package library

import (
	"sync"
	"velvettear/badger/internal/config"
	"velvettear/badger/internal/database"
	"velvettear/badger/internal/log"
	"velvettear/badger/internal/tools"
)

// exported function(s)
func Update() {
	timestamp := tools.LogTimestamp()
	log.Info("database update started...")
	// find and filter for unknown / changed files
	files, deletedTrackIDs := filterChangedFiles(findFiles(config.LibraryDirectory()))
	// if no changed files are detected and no files were deleted exit
	if len(files) == 0 && !removeDeletedTracks(deletedTrackIDs) {
		log.InfoTimed("database update finished, no changes were detected", timestamp)
		return
	}
	if len(files) > 0 {
		// setup waitgroup and communication channel
		ipc := make(chan wrapper)
		wait := new(sync.WaitGroup)
		wait.Add(2)
		// parse the files and store the generated metadata asynchronously
		go parseFiles(files, ipc, wait)
		go storeMetadata(ipc, wait)
		wait.Wait()
		close(ipc)
	}
	// persist the in memory database to the filesystem
	database.Persist()
	log.InfoTimed("database update finished", timestamp)
}