package download

import (
	"fmt"
	"librapi/services"
	"net/http"
	"os"
	"path/filepath"

	"github.com/rs/zerolog/log"
)

const URL = "/download"

func Handler(s services.IStore) func(http.ResponseWriter, *http.Request) {
	return func(w http.ResponseWriter, r *http.Request) {
		switch r.Method {
		case http.MethodGet:
			getDownload(w, r, s)
		default:
			http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
		}
	}
}

func getDownload(w http.ResponseWriter, r *http.Request, s services.IStore) {
	queryParams := r.URL.Query()
	downloadFiles, ok := queryParams["file"]
	if !ok {
		log.Error().Msg("file query param does not exist")
		http.Error(w, "file query param does not exist", http.StatusBadRequest)
		return
	}

	if len(downloadFiles) != 1 {
		log.Error().Msg("only one file is allowed to download")
		http.Error(w, "only one file is allowed to download", http.StatusBadRequest)
		return
	}

	filename := downloadFiles[0]
	filePath := filepath.Join(s.GetDir(), filename)

	if _, err := os.Stat(filePath); err != nil {
		if os.IsNotExist(err) {
			http.Error(w, "file does not exist", http.StatusInternalServerError)
			return
		}
		http.Error(w, "unexpected error occurred", http.StatusInternalServerError)
		return
	}

	http.ServeFile(w, r, filePath)

	w.Header().Set("Content-Disposition", fmt.Sprintf("attachment; filename=%s", filename))
	w.Header().Set("Content-Type", "application/pdf")
}