// ═══════════════════════════════════════════════════════════════════════════════
// GunCircle.io — Player Manager
// ═══════════════════════════════════════════════════════════════════════════════

import {
  Player,
  Bullet,
  XPOrb,
  RoomState,
  type PlayerInput,
  type GunConfig,
  type ClassBranch,
  vec2,
  type Vec2,
  PLAYER_BASE_HP,
  PLAYER_BASE_SPEED,
  PLAYER_BASE_RADIUS,
  PLAYER_FRICTION,
  ARENA_WIDTH,
  ARENA_HEIGHT,
  XP_LEVELS,
  MAX_LEVEL,
  STAT_COUNT,
  STAT_MAX_LEVEL,
  STAT_BONUSES,
  Stat,
  BASE_CRIT_MULTIPLIER,
  DEATH_XP_DROP_PCT,
  XP_KILL_PCT,
  RESPAWN_DELAY_MS,
  XP_ORB_LIFETIME_S,
  randFloat,
  randInt,
  clamp,
} from '@guncircle/shared';
import { GunSystem } from './gun-system.js';
import { BranchSystem } from './branch-system.js';

// ─── Pending respawn tracking ────────────────────────────────────────────────

interface PendingRespawn {
  playerId: string;
  respawnAt: number;
}

// ─── PlayerManager ───────────────────────────────────────────────────────────

export class PlayerManager {
  private gunSystem: GunSystem;
  private branchSystem: BranchSystem;
  private pendingRespawns: PendingRespawn[] = [];
  private lastShotTimes: Map<string, number> = new Map();
  private reloadTimers: Map<string, number> = new Map();
  private nextOrbId: number = 0;

  constructor(gunSystem: GunSystem, branchSystem: BranchSystem) {
    this.gunSystem = gunSystem;
    this.branchSystem = branchSystem;
  }

  // ─── Spawning ──────────────────────────────────────────────────────────────

  /**
   * Create and spawn a new player at a random position with base stats.
   */
  spawnPlayer(id: string, name: string, state: RoomState): Player {
    const player: Player = new Player();
    const spawnPos: Vec2 = this.randomSpawnPosition();

    player.x = spawnPos.x;
    player.y = spawnPos.y;
    player.name = name.substring(0, 16);
    player.hp = PLAYER_BASE_HP;
    player.maxHp = PLAYER_BASE_HP;
    player.level = 1;
    player.xp = 0;
    player.xpToNext = XP_LEVELS[1] ?? 50;
    player.gunType = 0; // Pistol
    player.classType = 0; // No branch
    player.score = 0;
    player.alive = true;
    player.radius = PLAYER_BASE_RADIUS;
    player.upgradePoints = 0;
    player.recoilOffset = 0;
    player.skinId = 0;
    player.vx = 0;
    player.vy = 0;

    // Set base gun stats
    const gun: GunConfig | undefined = this.gunSystem.getGunConfig(0);
    if (gun !== undefined) {
      player.ammo = gun.ammoMax;
      player.maxAmmo = gun.ammoMax;
    } else {
      player.ammo = 12;
      player.maxAmmo = 12;
    }
    player.isReloading = false;

    // Reset stats
    for (let i = 0; i < STAT_COUNT; i++) {
      player.stats[i] = 0;
    }

    state.players.set(id, player);
    this.lastShotTimes.set(id, 0);
    this.reloadTimers.delete(id);

    return player;
  }

  private randomSpawnPosition(): Vec2 {
    const margin: number = 100;
    return {
      x: randFloat(margin, ARENA_WIDTH - margin),
      y: randFloat(margin, ARENA_HEIGHT - margin),
    };
  }

  // ─── Input Processing ──────────────────────────────────────────────────────

  /**
   * Apply player input: movement and shooting.
   */
  applyInput(
    player: Player,
    input: PlayerInput,
    playerId: string,
    state: RoomState,
    currentTime: number,
    dt: number
  ): void {
    if (!player.alive) return;

    // Update aim angle
    player.angle = input.aimAngle;

    // Process movement
    if (input.moveAngle >= 0) {
      const moveSpeedStat: number = player.stats[Stat.MovementSpeed] ?? 0;
      const maxSpeed: number = PLAYER_BASE_SPEED * (1 + moveSpeedStat * 0.05);

      player.vx += Math.cos(input.moveAngle) * maxSpeed * 0.15;
      player.vy += Math.sin(input.moveAngle) * maxSpeed * 0.15;

