// Package mmlook implements the MMLook (漫漫看) Chinese manga base.
// GET {desktopUrl}/rank/1 for popular; JS eval+decrypt for pages; CF-protected.
package mmlook

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

	"github.com/PuerkitoBio/goquery"

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

type Config struct {
	Name           string
	BaseURL        string
	DesktopURL     string // desktop variant URL (may differ from BaseURL)
	Lang           string
	UseLegacyURL   bool
}

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

func New(cfg Config) *Source {
	if cfg.DesktopURL == "" {
		cfg.DesktopURL = cfg.BaseURL
	}
	if cfg.Lang == "" {
		cfg.Lang = "zh"
	}
	c := httpclient.NewClient(httpclient.WithRateLimit(1, 2))
	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) desktop() string { return strings.TrimRight(s.cfg.DesktopURL, "/") }
func (s *Source) mobile() string  { return strings.TrimRight(s.cfg.BaseURL, "/") }

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("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("mmlook: HTTP %d", resp.StatusCode)
	}
	return goquery.NewDocumentFromReader(resp.Body)
}

func (s *Source) mangaURL(id string) string {
	id = strings.Trim(id, "/")
	if s.cfg.UseLegacyURL {
		return fmt.Sprintf("http://%s/%s/", strings.TrimPrefix(strings.TrimPrefix(s.mobile(), "https://"), "http://"), id)
	}
	return fmt.Sprintf("%s/%s/", s.mobile(), id)
}

func (s *Source) GetPopularManga(page int) (source.MangasPage, error) {
	doc, err := s.get(context.Background(), fmt.Sprintf("%s/rank/1", s.desktop()))
	if err != nil {
		return source.MangasPage{}, err
	}
	var mangas []source.SManga
	doc.Find(".book-list li, .comics-list li, .rank-list li").Each(func(_ int, el *goquery.Selection) {
		m := source.SManga{}
		el.Find("a").First().Each(func(_ int, a *goquery.Selection) {
			if href, ok := a.Attr("href"); ok {
				m.URL = href
			}
		})
		el.Find("img").First().Each(func(_ int, img *goquery.Selection) {
			m.ThumbnailURL = imgAttr(img, s.cfg.BaseURL)
		})
		el.Find(".title, .name, h3, h4").First().Each(func(_ int, e *goquery.Selection) {
			m.Title = strings.TrimSpace(e.Text())
		})
		if m.URL != "" {
			mangas = append(mangas, m)
		}
	})
	return source.MangasPage{Mangas: mangas, HasNextPage: false}, nil
}

func (s *Source) GetLatestUpdates(page int) (source.MangasPage, error) {
	return s.GetPopularManga(page)
}

func (s *Source) GetSearchManga(page int, query string, filters []source.Filter) (source.MangasPage, error) {
	doc, err := s.get(context.Background(), fmt.Sprintf("%s/search?q=%s", s.mobile(), query))
	if err != nil {
		return source.MangasPage{}, err
	}
	var mangas []source.SManga
	doc.Find(".book-list li, .search-list li, .comics-list li").Each(func(_ int, el *goquery.Selection) {
		m := source.SManga{}
		el.Find("a").First().Each(func(_ int, a *goquery.Selection) {
			if href, ok := a.Attr("href"); ok {
				m.URL = href
			}
		})
		el.Find("img").First().Each(func(_ int, img *goquery.Selection) {
			m.ThumbnailURL = imgAttr(img, s.cfg.BaseURL)
		})
		el.Find(".title, .name, h3").First().Each(func(_ int, e *goquery.Selection) {
			m.Title = strings.TrimSpace(e.Text())
		})
		if m.URL != "" {
			mangas = append(mangas, m)
		}
	})
	return source.MangasPage{Mangas: mangas, HasNextPage: false}, nil
}

