src/lib/battle-engine/MultiBattleEngine.test.ts

/**
 * Tests for Multi-Piclet Battle Engine
 * Covers battles with up to 4 Piclets on the field at once
 */

import { describe, it, expect, beforeEach } from 'vitest';
import { MultiBattleEngine } from './MultiBattleEngine';
import { MultiBattleConfig, TurnActions } from './multi-piclet-types';
import { PicletType, AttackType } from './types';
import { 
  STELLAR_WOLF, 
  TOXIC_CRAWLER, 
  BERSERKER_BEAST, 
  AQUA_GUARDIAN 
} from './test-data';

describe('MultiBattleEngine', () => {
  let config: MultiBattleConfig;
  let engine: MultiBattleEngine;

  beforeEach(() => {
    config = {
      playerParty: [STELLAR_WOLF, BERSERKER_BEAST],
      opponentParty: [TOXIC_CRAWLER, AQUA_GUARDIAN],
      playerActiveCount: 1,
      opponentActiveCount: 1,
      battleType: 'single'
    };
    engine = new MultiBattleEngine(config);
  });

  describe('Battle Initialization', () => {
    it('should initialize single battle correctly', () => {
      const state = engine.getState();
      
      expect(state.turn).toBe(1);
      expect(state.phase).toBe('selection');
      expect(state.activePiclets.player).toHaveLength(2);
      expect(state.activePiclets.opponent).toHaveLength(2);
      
      // First position should be active, second should be null
      expect(state.activePiclets.player[0]).not.toBeNull();
      expect(state.activePiclets.player[1]).toBeNull();
      expect(state.activePiclets.opponent[0]).not.toBeNull();
      expect(state.activePiclets.opponent[1]).toBeNull();
    });

    it('should initialize double battle correctly', () => {
      const doubleConfig: MultiBattleConfig = {
        playerParty: [STELLAR_WOLF, BERSERKER_BEAST],
        opponentParty: [TOXIC_CRAWLER, AQUA_GUARDIAN],
        playerActiveCount: 2,
        opponentActiveCount: 2,
        battleType: 'double'
      };
      
      const doubleEngine = new MultiBattleEngine(doubleConfig);
      const state = doubleEngine.getState();
      
      // Both positions should be active
      expect(state.activePiclets.player[0]).not.toBeNull();
      expect(state.activePiclets.player[1]).not.toBeNull();
      expect(state.activePiclets.opponent[0]).not.toBeNull();
      expect(state.activePiclets.opponent[1]).not.toBeNull();
    });

    it('should handle parties correctly', () => {
      const state = engine.getState();
      
      expect(state.parties.player).toHaveLength(2);
      expect(state.parties.opponent).toHaveLength(2);
      expect(state.parties.player[0].name).toBe('Stellar Wolf');
      expect(state.parties.opponent[0].name).toBe('Toxic Crawler');
    });
  });

  describe('Action Generation', () => {
    it('should generate valid move actions for active Piclets', () => {
      const actions = engine.getValidActions('player');
      
      // Should have move actions for the active Piclet
      const moveActions = actions.filter(a => a.type === 'move');
      expect(moveActions.length).toBeGreaterThan(0);
      
      // All move actions should be for position 0 (the active Piclet)
      moveActions.forEach(action => {
        expect((action as any).position).toBe(0);
      });
    });

    it('should generate switch actions for party members', () => {
      const actions = engine.getValidActions('player');
      
      const switchActions = actions.filter(a => a.type === 'switch');
      expect(switchActions.length).toBeGreaterThan(0);
      
