import Phaser from '../vendor/phaser.js';
import { inView, orbitStep } from './Combat.js';
import { EnemyShip } from './EnemyShip.js';
import { neutralTypeConfig } from './EnemyTypes.js';

/**
 * A NEUTRAL ESCORT (data/combat.json → neutral / neutralTypes — frames
 * 20–27 of the enemy sheet, the player-side roster): the same craft
 * body as the hostiles (EnemyShip's art/armor/steering — the config
 * just says `side: 'player'`), but the AI is a small state machine
 * instead of the chase:
 *
 *   approach → (pirates? engage : escort)
 *   engage   → orbit the NEAREST pirate and lance it (Weapons.js's
 *              patterns — the same dispatch the hostiles run); the
 *              moment the last pirate is down it folds into escort
 *   escort   → hold the escort ring around the player for this ship's
 *              window (neutral.escortMin..escortMax seconds — the
 *              spawner rolls it per ship); a pirate up while escorting
 *              flips it back into engage
 *   break    → peel off and fly off-screen (no fire, no U-turn);
 *              CombatSystem despawns it the frame it is fully out
 *
 * PLAYER-SAFE BY CONSTRUCTION, not by promise: the only path that sets
 * wantsFire is engage-at-pirate; the player never enters the target
 * pool (js/combat/CombatSystem.js — auto-fire picks from the enemies
 * roster, and this is a different one); the collide passes never route
 * an 'ally' bolt/seeker into the player (Weapons.js's
 * missilesHitPlayer skips them), and the player's own bolts never touch
 * this roster (they hit `enemies`, not `allies`).
 *
 * `update(time, delta, player, pirates)` returns `{ wantsFire, target }`
 * (target = the pirate being fired at, or null) — CombatSystem does the
 * actual firing, so the on-screen gate + shared pattern dispatch stay
 * in one place, exactly like the pack's.
 */
export class NeutralShip extends EnemyShip {
  /**
   * @param {object} scene the combat scene
   * @param {number} x spawn
   * @param {number} y spawn
   * @param {number} index slot (orbit direction alternates)
   * @param {object} [c] the craft's FULL neutral config (merged — the
   *   EnemyTypes.neutralTypeConfig contract)
   * @param {object} [o]
   * @param {number} [o.escortMs] this ship's escort window (ms) — rolled
   *   per ship by the spawner (neutral.escortMin..escortMax) or the
   *   director
   * @param {Function} [o.viewFn] () => the camera's visible world rect
   *   (or null) — the break-off cull surface
   */
  constructor(scene, x, y, index, c = null, o = {}) {
    const cfg = c && typeof c === 'object' ? c : neutralTypeConfig();
    super(scene, x, y, index, cfg);

    this.side = 'player'; // the roster contract: never hostile to the player
    this.state = 'approach';
    this.escortMs = Math.max(0, Number(o.escortMs) || 0);
    this.escortStart = null;
    this.viewFn = typeof o.viewFn === 'function' ? o.viewFn : null;
    this.target = null; // the pirate engaged (null while escort/break)
    this.gone = false; // fully off-screen after the break-off
    this.escortRadius = Math.max(24, Number(cfg.escortRadius) || 110);
  }

  /**
   * Ally AI step (see the class doc).
   * @param {number} time scene time (ms)
   * @param {number} delta frame delta (ms)
   * @param {object|null} player the player's craft (steering/fire anchor)
   * @param {object[]} [pirates] the system's live enemy roster
   * @returns {{wantsFire: boolean, target: (object|null)}}
   */
  update(time, delta, player, pirates = []) {
    const out = { wantsFire: false, target: null };
    if (this.dead) return out;
    const dt = Math.min(delta, 64) / 1000;

    const px = player ? player.x : (this.lastPx ?? this.x);
    const py = player ? player.y : (this.lastPy ?? this.y);
    if (player) {
      this.lastPx = px;
      this.lastPy = py;
    }

    // Cloaked pirates are UNTARGETABLE (the same rule as pickTarget — the
    // player's guns can't lock them either), so they don't count as live
    // threats and never hold an engage state.
    const live = (pirates || []).filter((p) => p && !p.dead && !p.cloaked);

    // ---- the state machine: escort ↔ engage on the pirate count (the
    //      escort clock is stamped once per escort spell and keeps
    //      running through interruptions); window expiry is the one-way
    //      break-off.
    if (this.state === 'engage' && live.length === 0) {
      this.state = 'escort';
      if (this.escortStart == null) this.escortStart = time;
    } else if (this.state === 'escort' && live.length > 0) {
      this.state = 'engage';
    }

