import sqlite3 from 'sqlite3';
import {RdbmsConnection} from '@shopify/shopify-app-session-storage';

export class SqliteConnection implements RdbmsConnection {
  sessionStorageIdentifier: string;
  private ready: Promise<void>;
  private db: sqlite3.Database;

  constructor(
    database: string | sqlite3.Database,
    sessionStorageIdentifier: string,
  ) {
    this.sessionStorageIdentifier = sessionStorageIdentifier;
    this.ready = this.init(database);
  }

  async query(query: string, params: any[] = []): Promise<any[]> {
    await this.ready;

    return new Promise((resolve, reject) => {
      this.db.all(query, params, (err, result) => {
        if (err) {
          reject(err);
          return;
        }
        resolve(result);
      });
    });
  }

  async executeRawQuery(query: string): Promise<void> {
    await this.ready;

    return new Promise((resolve, reject) => {
      this.db.exec(query, (err: Error) => {
        if (err) {
          reject(err);
          return;
        }
        resolve();
      });
    });
  }

  async hasTable(tablename: string): Promise<boolean> {
    await this.ready;

    const query = `
    SELECT name FROM sqlite_schema
    WHERE
      type = 'table' AND
      name = ${this.getArgumentPlaceholder()};
    `;
    const rows = await this.query(query, [tablename]);
    return rows.length === 1;
  }

  getArgumentPlaceholder(_?: number): string {
    return `?`;
  }

  async connect(): Promise<void> {
    await this.ready;

    // Nothing to do here
    return Promise.resolve();
  }

  async disconnect(): Promise<void> {
    await this.ready;

    // Nothing to do here
    return Promise.resolve();
  }

  private async init(database: string | sqlite3.Database): Promise<void> {
    this.db =
      typeof database === 'string' ? new sqlite3.Database(database) : database;
  }
}