//nolint:gochecknoglobals
package main

import (
	"context"
	"fmt"
	"io"
	"log"
	"net/http"
	"os"
	"regexp"
	"runtime"
	"strconv"
	"sync"
	"time"

	"github.com/gocolly/colly/v2"
	id3 "github.com/mikkyang/id3-go"
	"go.xsfx.dev/workgroups"
)

const (
	URL    = "https://susallefolgen.netlify.app/"
	Artist = "Sanft & Sorgfältig"
)

type Episode struct {
	Title  string
	Number int
	Date   time.Time
	URL    string
	file   string
}

type Episodes struct {
	sync.Mutex
	Episodes []Episode
}

func (e *Episode) ParseTitle(title string) error {
	re := regexp.MustCompile(`^#(?P<episode>\d+)\s(?P<title>.+)`)
	match := re.FindStringSubmatch(title)

	number, err := strconv.Atoi(match[1])
	if err != nil {
		return fmt.Errorf("could not convert number string to int: %w", err)
	}

	e.Number = number

	e.Title = match[2]

	return nil
}

var episodes Episodes

func (e *Episode) Download() error {
	log.Printf("downloading: %d - %s", e.Number, e.Title)

	resp, err := http.Get(e.URL)
	if err != nil {
		return fmt.Errorf("could not download: %w", err)
	}
	defer resp.Body.Close()

	e.file = fmt.Sprintf("%d.mp3", e.Number)

	f, err := os.Create(e.file)
	if err != nil {
		return fmt.Errorf("could not create file: %w", err)
	}
	defer f.Close()

	if _, err := io.Copy(f, resp.Body); err != nil {
		return fmt.Errorf("could not copy body to file: %w", err)
	}

	return nil
}

func (e *Episode) Tag() error {
	f, err := id3.Open(e.file)
	if err != nil {
		return fmt.Errorf("could not open file: %w", err)
	}
	defer f.Close()

	title := fmt.Sprintf("#%03d %s", e.Number, e.Title)

	f.SetArtist(Artist)
	f.SetAlbum(title)
	f.SetTitle(title)

	return nil
}

//nolint:funlen
func main() {
	c := colly.NewCollector()

	c.OnHTML("body div.container div", func(e *colly.HTMLElement) {
		episode := Episode{}

		e.ForEach("strong", func(_ int, el *colly.HTMLElement) {
			if err := episode.ParseTitle(el.Text); err != nil {
				log.Fatal(err)
			}
		})

		e.ForEach("table.u-full-width tbody tr td em", func(_ int, el *colly.HTMLElement) {
			t, err := time.Parse("Mon, 02 Jan 2006", el.Text)
			if err != nil {
				log.Fatal(err)
			}

			episode.Date = t
		})

		e.ForEach("table.u-full-width tbody tr td a", func(_ int, el *colly.HTMLElement) {
			episode.URL = el.Attr("href")
		})

		episodes.Lock()
		episodes.Episodes = append(episodes.Episodes, episode)
		episodes.Unlock()
	})

	c.Visit(URL)

	// j, err := json.MarshalIndent(episodes, "", "    ")
	// if err != nil {
	// 	log.Fatal(err)
	// }

	// fmt.Print(string(j))

	d, ctx := workgroups.NewDispatcher(
		context.Background(),
		runtime.GOMAXPROCS(0),
		len(episodes.Episodes[:1]),
	)

	d.Start()

	for _, ep := range episodes.Episodes[:1] {
		ep := ep

		d.Append(workgroups.NewJob(ctx, func(ctx context.Context) error {
			select {
			default:
			case <-ctx.Done():
				return fmt.Errorf("got error from context: %w", ctx.Err())
			}

			if err := ep.Download(); err != nil {
				return fmt.Errorf("could not download: %w", err)
			}

			if err := ep.Tag(); err != nil {
				return fmt.Errorf("could not tag: %w", err)
			}

			return nil
		}))
	}

	d.Close()

	if err := d.Wait(); err != nil {
		log.Fatal(err)
	}
}