      // Should be able to switch the inactive party member into position 0
      const switchToPosition0 = switchActions.find(a => 
        (a as any).position === 0 && (a as any).partyIndex === 1
      );
      expect(switchToPosition0).toBeDefined();
    });
  });

  describe('Single Battle Execution', () => {
    it('should execute a single battle turn correctly', () => {
      const turnActions: TurnActions = {
        player: [{
          type: 'move',
          side: 'player',
          position: 0,
          moveIndex: 0 // Tackle
        }],
        opponent: [{
          type: 'move',
          side: 'opponent',
          position: 0,
          moveIndex: 0 // Tackle
        }]
      };

      const initialOpponentHp = engine.getState().activePiclets.opponent[0]!.currentHp;
      engine.executeTurn(turnActions);
      
      const finalOpponentHp = engine.getState().activePiclets.opponent[0]!.currentHp;
      expect(finalOpponentHp).toBeLessThan(initialOpponentHp);
      
      const log = engine.getLog();
      expect(log.some(msg => msg.includes('used Tackle'))).toBe(true);
    });

    it('should handle switch actions correctly', () => {
      const turnActions: TurnActions = {
        player: [{
          type: 'switch',
          side: 'player',
          position: 0,
          partyIndex: 1 // Switch to Berserker Beast
        }],
        opponent: [{
          type: 'move',
          side: 'opponent',
          position: 0,
          moveIndex: 0
        }]
      };

      const initialName = engine.getState().activePiclets.player[0]!.definition.name;
      engine.executeTurn(turnActions);
      const finalName = engine.getState().activePiclets.player[0]!.definition.name;
      
      expect(initialName).toBe('Stellar Wolf');
      expect(finalName).toBe('Berserker Beast');
      
      const log = engine.getLog();
      expect(log.some(msg => msg.includes('switched out'))).toBe(true);
      expect(log.some(msg => msg.includes('switched in'))).toBe(true);
    });
  });

  describe('Double Battle System', () => {
    let doubleEngine: MultiBattleEngine;

    beforeEach(() => {
      const doubleConfig: MultiBattleConfig = {
        playerParty: [STELLAR_WOLF, BERSERKER_BEAST],
        opponentParty: [TOXIC_CRAWLER, AQUA_GUARDIAN],
        playerActiveCount: 2,
        opponentActiveCount: 2,
        battleType: 'double'
      };
      doubleEngine = new MultiBattleEngine(doubleConfig);
    });

    it('should execute double battle turns correctly', () => {
      const turnActions: TurnActions = {
        player: [
          {
            type: 'move',
            side: 'player',
            position: 0,
            moveIndex: 0 // Stellar Wolf uses Tackle
          },
          {
            type: 'move',
            side: 'player',
            position: 1,
            moveIndex: 0 // Berserker Beast uses Tackle
          }
        ],
        opponent: [
          {
            type: 'move',
            side: 'opponent',
            position: 0,
            moveIndex: 0 // Toxic Crawler uses Tackle
          },
          {
            type: 'move',
            side: 'opponent',
            position: 1,
            moveIndex: 0 // Aqua Guardian uses Tackle
          }
        ]
      };

      doubleEngine.executeTurn(turnActions);
      
      const log = doubleEngine.getLog();
      expect(log.some(msg => msg.includes('Stellar Wolf used'))).toBe(true);
      expect(log.some(msg => msg.includes('Berserker Beast used'))).toBe(true);
      expect(log.some(msg => msg.includes('Toxic Crawler used'))).toBe(true);
      expect(log.some(msg => msg.includes('Aqua Guardian used'))).toBe(true);
    });

    it('should handle mixed actions in double battles', () => {
      const turnActions: TurnActions = {
        player: [
          {
            type: 'move',
            side: 'player',
            position: 0,
            moveIndex: 0 // Attack
          },
          {
            type: 'switch',
            side: 'player',
            position: 1,
            partyIndex: 0 // This would be switching to same Piclet, but tests the system
          }
        ],
        opponent: [
          {
            type: 'move',
            side: 'opponent',
            position: 0,
            moveIndex: 0
          },
          {
            type: 'move',
            side: 'opponent',
            position: 1,
            moveIndex: 0
          }
        ]
      };

      doubleEngine.executeTurn(turnActions);
      
      const log = doubleEngine.getLog();
      expect(log.some(msg => msg.includes('used'))).toBe(true);
    });
  });

