8);
  const target2 = sim2.cities[0];
  sim2.enemyMissiles.push({
    id: sim2.nextId++, fromX: target2.x, fromY: 0, toX: target2.x, toY: target2.y,
    targetSlot: target2.slot, targetKind: 'city', t: 0.5, dur: 4000, kind: 'single', splitAt: 2, splitDone: true,
  });
  const far = lerpPos(sim2.enemyMissiles[0]);
  fireInterceptor(sim2, sim2.bases[1], far.x + 5000, far.y);
  for (let i = 0; i < 60; i += 1) step(sim2, 16);
  check('missile far outside blast radius survives', sim2.enemyMissiles.length === 1);
}

// ── 6. Palette progression ────────────────────────────────────────────────────

console.log('Palette progression');
{
  let monotonic = true;
  for (let w = 2; w <= 60; w += 1) {
    if (paletteIndexForWave(w) < paletteIndexForWave(w - 1)) monotonic = false;
  }
  check('palette index monotonic non-decreasing', monotonic);
  check('palette index clamps at array end', paletteIndexForWave(9999) === PALETTES.length - 1);
}

// ── 7. Monte-carlo bot run ────────────────────────────────────────────────────

console.log('Monte-carlo bot run');
{
  for (const seed of [1, 2, 3, 4, 5]) {
    const sim = createGame(DEFAULT_CITIES, seed);
    let steps = 0;
    let scoreRegressed = false;
    let cityCountIncreased = false;
    let nanFound = false;
    let prevScore = 0;
    let prevCities = sim.aliveCities().length;
    const MAX_STEPS = 20000; // ~320s of sim time at 16ms/step

    while (sim.status === 'playing' && steps < MAX_STEPS) {
      // Bot: fire at whichever enemy missile is closest to impact (highest t),
      // but only one interceptor in flight at a time so ammo isn't wasted on
      // redundant shots at the same target.
      if (sim.enemyMissiles.length && sim.interceptors.length === 0) {
        let soonest = null; let soonestT = -1;
        for (const m of sim.enemyMissiles) {
          if (m.t > soonestT) { soonestT = m.t; soonest = m; }
        }
        if (soonest) {
          const pos = lerpPos(soonest);
          const base = pickFiringBase(sim, pos.x, pos.y);
          if (base) fireInterceptor(sim, base, pos.x, pos.y);
        }
      }
      step(sim, 16);
      steps += 1;

      if (sim.score < prevScore) scoreRegressed = true;
      prevScore = sim.score;
      const aliveCities = sim.aliveCities().length;
      if (aliveCities > prevCities) cityCountIncreased = true;
      prevCities = aliveCities;

      for (const list of [sim.enemyMissiles, sim.interceptors, sim.explosions]) {
        for (const e of list) {
          if (Number.isNaN(e.x ?? e.fromX) || Number.isNaN(e.y ?? e.fromY)) nanFound = true;
        }
      }
    }

    check(`seed ${seed}: no NaN values`, !nanFound);
    check(`seed ${seed}: score never regressed`, !scoreRegressed);
    check(`seed ${seed}: city count never increased`, !cityCountIncreased);
    check(`seed ${seed}: game over exactly when all cities dead`,
      sim.status === 'gameover' ? sim.aliveCities().length === 0 : true);
    check(`seed ${seed}: terminates within step bound`, steps < MAX_STEPS, `steps=${steps}`);
    console.log(`       seed ${seed}: status=${sim.status} wave=${sim.wave} score=${sim.score} steps=${steps}`);
  }
}

console.log(failures ? `\n${failures} FAILURE(S)` : '\nAll checks passed.');
process.exit(failures ? 1 : 0);