package main

import (
	"encoding/json"
	"fmt"
	"io/ioutil"
	"log"
	"net/http"

	"github.com/PuerkitoBio/goquery"
)

//M is matrix
type M struct {
	Matrix struct {
		Name string
		Mp3  string `json:"rendered_audio_url"`
	}
}

func main() {
	const pages = 43
	const host = "https://www.beatlab.com"
	for i := 1; i < pages; i++ {
		d, err := goquery.NewDocument(fmt.Sprintf("https://www.beatlab.com/users/10745/matrices?id=10745&page=%d", i))
		if err != nil {
			panic(err)
		}
		d.Find(".preview_track").Each(
			func(i int, s *goquery.Selection) {
				if v, ok := s.Attr("metadata_url"); ok {
					m, err := decode(host + v)
					if err != nil {
						fmt.Println(err)
						return
					}
					download(m)
				}
			})
	}
}

func decode(url string) (matrix M, err error) {
	resp, err := http.Get(url)
	if err != nil {
		return
	}
	defer resp.Body.Close()
	err = json.NewDecoder(resp.Body).Decode(&matrix)
	return
}

func download(matrix M) {
	log.Println("Downloading: ", matrix.Matrix.Name, matrix.Matrix.Mp3)
	resp, err := http.Get(matrix.Matrix.Mp3)
	if err != nil {
		fmt.Println(err)
		return
	}
	defer resp.Body.Close()
	data, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		fmt.Println(err)
		return
	}
	err = ioutil.WriteFile(matrix.Matrix.Name+".mp3", data, 0644)
	if err != nil {
		fmt.Println(err)
		return
	}
}