package app

import (
	"fmt"
	"io"
	"net/http"
	"net/url"
	"strings"

	"github.com/PuerkitoBio/goquery"
)

func downloadAssetFile(url string) ([]byte, error) {
	resp, err := http.Get(url)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()

	return io.ReadAll(resp.Body)
}

// FetchArticleHTML returns page's title, html and error
func FetchArticleHTML(urlToFetch string) (string, string, error) {
	url, err := url.Parse(urlToFetch)
	if err != nil {
		return "", "", err
	}

	resp, err := http.Get(url.String())
	if err != nil {
		return "", "", err
	}
	defer resp.Body.Close()

	doc, err := goquery.NewDocumentFromReader(resp.Body)
	if err != nil {
		return "", "", err
	}

	doc.Find(`head link[rel="stylesheet"]`).Each(func(i int, s *goquery.Selection) {
		v, ok := s.Attr("href")
		if !ok || v == "" {
			return
		}

		if strings.HasPrefix(v, "/") {
			styles, err := downloadAssetFile(fmt.Sprintf("https://%s%s", url.Hostname(), v))
			if err != nil {
				return
			}
			doc.Find("head").AppendHtml("<style>" + string(styles) + "</style>")
			s.Remove()
		}
	})

	doc.Find("a").Each(func(i int, s *goquery.Selection) {
		href, ok := s.Attr("href")
		if !ok || href == "" {
			return
		}

		if strings.HasPrefix(href, "/") {
			s.SetAttr("href", "https://"+url.Hostname()+href)
		}
	})

	doc.Find("script").Each(func(i int, s *goquery.Selection) {
		s.Remove()
	})

	title := doc.Find("head title").Text()

	html, _ := doc.Html()
	return title, html, err
}