package mrun

import (
	"context"
	"errors"
	. "testing"
	"time"

	"github.com/mediocregopher/mediocre-go-lib/mctx"
)

func TestThreadWait(t *T) {
	testErr := errors.New("test error")

	cancelCh := func(t time.Duration) <-chan struct{} {
		tCtx, _ := context.WithTimeout(context.Background(), t*2)
		return tCtx.Done()
	}

	wait := func(ctx context.Context, shouldTake time.Duration) error {
		start := time.Now()
		err := Wait(ctx, cancelCh(shouldTake*2))
		if took := time.Since(start); took < shouldTake || took > shouldTake*4/3 {
			t.Fatalf("wait took %v, should have taken %v", took, shouldTake)
		}
		return err
	}

	t.Run("noChildren", func(t *T) {
		t.Run("noBlock", func(t *T) {
			t.Run("noErr", func(t *T) {
				ctx := context.Background()
				ctx = WithThreads(ctx, 1, func() error { return nil })
				if err := Wait(ctx, nil); err != nil {
					t.Fatal(err)
				}
			})

			t.Run("err", func(t *T) {
				ctx := context.Background()
				ctx = WithThreads(ctx, 1, func() error { return testErr })
				if err := Wait(ctx, nil); err != testErr {
					t.Fatalf("should have got test error, got: %v", err)
				}
			})
		})

		t.Run("block", func(t *T) {
			t.Run("noErr", func(t *T) {
				ctx := context.Background()
				ctx = WithThreads(ctx, 1, func() error {
					time.Sleep(1 * time.Second)
					return nil
				})
				if err := wait(ctx, 1*time.Second); err != nil {
					t.Fatal(err)
				}
			})

			t.Run("err", func(t *T) {
				ctx := context.Background()
				ctx = WithThreads(ctx, 1, func() error {
					time.Sleep(1 * time.Second)
					return testErr
				})
				if err := wait(ctx, 1*time.Second); err != testErr {
					t.Fatalf("should have got test error, got: %v", err)
				}
			})

			t.Run("canceled", func(t *T) {
				ctx := context.Background()
				ctx = WithThreads(ctx, 1, func() error {
					time.Sleep(5 * time.Second)
					return testErr
				})
				if err := Wait(ctx, cancelCh(500*time.Millisecond)); err != ErrDone {
					t.Fatalf("should have got ErrDone, got: %v", err)
				}
			})
		})
	})

	ctxWithChild := func() (context.Context, context.Context) {
		ctx := context.Background()
		return ctx, mctx.NewChild(ctx, "child")
	}

	t.Run("children", func(t *T) {
		t.Run("noBlock", func(t *T) {
			t.Run("noErr", func(t *T) {
				ctx, childCtx := ctxWithChild()
				childCtx = WithThreads(childCtx, 1, func() error { return nil })
				ctx = mctx.WithChild(ctx, childCtx)
				if err := Wait(ctx, nil); err != nil {
					t.Fatal(err)
				}
			})

			t.Run("err", func(t *T) {
				ctx, childCtx := ctxWithChild()
				childCtx = WithThreads(childCtx, 1, func() error { return testErr })
				ctx = mctx.WithChild(ctx, childCtx)
				if err := Wait(ctx, nil); err != testErr {
					t.Fatalf("should have got test error, got: %v", err)
				}
			})
		})

		t.Run("block", func(t *T) {
			t.Run("noErr", func(t *T) {
				ctx, childCtx := ctxWithChild()
				childCtx = WithThreads(childCtx, 1, func() error {
					time.Sleep(1 * time.Second)
					return nil
				})
				ctx = mctx.WithChild(ctx, childCtx)
				if err := wait(ctx, 1*time.Second); err != nil {
					t.Fatal(err)
				}
			})

			t.Run("err", func(t *T) {
				ctx, childCtx := ctxWithChild()
				childCtx = WithThreads(childCtx, 1, func() error {
					time.Sleep(1 * time.Second)
					return testErr
				})
				ctx = mctx.WithChild(ctx, childCtx)
				if err := wait(ctx, 1*time.Second); err != testErr {
					t.Fatalf("should have got test error, got: %v", err)
				}
			})

			t.Run("canceled", func(t *T) {
				ctx, childCtx := ctxWithChild()
				childCtx = WithThreads(childCtx, 1, func() error {
					time.Sleep(5 * time.Second)
					return testErr
				})
				ctx = mctx.WithChild(ctx, childCtx)
				if err := Wait(ctx, cancelCh(500*time.Millisecond)); err != ErrDone {
					t.Fatalf("should have got ErrDone, got: %v", err)
				}
			})
		})
	})
}