package main

import (
    "fmt"
    "errors"
    "log"
    "os"
    "time"
    "strings"
    "path/filepath"
    "gopkg.in/fsnotify.v1"
    "github.com/mitchellh/go-homedir"
)

func isValidFile(filename string) bool {
    base := filepath.Base(filename)
    ignores := []string {".DS_Store", ".AppleDouble"}
    for _, ignore := range(ignores) {
        if base == ignore {
            return false
        }
    }
    prefixes := []string {"."}
    for _, prefix := range(prefixes) {
        if strings.HasPrefix(base, prefix) {
            return false
        }
    }
    suffixes := []string {".part", ".download", ".crdownload", "~", ".swp", ".partial"}
    for _, suffix := range(suffixes) {
        if strings.HasSuffix(base, suffix) {
            return false
        }
    }
    f, err := os.Open(filename)
    if err != nil {
        log.Println(err)
        return false
    }
    fi, err := f.Stat()
    if err != nil {
        log.Println(err)
        return false
    }
    if fi.IsDir() || fi.Size() == 0 {
        return false
    }
    return true
}

func exists(filename string) bool {
    _, err := os.Stat(filename)
    log.Println(err)
    return err == nil
}

func move(fpath string, destdir string) error {
    time.Sleep(100 * time.Millisecond)
    if isValidFile(fpath) {
        base := filepath.Base(fpath)
        i, dest := 0, filepath.Join(destdir, base)
        for exists(dest) {
            if i == 10 {
                log.Println("aaa")
                return errors.New("")
            }
            ext := filepath.Ext(dest)
            dest = strings.TrimSuffix(dest, ext) + fmt.Sprintf("-%d", i) + ext
            i++
        }
        if err := os.Rename(fpath, dest); err != nil {
            log.Println(err)
            return err
        }
    }
    return nil
}

func createDir(destdir string) error {
    if ! exists(destdir) {
        if err := os.Mkdir(destdir, 0700); err != nil {
            log.Println(err)
            return err
        }
        return nil
    }
    return nil
}

func main() {
    watcher, err := fsnotify.NewWatcher()
    if err != nil {
        os.Exit(1)
    }
    defer watcher.Close()

    done := make(chan bool)
    go func() {
        for {
            select {
            case event := <-watcher.Events:
                switch {
                case event.Op & fsnotify.Create == fsnotify.Create:
                    fpath := event.Name
                    destdir := filepath.Join(filepath.Dir(fpath), time.Now().Format("2006-01-02"))
                    log.Println(filepath.Dir(event.Name))
                    log.Println(destdir)
                    if createDir(destdir) == nil {
                        move(fpath, destdir)
                    }
                case event.Op & fsnotify.Rename == fsnotify.Rename:
                    if strings.HasSuffix(event.Name, ".part") {
                        fpath := strings.TrimSuffix(event.Name, ".part")
                        destdir := filepath.Join(filepath.Dir(fpath), time.Now().Format("2006-01-02"))
                        log.Println(destdir)
                        if createDir(destdir) == nil {
                            move(fpath, destdir)
                        }
                    }
                }
            }
        }
    }()
    dir, err := homedir.Expand("~/Downloads")
    if err != nil {
        os.Exit(1)
    }
    if watcher.Add(dir) != nil {
        os.Exit(1)
    }
    <-done
}