func (s *Source) GetMangaDetails(manga source.SManga) (source.SManga, error) {
	id := strings.Trim(util.SlugFromURL(manga.URL), "/")
	doc, err := s.get(context.Background(), fmt.Sprintf("%s/%s/", s.desktop(), id))
	if err != nil {
		return manga, err
	}
	result := source.SManga{URL: manga.URL}
	comicInfo := doc.Find(".comicInfo, .comic-info, #comicInfo")
	if comicInfo.Length() == 0 {
		comicInfo = doc.Find("body")
	}
	result.Title = strings.TrimSpace(comicInfo.Find("h1").First().Text())
	if result.Title == "" {
		result.Title = manga.Title
	}
	result.ThumbnailURL = imgAttr(comicInfo.Find("img").First(), s.cfg.BaseURL)
	comicInfo.Find(".detinfo span, .info span").Each(func(_ int, el *goquery.Selection) {
		text := el.Text()
		switch {
		case strings.HasPrefix(text, "作 者：") || strings.HasPrefix(text, "作者："):
			result.Author = strings.TrimSpace(text[strings.Index(text, "：")+3:])
		case strings.HasPrefix(text, "标 签：") || strings.HasPrefix(text, "标签："):
			result.Genre = strings.ReplaceAll(strings.TrimSpace(text[strings.Index(text, "：")+3:]), " ", ", ")
		case strings.HasPrefix(text, "状 态：") || strings.HasPrefix(text, "状态："):
			result.Status = util.StatusFromString(text)
		}
	})
	result.Description = strings.TrimSpace(comicInfo.Find(".content, .intro, .synopsis").Text())
	return result, nil
}

func (s *Source) GetChapterList(manga source.SManga) ([]source.SChapter, error) {
	id := strings.Trim(util.SlugFromURL(manga.URL), "/")
	doc, err := s.get(context.Background(), fmt.Sprintf("%s/%s/", s.desktop(), id))
	if err != nil {
		return nil, err
	}
	var chapters []source.SChapter
	doc.Find(".chapter-list li a, #chapter-list li a, .chapter a").Each(func(_ int, a *goquery.Selection) {
		ch := source.SChapter{Name: strings.TrimSpace(a.Text())}
		ch.URL, _ = a.Attr("href")
		if ch.URL != "" {
			chapters = append(chapters, ch)
		}
	})
	return chapters, nil
}

// evalScriptRe extracts a packed/obfuscated eval script
var evalScriptRe = regexp.MustCompile(`eval\(function\(p,a,c,k,e,(?:d|r)\).*?\)\)`)

// imageURLsRe extracts image URLs from unpacked content
var imageURLsRe = regexp.MustCompile(`https?://[^\s"']+\.(?:jpg|jpeg|png|webp)[^\s"']*`)

func (s *Source) GetPageList(chapter source.SChapter) ([]source.Page, error) {
	chURL := util.AbsURL(s.cfg.BaseURL, chapter.URL)
	doc, err := s.get(context.Background(), chURL)
	if err != nil {
		return nil, err
	}
	// try direct img tags first
	var pages []source.Page
	doc.Find(".readerArea img, .reading-content img, #chapter-images img").Each(func(i int, img *goquery.Selection) {
		if u := imgAttr(img, s.cfg.BaseURL); u != "" {
			pages = append(pages, source.Page{Index: i, ImageURL: u})
		}
	})
	if len(pages) > 0 {
		return pages, nil
	}
	// extract image URLs from scripts (packed JS decryption not fully implemented)
	doc.Find("script").Each(func(_ int, el *goquery.Selection) {
		script := el.Text()
		if !strings.Contains(script, "eval") && !strings.Contains(script, "image") {
			return
		}
		matches := imageURLsRe.FindAllString(script, -1)
		for _, u := range matches {
			pages = append(pages, source.Page{Index: len(pages), ImageURL: u})
		}
	})
	if len(pages) == 0 {
		return nil, fmt.Errorf("mmlook: could not extract page images (packed JS decryption not implemented)")
	}
	return pages, nil
}

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

func imgAttr(img *goquery.Selection, baseURL string) string {
	for _, attr := range []string{"data-lazy-src", "data-src", "data-cfsrc", "src"} {
		if v, ok := img.Attr(attr); ok && v != "" && !strings.HasPrefix(v, "data:") {
			return util.AbsURL(baseURL, v)
		}
	}
	return ""
}