backend/internal/api/routes/files.go

package routes

import (
	"bytes"
	"io"
	"log"
	"strings"
	"time"

	"github.com/gin-gonic/gin"
	"github.com/gofrs/uuid"
	"github.com/golang-jwt/jwt/v5"
	"github.com/h2non/filetype"
	"github.com/minio/minio-go/v7"
	"stereo.cat/backend/internal/auth"
	"stereo.cat/backend/internal/types"
)

func intoReader(buf []byte) io.Reader {
	return io.NopCloser(bytes.NewBuffer(buf))
}

func RegisterFileRoutes(cfg *types.StereoConfig, api *gin.RouterGroup) {
	api.POST("/upload", auth.JwtMiddleware(cfg.JWTSecret), func(c *gin.Context) {
		claims := c.MustGet("claims").(jwt.MapClaims)
		user := claims["user"].(auth.User)

		uid := user.ID
		if uid == "" {
			c.JSON(401, gin.H{"error": "unauthorized"})
			return
		}

		file, err := c.FormFile("file")
		if err != nil {
			c.JSON(400, gin.H{"error": "file is required"})
			return
		}

		if file.Size <= 0 {
			c.JSON(400, gin.H{"error": "file size must be greater than zero"})
			return
		}

		fileReader, err := file.Open()
		if err != nil {
			c.JSON(500, gin.H{"error": "couldn't open file"})
			log.Println(err)
			return
		}

		buf, err := io.ReadAll(fileReader)
		if err != nil {
			c.JSON(500, gin.H{"error": "couldn't open file"})
			log.Println(err)
			return
		}

		fileType, err := filetype.Match(buf)

		if err != nil {
			c.JSON(500, gin.H{"error": "couldn't open file"})
			log.Println(err)
			return
		}

		fileMeta := types.File{
			Owner:     uid,
			Name:      file.Filename,
			CreatedAt: time.Now(),
			Size:      int64(len(buf)),
			Mime:      fileType.MIME.Value,
		}

		if err := cfg.Database.Create(&fileMeta).Error; err != nil {
			c.JSON(500, gin.H{"error": "failed to save file metadata"})
			return
		}

		_, err = cfg.MinioClient.PutObject(cfg.Context, cfg.Bucket, fileMeta.ID.String(), intoReader(buf), fileMeta.Size, minio.PutObjectOptions{ContentType: fileMeta.Mime})

		if err != nil {
			c.JSON(500, gin.H{"error": "failed to upload file"})
			log.Println(err)
			return
		}

		c.JSON(200, gin.H{"message": "file uploaded successfully", "id": fileMeta.ID.String()})
	})

	api.DELETE("/:id", auth.JwtMiddleware(cfg.JWTSecret), func(c *gin.Context) {
		claims := c.MustGet("claims").(jwt.MapClaims)
		user := claims["user"].(auth.User)

		uid := c.Param("uid")
		uid = strings.TrimSpace(uid)
		if uid == "" {
			c.JSON(400, gin.H{"error": "uid is required"})
			return
		}

		if uid != user.ID {
			c.JSON(403, gin.H{"error": "you can only delete your own files"})
			return
		}

		fileID, err := uuid.FromString(strings.TrimSpace(c.Param("id")))
		if err != nil {
			c.JSON(404, gin.H{"error": "file not found"})
			return
		}

		var file *types.File

		cfg.Database.First(&file, fileID)

		if file == nil {
			c.JSON(404, gin.H{"error": "file not found"})
			return
		}

		if err := cfg.MinioClient.RemoveObject(cfg.Context, cfg.Bucket, fileID.String(), minio.RemoveObjectOptions{}); err != nil {
			c.JSON(500, gin.H{"error": "failed to delete file"})
			return
		}

		if err := cfg.Database.Delete(&file).Error; err != nil {
			c.JSON(500, gin.H{"error": "failed to delete file metadata"})
			return
		}

		c.JSON(200, gin.H{"message": "file deleted successfully"})
	})

	api.GET("/:id", func(c *gin.Context) {
		fileID := c.Param("id")
		fileID = strings.TrimSpace(fileID)

		var file *types.File

		id, err := uuid.FromString(fileID)
		if err != nil {
			c.JSON(500, gin.H{"error": "invalid file id"})
			log.Println(err)
			return
		}

		cfg.Database.First(&file, id)

		if file == nil {
			c.JSON(500, gin.H{"error": "file does not exist"})
			log.Println(err)
			return
		}

		object, err := cfg.MinioClient.GetObject(cfg.Context, cfg.Bucket, fileID, minio.GetObjectOptions{})
		if err != nil {
			c.JSON(500, gin.H{"error": "failed to retrieve file"})
			log.Println(err)
			return
		}

		c.DataFromReader(200, file.Size, file.Mime, object, nil)
	})

	api.GET("/list", auth.JwtMiddleware(cfg.JWTSecret), func(c *gin.Context) {
		claims := c.MustGet("claims").(jwt.MapClaims)
		user := claims["user"].(auth.User)

		var files []types.File
		if err := cfg.Database.Where("owner = ?", user.ID).Find(&files).Error; err != nil {
			c.JSON(500, gin.H{"error": "failed to retrieve files"})
			return
		}

		c.JSON(200, files)
	})
}