package main

import (
	"flag"
	"fmt"
	"log"
	"os"
	"path/filepath"
)

func main() {
	// Add directory specification flag with default value
	sort_dir := flag.String("d", "media/", "Specify the directory of files to be sorted.")
	flag.Parse()

	// Make sure the input directory is valid
	_, err := os.Stat(*sort_dir)
	if err != nil {
		log.Fatalf("A valid directory was not given: %v", err)
	}

	// Get the absolute path of the directory to be sorted
	media_dir_path, err := filepath.Abs(*sort_dir)
	if err != nil {
		log.Fatalf("Couldn't grab absolute filepath: %v", err)
	}

	// Make name for the destination directory of sorted files
	media_dir := filepath.Base(media_dir_path)
	sorted_media_dir := fmt.Sprintf("sorted_%s", media_dir)
	sorted_media_dir_path := fmt.Sprintf("%s/%s", filepath.Dir(media_dir_path), sorted_media_dir)

	// Debug output of the filepaths
	log.Default().Println(fmt.Sprintf("%s | %s | %s | %s", media_dir_path, media_dir, sorted_media_dir_path, sorted_media_dir))

	// Get a list of the files in the directory to be sorted
	files, err := os.ReadDir(media_dir_path)
	if err != nil {
		log.Fatal(err)
	}

	// Make the destination directory
	err = os.Mkdir(sorted_media_dir_path, 0755)
	if err != nil && !os.IsExist(err) {
		log.Fatalf("Couldn't create sorted files directroy: %v", err)
	}

	// Iterate through the list of files
	for _, file := range files {
		// Don't try to sort directories
		if file.IsDir() || file.Name() == ".gitkeep" {
			continue
		}
		// The name string of the file we're looking at
		current_file_name := file.Name()

		// Grab file info
		current_file, err := os.Stat(fmt.Sprintf("%s/%s", media_dir_path, current_file_name))
		if err != nil {
			log.Fatalf("Couldn't stat current file: %v", err)
		}

		// Save the last modified year and month
		current_file_year := current_file.ModTime().Year()
		current_file_month := current_file.ModTime().Month()

		// Make directories for the sorted files to go into
		err = os.Mkdir(fmt.Sprintf("%s/%d", sorted_media_dir_path, current_file_year), 0755)
		if err != nil && !os.IsExist(err) {
			log.Fatalf("Couldn't create new directory: %v", err)
		}

		new_directory_path := fmt.Sprintf("%d/%02d", current_file_year, current_file_month)
		err = os.Mkdir(fmt.Sprintf("%s/%s", sorted_media_dir_path, new_directory_path), 0755)
		if err != nil && !os.IsExist(err) {
			log.Fatalf("Couldn't create new directory: %v", err)
		}

		// Debug output of last modified year/month, and the file name
		log.Default().Println(fmt.Sprintf("%d/%02d | %s", current_file_year, current_file_month, current_file_name))

		// Set the current file path and the destination file path
		full_current_file_path := fmt.Sprintf("%s/%s", media_dir_path, current_file_name)
		full_new_file_path := fmt.Sprintf("%s/%s/%s", sorted_media_dir_path, new_directory_path, current_file_name)

		// Move the file
		err = os.Rename(full_current_file_path, full_new_file_path)
	}
}