      // Clamp speed
      const speed: number = Math.sqrt(player.vx * player.vx + player.vy * player.vy);
      if (speed > maxSpeed) {
        const scale: number = maxSpeed / speed;
        player.vx *= scale;
        player.vy *= scale;
      }
    }

    // Process shooting
    if (input.isShooting) {
      this.handleShoot(player, playerId, state, input.aimAngle, currentTime);
    }
  }

  // ─── Shooting ──────────────────────────────────────────────────────────────

  /**
   * Handle a single shot from the player's current gun.
   */
  handleShoot(
    player: Player,
    playerId: string,
    state: RoomState,
    aimAngle: number,
    currentTime: number
  ): void {
    if (!player.alive) return;
    if (player.isReloading) return;
    if (player.ammo <= 0) {
      // Auto-reload when empty
      this.startReload(player, playerId);
      return;
    }

    const gun: GunConfig | undefined = this.gunSystem.getGunConfig(player.gunType);
    if (gun === undefined) return;

    // Check fire rate
    const lastShot: number = this.lastShotTimes.get(playerId) ?? 0;
    const reloadSpdStat: number = player.stats[Stat.ReloadSpeed] ?? 0;
    const cooldown: number = this.gunSystem.calculateCooldown(gun, reloadSpdStat);

    if (currentTime - lastShot < cooldown) return;

    // Apply recoil
    const recoilStabStat: number = player.stats[Stat.RecoilStability] ?? 0;
    const recoilOffset: number = this.gunSystem.calculateRecoil(gun, recoilStabStat);
    player.recoilOffset = recoilOffset;

    // Calculate kickback
    const kickback: Vec2 = this.gunSystem.calculateKickback(gun, aimAngle);
    player.vx += kickback.x;
    player.vy += kickback.y;

    // Spawn bullet(s)
    if (gun.pelletCount > 1) {
      // Shotgun spread
      const halfSpread: number = gun.spread / 2;
      const pelletDamage: number = this.gunSystem.calculatePelletDamage(
        this.calculateDamage(player, gun),
        gun.pelletCount
      );

      for (let i = 0; i < gun.pelletCount; i++) {
        const t: number = gun.pelletCount <= 1 ? 0 : i / (gun.pelletCount - 1);
        const pelletAngle: number = aimAngle + recoilOffset - halfSpread + gun.spread * t;
        const spawnPos: Vec2 = this.gunSystem.getBulletSpawnPos(
          player.x,
          player.y,
          aimAngle,
          recoilOffset
        );

        const isCrit: boolean = this.rollCrit(player);
        const finalDamage: number = isCrit
          ? pelletDamage * (BASE_CRIT_MULTIPLIER + (player.stats[Stat.CritDamage] ?? 0) * 0.1)
          : pelletDamage;

        const bullet: Bullet = this.gunSystem.createBullet(
          gun,
          playerId,
          spawnPos,
          pelletAngle,
          finalDamage,
          isCrit
        );

        const bulletId: string = this.generateBulletId(state);
        state.bullets.set(bulletId, bullet);
      }
    } else {
      // Single bullet
      const spawnPos: Vec2 = this.gunSystem.getBulletSpawnPos(
        player.x,
        player.y,
        aimAngle,
        recoilOffset
      );

      const isCrit: boolean = this.rollCrit(player);
      const baseDamage: number = this.calculateDamage(player, gun);
      const finalDamage: number = isCrit
        ? baseDamage * (BASE_CRIT_MULTIPLIER + (player.stats[Stat.CritDamage] ?? 0) * 0.1)
        : baseDamage;

      const bullet: Bullet = this.gunSystem.createBullet(
        gun,
        playerId,
        spawnPos,
        aimAngle + recoilOffset,
        finalDamage,
        isCrit
      );

      const bulletId: string = this.generateBulletId(state);
      state.bullets.set(bulletId, bullet);
    }

    // Consume ammo
    player.ammo = Math.max(0, player.ammo - 1);
    this.lastShotTimes.set(playerId, currentTime);

