package service

import (
	"context"
	"fmt"
	"log"
	"tailly_clips/internal/domain"
	"tailly_clips/internal/ffmpeg"
	"tailly_clips/internal/moderation"
	"tailly_clips/internal/repository"
	"tailly_clips/internal/storage"
	"time"
)

type ModerationClient interface {
	CheckVideoUrl(ctx context.Context, videoUrl string) (bool, error)
	Close()
}
type ClipService interface {
	CreateClip(ctx context.Context, req domain.CreateClipRequest) (*domain.Clip, error)
	GetClip(ctx context.Context, clipID int) (*domain.Clip, error)
	GetUserClips(ctx context.Context, userID, limit, offset int) ([]*domain.Clip, int, error)
	GetClips(ctx context.Context, limit, offset int) ([]*domain.Clip, int, error)
	DeleteClip(ctx context.Context, clipID, userID int) error
}

type clipService struct {
	repo           repository.ClipRepository
	storage        storage.Storage
	videoProcessor ffmpeg.VideoProcessor
	modClient      *moderation.ModerationClient
}

func NewClipService(repo repository.ClipRepository, storage storage.Storage, processor ffmpeg.VideoProcessor, modClient *moderation.ModerationClient) ClipService {
	return &clipService{
		repo:           repo,
		storage:        storage,
		videoProcessor: processor,
		modClient:      modClient,
	}
}

func (s *clipService) CreateClip(ctx context.Context, req domain.CreateClipRequest) (*domain.Clip, error) {
	const op = "service/clipService.CreateClip"

	// 1. Обрезаем видео до 30 секунд в памяти
	trimmedVideoData, err := s.videoProcessor.TrimVideo(req.VideoData, 30)
	if err != nil {
		return nil, fmt.Errorf("%s: failed to trim video: %w", op, err)
	}

	// 2. Параллельно выполняем операции
	videoURLChan := make(chan string, 1)
	videoErrChan := make(chan error, 1)
	thumbnailChan := make(chan string, 1)
	thumbnailErrChan := make(chan error, 1)
	durationChan := make(chan int, 1)
	durationErrChan := make(chan error, 1)

	// Горутина для загрузки видео в S3
	go func() {
		videoURL, err := s.storage.UploadVideo(ctx, trimmedVideoData, req.FileName, req.UserID)
		if err != nil {
			videoErrChan <- fmt.Errorf("%s: failed to upload video: %w", op, err)
			return
		}
		videoURLChan <- videoURL
	}()

	// Горутина для генерации превью
	go func() {
		thumbnailData, err := s.videoProcessor.GenerateThumbnail(trimmedVideoData)
		if err != nil {
			thumbnailErrChan <- fmt.Errorf("%s: failed to generate thumbnail: %w", op, err)
			return
		}

		thumbnailURL, err := s.storage.UploadThumbnail(ctx, thumbnailData, req.UserID)
		if err != nil {
			thumbnailErrChan <- fmt.Errorf("%s: failed to upload thumbnail: %w", op, err)
			return
		}
		thumbnailChan <- thumbnailURL
	}()

	// Горутина для получения длительности
	go func() {
		duration, err := s.videoProcessor.GetDuration(trimmedVideoData)
		if err != nil {
			durationErrChan <- fmt.Errorf("%s: failed to get duration: %w", op, err)
			return
		}
		durationChan <- duration
	}()

	// 3. Ждем результаты всех операций
	var videoURL, thumbnailURL string
	var duration int

	// Ждем загрузки видео
	select {
	case videoURL = <-videoURLChan:
	case err := <-videoErrChan:
		return nil, err
	case <-ctx.Done():
		return nil, fmt.Errorf("%s: operation cancelled", op)
	}

	// Ждем генерации превью
	select {
	case thumbnailURL = <-thumbnailChan:
	case err := <-thumbnailErrChan:
		s.storage.DeleteVideo(ctx, videoURL)
		return nil, err
	case <-ctx.Done():
		s.storage.DeleteVideo(ctx, videoURL)
		return nil, fmt.Errorf("%s: operation cancelled", op)
	}

