package sinmh

import (
	"context"
	"fmt"
	"io"
	"net/http"
	"net/url"
	"regexp"
	"strconv"
	"strings"
	"time"

	"github.com/PuerkitoBio/goquery"

	"goyomi/internal/httpclient/flare"
	"goyomi/internal/source"
)

type Config struct {
	Name      string
	BaseURL   string
	Lang      string
	MobileURL string
}

type Source struct {
	cfg         Config
	client      *flare.Client
	id          int64
	imageHost   string
	categories  []Category
	dateFormat   string
}

type Category struct {
	Name      string
	Values    []string
	URIParts  []string
}

func New(cfg Config) *Source {
	if cfg.MobileURL == "" {
		cfg.MobileURL = strings.Replace(cfg.BaseURL, "www.", "m.", 1)
	}
	c := flare.NewClient(flare.WithRateLimit(2, 1))
	s := &Source{
		cfg:        cfg,
		client:     c,
		id:         source.GenerateSourceID(cfg.Name, cfg.Lang),
		dateFormat: "2006-01-02",
	}
	return s
}

func (s *Source) ID() int64   { return s.id }
func (s *Source) Name() string { return s.cfg.Name }
func (s *Source) Lang() string { return s.cfg.Lang }

func (s *Source) SupportsLatest() bool { return true }

func (s *Source) parseCategories(doc *goquery.Document) {
	if len(s.categories) > 0 {
		return
	}

	doc.Find("div.filter-nav label").Each(func(i int, sel *goquery.Selection) {
		name := sel.Text()
		var cat Category
		cat.Name = name

		sel.Parent().Find("a").Each(func(_ int, a *goquery.Selection) {
			text := a.Text()
			href := a.AttrOr("href", "")
			cat.Values = append(cat.Values, text)
			cat.URIParts = append(cat.URIParts, strings.TrimPrefix(strings.TrimSuffix(href, "/"), "/list/"))
		})

		if len(cat.Values) > 0 {
			s.categories = append(s.categories, cat)
		}
	})
}

func (s *Source) GetPopularManga(page int) (source.MangasPage, error) {
	doc, err := s.fetchDoc(fmt.Sprintf("%s/list/click/?page=%d", s.cfg.BaseURL, page))
	if err != nil {
		return source.MangasPage{}, err
	}

	s.parseCategories(doc)

	mangas := make([]source.SManga, 0)
	doc.Find("#contList > li, li.list-comic").Each(func(_ int, sel *goquery.Selection) {
		m := s.mangaFromElement(sel)
		if m.URL != "" {
			mangas = append(mangas, m)
		}
	})

	hasNext := doc.Find("ul.pagination > li.next:not(.disabled)").Length() > 0
	return source.MangasPage{Mangas: mangas, HasNextPage: hasNext}, nil
}

func (s *Source) mangaFromElement(sel *goquery.Selection) source.SManga {
	titleSel := sel.Find("p > a, h3 > a")
	title := titleSel.Text()
	href := titleSel.AttrOr("href", "")
	img := sel.Find("img")
	thumb := img.AttrOr("src", "")
	if thumb == "" {
		thumb = img.AttrOr("data-src", "")
	}

	return source.SManga{
		URL:          href,
		Title:        strings.TrimSpace(title),
		ThumbnailURL: thumb,
	}
}

func (s *Source) GetLatestUpdates(page int) (source.MangasPage, error) {
	doc, err := s.fetchDoc(fmt.Sprintf("%s/list/update/?page=%d", s.cfg.BaseURL, page))
	if err != nil {
		return source.MangasPage{}, err
	}

	mangas := make([]source.SManga, 0)
	doc.Find("#contList > li, li.list-comic").Each(func(_ int, sel *goquery.Selection) {
		m := s.mangaFromElement(sel)
		if m.URL != "" {
			mangas = append(mangas, m)
		}
	})

	hasNext := doc.Find("ul.pagination > li.next:not(.disabled)").Length() > 0
	return source.MangasPage{Mangas: mangas, HasNextPage: hasNext}, nil
}

func (s *Source) GetSearchManga(page int, query string, filters []source.Filter) (source.MangasPage, error) {
	if query != "" {
		doc, err := s.fetchDoc(fmt.Sprintf("%s/search/?keywords=%s&page=%d", s.cfg.BaseURL, url.QueryEscape(query), page))
		if err != nil {
			return source.MangasPage{}, err
		}

