package workerpool

import (
	"errors"
	"sync"
	"testing"
	"time"

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

func TestNewWorkerPool(t *testing.T) {
	t.Run("default size pool", func(t *testing.T) {
		pool := NewWorkerPool(0)
		assert.NotNil(t, pool)
	})

	t.Run("custom size pool", func(t *testing.T) {
		size := 100
		pool := NewWorkerPool(size)
		assert.NotNil(t, pool)
	})
}

func TestSubmit(t *testing.T) {
	t.Run("submit task to worker pool", func(t *testing.T) {
		pool := NewWorkerPool(10)
		var wg sync.WaitGroup
		wg.Add(1)

		err := pool.Submit(func() {
			defer wg.Done()
			time.Sleep(100 * time.Millisecond)
		})
		assert.NoError(t, err)

		wg.Wait()
	})
}

func TestSubmitAndWaitAll(t *testing.T) {
	t.Run("submit and wait all tasks succeed", func(t *testing.T) {
		pool := NewWorkerPool(10)
		tasks := []func() error{
			func() error {
				time.Sleep(100 * time.Millisecond)
				return nil
			},
			func() error {
				time.Sleep(50 * time.Millisecond)
				return nil
			},
		}

		taskErrCh, submitErr := pool.SubmitAndWaitAll(tasks...)
		assert.NoError(t, submitErr)
		close(taskErrCh)
		for err := range taskErrCh {
			assert.NoError(t, err)
		}
	})

	t.Run("submit and wait all tasks with errors", func(t *testing.T) {
		pool := NewWorkerPool(10)
		expectedError := errors.New("task error")
		tasks := []func() error{
			func() error {
				time.Sleep(100 * time.Millisecond)
				return nil
			},
			func() error {
				time.Sleep(50 * time.Millisecond)
				return expectedError
			},
		}

		taskErrCh, submitErr := pool.SubmitAndWaitAll(tasks...)
		assert.NoError(t, submitErr)
		close(taskErrCh)
		foundError := false
		for err := range taskErrCh {
			if err != nil {
				foundError = true
				assert.Equal(t, expectedError, err)
			}
		}
		assert.True(t, foundError)
	})
}