import { describe, it, expect } from 'vitest';
import { createPart, createParts, createPartPool, mergePartPools, PartPool } from '@/core/part-factory';

describe('createPart', () => {
  it('should create a part with given template and id', () => {
    const part = createPart<{ player: string }>(
      { regionId: 'board', position: [1, 2], player: 'X' },
      'piece-1'
    );
    expect(part.id).toBe('piece-1');
    expect(part.regionId).toBe('board');
    expect(part.position).toEqual([1, 2]);
    expect(part.player).toBe('X');
  });

  it('should apply default values for regionId and position when not provided', () => {
    const part = createPart({}, 'piece-1');
    expect(part.regionId).toBe('');
    expect(part.position).toEqual([]);
  });

  it('should allow overriding default values', () => {
    const part = createPart({ regionId: 'custom', position: [0] }, 'piece-1');
    expect(part.regionId).toBe('custom');
    expect(part.position).toEqual([0]);
  });

  it('should preserve metadata fields', () => {
    type TestMeta = { type: string; count: number };
    const part = createPart<TestMeta>(
      { regionId: 'board', position: [0], type: 'kitten', count: 5 },
      'piece-1'
    );
    expect(part.type).toBe('kitten');
    expect(part.count).toBe(5);
  });
});

describe('createParts', () => {
  it('should create multiple parts with auto-generated IDs', () => {
    const parts = createParts(
      { regionId: 'deck', position: [] },
      3,
      'card'
    );
    expect(parts.length).toBe(3);
    expect(parts[0].id).toBe('card-1');
    expect(parts[1].id).toBe('card-2');
    expect(parts[2].id).toBe('card-3');
  });

  it('should create parts with identical properties', () => {
    const parts = createParts(
      { regionId: 'deck', position: [], type: 'token' },
      2,
      'token'
    );
    expect(parts[0].regionId).toBe('deck');
    expect(parts[1].regionId).toBe('deck');
    expect(parts[0].type).toBe('token');
    expect(parts[1].type).toBe('token');
  });

  it('should create zero parts when count is 0', () => {
    const parts = createParts({}, 0, 'empty');
    expect(parts.length).toBe(0);
  });
});

describe('createPartPool', () => {
  it('should create a pool with specified count', () => {
    const pool = createPartPool(
      { regionId: 'supply', position: [] },
      5,
      'token'
    );
    expect(pool.remaining()).toBe(5);
    expect(Object.keys(pool.parts).length).toBe(5);
  });

  it('should generate parts with correct IDs', () => {
    const pool = createPartPool({}, 3, 'piece');
    expect(pool.parts['piece-1']).toBeDefined();
    expect(pool.parts['piece-2']).toBeDefined();
    expect(pool.parts['piece-3']).toBeDefined();
  });

  it('should draw parts from the pool', () => {
    const pool = createPartPool({}, 2, 'card');
    const drawn = pool.draw();
    expect(drawn).toBeDefined();
    expect(drawn!.id).toBe('card-2');
    expect(pool.remaining()).toBe(1);
  });

  it('should return undefined when pool is empty', () => {
    const pool = createPartPool({}, 1, 'card');
    pool.draw();
    const drawn = pool.draw();
    expect(drawn).toBeUndefined();
  });

  it('should return part to pool', () => {
    const pool = createPartPool({ regionId: 'board', position: [0, 0] }, 1, 'card');
    const drawn = pool.draw();
    expect(pool.remaining()).toBe(0);

    pool.return(drawn!);
    expect(pool.remaining()).toBe(1);
    expect(drawn!.regionId).toBe('');
    expect(drawn!.position).toEqual([]);
  });

  it('should store parts as Record keyed by ID', () => {
    const pool = createPartPool({}, 2, 'piece');
    expect(typeof pool.parts).toBe('object');
    expect(pool.parts['piece-1']).toBeDefined();
    expect(pool.parts['piece-2']).toBeDefined();
  });
});

describe('mergePartPools', () => {
  it('should merge multiple pools', () => {
    const pool1 = createPartPool({ regionId: 'deck1', position: [] }, 2, 'card1');
    const pool2 = createPartPool({ regionId: 'deck2', position: [] }, 3, 'card2');
    const merged = mergePartPools(pool1, pool2);

    expect(Object.keys(merged.parts).length).toBe(5);
    // Parts with regionId: '' are available; pool parts have regionId from template
    // After merge, available = parts with regionId === ''
    expect(merged.remaining()).toBe(0); // parts have regionId: 'deck1' or 'deck2'
    expect(merged.parts['card1-1']).toBeDefined();
    expect(merged.parts['card2-3']).toBeDefined();
  });

  it('should use first pool template', () => {
    const pool1 = createPartPool({ regionId: 'deck1', position: [] }, 1, 'card1');
    const pool2 = createPartPool({ regionId: 'deck2', position: [] }, 1, 'card2');
    const merged = mergePartPools(pool1, pool2);

    expect(merged.template.regionId).toBe('deck1');
  });

  it('should return empty pool when no pools provided', () => {
    const merged = mergePartPools();
    expect(Object.keys(merged.parts).length).toBe(0);
    expect(merged.remaining()).toBe(0);
  });

  it('should only count available parts for remaining()', () => {
    const pool1 = createPartPool({}, 2, 'card');
    const pool2 = createPartPool({}, 2, 'token');

    const drawn = pool1.draw();
    drawn!.regionId = 'board';
    drawn!.position = [0, 0];

    const merged = mergePartPools(pool1, pool2);
    expect(merged.remaining()).toBe(3);
  });

  it('should handle drawing from merged pool', () => {
    const pool1 = createPartPool({}, 2, 'card');
    const pool2 = createPartPool({}, 2, 'token');
    const merged = mergePartPools(pool1, pool2);

    const drawn = merged.draw();
    expect(drawn).toBeDefined();
    expect(merged.remaining()).toBe(3);
  });
});