		mangas := make([]source.SManga, 0)
		doc.Find("#contList > li, li.list-comic").Each(func(_ int, sel *goquery.Selection) {
			m := s.mangaFromElement(sel)
			if m.URL != "" {
				mangas = append(mangas, m)
			}
		})

		hasNext := doc.Find("ul.pagination > li.next:not(.disabled)").Length() > 0
		return source.MangasPage{Mangas: mangas, HasNextPage: hasNext}, nil
	}

	categories := make([]string, 0)
	sortOrder := ""

	for _, f := range filters {
		if sel, ok := f.(*source.SelectFilter); ok {
			values := sel.Values
			if len(values) > sel.Selected && sel.Selected >= 0 {
				val := values[sel.Selected]
				if strings.Contains(sel.FilterName, "Sort") || strings.Contains(sel.FilterName, "排序") {
					sortOrder = val
				} else {
					categories = append(categories, val)
				}
			}
		}
	}

	urlParts := []string{"/list/"}
	urlParts = append(urlParts, categories...)
	if sortOrder != "" {
		urlParts = append(urlParts, sortOrder)
	}
	urlParts = append(urlParts, "/")

	searchURL := s.cfg.BaseURL + strings.Join(urlParts, "-") + fmt.Sprintf("?page=%d", page)

	doc, err := s.fetchDoc(searchURL)
	if err != nil {
		return source.MangasPage{}, err
	}

	mangas := make([]source.SManga, 0)
	doc.Find("#contList > li, li.list-comic").Each(func(_ int, sel *goquery.Selection) {
		m := s.mangaFromElement(sel)
		if m.URL != "" {
			mangas = append(mangas, m)
		}
	})

	hasNext := doc.Find("ul.pagination > li.next:not(.disabled)").Length() > 0
	return source.MangasPage{Mangas: mangas, HasNextPage: hasNext}, nil
}

func (s *Source) GetMangaDetails(manga source.SManga) (source.SManga, error) {
	doc, err := s.fetchDoc(s.cfg.MobileURL + manga.URL)
	if err != nil {
		return manga, err
	}

	title := doc.Find(".book-title h1").Text()
	detailsList := doc.Find(".detail-list")
	author := detailsList.Find("strong:contains(作者) ~ *").Text()
	description := doc.Find("#intro-all").Text()
	description = strings.TrimPrefix(description, "漫画简介：")
	description = strings.TrimSpace(description)

	genre := doc.Find("div.breadcrumb-bar a[href^=/list/]").Map(func(_ int, sel *goquery.Selection) string {
		return sel.Text()
	})
	genre = append(genre, detailsList.Find("strong:contains(类型) ~ a").Text())

	statusText := detailsList.Find("strong:contains(状态) + *").Text()
	status := 0
	switch statusText {
	case "连载中":
		status = 1
	case "已完结":
		status = 2
	}

	thumbnail := doc.Find("div.book-cover img").AttrOr("src", "")

	manga.Title = strings.TrimSpace(title)
	manga.Author = strings.TrimSpace(author)
	manga.Description = strings.TrimSpace(description)
	manga.Genre = strings.Join(genre, ", ")
	manga.Status = status
	manga.ThumbnailURL = thumbnail
	manga.Initialized = true

	return manga, nil
}

func (s *Source) GetChapterList(manga source.SManga) ([]source.SChapter, error) {
	doc, err := s.fetchDoc(s.cfg.MobileURL + manga.URL)
	if err != nil {
		return nil, err
	}

	chapters := make([]source.SChapter, 0)
	doc.Find(".chapter-body li > a").Each(func(_ int, sel *goquery.Selection) {
		href := sel.AttrOr("href", "")
		name := sel.Text()
		if sel.Children().Length() > 0 {
			name = sel.Children().First().Text()
		}
		chapters = append(chapters, source.SChapter{
			URL: href,
			Name: strings.TrimSpace(name),
		})
	})

	if len(chapters) > 0 {
		dateSel := doc.Find(".date")
		if dateSel.Length() > 0 {
			dateText := dateSel.First().Text()
			if t, err := time.Parse(s.dateFormat, strings.TrimSpace(dateText)); err == nil {
				chapters[0].DateUpload = t.UnixMilli()
			}
		}
	}

