src/lib/battle-engine/MultiBattleEngine.ts

/**
 * Multi-Piclet Battle Engine
 * Supports up to 4 Piclets on the field at once (2 per side)
 * Extends the single-Piclet battle system with party management and multi-targeting
 */

import {
  MultiBattleState,
  MultiBattleAction,
  MultiMoveAction,
  MultiSwitchAction,
  TurnActions,
  PicletTarget,
  BattleSide,
  FieldPosition,
  MultiBattleConfig,
  ActionPriority,
  VictoryCondition,
  MultiEffectTarget
} from './multi-piclet-types';

import {
  BattlePiclet,
  PicletDefinition,
  BattleEffect,
  Move,
  BaseStats,
  StatusEffect
} from './types';

import { getEffectivenessMultiplier } from '../types/picletTypes';

export class MultiBattleEngine {
  private state: MultiBattleState;
  private victoryCondition: VictoryCondition;

  constructor(config: MultiBattleConfig, victoryCondition: VictoryCondition = { type: 'allFainted' }) {
    this.victoryCondition = victoryCondition;
    this.state = this.initializeBattle(config);
    this.log('Multi-Piclet battle started!');
    this.logActivePiclets();
  }

  private initializeBattle(config: MultiBattleConfig): MultiBattleState {
    // Initialize active Piclets from parties
    const playerActive: Array<BattlePiclet | null> = [null, null];
    const opponentActive: Array<BattlePiclet | null> = [null, null];

    // Set up initial active Piclets
    for (let i = 0; i < config.playerActiveCount && i < config.playerParty.length; i++) {
      playerActive[i] = this.createBattlePiclet(config.playerParty[i], 50);
    }

    for (let i = 0; i < config.opponentActiveCount && i < config.opponentParty.length; i++) {
      opponentActive[i] = this.createBattlePiclet(config.opponentParty[i], 50);
    }

    return {
      turn: 1,
      phase: 'selection',
      activePiclets: {
        player: playerActive,
        opponent: opponentActive
      },
      parties: {
        player: config.playerParty,
        opponent: config.opponentParty
      },
      fieldEffects: [],
      log: [],
      winner: undefined
    };
  }

  private createBattlePiclet(definition: PicletDefinition, level: number): BattlePiclet {
    // Same logic as original BattleEngine
    const statMultiplier = 1 + (level - 50) * 0.02;
    
    const hp = Math.floor(definition.baseStats.hp * statMultiplier);
    const attack = Math.floor(definition.baseStats.attack * statMultiplier);
    const defense = Math.floor(definition.baseStats.defense * statMultiplier);
    const speed = Math.floor(definition.baseStats.speed * statMultiplier);

    return {
      definition,
      currentHp: hp,
      maxHp: hp,
      level,
      attack,
      defense,
      speed,
      accuracy: 100,
      statusEffects: [],
      moves: definition.movepool.slice(0, 4).map(move => ({
        move,
        currentPP: move.pp
      })),
      statModifiers: {},
      temporaryEffects: []
    };
  }

  public getState(): MultiBattleState {
    return JSON.parse(JSON.stringify(this.state));
  }

  public isGameOver(): boolean {
    return this.state.phase === 'ended';
  }

  public getWinner(): 'player' | 'opponent' | 'draw' | undefined {
    return this.state.winner;
  }

  public getActivePiclets(): { player: BattlePiclet[], opponent: BattlePiclet[] } {
    return {
      player: this.state.activePiclets.player.filter(p => p !== null) as BattlePiclet[],
      opponent: this.state.activePiclets.opponent.filter(p => p !== null) as BattlePiclet[]
    };
  }

  public getAvailableSwitches(side: BattleSide): Array<{ partyIndex: number, piclet: PicletDefinition }> {
    const available: Array<{ partyIndex: number, piclet: PicletDefinition }> = [];
    const activePicletNames = this.state.activePiclets[side]
      .filter(p => p !== null)
      .map(p => p!.definition.name);

    this.state.parties[side].forEach((partyMember, index) => {
      if (!activePicletNames.includes(partyMember.name)) {
        available.push({ partyIndex: index, piclet: partyMember });
      }
    });

    return available;
  }

  public getValidActions(side: BattleSide): MultiBattleAction[] {
    const actions: MultiBattleAction[] = [];
    const activePiclets = this.state.activePiclets[side];

    // Add move actions for each active Piclet
    activePiclets.forEach((piclet, position) => {
      if (piclet) {
        piclet.moves.forEach((moveData, moveIndex) => {
          if (moveData.currentPP > 0) {
            actions.push({
              type: 'move',
              side,
              position: position as FieldPosition,
              moveIndex
            });
          }
        });
      }
    });

