Initial commit

Signed-off-by: Thomas Klaehn <thomas.klaehn@perinet.io>

internal/storage/storage.go

@@ -0,0 +1,117 @@
+package storage
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"regexp"
+	"strings"
+	"time"
+)
+
+// Storage handles local file system operations for FIT files
+type Storage struct {
+	outputDir string
+}
+
+// New creates a new Storage instance
+func New(outputDir string) (*Storage, error) {
+	// Create output directory if it doesn't exist
+	if err := os.MkdirAll(outputDir, 0755); err != nil {
+		return nil, fmt.Errorf("failed to create output directory: %w", err)
+	}
+
+	return &Storage{
+		outputDir: outputDir,
+	}, nil
+}
+
+// Save saves a FIT file to the output directory
+func (s *Storage) Save(activityID int64, activityName string, date time.Time, data []byte) (string, error) {
+	// Generate filename
+	filename := s.generateFilename(activityID, activityName, date)
+	filepath := filepath.Join(s.outputDir, filename)
+
+	// Check if file already exists
+	if _, err := os.Stat(filepath); err == nil {
+		return filepath, nil // File already exists, no need to save
+	}
+
+	// Write to temporary file first (atomic write)
+	tmpFile := filepath + ".tmp"
+	if err := os.WriteFile(tmpFile, data, 0644); err != nil {
+		return "", fmt.Errorf("failed to write temporary FIT file: %w", err)
+	}
+
+	// Verify file integrity (non-zero size)
+	if len(data) == 0 {
+		_ = os.Remove(tmpFile)
+		return "", fmt.Errorf("FIT file is empty")
+	}
+
+	// Rename temporary file to actual file (atomic operation)
+	if err := os.Rename(tmpFile, filepath); err != nil {
+		_ = os.Remove(tmpFile)
+		return "", fmt.Errorf("failed to rename temporary FIT file: %w", err)
+	}
+
+	return filepath, nil
+}
+
+// Exists checks if a FIT file already exists for an activity
+func (s *Storage) Exists(activityID int64) bool {
+	// List files in output directory
+	files, err := os.ReadDir(s.outputDir)
+	if err != nil {
+		return false
+	}
+
+	// Check if any file starts with the activity ID
+	prefix := fmt.Sprintf("%d_", activityID)
+	for _, file := range files {
+		if strings.HasPrefix(file.Name(), prefix) {
+			return true
+		}
+	}
+
+	return false
+}
+
+// generateFilename generates a filename for a FIT file
+// Format: {activityID}_{date}_{name}.fit
+func (s *Storage) generateFilename(activityID int64, activityName string, date time.Time) string {
+	// Format date as YYYY-MM-DD
+	dateStr := date.Format("2006-01-02")
+
+	// Sanitize activity name (remove special characters)
+	name := sanitizeFilename(activityName)
+	if name == "" {
+		name = "activity"
+	}
+
+	// Limit name length
+	if len(name) > 50 {
+		name = name[:50]
+	}
+
+	return fmt.Sprintf("%d_%s_%s.fit", activityID, dateStr, name)
+}
+
+// sanitizeFilename removes special characters from filename
+func sanitizeFilename(name string) string {
+	// Replace spaces with dashes
+	name = strings.ReplaceAll(name, " ", "-")
+
+	// Remove special characters (keep alphanumeric, dash, underscore)
+	re := regexp.MustCompile(`[^a-zA-Z0-9_-]`)
+	name = re.ReplaceAllString(name, "")
+
+	// Remove multiple consecutive dashes
+	re = regexp.MustCompile(`-+`)
+	name = re.ReplaceAllString(name, "-")
+
+	// Trim dashes from start and end
+	name = strings.Trim(name, "-")
+
+	return name
+}