package main

import (
	"fmt"
	"log"
	"os"
	"path/filepath"
	"regexp"
	"strings"
)

func checkForSubsDir(dir []os.DirEntry) string {
	for _, item := range dir {
		if strings.ToLower(item.Name()) == "subs" {
			return item.Name()
		}
	}
	return ""
}

func processSeason(seasonDir string) {

	// Get files within each directory
	seasonsDirList, err := os.ReadDir(seasonDir)
	if err != nil {
		log.Fatal(err)
	}

	// Ensure there's a subs directory
	subsDir := checkForSubsDir(seasonsDirList)
	if len(subsDir) == 0 {
		return
	}

	// Go through each file
	for _, seasonsDirItems := range seasonsDirList {

		// If ends with .txt, ignore
		if filepath.Ext(seasonsDirItems.Name()) == ".txt" {
			continue
		}

		// If this is a directory, ignore
		fileInfo, err := os.Stat(seasonDir + "/" + seasonsDirItems.Name())
		if err != nil {
			log.Fatal(err)
		}
		if fileInfo.IsDir() {
			continue
		}

		// Get the filename without extension
		filename := strings.TrimSuffix(seasonsDirItems.Name(), filepath.Ext(seasonsDirItems.Name()))

		// Ensure the directory within subs exist matching this filename
		episodeSubsDir := seasonDir + "/" + subsDir + "/" + filename
		if _, err := os.Stat(episodeSubsDir); !os.IsNotExist(err) {
			episodeSubsList, err := os.ReadDir(episodeSubsDir)
			if err != nil {
				log.Fatal(err)
			}

			// Go through sub's directory, sort for English only
			for _, episodeSubsItems := range episodeSubsList {
				ensureLanguage, _ := regexp.MatchString(`_[Ee]nglish.srt`, episodeSubsItems.Name())

				// Move the srt files within the directory into the season's directory
				if ensureLanguage {
					newSubsName := filename + "_" + episodeSubsItems.Name()
					err := os.Rename(episodeSubsDir+"/"+episodeSubsItems.Name(), seasonDir+"/"+newSubsName)
					if err != nil {
						log.Fatal(err)
					}
				}
			}
		}
	}

	// Delete Subs folder
	err = os.RemoveAll(seasonDir + "/" + subsDir)
	if err != nil {
		log.Fatal(err)
	}
}

func formatSeason(seasonNumber string) string {
	// If it starts with a '.', it is in the '.Sxx.' format
	if seasonNumber[0] == '.' {
		return seasonNumber[2 : len(seasonNumber)-1]
	}

	// Else, it is in the 'Season xx' format (do nothing)
	return seasonNumber
}

func main() {
	cliArgs := os.Args
	fmt.Println()
	if len(cliArgs) < 2 {
		fmt.Println("Missing directory!")
		os.Exit(1)
	}
	topDir := os.Args[1]

	// Confirm directory
	fmt.Print("Press <ENTER> to confirm with directory: \n\t" + topDir)
	_, err := fmt.Scanln()
	if err != nil {
		log.Fatal(err)
	}

	// Read in the top directory
	topDirList, err := os.ReadDir(topDir)
	if err != nil {
		log.Fatal(err)
	}

	// Each of the seasons directories
	for _, seasonsDir := range topDirList {

		// Ensure there's a 'Sxx' in the name (for the season number)
		seasonRegex := regexp.MustCompile(`.[sS][0-9]{1,2}.`)
		ensureSeason := seasonRegex.MatchString(seasonsDir.Name())

		// Or if the folder is just called 'Season xx'
		if !ensureSeason {
			seasonRegex = regexp.MustCompile(`[sS]eason\s[0-9]{1,2}`)
			ensureSeason = seasonRegex.MatchString(seasonsDir.Name())
		}

		// Process the season if it is a season folder
		if ensureSeason {
			processSeason(topDir + seasonsDir.Name())

			// Rename the season folder to 'Season xx'
			seasonFound := seasonRegex.FindStringSubmatch(seasonsDir.Name())
			seasonNumber := formatSeason(seasonFound[0])
			err := os.Rename(topDir+seasonsDir.Name(), topDir+"Season "+seasonNumber)
			if err != nil {
				log.Fatal(err)
			}
		}

		fmt.Println("Complete")

	}
}