  describe('Action Priority System', () => {
    it('should prioritize switch actions over moves', () => {
      const doubleConfig: MultiBattleConfig = {
        playerParty: [STELLAR_WOLF, BERSERKER_BEAST],
        opponentParty: [TOXIC_CRAWLER, AQUA_GUARDIAN],
        playerActiveCount: 2,
        opponentActiveCount: 2,
        battleType: 'double'
      };
      const doubleEngine = new MultiBattleEngine(doubleConfig);

      const turnActions: TurnActions = {
        player: [
          {
            type: 'move',
            side: 'player',
            position: 0,
            moveIndex: 0 // Regular move
          }
        ],
        opponent: [
          {
            type: 'switch',
            side: 'opponent',
            position: 0,
            partyIndex: 1 // Switch action (should go first)
          }
        ]
      };

      doubleEngine.executeTurn(turnActions);
      
      const log = doubleEngine.getLog();
      const switchIndex = log.findIndex(msg => msg.includes('switched'));
      const moveIndex = log.findIndex(msg => msg.includes('used'));
      
      // Switch should happen before move (if both occurred)
      if (switchIndex !== -1 && moveIndex !== -1) {
        expect(switchIndex).toBeLessThan(moveIndex);
      }
    });

    it('should use speed for same priority actions', () => {
      // Stellar Wolf (speed 70) vs Toxic Crawler (speed 55)
      const turnActions: TurnActions = {
        player: [{
          type: 'move',
          side: 'player',
          position: 0,
          moveIndex: 0 // Tackle (priority 0)
        }],
        opponent: [{
          type: 'move',
          side: 'opponent',
          position: 0,
          moveIndex: 0 // Tackle (priority 0)
        }]
      };

      engine.executeTurn(turnActions);
      
      const log = engine.getLog();
      const stellarIndex = log.findIndex(msg => msg.includes('Stellar Wolf used'));
      const toxicIndex = log.findIndex(msg => msg.includes('Toxic Crawler used'));
      
      // Stellar Wolf should go first due to higher speed
      expect(stellarIndex).toBeLessThan(toxicIndex);
    });
  });

  describe('Victory Conditions', () => {
    it('should end battle when all opponent Piclets faint', () => {
      // Create a battle with single-Piclet opponent party (no reserves)
      const singleOpponentConfig: MultiBattleConfig = {
        playerParty: [STELLAR_WOLF, BERSERKER_BEAST],
        opponentParty: [TOXIC_CRAWLER], // Only one Piclet, no reserves
        playerActiveCount: 1,
        opponentActiveCount: 1,
        battleType: 'single'
      };
      const singleEngine = new MultiBattleEngine(singleOpponentConfig);
      
      // Set opponent to very low HP
      (singleEngine as any).state.activePiclets.opponent[0]!.currentHp = 1;
      
      const turnActions: TurnActions = {
        player: [{
          type: 'move',
          side: 'player',
          position: 0,
          moveIndex: 0
        }],
        opponent: [{
          type: 'move',
          side: 'opponent',
          position: 0,
          moveIndex: 0
        }]
      };

      singleEngine.executeTurn(turnActions);
      
      expect(singleEngine.isGameOver()).toBe(true);
      expect(singleEngine.getWinner()).toBe('player');
    });

    it('should continue battle when reserves are available', () => {
      // This test would require implementing automatic switching
      // when a Piclet faints, which is more complex
      expect(true).toBe(true); // Placeholder
    });
  });

  describe('Targeting System', () => {
    it('should target opponents correctly in single battles', () => {
      const turnActions: TurnActions = {
        player: [{
          type: 'move',
          side: 'player',
          position: 0,
          moveIndex: 0 // Attack should hit opponent
        }],
        opponent: [{
          type: 'move',
          side: 'opponent',
          position: 0,
          moveIndex: 0
        }]
      };

      const initialHp = engine.getState().activePiclets.opponent[0]!.currentHp;
      engine.executeTurn(turnActions);
      const finalHp = engine.getState().activePiclets.opponent[0]!.currentHp;
      
      expect(finalHp).toBeLessThan(initialHp);
    });

    it('should target all opponents in double battles', () => {
      const doubleConfig: MultiBattleConfig = {
        playerParty: [STELLAR_WOLF, BERSERKER_BEAST],
        opponentParty: [TOXIC_CRAWLER, AQUA_GUARDIAN],
        playerActiveCount: 2,
        opponentActiveCount: 2,
        battleType: 'double'
      };
      const doubleEngine = new MultiBattleEngine(doubleConfig);