    // Auto-reload when empty
    if (player.ammo <= 0) {
      this.startReload(player, playerId);
    }
  }

  private rollCrit(player: Player): boolean {
    const critChance: number = (player.stats[Stat.CritChance] ?? 0) * 0.03;
    return Math.random() < critChance;
  }

  private generateBulletId(state: RoomState): string {
    return `b_${state.tick}_${Math.random().toString(36).substring(2, 9)}`;
  }

  // ─── Reloading ─────────────────────────────────────────────────────────────

  /**
   * Start reloading the player's gun.
   */
  startReload(player: Player, playerId: string): void {
    if (player.isReloading) return;
    if (player.ammo >= player.maxAmmo) return;

    const gun: GunConfig | undefined = this.gunSystem.getGunConfig(player.gunType);
    if (gun === undefined) return;

    const reloadSpdStat: number = player.stats[Stat.ReloadSpeed] ?? 0;
    const reloadTime: number = this.gunSystem.calculateReloadTime(gun, reloadSpdStat);

    player.isReloading = true;
    this.reloadTimers.set(playerId, reloadTime);
  }

  /**
   * Update all reload timers. Call every tick.
   * dt is in milliseconds.
   */
  updateReloads(players: Map<string, Player>, dtMs: number): void {
    for (const [playerId, player] of players.entries()) {
      if (!player.isReloading) continue;

      let remaining: number | undefined = this.reloadTimers.get(playerId);
      if (remaining === undefined) {
        // Timer missing — fix it
        const gun: GunConfig | undefined = this.gunSystem.getGunConfig(player.gunType);
        remaining = gun !== undefined ? gun.reloadTimeMs : 1500;
      }

      remaining -= dtMs;
      this.reloadTimers.set(playerId, remaining);

      if (remaining <= 0) {
        // Reload complete
        const gun: GunConfig | undefined = this.gunSystem.getGunConfig(player.gunType);
        player.ammo = gun !== undefined ? gun.ammoMax : player.maxAmmo;
        player.isReloading = false;
        this.reloadTimers.delete(playerId);
      }
    }
  }

  // ─── Damage & Death ────────────────────────────────────────────────────────

  /**
   * Apply damage to a player. Returns true if the player died.
   */
  takeDamage(player: Player, damage: number, isCrit: boolean): boolean {
    if (!player.alive) return false;
    if (damage <= 0) return false;

    player.hp = Math.max(0, player.hp - damage);

    if (player.hp <= 0) {
      return true; // Player died
    }
    return false;
  }

  /**
   * Handle player death: drop XP orbs, reset stats, mark !alive.
   */
  onDeath(
    player: Player,
    playerId: string,
    state: RoomState,
    killerId?: string
  ): void {
    if (player.alive) {
      // Drop 50% of held XP as orbs
      this.dropXpOrbs(player, state);

      // Award kill to killer
      if (killerId !== undefined) {
        const killer: Player | undefined = state.players.get(killerId);
        if (killer !== undefined && killer.alive) {
          killer.score += 1;
          // Award 50% of victim's XP to killer
          const xpReward: number = Math.floor(player.xp * XP_KILL_PCT);
          killer.xp += xpReward;
          this.checkLevelUp(killer);
        }
      }

      // Reset player
      player.alive = false;
      player.hp = 0;
      player.vx = 0;
      player.vy = 0;

      // Schedule respawn
      this.pendingRespawns.push({
        playerId,
        respawnAt: Date.now() + RESPAWN_DELAY_MS,
      });
    }
  }

  /**
   * Drop XP orbs at player's death position. Total value = 50% of held XP.
   */
  private dropXpOrbs(player: Player, state: RoomState): void {
    const dropAmount: number = Math.floor(player.xp * DEATH_XP_DROP_PCT);
    if (dropAmount <= 0) return;

    const orbCount: number = Math.min(10, Math.max(3, player.level));
    const xpPerOrb: number = Math.floor(dropAmount / orbCount);

    if (xpPerOrb <= 0) return;

    for (let i = 0; i < orbCount; i++) {
      const angle: number = Math.random() * Math.PI * 2;
      const dist: number = randFloat(10, 50);
      const orb: XPOrb = new XPOrb();
      orb.x = clamp(player.x + Math.cos(angle) * dist, 0, ARENA_WIDTH);
      orb.y = clamp(player.y + Math.sin(angle) * dist, 0, ARENA_HEIGHT);
      orb.value = xpPerOrb;
      orb.lifetime = XP_ORB_LIFETIME_S;

      const orbId: string = `orb_${this.nextOrbId++}`;
      state.xpOrbs.set(orbId, orb);
    }
  }

