import { TaskManager } from "./task_manager.mjs";
import { Transaction } from "./transaction.mjs";
import { query } from "./query.mjs";


export class Database {
  constructor(dbName, adapter) {
    this.dbName = dbName;
    this.adapter = adapter;
    this.version = null;
    this.path = null;

    this.taskManager = new TaskManager();
  }

  async open() {
    let response = await this.adapter.open(this.dbName);

    if (response) {
      if (response.hasOwnProperty('version')) {
        this.version = response.version;
      }
      if (response.hasOwnProperty('path')) {
        this.path = response.path;
      }
    }

    // Allow chaining
    return this;
  }

  close() {
    return this.adapter.close(this.dbName);
  }

  transaction() {
    return new Transaction(
      this.dbName,
      this.adapter,
      this.taskManager.enqueue.bind(this.taskManager)
    );
  }

  async autoTransaction(cb, inheritTx) {
    let tx = inheritTx || this.transaction();
    let result;

    try {
      result = await cb(tx);
    } catch (e) {
      if (!inheritTx) {
        await tx.rollback();
      }
      throw e;
    }

    if (!inheritTx) {
      await tx.commit();
    }

    return result;
  }


  // Execute a single SQL statement
  async sql(sql, ...args) {
    const completeCb = await this.taskManager.enqueue();

    let result;
    let error;
    try {
      result = await this.adapter.sql(this.dbName, ...query(sql, ...args));
    } catch (e) {
      error = e;
    }
    completeCb();

    if (error) {
      throw error;
    }
    return new Result(result);
  }
}