Implement multi-file upload functionality for companies and enhance file upload routes

pkg/filestore/upload_helper.go

@@ -0,0 +1,128 @@
+package filestore
+
+import (
+	"errors"
+	"mime"
+	"mime/multipart"
+	"path/filepath"
+	"strings"
+)
+
+const (
+	// MaxUploadSize is the maximum allowed size per file (100 MB).
+	MaxUploadSize = 100 * 1024 * 1024
+	// MaxBatchUploadFiles is the maximum number of files per batch request.
+	MaxBatchUploadFiles = 20
+)
+
+// UploadedFileResult holds metadata for a successfully stored file.
+type UploadedFileResult struct {
+	FileID      string `json:"file_id"`
+	Filename    string `json:"filename"`
+	ContentType string `json:"content_type"`
+	Size        int64  `json:"size"`
+}
+
+// FailedUploadResult describes a file that could not be uploaded.
+type FailedUploadResult struct {
+	Filename string `json:"filename"`
+	Error    string `json:"error"`
+	Code     string `json:"code,omitempty"`
+}
+
+// UploadFromMultipartFile validates and stores a single multipart file.
+func UploadFromMultipartFile(service FileStoreService, file *multipart.FileHeader, opts UploadOptions) (UploadedFileResult, error) {
+	if file == nil {
+		return UploadedFileResult{}, NewError(ErrCodeInvalidInput, "file is required")
+	}
+
+	contentType := detectContentType(file)
+
+	validator := NewFileValidator(MaxUploadSize, SupportedMimeTypes)
+	if err := validator.ValidateFile(file.Filename, contentType, file.Size); err != nil {
+		return UploadedFileResult{}, err
+	}
+
+	src, err := file.Open()
+	if err != nil {
+		return UploadedFileResult{}, NewErrorWithCause(ErrCodeUploadFailed, "failed to open uploaded file", err)
+	}
+	defer src.Close()
+
+	if opts.Filename == "" {
+		opts.Filename = file.Filename
+	}
+	if opts.ContentType == "" {
+		opts.ContentType = contentType
+	}
+	if opts.MaxSize == 0 {
+		opts.MaxSize = MaxUploadSize
+	}
+
+	fileID, err := service.Upload("", file.Filename, src, opts)
+	if err != nil {
+		return UploadedFileResult{}, err
+	}
+
+	return UploadedFileResult{
+		FileID:      fileID,
+		Filename:    file.Filename,
+		ContentType: contentType,
+		Size:        file.Size,
+	}, nil
+}
+
+// UploadManyFromMultipart uploads multiple files and returns successes and failures.
+func UploadManyFromMultipart(service FileStoreService, files []*multipart.FileHeader, opts UploadOptions) ([]UploadedFileResult, []FailedUploadResult) {
+	uploaded := make([]UploadedFileResult, 0, len(files))
+	failed := make([]FailedUploadResult, 0)
+
+	for _, file := range files {
+		result, err := UploadFromMultipartFile(service, file, opts)
+		if err != nil {
+			code := ErrCodeUploadFailed
+			var fsErr *FileStoreError
+			if errors.As(err, &fsErr) {
+				code = fsErr.Code
+			}
+			failed = append(failed, FailedUploadResult{
+				Filename: file.Filename,
+				Error:    err.Error(),
+				Code:     code,
+			})
+			continue
+		}
+		uploaded = append(uploaded, result)
+	}
+
+	return uploaded, failed
+}
+
+func detectContentType(file *multipart.FileHeader) string {
+	contentType := file.Header.Get("Content-Type")
+	if contentType == "" {
+		ext := filepath.Ext(file.Filename)
+		if detected := mime.TypeByExtension(ext); detected != "" {
+			contentType = detected
+		} else {
+			contentType = "application/octet-stream"
+		}
+	}
+	return strings.TrimSpace(strings.Split(contentType, ";")[0])
+}
+
+// CollectMultipartFiles returns file headers from the "files" field, or a single "file" if present.
+func CollectMultipartFiles(form *multipart.Form) []*multipart.FileHeader {
+	if form == nil {
+		return nil
+	}
+
+	files := form.File["files"]
+	if len(files) > 0 {
+		return files
+	}
+	if file := form.File["file"]; len(file) > 0 {
+		return file
+	}
+	return nil
+}