import knex, { Knex } from 'knex'
import knexStringcase from 'knex-stringcase'

import { KnexTransaction, KnexTransactionImpl } from './KnexTransaction.js'
import { Database } from '../../Database.js'
import type { DbConfig } from '../../types.js'

/**
 * Represents a KnexDatabase class that extends Database and provides methods for interacting with a Knex database.
 */
export class KnexDatabase extends Database<KnexTransaction> {
  /**
   * A static property that provides a Knex instance based on the given configuration.
   * @param {knex.Knex.Config<any>} config - The configuration object for Knex.
   * @returns {knex.Knex<any, unknown[]>} A Knex instance based on the provided configuration.
   */
  private static knexProvider: (config: knex.Knex.Config<any>) => knex.Knex<any, unknown[]> = knex
  /**
   * Represents a Knex client for interacting with a database.
   * @type {Knex}
   */
  public readonly client: Knex

  /**
   * Constructor for creating a new instance of a database connection using Knex.
   * @param {DbConfig<'knex'>} config - The configuration object for the Knex database.
   * @returns None
   */
  constructor(config: DbConfig<'knex'>) {
    super(config)

    this.client = KnexDatabase.knexProvider(this.constructConfig(config))
  }

  /**
   * Constructs a Knex configuration object based on the provided DbConfig.
   * @param {DbConfig<'knex'>} config - The database configuration object.
   * @returns The Knex configuration object with appropriate settings based on the input config.
   */
  private constructConfig(config: DbConfig<'knex'>) {
    const knexConfig = {
      client: config.driver,
      connection: {
        host: config.host,
        port: config.port,
        user: config.username,
        password: config.password,
        database: config.database,
      },
      pool: {
        min: 1,
        max: config.maxConnections,
      },
    }

    return config.convertCamelToSnake ? knexStringcase(knexConfig) : knexConfig
  }

  /**
   * Override method to start a new transaction using KnexTransactionImpl.
   * @returns {Promise<KnexTransaction>} A promise that resolves to a KnexTransaction object.
   */
  public override async transaction(): Promise<KnexTransaction> {
    return await KnexTransactionImpl.newTransaction(this.client, this)
  }
}