package playback

import (
	"net/http"
	"os"
	"path/filepath"
	"strings"
)

// MimeFromExtension returns a MIME type based on the file extension.
// Falls back to "application/octet-stream" for unknown extensions.
func MimeFromExtension(name string) string {
	ext := strings.ToLower(filepath.Ext(name))
	switch ext {
	case ".mp4", ".m4v":
		return "video/mp4"
	case ".mkv":
		return "video/x-matroska"
	case ".webm":
		return "video/webm"
	case ".avi":
		return "video/x-msvideo"
	case ".mov":
		return "video/quicktime"
	case ".ts":
		return "video/mp2t"
	case ".flv":
		return "video/x-flv"
	case ".wmv":
		return "video/x-ms-wmv"
	default:
		return "application/octet-stream"
	}
}

// ServeDirectPlay serves a media file with HTTP byte-range support.
// Uses http.ServeContent for proper range handling, which supports
// Range requests, conditional requests (If-Modified-Since, If-None-Match),
// and Content-Type detection.
func ServeDirectPlay(w http.ResponseWriter, r *http.Request, filePath string) error {
	f, err := os.Open(filePath)
	if err != nil {
		if os.IsNotExist(err) {
			http.Error(w, "file not found", http.StatusNotFound)
			return err
		}
		http.Error(w, "internal server error", http.StatusInternalServerError)
		return err
	}
	defer f.Close()

	stat, err := f.Stat()
	if err != nil {
		http.Error(w, "internal server error", http.StatusInternalServerError)
		return err
	}

	// Set Content-Type explicitly so ServeContent does not sniff.
	w.Header().Set("Content-Type", MimeFromExtension(filePath))

	http.ServeContent(w, r, stat.Name(), stat.ModTime(), f)
	return nil
}