package scheduler

import (
	"context"
	"testing"
	"time"

	"github.com/stretchr/testify/assert"
)

func TestScheduler(t *testing.T) {
	ctx := context.Background()

	var buf int

	s := NewSchedulerCycle(ctx, 1)
	taskID := s.Delay(func(ctx context.Context) (any, error) {
		time.Sleep(50 * time.Millisecond)
		buf += 1
		return nil, nil
	}, WithExecInterval(2*time.Millisecond))

	assert.NotEmpty(t, taskID)
	assert.False(t, s.TasksDone())

	time.Sleep(2 * time.Millisecond)

	details := s.GetTaskDetails(taskID)
	assert.Equal(t, "running", details.State)
	assert.LessOrEqual(t, details.ElapsedTime, 50*time.Millisecond)

	time.Sleep(50 * time.Millisecond)

	assert.True(t, s.TasksDone())
}

func TestSchedulerLoad(t *testing.T) {
	ctx := context.Background()

	s := NewSchedulerCycle(ctx, 1)

	for i := 0; i < 500; i++ {
		s.Delay(func(ctx context.Context) (any, error) {
			time.Sleep(1 * time.Millisecond)
			return nil, nil
		}, WithExecInterval(1*time.Millisecond))
	}

	assert.Eventually(t, func() bool {
		return s.TasksDone()
	}, time.Second, 250*time.Millisecond)
}

func TestSchedulerExecInterval(t *testing.T) {
	ctx := context.Background()

	s := NewSchedulerCycle(ctx, 1)

	s.Delay(
		func(ctx context.Context) (any, error) {
			return nil, ErrJobNotCompletedYet
		},
		WithMaxDuration(50*time.Millisecond),
		WithExecInterval(2*time.Millisecond),
	)

	time.Sleep(100 * time.Millisecond)

	assert.True(t, s.TasksDone())
}

func TestSchedulerContextDone(t *testing.T) {
	ctx, fnCancel := context.WithCancel(context.Background())

	s := NewSchedulerCycle(ctx, 1)

	for i := 0; i < 250; i++ {
		s.Delay(
			func(ctx context.Context) (any, error) {
				return nil, ErrJobNotCompletedYet
			},
			WithMaxDuration(100*time.Millisecond),
			WithExecInterval(2*time.Millisecond),
		)
	}

	go func() {
		time.Sleep(50 * time.Millisecond)
		fnCancel()
	}()

	<-s.Done()
}