import type { File } from './types';

const DB_NAME = 'csound-files-db';
const DB_VERSION = 3;
const STORE_NAME = 'files';

/**
 * Database wrapper for IndexedDB operations
 */
class FileDatabase {
  private db: IDBDatabase | null = null;
  private initPromise: Promise<void> | null = null;

  /**
   * Initialize the database connection
   */
  async init(): Promise<void> {
    if (this.db) {
      return;
    }

    if (this.initPromise) {
      return this.initPromise;
    }

    this.initPromise = new Promise((resolve, reject) => {
      const request = indexedDB.open(DB_NAME, DB_VERSION);

      request.onerror = () => {
        reject(new Error(`Failed to open database: ${request.error?.message}`));
      };

      request.onsuccess = () => {
        this.db = request.result;
        resolve();
      };

      request.onupgradeneeded = (event) => {
        const db = (event.target as IDBOpenDBRequest).result;

        // Delete old stores if they exist
        if (db.objectStoreNames.contains('projects')) {
          db.deleteObjectStore('projects');
        }
        if (db.objectStoreNames.contains('workspaces')) {
          db.deleteObjectStore('workspaces');
        }

        // Create files store if it doesn't exist
        if (!db.objectStoreNames.contains(STORE_NAME)) {
          db.createObjectStore(STORE_NAME, {
            keyPath: 'id',
          });
        }
      };
    });

    return this.initPromise;
  }

  /**
   * Ensure database is initialized
   */
  private async ensureDb(): Promise<IDBDatabase> {
    await this.init();
    if (!this.db) {
      throw new Error('Database not initialized');
    }
    return this.db;
  }

  /**
   * Get a file by ID
   */
  async get(id: string): Promise<File | null> {
    const db = await this.ensureDb();

    return new Promise((resolve, reject) => {
      const transaction = db.transaction([STORE_NAME], 'readonly');
      const store = transaction.objectStore(STORE_NAME);
      const request = store.get(id);

      request.onsuccess = () => {
        resolve(request.result || null);
      };

      request.onerror = () => {
        reject(new Error(`Failed to get file: ${request.error?.message}`));
      };
    });
  }

  /**
   * Get all files
   */
  async getAll(): Promise<File[]> {
    const db = await this.ensureDb();

    return new Promise((resolve, reject) => {
      const transaction = db.transaction([STORE_NAME], 'readonly');
      const store = transaction.objectStore(STORE_NAME);
      const request = store.getAll();

      request.onsuccess = () => {
        resolve(request.result || []);
      };

      request.onerror = () => {
        reject(new Error(`Failed to get all files: ${request.error?.message}`));
      };
    });
  }

  /**
   * Save or update a file
   */
  async put(file: File): Promise<void> {
    const db = await this.ensureDb();

    return new Promise((resolve, reject) => {
      const transaction = db.transaction([STORE_NAME], 'readwrite');
      const store = transaction.objectStore(STORE_NAME);
      const request = store.put(file);

      request.onsuccess = () => {
        resolve();
      };

      request.onerror = () => {
        reject(new Error(`Failed to save file: ${request.error?.message}`));
      };
    });
  }

  /**
   * Delete a file by ID
   */
  async delete(id: string): Promise<void> {
    const db = await this.ensureDb();

    return new Promise((resolve, reject) => {
      const transaction = db.transaction([STORE_NAME], 'readwrite');
      const store = transaction.objectStore(STORE_NAME);
      const request = store.delete(id);

      request.onsuccess = () => {
        resolve();
      };

      request.onerror = () => {
        reject(new Error(`Failed to delete file: ${request.error?.message}`));
      };
    });
  }

  /**
   * Clear all files (use with caution!)
   */
  async clear(): Promise<void> {
    const db = await this.ensureDb();

    return new Promise((resolve, reject) => {
      const transaction = db.transaction([STORE_NAME], 'readwrite');
      const store = transaction.objectStore(STORE_NAME);
      const request = store.clear();

      request.onsuccess = () => {
        resolve();
      };

      request.onerror = () => {
        reject(new Error(`Failed to clear files: ${request.error?.message}`));
      };
    });
  }

  /**
   * Close the database connection
   */
  close(): void {
    if (this.db) {
      this.db.close();
      this.db = null;
      this.initPromise = null;
    }
  }
}

export { FileDatabase };