const DatabaseManager = require('../models/database');
const fs = require('fs');
const path = require('path');

describe('Database Manager', () => {
  const testDbPath = path.join(__dirname, '..', 'test_inventory.db');

  beforeEach(() => {
    // Clean up any existing test database
    if (fs.existsSync(testDbPath)) {
      fs.unlinkSync(testDbPath);
    }
    
    // Override the database path for testing
    DatabaseManager.dbPath = testDbPath;
  });

  afterEach(() => {
    DatabaseManager.close();
    
    // Clean up test database
    if (fs.existsSync(testDbPath)) {
      fs.unlinkSync(testDbPath);
    }
  });

  test('should initialize database successfully', () => {
    expect(() => {
      DatabaseManager.initialize();
    }).not.toThrow();
    
    expect(DatabaseManager.getDatabase()).toBeDefined();
  });

  test('should create tables with correct schema', () => {
    DatabaseManager.initialize();
    const db = DatabaseManager.getDatabase();
    
    // Check if items table exists
    const itemsTable = db.prepare("SELECT name FROM sqlite_master WHERE type='table' AND name='items'").get();
    expect(itemsTable).toBeDefined();
    
    // Check if transactions table exists
    const transactionsTable = db.prepare("SELECT name FROM sqlite_master WHERE type='table' AND name='transactions'").get();
    expect(transactionsTable).toBeDefined();
  });

  test('should create indexes correctly', () => {
    DatabaseManager.initialize();
    const db = DatabaseManager.getDatabase();
    
    // Check if indexes exist
    const indexes = db.prepare("SELECT name FROM sqlite_master WHERE type='index'").all();
    const indexNames = indexes.map(idx => idx.name);
    
    expect(indexNames).toContain('idx_items_barcode');
    expect(indexNames).toContain('idx_items_name');
    expect(indexNames).toContain('idx_transactions_item_id');
    expect(indexNames).toContain('idx_transactions_created_at');
  });

  test('should handle transaction execution', () => {
    DatabaseManager.initialize();
    const db = DatabaseManager.getDatabase();
    
    const result = DatabaseManager.executeTransaction(() => {
      const insert = db.prepare('INSERT INTO items (name, quantity) VALUES (?, ?)');
      return insert.run('Test Item', 10);
    });
    
    expect(result.changes).toBe(1);
    expect(result.lastInsertRowid).toBeDefined();
  });

  test('should throw error when accessing uninitialized database', () => {
    expect(() => {
      DatabaseManager.getDatabase();
    }).toThrow('Database not initialized. Call initialize() first.');
  });
});