  // ─── Respawn ───────────────────────────────────────────────────────────────

  /**
   * Process pending respawns. Call every tick.
   */
  processRespawns(state: RoomState): void {
    const now: number = Date.now();
    const stillPending: PendingRespawn[] = [];

    for (const pending of this.pendingRespawns) {
      if (now >= pending.respawnAt) {
        const player: Player | undefined = state.players.get(pending.playerId);
        if (player !== undefined) {
          this.respawnPlayer(player);
        }
      } else {
        stillPending.push(pending);
      }
    }

    this.pendingRespawns = stillPending;
  }

  /**
   * Respawn a player: new random position, reset to level 1, base stats.
   */
  respawnPlayer(player: Player): void {
    const spawnPos: Vec2 = this.randomSpawnPosition();
    player.x = spawnPos.x;
    player.y = spawnPos.y;
    player.vx = 0;
    player.vy = 0;
    player.angle = 0;
    player.recoilOffset = 0;

    // Keep level and XP but reset HP
    player.hp = player.maxHp;
    player.alive = true;

    // Reset gun to pistol
    player.gunType = 0;
    const gun: GunConfig | undefined = this.gunSystem.getGunConfig(0);
    if (gun !== undefined) {
      player.ammo = gun.ammoMax;
      player.maxAmmo = gun.ammoMax;
    }
    player.isReloading = false;
  }

  // ─── Leveling & Upgrades ───────────────────────────────────────────────────

  /**
   * Check if player has enough XP to level up. Award points and update thresholds.
   */
  checkLevelUp(player: Player): boolean {
    if (player.level >= MAX_LEVEL) return false;

    let leveledUp: boolean = false;

    while (player.level < MAX_LEVEL && player.xp >= (XP_LEVELS[player.level] ?? Infinity)) {
      player.level += 1;
      player.upgradePoints += 1;
      leveledUp = true;

      // Update xpToNext
      if (player.level < MAX_LEVEL) {
        player.xpToNext = XP_LEVELS[player.level] ?? player.xpToNext;
      } else {
        player.xpToNext = 999999;
      }

      // Apply level-based stat updates
      this.onLevelUp(player);
    }

    return leveledUp;
  }

  private onLevelUp(player: Player): void {
    // Recalculate max HP
    player.maxHp = this.calculateMaxHp(player);
    // Heal on level up
    player.hp = player.maxHp;
  }

  /**
   * Apply a stat upgrade choice to a player.
   * choice: 0-8 for stats, or 100+ for branch selection.
   */
  applyUpgrade(player: Player, choice: number): boolean {
    if (player.upgradePoints <= 0) return false;

    // Branch selection: choice >= 100 means branch index
    if (choice >= 100) {
      const branchIdx: number = choice - 100;
      const branch: ClassBranch | undefined = this.branchSystem.getBranchByIndex(branchIdx);
      if (branch === undefined) return false;
      if (branch.levelRequired > player.level) return false;

      this.branchSystem.applyBranch(player, branch.id);
      player.upgradePoints -= 1;

      // Apply branch bonuses
      player.maxHp = this.calculateMaxHp(player);
      player.hp = Math.min(player.hp, player.maxHp);

      return true;
    }

    // Stat upgrade
    if (choice < 0 || choice >= STAT_COUNT) return false;

    const currentLevel: number = player.stats[choice] ?? 0;
    if (currentLevel >= STAT_MAX_LEVEL) return false;

    player.stats[choice] = currentLevel + 1;
    player.upgradePoints -= 1;

    // Apply immediate effects
    if (choice === Stat.MaxHp) {
      player.maxHp = this.calculateMaxHp(player);
      player.hp = Math.min(player.hp + STAT_BONUSES[Stat.MaxHp].perLevel, player.maxHp);
    }

    return true;
  }

  // ─── Stat Calculations ─────────────────────────────────────────────────────

  /**
   * Calculate max HP with stat and branch bonuses.
   */
  calculateMaxHp(player: Player): number {
    const baseHp: number = PLAYER_BASE_HP;
    const hpStat: number = player.stats[Stat.MaxHp] ?? 0;
    const hpBonus: number = hpStat * STAT_BONUSES[Stat.MaxHp].perLevel;

