const metaltest = (title) => {
  const suite = []
  const only = []
  const before = []
  const after = []

  let success = 0
  let fail = 0
  const testSuccess = []
  const testFail = []

  const runner = (name, fn) => {
    suite.push({ name, fn })
  }

  runner.only = (name, fn) => { only.push({ name, fn }) }
  runner.before = (fn) => { before.push(fn) }
  runner.after = (fn) => { after.push(fn) }

  const notify = async (reporters, event, ...args) => {
    for (const reporter of reporters) {
      if (!reporter[event]) continue

      await reporter[event](...args)
    }
  }

  runner.run = async (...reporters) => {
    notify(reporters, 'start', title)
    notify(reporters, 'before')

    const tests = only.length ? only : suite
    for (const test of tests) {
      try {
        for (const fn of before) await fn()
        await test.fn()
        success++
        notify(reporters, 'success', test)
      }
      catch (error) {
        fail++

        testFail.push(Object.assign({}, test, { error }))
        notify(reporters, 'fail', test, error)
      }
    }

    for (const fn of after) await fn()
    notify(reporters, 'after')

    const stats = { title, success, fail, total: success + fail, testSuccess, testFail }
    notify(reporters, 'end', stats)

    return stats
  }

  return runner
}

export { metaltest }