    // ---- break: peel off and fly OUT (no fire, no U-turn)
    if (this.state === 'break') {
      const dx = this.x - px;
      const dy = this.y - py;
      const d = Math.hypot(dx, dy);
      const dirx = d > 1 ? dx / d : 1;
      const diry = d > 1 ? dy / d : 0;
      this._steer(px + dirx * 900, py + diry * 900, this.speed, dt);
      const body = this.body;
      const want = body && body.velocity.length() > 4
        ? Math.atan2(body.velocity.y, body.velocity.x)
        : Math.atan2(diry, dirx);
      this.rotateToward(want + this.artOffset, dt);
      // Fully off the camera's visible rect → the encounter's end.
      const view = this.viewFn ? this.viewFn() : null;
      if (view && !inView(this.x, this.y, Math.max(this.hitRadius, (this.size || 0) / 2), view)) {
        this.gone = true; // CombatSystem despawns it this frame
      }
      return out;
    }

    const wpn = this.wpn ?? {};
    const range = Number(wpn.range) || 0;

    // ---- approach: stream in from the spawn bearing onto the escort ring
    if (this.state === 'approach') {
      this._orbit(px, py, this.escortRadius, dt);
      if (Math.hypot(px - this.x, py - this.y) < this.escortRadius * 1.6) {
        this.state = live.length > 0 ? 'engage' : 'escort';
        if (this.state === 'escort' && this.escortStart == null) this.escortStart = time;
      }
      return out;
    }

    // ---- engage: orbit the NEAREST pirate and lance it
    if (this.state === 'engage') {
      let best = null;
      let bestD = Infinity;
      for (const p of live) {
        const d2 = (p.x - this.x) ** 2 + (p.y - this.y) ** 2;
        if (d2 < bestD) { bestD = d2; best = p; }
      }
      this.target = best;
      if (best) {
        this._orbit(best.x, best.y, this.orbitRadius, dt);
        // Fire gate (engage only — the player is NEVER a target): in
        // range, roughly aimed, off cooldown — the same honesty as the
        // hostiles.
        if (range > 0) {
          const distT = Math.hypot(best.x - this.x, best.y - this.y);
          if (distT < range && time >= this.nextFireAt) {
            const toT = Math.atan2(best.y - this.y, best.x - this.x);
            if (Math.abs(Phaser.Math.Angle.Wrap(toT - this.heading())) < 0.6) {
              this.nextFireAt = time + (Number(wpn.cooldown) || 1.4) * 1000 * (0.85 + Math.random() * 0.4);
              out.wantsFire = true;
              out.target = best;
            }
          }
        }
        return out;
      }
      // The last pirate went down mid-frame → fold into escort.
      this.state = 'escort';
      if (this.escortStart == null) this.escortStart = time;
    }

    // ---- escort: hold the ring around the player until the window lapses
    this.target = null;
    this._orbit(px, py, this.escortRadius, dt);
    if (this.escortStart == null) this.escortStart = time;
    if (time - this.escortStart >= this.escortMs) this.state = 'break';
    return out;
  }

  /**
   * Steer to a point on the orbit ring around (cx, cy) — the same
   * exponential approach the hostiles run (EnemyShip.update); the
   * facing rule is the same too: face the motion while closing, face
   * the center (aiming) on the ring.
   * @private
   */
  _orbit(cx, cy, radius, dt) {
    const t = orbitStep(cx, cy, this.orbitAngle, this.orbitDir, this.orbitSpeed, dt, radius);
    this.orbitAngle = t.angle;
    const sp = Math.hypot(t.x - this.x, t.y - this.y) > radius * 0.9 ? this.speed : this.speed * 0.55;
    this._steer(t.x, t.y, sp, dt);
    const distC = Math.hypot(cx - this.x, cy - this.y);
    const toC = Math.atan2(cy - this.y, cx - this.x);
    const body = this.body;
    const want = distC < radius * 1.5
      ? toC
      : body && body.velocity.length() > 4 ? Math.atan2(body.velocity.y, body.velocity.x) : toC;
    this.rotateToward(want + this.artOffset, dt);
  }

  /** Exponential approach toward (tx, ty) at speed sp (dt in seconds). @private */
  _steer(tx, ty, sp, dt) {
    const dx = tx - this.x;
    const dy = ty - this.y;
    const d = Math.hypot(dx, dy) || 1;
    const k = 1 - Math.exp(-this.turn * dt);
    const body = this.body;
    if (body) {
      body.velocity.x += ((dx / d) * sp - body.velocity.x) * k;
      body.velocity.y += ((dy / d) * sp - body.velocity.y) * k;
    }
  }
}