    // Add switch actions for empty slots or when Piclets can be switched
    this.state.parties[side].forEach((partyMember, partyIndex) => {
      // Check if this party member is not currently active
      const isActive = activePiclets.some(active => 
        active?.definition.name === partyMember.name
      );
      
      if (!isActive) {
        // Can switch into any position that has a Piclet (replacement) or empty slot
        activePiclets.forEach((slot, position) => {
          actions.push({
            type: 'switch',
            side,
            position: position as FieldPosition,
            partyIndex
          });
        });
      }
    });

    return actions;
  }

  public executeTurn(turnActions: TurnActions): void {
    if (this.state.phase !== 'selection') {
      throw new Error('Cannot execute turn - battle is not in selection phase');
    }

    this.state.phase = 'execution';
    this.log(`Turn ${this.state.turn} - Executing actions`);

    // Determine action order based on priority and speed
    const allActions = this.determineActionOrder(turnActions);

    // Execute actions in order
    for (const actionPriority of allActions) {
      if (this.state.phase === 'ended') break;
      this.executeAction(actionPriority.action, actionPriority.side, actionPriority.position);
    }

    // End of turn processing
    this.processTurnEnd();

    // Check for battle end
    this.checkBattleEnd();

    if (this.state.phase !== 'ended') {
      this.state.turn++;
      this.state.phase = 'selection';
    }
  }

  private determineActionOrder(turnActions: TurnActions): ActionPriority[] {
    const allActionPriorities: ActionPriority[] = [];

    // Process player actions
    turnActions.player.forEach(action => {
      const priority = this.getActionPriority(action);
      const piclet = this.state.activePiclets.player[action.position];
      allActionPriorities.push({
        action,
        side: 'player',
        position: action.position,
        priority,
        speed: piclet?.speed || 0,
        randomTiebreaker: Math.random()
      });
    });

    // Process opponent actions
    turnActions.opponent.forEach(action => {
      const priority = this.getActionPriority(action);
      const piclet = this.state.activePiclets.opponent[action.position];
      allActionPriorities.push({
        action,
        side: 'opponent',
        position: action.position,
        priority,
        speed: piclet?.speed || 0,
        randomTiebreaker: Math.random()
      });
    });

    // Sort by priority (higher first), then speed (higher first), then random
    return allActionPriorities.sort((a, b) => {
      if (a.priority !== b.priority) return b.priority - a.priority;
      if (a.speed !== b.speed) return b.speed - a.speed;
      return a.randomTiebreaker - b.randomTiebreaker;
    });
  }

  private getActionPriority(action: MultiBattleAction): number {
    if (action.type === 'switch') return 6; // Switches have highest priority
    
    const piclet = this.state.activePiclets[action.side][action.position];
    if (!piclet) return 0;
    
    const move = piclet.moves[action.moveIndex]?.move;
    return move?.priority || 0;
  }

  private executeAction(action: MultiBattleAction, side: BattleSide, position: FieldPosition): void {
    const piclet = this.state.activePiclets[side][position];
    if (!piclet) return;

    if (action.type === 'move') {
      this.executeMove(action as MultiMoveAction, side, position);
    } else if (action.type === 'switch') {
      this.executeSwitch(action as MultiSwitchAction, side, position);
    }
  }

  private executeMove(action: MultiMoveAction, side: BattleSide, position: FieldPosition): void {
    const attacker = this.state.activePiclets[side][position];
    if (!attacker) return;

    const moveData = attacker.moves[action.moveIndex];
    if (!moveData || moveData.currentPP <= 0) {
      this.log(`${attacker.definition.name} has no PP left for that move!`);
      return;
    }

    const move = moveData.move;
    this.log(`${attacker.definition.name} used ${move.name}!`);

    // Consume PP
    moveData.currentPP--;

    // Check if move hits (simplified for now)
    if (!this.checkMoveHits(move, attacker)) {
      this.log(`${attacker.definition.name}'s attack missed!`);
      return;
    }

    // Process effects for each target
    const targets = this.resolveTargets(move, side, position, action.targets);
    
    for (const effect of move.effects) {
      this.processMultiEffect(effect, attacker, targets, move);
    }
  }

  private executeSwitch(action: MultiSwitchAction, side: BattleSide, position: FieldPosition): void {
    const currentPiclet = this.state.activePiclets[side][position];
    const newPiclet = this.state.parties[side][action.partyIndex];
    
    if (!newPiclet) return;

    // Create battle instance of new Piclet
    const battlePiclet = this.createBattlePiclet(newPiclet, 50);
    
