package main

import (
	_ "embed"
	"io/fs"
	"os"
	"path/filepath"
	"runtime"
	"strconv"
	"strings"
	"sync"
	"time"

	"git.velvettear.de/velvettear/id3tool/internal/config"
	"git.velvettear.de/velvettear/loggo"
	"github.com/bogem/id3v2/v2"
)

var taskLimiter = make(chan struct{}, runtime.NumCPU())
var taskCommunication = make(chan task)
var waitGroup = sync.WaitGroup{}
var counter int
var taskState = make(map[int]task)

func main() {
	loggo.SetLogFormat("[$LOGLEVEL$] > $MESSAGE$ ($EXTRAS$) [$TIMEDIFF$]")

	config.CheckArguments()

	if len(config.Directory) == 0 {
		loggo.Fatal("no directory provided")
	}
	stats, err := os.Stat(config.Directory)
	if err != nil {
		loggo.Fatal("could not get stats for provided directory", err.Error())
	}
	if !stats.IsDir() {
		loggo.Fatal("provided argument is not a valid directory")
	}

	filepath.WalkDir(config.Directory, filterValidFiles)
	waitGroup.Wait()
}

func filterValidFiles(path string, dir fs.DirEntry, err error) error {
	if err != nil {
		return err
	}

	extension := filepath.Ext(path)
	if dir.IsDir() || (extension != ".flac" && extension != ".mp3") {
		return nil
	}

	counter++
	waitGroup.Add(1)
	taskLimiter <- struct{}{}
	tmp := task{counter, path, false}
	go func(tmp task) {
		go func(tmp task) {
			time.Sleep(time.Duration(config.Timeout) * time.Second)
			tmp.timeout = true
			taskCommunication <- tmp
			<-taskLimiter
		}(tmp)
		cleanFrames(tmp.id, tmp.file)
		tmp.timeout = false
		taskCommunication <- tmp
		<-taskLimiter
	}(tmp)

	result := <-taskCommunication
	check := taskState[result.id]
	if check.id == 0 {
		taskState[result.id] = result
		if result.timeout {
			loggo.Warning("(" + strconv.Itoa(result.id) + ") cleaning of file's '" + result.file + "' id3 tags timed out")
		}
	}

	waitGroup.Done()
	return nil
}

func cleanFrames(id int, file string) {
	if len(file) == 0 {
		return
	}

	timestamp := time.Now()
	loggo.Info("(" + strconv.Itoa(id) + ") cleaning file's '" + file + "' id3 tags...")

	tag, err := id3v2.Open(file, id3v2.Options{Parse: true})
	if err != nil {
		loggo.Error("("+strconv.Itoa(id)+") encountered an error opening the file '"+file+"' for reading the id3 tags", err.Error())
		return
	}
	defer tag.Close()

	deleted := 0
	for key := range tag.AllFrames() {
		filter := frameFilter(key)
		if !filter {
			continue
		}
		tag.DeleteFrames(key)
		deleted++

	}
	if deleted > 0 {
		loggo.Debug("(" + strconv.Itoa(id) + ") saving modified id3 tags (" + strconv.Itoa(deleted) + " deleted) to file '" + file + "'...")
		err := tag.Save()
		if err != nil {
			loggo.Error("("+strconv.Itoa(id)+") encountered an error saving the modified id3 tags to file '"+file+"'", err.Error())
			return
		}
		loggo.DebugTimed("("+strconv.Itoa(id)+") deleted "+strconv.Itoa(deleted)+" tag(s) from file '"+file+"'", timestamp.UnixMilli())
	}

	loggo.DebugTimed("("+strconv.Itoa(id)+") finished cleaning file's '"+file+"' id3 tags", timestamp.UnixMilli())
}

func frameFilter(frame string) bool {
	for _, frameToKeep := range config.FramesToKeep {
		if strings.EqualFold(frameToKeep, frame) {
			return false
		}
	}
	return true
}

type task struct {
	id      int
	file    string
	timeout bool
}