'use strict'

const { loadTesters } = require('../../services')

/**
 * Load a collection of ServiceTester objects and register them with Mocha.
 */
class Runner {
  /**
   * Function to invoke before each test. This is a stub which can be
   * overridden on instances.
   */
  beforeEach() {}

  /**
   * Prepare the runner by loading up all the ServiceTester objects.
   */
  prepare() {
    this.testers = loadTesters()
    this.testers.forEach(tester => {
      tester.beforeEach = () => {
        this.beforeEach()
      }
    })
  }

  _testersForService(service) {
    return this.testers.filter(t => t.id.toLowerCase().startsWith(service))
  }

  /**
   * Limit the test run to the specified services.
   *
   * @param services An array of service id prefixes to run
   */
  only(services) {
    const normalizedServices = new Set(services.map(v => v.toLowerCase()))

    const missingServices = []
    normalizedServices.forEach(service => {
      const testers = this._testersForService(service)

      if (testers.length === 0) {
        missingServices.push(service)
      }

      testers.forEach(tester => {
        tester.only()
      })
    })

    // Throw at the end, to provide a better error message.
    if (missingServices.length > 0) {
      throw Error('Unknown services: ' + missingServices.join(', '))
    }
  }

  /**
   * Register the tests with Mocha.
   */
  toss() {
    this.testers.forEach(tester => {
      tester.toss()
    })
  }
}
module.exports = Runner