package mangasee

import (
	"embed"
	"encoding/json"
	"fmt"
	"net/http"
	"strconv"
	"strings"

	"github.com/PuerkitoBio/goquery"
	"github.com/headzoo/surf"
	"github.com/headzoo/surf/browser"
	"github.com/mmcdole/gofeed/rss"
	"rogchap.com/v8go"
)

//go:embed underscore-min.js
//go:embed fakequery.js
var jslib embed.FS

type App struct {
	vm      *v8go.Isolate
	browser *browser.Browser
	fp      rss.Parser
	http    *http.Client
	js      [][]byte
}

type MangaSeeChapter struct {
	Chapter     string
	Type        string
	Page        string
	Date        string
	ChapterName string
	Directory   string
}

func ChapterImage(chstr string) string {
	ch := chstr[1 : len(chstr)-1]
	odd := chstr[len(chstr)-1:]
	if odd == "0" {
		return ch
	} else {
		return fmt.Sprintf("%s.%s", ch, odd)
	}
}

func (app *App) GetFeed(uri string) (feed *rss.Feed, err error) {
	resp, err := app.http.Get(uri)
	if err != nil {
		return
	}

	feed, err = app.fp.Parse(resp.Body)
	if err != nil {
		return
	}

	return
}

func (app *App) GetChapterImages(uri string) (pages []string, err error) {
	vm, err := v8go.NewContext(app.vm)
	if err != nil {
		return
	}
	defer vm.Close()

	err = app.browser.Open(uri)
	if err != nil {
		return
	}

	for _, f := range app.js {
		_, err = vm.RunScript(string(f), "app.js")
		if err != nil {
			return
		}
	}

	app.browser.Dom().Find("script").Each(func(_ int, s *goquery.Selection) {
		if strings.Contains(s.Text(), "function MainFunction($http, $timeout){") {
			_, err := vm.RunScript(s.Text(), "main.js")
			if err != nil {
				return
			}
		}
	})

	_, err = vm.RunScript("MainFunction()", "main.js")
	if err != nil {
		return
	}

	curpathname, err := vm.RunScript("CurPathName", "main.js")
	if err != nil {
		return
	}

	chidx, err := vm.RunScript("IndexName", "main.js")
	if err != nil {
		return
	}

	chjson, err := vm.RunScript("JSON.stringify(CurChapter)", "main.js")
	if err != nil {
		return
	}

	var ch MangaSeeChapter
	err = json.Unmarshal([]byte(chjson.String()), &ch)

	page, err := strconv.Atoi(ch.Page)
	if err != nil {
		return
	}

	for i := 1; i <= page; i++ {
		pages = append(pages, fmt.Sprintf("https://%s/manga/%s/%s-%.3d.png", curpathname.String(), chidx.String(), ChapterImage(ch.Chapter), i))
	}

	return
}

func New() (app *App, err error) {
	app = new(App)

	underscore, err := jslib.ReadFile("underscore-min.js")
	if err != nil {
		return
	}

	fq, err := jslib.ReadFile("fakequery.js")
	if err != nil {
		return
	}

	app.js = append(app.js, underscore)
	app.js = append(app.js, fq)

	app.http = &http.Client{}
	app.vm, err = v8go.NewIsolate()
	if err != nil {
		panic(err)
	}

	app.browser = surf.NewBrowser()
	app.fp = rss.Parser{}

	return
}