package endpoints

import (
	"encoding/json"
	"fmt"
	"log"
	"math/rand"
	"net/http"
	"os"

	audio "physick.ru/culture_exam/Audio"
	settings "physick.ru/culture_exam/Settings"
)

type Song struct {
	Name string
	Duration int
	Start int
	Meta audio.TrackMeta
}

type SongsList struct {
	Songs []Song
}

var cache *SongsList = nil

func (base Song) String() string {
	var outp, jsonErr = json.Marshal(base)
	if jsonErr != nil {
		return fmt.Sprintf("Failed to parse settings: %s", jsonErr.Error())
	}
	return string(outp)
}

func (base SongsList) String() string {
	var outp, jsonErr = json.Marshal(base)
	if jsonErr != nil {
		return fmt.Sprintf("Failed to parse settings: %s", jsonErr.Error())
	}
	return string(outp)
}

func getSongs(w http.ResponseWriter, r *http.Request) {
	var songsList, err = GetAvaliableSongs()
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		log.Printf("Failed to get files: %v\n", err.Error())
		return
	}
	w.Header().Add("Content-Type", "application/json")
	fmt.Fprint(w, songsList)
}

func getRandomSong(w http.ResponseWriter, r *http.Request) {
	var songsList, err = GetAvaliableSongs()
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		log.Printf("Failed to get files: %v\n", err.Error())
		return
	}
	var index = rand.Intn(len(songsList.Songs))
	w.Header().Add("Content-Type", "application/json")
	var outp = songsList.Songs[index]
	outp.Start = settings.Current.Distribution.GetDistributedInt(outp.Duration)
	fmt.Fprint(w, outp)
}

func GetAvaliableSongs() (SongsList, error) {
	if cache != nil {
		return *cache, nil
	}
	var files, dirErr = os.ReadDir(settings.Current.SongsLocation)
	if dirErr != nil {
		return SongsList{}, dirErr
	}
	var outp = SongsList {
		Songs: make([]Song, 0, len(files)),
	}
	for i, v := range files {
		fmt.Printf("Indexing %d/%d\n", i+1, len(files))
		var fullPath = fmt.Sprintf("%s/%s", settings.Current.SongsLocation, v.Name())
		var duration, durErr = audio.GetSongDuration(fullPath)
		if durErr != nil {
			log.Printf("Failed to parse file metadata: File: %s, error: %s\n", fullPath, durErr.Error())
			continue
		}
		var meta, metaErr = audio.GenerateMetadata(v.Name())
		if metaErr != nil {
			log.Printf("Failed to get metadata from file: %s", metaErr)
			continue
		}
		var song = Song {
			Name: v.Name(),
			Duration: int(duration.Seconds()),
			Meta: meta,
		}
		outp.Songs = append(outp.Songs, song)
	}
	cache = &outp
	return outp, nil
}