      // Create a multi-target move for testing
      const multiTargetMove = {
        name: 'Mass Strike',
        type: 'normal' as any,
        power: 30,
        accuracy: 100,
        pp: 10,
        priority: 0,
        flags: [] as any,
        effects: [{
          type: 'damage' as any,
          target: 'allOpponents' as any,
          amount: 'normal' as any
        }]
      };

      // Add the move to the attacker
      (doubleEngine as any).state.activePiclets.player[0].moves[0] = {
        move: multiTargetMove,
        currentPP: 10
      };

      const initialHp1 = doubleEngine.getState().activePiclets.opponent[0]!.currentHp;
      const initialHp2 = doubleEngine.getState().activePiclets.opponent[1]!.currentHp;

      const turnActions: TurnActions = {
        player: [{
          type: 'move',
          side: 'player',
          position: 0,
          moveIndex: 0 // Multi-target move
        }],
        opponent: [
          { type: 'move', side: 'opponent', position: 0, moveIndex: 0 },
          { type: 'move', side: 'opponent', position: 1, moveIndex: 0 }
        ]
      };

      doubleEngine.executeTurn(turnActions);

      const finalHp1 = doubleEngine.getState().activePiclets.opponent[0]!.currentHp;
      const finalHp2 = doubleEngine.getState().activePiclets.opponent[1]!.currentHp;

      // Both opponents should take damage
      expect(finalHp1).toBeLessThan(initialHp1);
      expect(finalHp2).toBeLessThan(initialHp2);
    });

    it('should target self correctly', () => {
      // Create a self-targeting move (like heal)
      const selfTargetMove = {
        name: 'Self Heal',
        type: 'normal' as any,
        power: 0,
        accuracy: 100,
        pp: 10,
        priority: 0,
        flags: [] as any,
        effects: [{
          type: 'heal' as any,
          target: 'self' as any,
          amount: 'medium' as any
        }]
      };

      // Damage the Piclet first then heal
      (engine as any).state.activePiclets.player[0].currentHp = 50;
      
      // Add the heal move
      (engine as any).state.activePiclets.player[0].moves[0] = {
        move: selfTargetMove,
        currentPP: 10
      };

      const initialHp = engine.getState().activePiclets.player[0]!.currentHp;

      const turnActions: TurnActions = {
        player: [{
          type: 'move',
          side: 'player',
          position: 0,
          moveIndex: 0 // Self-heal move
        }],
        opponent: [{
          type: 'move',
          side: 'opponent',
          position: 0,
          moveIndex: 0
        }]
      };

      engine.executeTurn(turnActions);

      const finalHp = engine.getState().activePiclets.player[0]!.currentHp;
      
      // Player should have more HP after healing
      expect(finalHp).toBeGreaterThan(initialHp);
    });
  });

  describe('Status Effects in Multi-Battle', () => {
    it('should process status effects for all active Piclets', () => {
      const doubleConfig: MultiBattleConfig = {
        playerParty: [STELLAR_WOLF, BERSERKER_BEAST],
        opponentParty: [TOXIC_CRAWLER, AQUA_GUARDIAN],
        playerActiveCount: 2,
        opponentActiveCount: 2,
        battleType: 'double'
      };
      const doubleEngine = new MultiBattleEngine(doubleConfig);

