package main

import (
    "fmt"
    "io/ioutil"
    "log"
    "time"
    "math/rand"
    "os/exec"
)

const (
    DCONF_PATH   = "/org/mate/desktop/background/picture-filename"
    PICS_PATH    = "/home/anon/Pictures/"
    DURATION_MIN = 10
)

func main() {
    rand.Seed(time.Now().UTC().UnixNano())
    changeBackground(getAllPictures())
}

func changeBackground(pictures []string) {
    for true {
        pos := rand.Intn(len(pictures))
        dconf_params := fmt.Sprintf("dconf write %s \"'%s/%s'\"", DCONF_PATH, PICS_PATH, pictures[pos])

        cmd := exec.Command("bash", "-c", dconf_params)
        cmd.Run()

        time.Sleep(DURATION_MIN * time.Minute)
        pictures = getAllPictures()
    }
}

func getAllPictures() []string {
    var pics []string
    files, err := ioutil.ReadDir(PICS_PATH)

    if err != nil {
        log.Fatal(err)
    }

    for _, file := range files {
        pics = append(pics, file.Name())
    }

    return pics
}