package main

import (
	"fmt"
	"log"
	"os"
	"path/filepath"
	"strings"
	"time"

	"github.com/fsnotify/fsnotify"
)

// Watches the downloads directory for autohotkey files and makes sure that only the newest one downloaded exists at a time
func downloadsFileWatcher() {
	downloadsWatcher, err := fsnotify.NewWatcher()
	if err != nil {
		log.Fatal("NewWatcher failed: ", err)
	}
	defer downloadsWatcher.Close()

	done := make(chan bool)
	go func() {
		defer close(done)
		defer log.Printf("file watcher go routine shutting down!") // could be from returns below?

		for {
			select {

			case event, ok := <-downloadsWatcher.Events:
				if !ok {
					log.Printf("downloads watcher _event_ NOT OK TERMINATING ARRRGGHGHH: %v", err)
					return
				}
				if event.Op == fsnotify.Create {
					if strings.Contains(event.Name, ".ahk") {
						err = cleanDownloadsAHK()
						if err != nil {
							log.Printf("failed to clean downloads: %v", err)
						}
					}
				}

			case err, ok := <-downloadsWatcher.Errors:
				if !ok {
					log.Printf("downloads watcher _error_ NOT OK TERMINATING ARRRGGHGHH: %v", err)
					return
				}
				log.Printf("downloads watcher error: %v", err)
			}
		}

	}()
	err = downloadsWatcher.Add(downloadsFolderPath)
	if err != nil {
		log.Fatal("downloads watcher add down failed:", err)
	}

	<-done
}

func cleanDownloadsAHK() error {
	err := filepath.Walk(downloadsFolderPath, func(path string, info os.FileInfo, err error) error {
		if err != nil {
			return fmt.Errorf("failed to walk file: %v", err)
		}

		// ignore files that aren't AHK
		if !strings.Contains(info.Name(), ".ahk") {
			return nil
		}

		// ignore files downloaded in the past 5 minutes
		if info.ModTime().After(time.Now().Add(time.Minute * -1)) {
			return nil
		}

		log.Printf("removing old .ahk file - %s", info.Name())
		err = os.Remove(fmt.Sprintf("%s/%s", downloadsFolderPath, info.Name()))
		if err != nil {
			return fmt.Errorf("failed to delete old .ahk '%s': %v", info.Name(), err)
		}

		return nil
	})

	if err != nil {
		return fmt.Errorf("failed to walk downloads directory: %v", err)
	}

	return nil
}