// Package mccms implements the MCCMS (Chinese manga CMS) manga base.
// HTML scraping; popular/latest via category pages; pages via data-original img attr.
package mccms

import (
	"context"
	"fmt"
	"net/http"
	"strings"

	"github.com/PuerkitoBio/goquery"

	"goyomi/internal/httpclient/flare"
	"goyomi/internal/source"
	"goyomi/sources/base/util"
)

type Config struct {
	Name               string
	BaseURL            string
	Lang               string
	LazyLoadAttr       string // default: "data-original"
	UseMobilePageList  bool
}

type Source struct {
	cfg    Config
	client *flare.Client
	id     int64
}

func New(cfg Config) *Source {
	if cfg.LazyLoadAttr == "" {
		cfg.LazyLoadAttr = "data-original"
	}
	c := flare.NewClient(flare.WithRateLimit(2, 3))
	return &Source{cfg: cfg, client: c, id: source.GenerateSourceID(cfg.Name, cfg.Lang)}
}

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) base() string { return strings.TrimRight(s.cfg.BaseURL, "/") }

var pcUA = "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:109.0) Gecko/20100101 Firefox/121.0"

func (s *Source) get(ctx context.Context, rawURL string) (*goquery.Document, error) {
	req, err := http.NewRequestWithContext(ctx, http.MethodGet, rawURL, nil)
	if err != nil {
		return nil, err
	}
	req.Header.Set("User-Agent", pcUA)
	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("mccms: HTTP %d", resp.StatusCode)
	}
	return goquery.NewDocumentFromReader(resp.Body)
}

func (s *Source) parseListing(doc *goquery.Document) source.MangasPage {
	var mangas []source.SManga
	doc.Find(".common-comic-item").Each(func(_ int, el *goquery.Selection) {
		titleEl := el.Find(".comic__title").First().Find("a").First()
		if titleEl.Length() == 0 {
			return
		}
		href := titleEl.AttrOr("href", "")
		// strip /index.php prefix
		href = strings.TrimPrefix(href, "/index.php")
		m := source.SManga{
			URL:   href,
			Title: strings.TrimSpace(titleEl.Text()),
		}
		if img := el.Find("img").First(); img.Length() > 0 {
			m.ThumbnailURL = util.AbsURL(s.cfg.BaseURL, img.AttrOr("data-original", img.AttrOr("src", "")))
		}
		if m.URL != "" && m.Title != "" {
			mangas = append(mangas, m)
		}
	})

	// Pagination: last two links in #Pagination or .NewPages differ → has next
	hasNext := false
	doc.Find("#Pagination a, .NewPages a").Each(func(_ int, _ *goquery.Selection) {})
	buttons := doc.Find("#Pagination a, .NewPages a")
	n := buttons.Length()
	if n >= 2 {
		last := strings.TrimSpace(buttons.Eq(n - 1).AttrOr("href", "a"))
		secondLast := strings.TrimSpace(buttons.Eq(n - 2).AttrOr("href", "b"))
		hasNext = last != secondLast
	}
	return source.MangasPage{Mangas: mangas, HasNextPage: hasNext}
}

func (s *Source) GetPopularManga(page int) (source.MangasPage, error) {
	doc, err := s.get(context.Background(), fmt.Sprintf("%s/category/order/hits/page/%d", s.base(), page))
	if err != nil {
		return source.MangasPage{}, err
	}
	return s.parseListing(doc), nil
}

func (s *Source) GetLatestUpdates(page int) (source.MangasPage, error) {
	doc, err := s.get(context.Background(), fmt.Sprintf("%s/category/order/addtime/page/%d", s.base(), page))
	if err != nil {
		return source.MangasPage{}, err
	}
	return s.parseListing(doc), nil
}

func (s *Source) GetSearchManga(page int, query string, filters []source.Filter) (source.MangasPage, error) {
	u := fmt.Sprintf("%s/search/%s/%d", s.base(), query, page)
	doc, err := s.get(context.Background(), u)
	if err != nil {
		return source.MangasPage{}, err
	}
	return s.parseListing(doc), nil
}

func (s *Source) GetMangaDetails(manga source.SManga) (source.SManga, error) {
	doc, err := s.get(context.Background(), util.AbsURL(s.cfg.BaseURL, manga.URL))
	if err != nil {
		return manga, err
	}
	result := source.SManga{URL: manga.URL}

	box := doc.Find(".de-info__box").First()
	result.Title = strings.TrimSpace(box.Find(".comic-title").First().Text())
	if result.Title == "" {
		result.Title = manga.Title
	}
	if img := box.Find("img").First(); img.Length() > 0 {
		result.ThumbnailURL = util.AbsURL(s.cfg.BaseURL, img.AttrOr("src", ""))
	}
	result.Author = strings.TrimSpace(box.Find(".name").First().Text())
	result.Description = strings.TrimSpace(box.Find(".intro-total").First().Text())

	var genres []string
	box.Find(".comic-status a").Each(func(_ int, a *goquery.Selection) {
		if t := strings.TrimSpace(a.Text()); t != "" {
			genres = append(genres, t)
		}
	})
	result.Genre = strings.Join(genres, ", ")
	return result, nil
}

func removePathPrefix(href string) string {
	return strings.TrimPrefix(href, "/index.php")
}

func (s *Source) GetChapterList(manga source.SManga) ([]source.SChapter, error) {
	doc, err := s.get(context.Background(), util.AbsURL(s.cfg.BaseURL, manga.URL))
	if err != nil {
		return nil, err
	}
	var chapters []source.SChapter
	doc.Find(".chapter__list-box > li").Each(func(_ int, el *goquery.Selection) {
		link := el.Children().First()
		href := removePathPrefix(link.AttrOr("href", ""))
		if href == "" {
			return
		}
		chapters = append(chapters, source.SChapter{
			URL:  href,
			Name: strings.TrimSpace(link.Text()),
		})
	})
	// Reverse to get descending order (latest first)
	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) GetPageList(chapter source.SChapter) ([]source.Page, error) {
	doc, err := s.get(context.Background(), util.AbsURL(s.cfg.BaseURL, chapter.URL))
	if err != nil {
		return nil, err
	}
	var pages []source.Page
	if s.cfg.UseMobilePageList {
		doc.Find(".comic-list img").Each(func(i int, img *goquery.Selection) {
			u := img.AttrOr("src", "")
			if u != "" {
				pages = append(pages, source.Page{Index: i, ImageURL: util.AbsURL(s.cfg.BaseURL, u)})
			}
		})
	} else {
		doc.Find(fmt.Sprintf("img[%s]", s.cfg.LazyLoadAttr)).Each(func(i int, img *goquery.Selection) {
			u := img.AttrOr(s.cfg.LazyLoadAttr, "")
			if u != "" {
				pages = append(pages, source.Page{Index: i, ImageURL: u})
			}
		})
	}
	return pages, nil
}

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