    // Switch out current Piclet (if any)
    if (currentPiclet) {
      this.log(`${currentPiclet.definition.name} switched out!`);
      // Trigger switch-out abilities here
    }

    // Switch in new Piclet
    this.state.activePiclets[side][position] = battlePiclet;
    this.log(`${battlePiclet.definition.name} switched in!`);
    
    // Trigger switch-in abilities here
    this.processAbilityTrigger(battlePiclet, 'onSwitchIn');
  }

  private resolveTargets(move: Move, attackerSide: BattleSide, attackerPosition: FieldPosition, targetOverride?: any): BattlePiclet[] {
    const targets: BattlePiclet[] = [];
    const attacker = this.state.activePiclets[attackerSide][attackerPosition];
    if (!attacker) return targets;

    // Check if move effects specify targets, default to opponent
    const effectTargets = move.effects.map(e => (e as any).target).filter(t => t);
    const primaryTarget = effectTargets[0] || 'opponent';

    switch (primaryTarget) {
      case 'self':
        targets.push(attacker);
        break;
        
      case 'opponent':
        // Target first available opponent (can be enhanced for player choice)
        const opponentSide = attackerSide === 'player' ? 'opponent' : 'player';
        const opponents = this.state.activePiclets[opponentSide].filter(p => p !== null) as BattlePiclet[];
        if (opponents.length > 0) {
          targets.push(opponents[0]);
        }
        break;
        
      case 'allOpponents':
        const oppSide = attackerSide === 'player' ? 'opponent' : 'player';
        const allOpponents = this.state.activePiclets[oppSide].filter(p => p !== null) as BattlePiclet[];
        targets.push(...allOpponents);
        break;
        
      case 'ally':
        // Target ally (for double battles)
        const allies = this.state.activePiclets[attackerSide].filter(p => p !== null && p !== attacker) as BattlePiclet[];
        if (allies.length > 0) {
          targets.push(allies[0]);
        }
        break;
        
      case 'allAllies':
        const allAllies = this.state.activePiclets[attackerSide].filter(p => p !== null && p !== attacker) as BattlePiclet[];
        targets.push(...allAllies);
        break;
        
      case 'all':
        // Target all active Piclets
        for (const side of ['player', 'opponent'] as BattleSide[]) {
          const activePiclets = this.state.activePiclets[side].filter(p => p !== null) as BattlePiclet[];
          targets.push(...activePiclets);
        }
        break;
        
      case 'random':
        // Target random active Piclet
        const allActive: BattlePiclet[] = [];
        for (const side of ['player', 'opponent'] as BattleSide[]) {
          const activePiclets = this.state.activePiclets[side].filter(p => p !== null) as BattlePiclet[];
          allActive.push(...activePiclets);
        }
        if (allActive.length > 0) {
          const randomIndex = Math.floor(Math.random() * allActive.length);
          targets.push(allActive[randomIndex]);
        }
        break;
        
      case 'weakest':
        // Target Piclet with lowest HP percentage
        const allActivePiclets: BattlePiclet[] = [];
        for (const side of ['player', 'opponent'] as BattleSide[]) {
          const activePiclets = this.state.activePiclets[side].filter(p => p !== null) as BattlePiclet[];
          allActivePiclets.push(...activePiclets);
        }
        if (allActivePiclets.length > 0) {
          const weakest = allActivePiclets.reduce((weak, current) => 
            (current.currentHp / current.maxHp) < (weak.currentHp / weak.maxHp) ? current : weak
          );
          targets.push(weakest);
        }
        break;
        
      case 'strongest':
        // Target Piclet with highest HP percentage
        const allActiveForStrongest: BattlePiclet[] = [];
        for (const side of ['player', 'opponent'] as BattleSide[]) {
          const activePiclets = this.state.activePiclets[side].filter(p => p !== null) as BattlePiclet[];
          allActiveForStrongest.push(...activePiclets);
        }
        if (allActiveForStrongest.length > 0) {
          const strongest = allActiveForStrongest.reduce((strong, current) => 
            (current.currentHp / current.maxHp) > (strong.currentHp / strong.maxHp) ? current : strong
          );
          targets.push(strongest);
        }
        break;
        
      default:
        // Fallback to first opponent
        const defaultOpponentSide = attackerSide === 'player' ? 'opponent' : 'player';
        const defaultOpponents = this.state.activePiclets[defaultOpponentSide].filter(p => p !== null) as BattlePiclet[];
        if (defaultOpponents.length > 0) {
          targets.push(defaultOpponents[0]);
        }
    }