	for i, j := 0, len(chapters)-1; i < j; i, j = i+1, j-1 {
		chapters[i], chapters[j] = chapters[j], chapters[i]
	}

	return chapters, nil
}

func (s *Source) fetchImageHost() (string, error) {
	if s.imageHost != "" {
		return s.imageHost, nil
	}

	req, err := http.NewRequestWithContext(context.Background(), http.MethodGet, s.cfg.BaseURL+"/js/config.js", nil)
	if err != nil {
		return "", err
	}
	resp, err := s.client.Do(req)
	if err != nil {
		return "", err
	}
	defer resp.Body.Close()

	body, _ := io.ReadAll(resp.Body)
	re := regexp.MustCompile(`""resHost:.+?"?domain"?:\["(.+?)""""`)
	matches := re.FindStringSubmatch(string(body))
	if len(matches) > 1 {
		s.imageHost = matches[1]
		return s.imageHost, nil
	}

	return "", fmt.Errorf("could not find image host")
}

func (s *Source) GetPageList(chapter source.SChapter) ([]source.Page, error) {
	doc, err := s.fetchDoc(s.cfg.MobileURL + chapter.URL)
	if err != nil {
		return nil, err
	}

	imageHost, err := s.fetchImageHost()
	if err != nil {
		return nil, err
	}

	var images []string
	doc.Find("body > script").Each(func(_ int, sel *goquery.Selection) {
		html, err := sel.Html()
		if err != nil {
			return
		}
		if strings.Contains(html, "chapterImages") {
			re := regexp.MustCompile(`chapterImages = (.+?);`)
			m := re.FindStringSubmatch(html)
			if len(m) > 1 {
				imagesStr := m[1]
				if len(imagesStr) > 2 {
					imagesStr = imagesStr[1 : len(imagesStr)-1]
					imagesStr = strings.ReplaceAll(imagesStr, `\`, "")
					images = strings.Split(imagesStr, `","`)
				}
			}
		}
	})

	if len(images) == 0 {
		return nil, fmt.Errorf("no images found")
	}

	pathRe := regexp.MustCompile(`chapterPath = "(.+?)"`)
	firstScript := doc.Find("body > script").First()
	html, _ := firstScript.Html()
	pathMatch := pathRe.FindStringSubmatch(html)
	path := ""
	if len(pathMatch) > 1 {
		path = pathMatch[1]
	}

	pages := make([]source.Page, len(images))
	for i, img := range images {
		imgURL := img
		switch {
		case strings.HasPrefix(imgURL, "https://"):
			// already full URL
		case strings.HasPrefix(imgURL, "/"):
			imgURL = imageHost + imgURL
		default:
			imgURL = imageHost + "/" + path + img
		}
		pages[i] = source.Page{Index: i, ImageURL: imgURL}
	}

	return pages, nil
}

func (s *Source) GetImageURL(page source.Page) (string, error) {
	return page.ImageURL, nil
}

func (s *Source) GetFilterList() []source.Filter {
	filters := make([]source.Filter, 0)

	for _, cat := range s.categories {
		options := make([]string, len(cat.Values))
		copy(options, cat.Values)
		filters = append(filters, &source.SelectFilter{
			FilterName: cat.Name,
			Values:     options,
			Selected:   0,
		})
	}

	filters = append(filters, &source.SelectFilter{
		FilterName: "排序方式",
		Values:     []string{"post/", "-post/", "update/", "-update/", "click/", "-click/"},
		Selected:   0,
	})

	return filters
}

func (s *Source) fetchDoc(url string) (*goquery.Document, error) {
	req, err := http.NewRequestWithContext(context.Background(), http.MethodGet, url, nil)
	if err != nil {
		return nil, err
	}
	req.Header.Set("User-Agent", "Mozilla/5.0")
	req.Header.Set("Referer", s.cfg.BaseURL)

	resp, err := s.client.Do(req)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("HTTP %d for %s", resp.StatusCode, url)
	}

	html, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, err
	}

	return goquery.NewDocumentFromReader(strings.NewReader(string(html)))
}

func parseChapterNumber(s string) float32 {
	f, _ := strconv.ParseFloat(s, 32)
	if f == 0 {
		return -1
	}
	return float32(f)
}

var _ source.CatalogueSource = (*Source)(nil)