	// Ждем получения длительности
	select {
	case duration = <-durationChan:
	case err := <-durationErrChan:
		s.storage.DeleteVideo(ctx, videoURL)
		s.storage.DeleteThumbnail(ctx, thumbnailURL)
		return nil, err
	case <-ctx.Done():
		s.storage.DeleteVideo(ctx, videoURL)
		s.storage.DeleteThumbnail(ctx, thumbnailURL)
		return nil, fmt.Errorf("%s: operation cancelled", op)
	}

	// 4. Модерируем обрезанное видео по URL
	videoAllowed, err := s.modClient.CheckVideoUrl(ctx, videoURL)
	if err != nil {
		s.storage.DeleteVideo(ctx, videoURL)
		s.storage.DeleteThumbnail(ctx, thumbnailURL)
		return nil, fmt.Errorf("%s: video moderation failed: %w", op, err)
	}
	if !videoAllowed {
		s.storage.DeleteVideo(ctx, videoURL)
		s.storage.DeleteThumbnail(ctx, thumbnailURL)
		return nil, fmt.Errorf("%s: video rejected by moderation service", op)
	}

	// 5. Создаем клип в БД
	clip := &domain.Clip{
		Title:         req.Title,
		VideoURL:      videoURL,
		ThumbnailURL:  thumbnailURL,
		Duration:      duration,
		AuthorID:      req.UserID,
		LikesCount:    0,
		CommentsCount: 0,
		CreatedAt:     time.Now(),
		UpdatedAt:     time.Now(),
	}

	if err := s.repo.Create(ctx, clip); err != nil {
		s.storage.DeleteVideo(ctx, videoURL)
		s.storage.DeleteThumbnail(ctx, thumbnailURL)
		return nil, fmt.Errorf("failed to create clip: %w", err)
	}

	return clip, nil
}

func (s *clipService) GetClip(ctx context.Context, clipID int) (*domain.Clip, error) {
	clip, err := s.repo.GetByID(ctx, clipID)
	if err != nil {
		return nil, fmt.Errorf("failed to get clip: %w", err)
	}
	return clip, nil
}

func (s *clipService) GetUserClips(ctx context.Context, userID, limit, offset int) ([]*domain.Clip, int, error) {
	clips, totalCount, err := s.repo.GetByAuthorID(ctx, userID, limit, offset)
	if err != nil {
		return nil, 0, fmt.Errorf("failed to get user clips: %w", err)
	}
	return clips, totalCount, nil
}

func (s *clipService) GetClips(ctx context.Context, limit, offset int) ([]*domain.Clip, int, error) {
	clips, totalCount, err := s.repo.GetAll(ctx, limit, offset)
	if err != nil {
		return nil, 0, fmt.Errorf("failed to get clips: %w", err)
	}
	return clips, totalCount, nil
}

func (s *clipService) DeleteClip(ctx context.Context, clipID, userID int) error {
	// Получаем клип для проверки прав и получения URL
	clip, err := s.repo.GetByID(ctx, clipID)
	if err != nil {
		return fmt.Errorf("failed to get clip: %w", err)
	}

	// Проверяем права доступа
	if clip.AuthorID != userID {
		return fmt.Errorf("user %d is not the author of clip %d", userID, clipID)
	}

	// Удаляем файлы из S3
	fileURLs := []string{clip.VideoURL, clip.ThumbnailURL}
	if err := s.storage.BulkDelete(ctx, fileURLs); err != nil {
		return fmt.Errorf("failed to delete files from S3: %w", err)
	}

	// Удаляем клип из БД
	if err := s.repo.Delete(ctx, clipID); err != nil {
		// Логируем ошибку но не возвращаем её, так как файлы уже удалены
		log.Printf("WARNING: Failed to delete clip %d from database after S3 deletion: %v", clipID, err)
	}

	return nil
}