      // Apply poison to both active player Piclets
      (doubleEngine as any).state.activePiclets.player[0]!.statusEffects.push('poison');
      (doubleEngine as any).state.activePiclets.player[1]!.statusEffects.push('poison');

      const turnActions: TurnActions = {
        player: [
          { type: 'move', side: 'player', position: 0, moveIndex: 0 },
          { type: 'move', side: 'player', position: 1, moveIndex: 0 }
        ],
        opponent: [
          { type: 'move', side: 'opponent', position: 0, moveIndex: 0 },
          { type: 'move', side: 'opponent', position: 1, moveIndex: 0 }
        ]
      };

      doubleEngine.executeTurn(turnActions);
      
      const log = doubleEngine.getLog();
      const poisonMessages = log.filter(msg => msg.includes('hurt by poison'));
      expect(poisonMessages.length).toBe(2); // Both Piclets should take poison damage
    });
  });

  describe('Active Piclet Tracking', () => {
    it('should correctly track active Piclets', () => {
      const actives = engine.getActivePiclets();
      
      expect(actives.player).toHaveLength(1);
      expect(actives.opponent).toHaveLength(1);
      expect(actives.player[0].definition.name).toBe('Stellar Wolf');
      expect(actives.opponent[0].definition.name).toBe('Toxic Crawler');
    });

    it('should update active tracking after switches', () => {
      const turnActions: TurnActions = {
        player: [{
          type: 'switch',
          side: 'player',
          position: 0,
          partyIndex: 1 // Switch to Berserker Beast
        }],
        opponent: [{
          type: 'move',
          side: 'opponent',
          position: 0,
          moveIndex: 0
        }]
      };

      engine.executeTurn(turnActions);
      
      const actives = engine.getActivePiclets();
      expect(actives.player[0].definition.name).toBe('Berserker Beast');
    });
  });

  describe('Party Management', () => {
    it('should track available switches correctly', () => {
      const availableSwitches = engine.getAvailableSwitches('player');
      
      expect(availableSwitches).toHaveLength(1);
      expect(availableSwitches[0].piclet.name).toBe('Berserker Beast');
      expect(availableSwitches[0].partyIndex).toBe(1);
    });

    it('should update available switches after switching', () => {
      const turnActions: TurnActions = {
        player: [{
          type: 'switch',
          side: 'player',
          position: 0,
          partyIndex: 1 // Switch to Berserker Beast
        }],
        opponent: [{
          type: 'move',
          side: 'opponent',
          position: 0,
          moveIndex: 0
        }]
      };

      engine.executeTurn(turnActions);
      
      const availableSwitches = engine.getAvailableSwitches('player');
      expect(availableSwitches).toHaveLength(1);
      expect(availableSwitches[0].piclet.name).toBe('Stellar Wolf');
      expect(availableSwitches[0].partyIndex).toBe(0);
    });

    it('should handle fainted Piclets correctly', () => {
      // Set player Piclet to very low HP
      (engine as any).state.activePiclets.player[0]!.currentHp = 1;

      const turnActions: TurnActions = {
        player: [{
          type: 'move',
          side: 'player',
          position: 0,
          moveIndex: 0
        }],
        opponent: [{
          type: 'move',
          side: 'opponent',
          position: 0,
          moveIndex: 0 // This should cause player to faint
        }]
      };

      engine.executeTurn(turnActions);
      
      const log = engine.getLog();
      expect(log.some(msg => msg.includes('fainted!'))).toBe(true);
      
      // Active Piclet should be removed (null)
      const state = engine.getState();
      expect(state.activePiclets.player[0]).toBeNull();
    });

  });

  describe('Edge Cases', () => {
    it('should handle empty action arrays gracefully', () => {
      const turnActions: TurnActions = {
        player: [],
        opponent: [{
          type: 'move',
          side: 'opponent',
          position: 0,
          moveIndex: 0
        }]
      };

      expect(() => {
        engine.executeTurn(turnActions);
      }).not.toThrow();
    });

    it('should handle invalid positions gracefully', () => {
      const turnActions: TurnActions = {
        player: [{
          type: 'move',
          side: 'player',
          position: 1, // Invalid position (empty slot)
          moveIndex: 0
        }],
        opponent: [{
          type: 'move',
          side: 'opponent',
          position: 0,
          moveIndex: 0
        }]
      };

      expect(() => {
        engine.executeTurn(turnActions);
      }).not.toThrow();
    });
  });
});