tailly_back_v2/internal/service/post_service.go

package service

import (
	"bytes"
	"context"
	"encoding/base64"
	"errors"
	"fmt"
	"github.com/aws/aws-sdk-go/aws/credentials"
	"image/jpeg"
	"image/png"
	"strings"
	"tailly_back_v2/internal/domain"
	"tailly_back_v2/internal/repository"
	"tailly_back_v2/internal/utils"
	"tailly_back_v2/pkg/S3"
	"tailly_back_v2/pkg/moderation"
	"time"

	"github.com/aws/aws-sdk-go/aws"
	"github.com/aws/aws-sdk-go/aws/session"
	"github.com/aws/aws-sdk-go/service/s3/s3manager"
)

// Интерфейс сервиса постов
type PostService interface {
	Create(ctx context.Context, authorID int, title, content string) (*domain.Post, error)
	GetByID(ctx context.Context, id int) (*domain.Post, error)
	GetAll(ctx context.Context) ([]*domain.Post, error)
	GetByAuthorID(ctx context.Context, authorID int) ([]*domain.Post, error)
	Update(ctx context.Context, id int, title, content string) (*domain.Post, error)
	Delete(ctx context.Context, id int) error
}

// Реализация сервиса постов
type postService struct {
	postRepo repository.PostRepository
}

// Конструктор сервиса
func NewPostService(postRepo repository.PostRepository) PostService {
	return &postService{postRepo: postRepo}
}

// Создание нового поста
func (s *postService) Create(ctx context.Context, authorID int, title, content string) (*domain.Post, error) {
	const op = "service/postService.Create"
	// Валидация
	if content == "" {
		return nil, errors.New("post content cannot be empty")
	}

	// Определяем формат и извлекаем данные
	var base64Data, ext, contentType string
	switch {
	case strings.HasPrefix(content, "data:image/jpeg;base64,"):
		base64Data = strings.TrimPrefix(content, "data:image/jpeg;base64,")
		ext = "jpg"
		contentType = "image/jpeg"
	case strings.HasPrefix(content, "data:image/png;base64,"):
		base64Data = strings.TrimPrefix(content, "data:image/png;base64,")
		ext = "png"
		contentType = "image/png"
	case strings.HasPrefix(content, "data:image/webp;base64,"):
		base64Data = strings.TrimPrefix(content, "data:image/webp;base64,")
		ext = "webp"
		contentType = "image/webp"
	default:
		return nil, errors.New("invalid image format, expected JPEG, PNG or WebP")
	}

	// Декодируем base64
	imgData, err := base64.StdEncoding.DecodeString(base64Data)
	if err != nil {
		return nil, fmt.Errorf("%s: failed to decode base64: %w", op, err)
	}

	// Проверяем размер
	if len(imgData) > 10_000_000 {
		return nil, errors.New("image too large (max 10MB)")
	}

	// Проверяем валидность изображения
	switch ext {
	case "jpg":
		if _, err := jpeg.Decode(bytes.NewReader(imgData)); err != nil {
			return nil, fmt.Errorf("%s: invalid JPEG image: %w", op, err)
		}
	case "png":
		if _, err := png.Decode(bytes.NewReader(imgData)); err != nil {
			return nil, fmt.Errorf("%s: invalid PNG image: %w", op, err)
		}
	}

	// Модерация изображения
	modClient, err := moderation.NewModerationClient("tailly_censor:50051")
	if err != nil {
		return nil, fmt.Errorf("%s: failed to create moderation client: %w", op, err)
	}
	defer modClient.Close()

	allowed, err := modClient.CheckImage(ctx, imgData)
	if err != nil {
		return nil, fmt.Errorf("%s: image moderation failed: %w", op, err)
	}
	if !allowed {
		return nil, errors.New("image rejected by moderation service")
	}

	// Загрузка в S3
	randName := utils.GenerateId() + ".jpg"
	sess := session.Must(session.NewSession(&aws.Config{
		Region:           aws.String("ru-central1"),
		Endpoint:         aws.String("https://s3.regru.cloud"),
		S3ForcePathStyle: aws.Bool(true),
		Credentials: credentials.NewStaticCredentials(
			"TJ946G2S1Z5FEI3I7DQQ",
			"C2H2aITHRDpek8H921yhnrINZwDoADsjW3F6HURl",
			"",
		),
	}))

	uploader := s3manager.NewUploader(sess)
	s3Key := fmt.Sprintf("posts/%d/%s", authorID, randName)

	_, err = uploader.Upload(&s3manager.UploadInput{
		Bucket:      aws.String("tailly"),
		Key:         aws.String(s3Key),
		Body:        bytes.NewReader(imgData),
		ContentType: aws.String(contentType),
	})
	if err != nil {
		return nil, fmt.Errorf("%s: failed to upload to S3: %w", op, err)
	}

	imageURL := fmt.Sprintf("https://s3.regru.cloud/%s/%s", "tailly", s3Key)

	post := &domain.Post{
		Title:     title,
		Content:   imageURL,
		AuthorID:  authorID,
		CreatedAt: time.Now(),
		UpdatedAt: time.Now(),
	}

	if err := s.postRepo.Create(ctx, post); err != nil {
		return nil, fmt.Errorf("%s: failed to save post: %w", op, err)
	}

	return post, nil
}

// Получение поста по ID
func (s *postService) GetByID(ctx context.Context, id int) (*domain.Post, error) {
	post, err := s.postRepo.GetByID(ctx, id)
	if err != nil {
		if errors.Is(err, repository.ErrPostNotFound) {
			return nil, errors.New("post not found")
		}
		return nil, err
	}
	return post, nil
}

// Получение всех постов
func (s *postService) GetAll(ctx context.Context) ([]*domain.Post, error) {
	posts, err := s.postRepo.GetAll(ctx)
	if err != nil {
		return nil, err
	}

	// Возвращаем пустой слайс вместо nil
	if posts == nil {
		return []*domain.Post{}, nil
	}

	return posts, nil
}

// Получение постов автора
func (s *postService) GetByAuthorID(ctx context.Context, authorID int) ([]*domain.Post, error) {
	posts, err := s.postRepo.GetByAuthorID(ctx, authorID)
	if err != nil {
		return nil, err
	}

	if posts == nil {
		return []*domain.Post{}, nil
	}

	return posts, nil
}

// Обновление поста
func (s *postService) Update(ctx context.Context, id int, title, content string) (*domain.Post, error) {
	// Получаем существующий пост
	post, err := s.postRepo.GetByID(ctx, id)
	if err != nil {
		return nil, err
	}

	// Обновляем поля
	post.Title = title
	post.Content = content
	post.UpdatedAt = time.Now()

	if err := s.postRepo.Update(ctx, post); err != nil {
		return nil, err
	}

	return post, nil
}

// Удаление поста
func (s *postService) Delete(ctx context.Context, id int) error {

	post, err := s.postRepo.GetByID(ctx, id)
	if err != nil {
		if errors.Is(err, repository.ErrPostNotFound) {
			return errors.New("post not found")
		}
		return err
	}

	err = S3.DeleteFromS3(post.Content)
	if err != nil {
		return err
	}
	return s.postRepo.Delete(ctx, id)
}