package waiterr_test

import (
	"errors"
	"testing"
	"testing/synctest"

	"github.com/nalgeon/be"

	"codeberg.org/danjones000/waiterr"
)

func TestGo(t *testing.T) {
	we := waiterr.New()
	err := errors.New("uh-oh")
	var run bool
	we.Go(func() error {
		run = true
		return err
	})

	be.Err(t, we.Wait(), err)
	be.True(t, run)
}

func TestWait(t *testing.T) {
	we := waiterr.New()
	er1 := errors.New("uh-oh")
	er2 := errors.New("oops")
	we.Go(func() error { return er1 })
	we.Go(func() error { return nil })
	we.Go(func() error { return er2 })

	err := we.Wait()
	be.Err(t, err, er1, er2)
	if ers, ok := err.(interface{ Unwrap() []error }); ok {
		all := ers.Unwrap()
		be.Equal(t, len(all), 2)
		be.True(t, all[0] == er1 || all[0] == er2)
		be.True(t, all[1] == er2 || all[1] == er1)
	} else {
		t.Fatal("Returned error should have Unwrap method")
	}
}

func TestWaitForError(tt *testing.T) {
	tt.Run("first error", func(t *testing.T) {
		we := waiterr.New()
		er1 := errors.New("uh-oh")
		er2 := errors.New("oops")
		we.Go(func() error { return nil })
		we.Go(func() error { return er1 })
		we.Go(func() error { return er2 })

		err := we.WaitForError()
		// Due to how goroutines run, it is possible that either of those return first. This is an acceptable limitation
		be.True(t, err == er1 || err == er2)
	})

	tt.Run("no error", func(t *testing.T) {
		we := waiterr.New()
		we.Go(func() error { return nil })
		we.Go(func() error { return nil })
		we.Go(func() error { return nil })

		err := we.WaitForError()
		be.Err(t, err, nil)
	})

	tt.Run("first error set", func(tt2 *testing.T) {
		we := waiterr.New()
		expectedErr := errors.New("pre-set error")

		synctest.Test(tt2, func(t *testing.T) {
			we.Go(func() error { return expectedErr })
			// synctest.Wait ensures that the gorouting has finished before anything else.
			synctest.Wait()

			we.Go(func() error { return errors.New("another error") })
			synctest.Wait()

			we.Go(func() error { return nil })

			actualErr := we.WaitForError()
			be.Err(t, actualErr, expectedErr)
		})
	})
}

func TestUnwrap(tt *testing.T) {
	tt.Run("two errors", func(t *testing.T) {
		we := waiterr.New()
		er1 := errors.New("error one")
		er2 := errors.New("error two")

		we.Go(func() error { return er1 })
		we.Go(func() error { return nil })
		we.Go(func() error { return er2 })
		we.Go(func() error { return nil })

		_ = we.Wait() // Ensure all goroutines complete

		unwrapped := we.Unwrap()
		be.Equal(t, len(unwrapped), 2)
		be.True(t, (unwrapped[0] == er1 && unwrapped[1] == er2) || (unwrapped[0] == er2 && unwrapped[1] == er1))

	})

	tt.Run("no errors", func(t *testing.T) {
		weNoErr := waiterr.New()
		weNoErr.Go(func() error { return nil })
		weNoErr.Go(func() error { return nil })
		_ = weNoErr.Wait()
		be.Equal(t, weNoErr.Unwrap(), nil)
	})
}