    return targets;
  }

  private processMultiEffect(effect: BattleEffect, attacker: BattlePiclet, targets: BattlePiclet[], move: Move): void {
    // Process effect on each target
    for (const target of targets) {
      this.processEffect(effect, attacker, target, move);
    }
  }

  private processEffect(effect: BattleEffect, attacker: BattlePiclet, target: BattlePiclet, move: Move): void {
    // Check condition
    if (effect.condition && !this.checkCondition(effect.condition, attacker, target)) {
      return;
    }

    switch (effect.type) {
      case 'damage':
        this.processDamageEffect(effect, attacker, target, move);
        break;
      case 'heal':
        this.processHealEffect(effect, target);
        break;
      case 'modifyStats':
        this.processModifyStatsEffect(effect, target);
        break;
      case 'applyStatus':
        this.processApplyStatusEffect(effect, target);
        break;
      // Add other effect types as needed
      default:
        this.log(`Effect ${effect.type} not implemented in multi-battle yet`);
    }
  }

  // Simplified effect processors (can be expanded)
  private processDamageEffect(effect: any, attacker: BattlePiclet, target: BattlePiclet, move: Move): void {
    const damage = this.calculateDamage(attacker, target, move);
    target.currentHp = Math.max(0, target.currentHp - damage);
    this.log(`${target.definition.name} took ${damage} damage!`);
  }

  private processHealEffect(effect: any, target: BattlePiclet): void {
    const healAmount = Math.floor(target.maxHp * 0.5); // Simplified
    const oldHp = target.currentHp;
    target.currentHp = Math.min(target.maxHp, target.currentHp + healAmount);
    const actualHeal = target.currentHp - oldHp;
    
    if (actualHeal > 0) {
      this.log(`${target.definition.name} recovered ${actualHeal} HP!`);
    }
  }

  private processModifyStatsEffect(effect: any, target: BattlePiclet): void {
    // Simplified stat modification
    if (effect.stats?.attack === 'increase') {
      target.attack = Math.floor(target.attack * 1.25);
      this.log(`${target.definition.name}'s attack rose!`);
    }
  }

  private processApplyStatusEffect(effect: any, target: BattlePiclet): void {
    if (!target.statusEffects.includes(effect.status)) {
      target.statusEffects.push(effect.status);
      this.log(`${target.definition.name} was ${effect.status}ed!`);
    }
  }

  private calculateDamage(attacker: BattlePiclet, target: BattlePiclet, move: Move): number {
    // Simplified damage calculation
    const baseDamage = move.power || 50;
    const effectiveness = getEffectivenessMultiplier(
      move.type,
      target.definition.primaryType,
      target.definition.secondaryType
    );

    let damage = Math.floor((baseDamage * (attacker.attack / target.defense) * 0.5) + 10);
    damage = Math.floor(damage * effectiveness);
    
    return Math.max(1, damage);
  }

  private checkMoveHits(move: Move, attacker: BattlePiclet): boolean {
    return Math.random() * 100 < move.accuracy;
  }

  private checkCondition(condition: string, attacker: BattlePiclet, target: BattlePiclet): boolean {
    switch (condition) {
      case 'always':
        return true;
      case 'ifLowHp':
        return attacker.currentHp / attacker.maxHp < 0.25;
      default:
        return true;
    }
  }

  private processAbilityTrigger(piclet: BattlePiclet, trigger: string): void {
    // Process special ability triggers
    if (piclet.definition.specialAbility.triggers) {
      for (const abilityTrigger of piclet.definition.specialAbility.triggers) {
        if (abilityTrigger.event === trigger) {
          this.log(`${piclet.definition.name}'s ${piclet.definition.specialAbility.name} activated!`);
          // Process trigger effects
        }
      }
    }
  }

  private processTurnEnd(): void {
    // Process status effects for all active Piclets
    for (const side of ['player', 'opponent'] as BattleSide[]) {
      for (const piclet of this.state.activePiclets[side]) {
        if (piclet) {
          this.processStatusEffects(piclet);
          this.processTemporaryEffects(piclet);
        }
      }
    }

    // Process field effects
    this.processFieldEffects();

    // Handle fainted Piclets
    this.handleFaintedPiclets();
  }

  private handleFaintedPiclets(): void {
    for (const side of ['player', 'opponent'] as BattleSide[]) {
      for (let position = 0; position < this.state.activePiclets[side].length; position++) {
        const piclet = this.state.activePiclets[side][position];
        if (piclet && piclet.currentHp <= 0) {
          this.log(`${piclet.definition.name} fainted!`);
          
          // Remove fainted Piclet from active slot
          this.state.activePiclets[side][position] = null;
          
