first set of files

internal/parser/detector.go

@@ -0,0 +1,55 @@
+// internal/parser/detector.go
+package parser
+
+import (
+    "bytes"
+    "os"
+)
+
+type FileType string
+
+const (
+    FileTypeFIT     FileType = "fit"
+    FileTypeTCX     FileType = "tcx"
+    FileTypeGPX     FileType = "gpx"
+    FileTypeUnknown FileType = "unknown"
+)
+
+func DetectFileType(filepath string) (FileType, error) {
+    file, err := os.Open(filepath)
+    if err != nil {
+        return FileTypeUnknown, err
+    }
+    defer file.Close()
+    
+    // Read first 512 bytes for detection
+    header := make([]byte, 512)
+    n, err := file.Read(header)
+    if err != nil && n == 0 {
+        return FileTypeUnknown, err
+    }
+    
+    header = header[:n]
+    
+    return DetectFileTypeFromData(header), nil
+}
+
+func DetectFileTypeFromData(data []byte) FileType {
+    // Check for FIT file signature
+    if len(data) >= 8 && bytes.Equal(data[8:12], []byte(".FIT")) {
+        return FileTypeFIT
+    }
+    
+    // Check for XML-based formats
+    if bytes.HasPrefix(data, []byte("<?xml")) {
+        if bytes.Contains(data[:200], []byte("<gpx")) ||
+           bytes.Contains(data[:200], []byte("topografix.com/GPX")) {
+            return FileTypeGPX
+        }
+        if bytes.Contains(data[:500], []byte("TrainingCenterDatabase")) {
+            return FileTypeTCX
+        }
+    }
+    
+    return FileTypeUnknown
+}