package mrun

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

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

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

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

	wait := func(ctx mctx.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 := mctx.New()
				Thread(ctx, func(mctx.Context) error { return nil })
				if err := Wait(ctx, nil); err != nil {
					t.Fatal(err)
				}
			})

			t.Run("err", func(t *T) {
				ctx := mctx.New()
				Thread(ctx, func(mctx.Context) 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 := mctx.New()
				Thread(ctx, func(mctx.Context) 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 := mctx.New()
				Thread(ctx, func(mctx.Context) 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 := mctx.New()
				Thread(ctx, func(mctx.Context) 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() (mctx.Context, mctx.Context) {
		ctx := mctx.New()
		return ctx, mctx.ChildOf(ctx, "child")
	}

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

			t.Run("err", func(t *T) {
				ctx, childCtx := ctxWithChild()
				Thread(childCtx, func(mctx.Context) 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, childCtx := ctxWithChild()
				Thread(childCtx, func(mctx.Context) 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, childCtx := ctxWithChild()
				Thread(childCtx, func(mctx.Context) 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, childCtx := ctxWithChild()
				Thread(childCtx, func(mctx.Context) 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)
				}
			})
		})
	})
}

func TestEvent(t *T) {
	ch := make(chan int, 10)
	ctx := mctx.New()
	ctxChild := mctx.ChildOf(ctx, "child")

	mkHook := func(i int) Hook {
		return func(mctx.Context) error {
			ch <- i
			return nil
		}
	}

	OnEvent(ctx, 0, mkHook(0))
	OnEvent(ctxChild, 0, mkHook(1))
	OnEvent(ctx, 0, mkHook(2))

	bogusErr := errors.New("bogus error")
	OnEvent(ctxChild, 0, func(mctx.Context) error { return bogusErr })

	OnEvent(ctx, 0, mkHook(3))
	OnEvent(ctx, 0, mkHook(4))

	massert.Fatal(t, massert.All(
		massert.Equal(bogusErr, TriggerEvent(ctx, 0)),
		massert.Equal(0, <-ch),
		massert.Equal(1, <-ch),
		massert.Equal(2, <-ch),
	))

	// after the error the 3 and 4 Hooks should still be registered, but not
	// called yet.

	select {
	case <-ch:
		t.Fatal("Hooks should not have been called yet")
	default:
	}

	massert.Fatal(t, massert.All(
		massert.Nil(TriggerEvent(ctx, 0)),
		massert.Equal(3, <-ch),
		massert.Equal(4, <-ch),
	))
}