          // Trigger faint abilities
          this.processAbilityTrigger(piclet, 'onKO');
          
          // For now, we don't auto-switch reserves in this simplified implementation
          // In a full implementation, the player would choose a replacement
        }
      }
    }
  }

  private processStatusEffects(piclet: BattlePiclet): void {
    for (const status of piclet.statusEffects) {
      switch (status) {
        case 'burn':
        case 'poison':
          const damage = Math.floor(piclet.maxHp / 8);
          piclet.currentHp = Math.max(0, piclet.currentHp - damage);
          this.log(`${piclet.definition.name} hurt by ${status}!`);
          break;
      }
    }
  }

  private processTemporaryEffects(piclet: BattlePiclet): void {
    piclet.temporaryEffects = piclet.temporaryEffects.filter(effect => {
      effect.duration--;
      return effect.duration > 0;
    });
  }

  private processFieldEffects(): void {
    this.state.fieldEffects = this.state.fieldEffects.filter(effect => {
      effect.duration--;
      if (effect.duration <= 0) {
        this.log(`Field effect '${effect.name}' ended!`);
        return false;
      }
      return true;
    });
  }

  private checkBattleEnd(): void {
    const winner = this.determineWinner();
    if (winner) {
      this.state.winner = winner;
      this.state.phase = 'ended';
      this.log(`Battle ended! Winner: ${winner}`);
    }
  }

  private determineWinner(): 'player' | 'opponent' | 'draw' | null {
    // Count living active Piclets (not null and HP > 0)
    const playerActiveLiving = this.state.activePiclets.player.filter(p => p !== null && p.currentHp > 0);
    const opponentActiveLiving = this.state.activePiclets.opponent.filter(p => p !== null && p.currentHp > 0);
    
    // Check for healthy reserves
    const playerHealthyReserves = this.getHealthyReserves('player');
    const opponentHealthyReserves = this.getHealthyReserves('opponent');
    
    const playerHasUsablePiclets = playerActiveLiving.length > 0 || playerHealthyReserves.length > 0;
    const opponentHasUsablePiclets = opponentActiveLiving.length > 0 || opponentHealthyReserves.length > 0;

    // Check victory conditions based on type
    switch (this.victoryCondition.type) {
      case 'allFainted':
        if (!playerHasUsablePiclets) {
          if (!opponentHasUsablePiclets) {
            return 'draw';
          }
          return 'opponent';
        }
        if (!opponentHasUsablePiclets) {
          return 'player';
        }
        break;
        
      case 'custom':
        if (this.victoryCondition.customCheck) {
          return this.victoryCondition.customCheck(this.state);
        }
        break;
    }

    return null;
  }

  private getHealthyReserves(side: BattleSide): PicletDefinition[] {
    // Get party members that have never been used in battle
    // We need to track which party members have been on the field
    const usedPicletNames = new Set<string>();
    
    // Add currently active Piclets
    this.state.activePiclets[side].forEach(p => {
      if (p !== null) {
        usedPicletNames.add(p.definition.name);
      }
    });
    
    // For a full implementation, we would also track previously active Piclets that fainted
    // For now, we estimate by checking the initial setup - if there are more party members
    // than active slots, the rest are reserves
    const activeSlots = this.state.activePiclets[side].length;
    const initialActiveCount = Math.min(this.state.parties[side].length, activeSlots);
    
    // Mark the first N party members as "used" (they were initially active)
    for (let i = 0; i < initialActiveCount; i++) {
      if (this.state.parties[side][i]) {
        usedPicletNames.add(this.state.parties[side][i].name);
      }
    }
    
    return this.state.parties[side].filter(partyMember => 
      !usedPicletNames.has(partyMember.name)
    );
  }

  private logActivePiclets(): void {
    const playerActives = this.state.activePiclets.player.filter(p => p !== null) as BattlePiclet[];
    const opponentActives = this.state.activePiclets.opponent.filter(p => p !== null) as BattlePiclet[];
    
    this.log(`Player active: ${playerActives.map(p => p.definition.name).join(', ')}`);
    this.log(`Opponent active: ${opponentActives.map(p => p.definition.name).join(', ')}`);
  }

  private log(message: string): void {
    this.state.log.push(message);
  }

  public getLog(): string[] {
    // Strip battle prefixes from all log messages for display
    return this.state.log.map(message => this.stripBattlePrefixes(message));
  }
  
  private stripBattlePrefixes(message: string): string {
    // Remove player- and enemy- prefixes from messages
    return message
      .replace(/player-/g, '')
      .replace(/enemy-/g, '');
  }
}