    // Branch bonuses
    const branchBonuses: Record<Stat, number> =
      this.branchSystem.calculateBranchBonuses(player);
    const branchHpBonus: number = branchBonuses[Stat.MaxHp];

    return Math.floor(baseHp + hpBonus + baseHp * branchHpBonus);
  }

  /**
   * Calculate movement speed with stat and branch bonuses.
   */
  calculateSpeed(player: Player): number {
    const moveStat: number = player.stats[Stat.MovementSpeed] ?? 0;
    const branchBonuses: Record<Stat, number> =
      this.branchSystem.calculateBranchBonuses(player);
    const branchMoveBonus: number = branchBonuses[Stat.MovementSpeed];

    return PLAYER_BASE_SPEED * (1 + moveStat * 0.05 + branchMoveBonus);
  }

  /**
   * Calculate damage multiplier from stats and branches.
   */
  calculateDamage(player: Player, gun: GunConfig): number {
    const dmgStat: number = player.stats[Stat.BulletDamage] ?? 0;
    const branchBonuses: Record<Stat, number> =
      this.branchSystem.calculateBranchBonuses(player);
    const branchDmgBonus: number = branchBonuses[Stat.BulletDamage];

    return gun.damage * (1 + dmgStat * 0.1 + branchDmgBonus);
  }

  /**
   * Calculate HP regeneration per second.
   */
  calculateHpRegen(player: Player): number {
    const regenStat: number = player.stats[Stat.HpRegen] ?? 0;
    const baseRegen: number = 1; // HP per second
    const statBonus: number = regenStat * STAT_BONUSES[Stat.HpRegen].perLevel;

    const branchBonuses: Record<Stat, number> =
      this.branchSystem.calculateBranchBonuses(player);
    const branchRegenBonus: number = branchBonuses[Stat.HpRegen];

    return baseRegen + statBonus + baseRegen * branchRegenBonus;
  }

  /**
   * Get the recoil stability factor (0-1, higher = less recoil).
   */
  calculateRecoilStability(player: Player): number {
    const stabStat: number = player.stats[Stat.RecoilStability] ?? 0;
    const branchBonuses: Record<Stat, number> =
      this.branchSystem.calculateBranchBonuses(player);
    const branchStabBonus: number = branchBonuses[Stat.RecoilStability];

    return Math.min(1, stabStat * 0.1 + branchStabBonus);
  }

  /**
   * Get the effective reload speed bonus.
   */
  calculateReloadBonus(player: Player): number {
    const reloadStat: number = player.stats[Stat.ReloadSpeed] ?? 0;
    const branchBonuses: Record<Stat, number> =
      this.branchSystem.calculateBranchBonuses(player);
    const branchReloadBonus: number = branchBonuses[Stat.ReloadSpeed];

    return reloadStat * 0.1 + branchReloadBonus;
  }

  // ─── Utility ───────────────────────────────────────────────────────────────

  /**
   * Get the pending respawn list (for cleanup).
   */
  getPendingRespawns(): PendingRespawn[] {
    return this.pendingRespawns;
  }

  /**
   * Remove a player's pending respawn.
   */
  clearPendingRespawn(playerId: string): void {
    this.pendingRespawns = this.pendingRespawns.filter((p) => p.playerId !== playerId);
  }

  /**
   * Get remaining reload time for a player (in ms).
   */
  getReloadRemaining(playerId: string): number {
    return this.reloadTimers.get(playerId) ?? 0;
  }

  /**
   * Clean up all tracking data for a player.
   */
  removePlayer(playerId: string): void {
    this.lastShotTimes.delete(playerId);
    this.reloadTimers.delete(playerId);
    this.pendingRespawns = this.pendingRespawns.filter((p) => p.playerId !== playerId);
  }

  /**
   * Reset all player tracking.
   */
  reset(): void {
    this.pendingRespawns = [];
    this.lastShotTimes.clear();
    this.reloadTimers.clear();
    this.nextOrbId = 0;
  }
}