package server

import (
	"errors"
	"net/http"
	"os"
	"path/filepath"
	"time"

	"music-server/internal/backend"
	"music-server/internal/logging"

	"github.com/labstack/echo/v5"
	"go.uber.org/zap"
)

// serveFile sends a file with support for Range requests and caching headers.
// contentType may be empty to detect it from the file extension.
func serveFile(c *echo.Context, f *os.File, contentType string) error {
	defer f.Close()
	info, err := f.Stat()
	if err != nil {
		return err
	}
	if info.IsDir() {
		return echo.NewHTTPError(http.StatusNotFound, "Not Found")
	}
	if contentType != "" {
		c.Response().Header().Set(echo.HeaderContentType, contentType)
	}
	http.ServeContent(c.Response(), c.Request(), filepath.Base(f.Name()), info.ModTime(), f)
	return nil
}

// serveSong streams a song. The write deadline is lifted because songs can take long to send to slow clients.
func serveSong(c *echo.Context, path string, err error) error {
	if err != nil {
		return songError(err)
	}
	f, err := os.Open(path)
	if err != nil {
		return echo.NewHTTPError(http.StatusNotFound, "Not Found")
	}
	_ = http.NewResponseController(c.Response()).SetWriteDeadline(time.Time{})
	return serveFile(c, f, "audio/mpeg")
}

// songError maps backend errors to HTTP errors.
func songError(err error) error {
	switch {
	case errors.Is(err, backend.ErrQueueEmpty), errors.Is(err, backend.ErrNoSongs), errors.Is(err, backend.ErrNotFound):
		return echo.NewHTTPError(http.StatusNotFound, err.Error())
	case errors.Is(err, backend.ErrInvalidName):
		return echo.NewHTTPError(http.StatusBadRequest, err.Error())
	case errors.Is(err, backend.ErrUpstream):
		return echo.NewHTTPError(http.StatusBadGateway, err.Error())
	default:
		logging.GetLogger().Error("Request failed", zap.Error(err))
		return echo.NewHTTPError(http.StatusInternalServerError, "Internal Server Error")
	}
}