// Package keyoapp implements the Keyoapp manga base.
// HTML scraping; popular from homepage; pages via CDN URL extracted from inline JS.
package keyoapp

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

	// Override popular manga selector. Empty means use default.
	PopularSelector string
	// Override description selector. Empty means use default.
	DescriptionSelector string
	// Override status selector. Empty means use default.
	StatusSelector string
	// Override author selector. Empty means use default.
	AuthorSelector string
	// Override artist selector. Empty means use default.
	ArtistSelector string
}

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

func New(cfg Config) *Source {
	c := flare.NewClient(flare.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) base() 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("keyoapp: HTTP %d", resp.StatusCode)
	}
	return goquery.NewDocumentFromReader(resp.Body)
}

var imgURLRe = regexp.MustCompile(`url\(['"]?([^('")\s]+)`)

func getImageURL(el *goquery.Selection, baseURL string) string {
	// Find any descendant with background-image style
	var u string
	el.Find("*[style]").Each(func(_ int, s *goquery.Selection) {
		if u != "" {
			return
		}
		style := s.AttrOr("style", "")
		if !strings.Contains(style, "background-image") {
			return
		}
		if m := imgURLRe.FindStringSubmatch(style); len(m) > 1 {
			raw := m[1]
			// strip w= query that keyoapp uses for thumbnail sizing
			if parsed, err := url.Parse(raw); err == nil {
				q := parsed.Query()
				q.Del("w")
				parsed.RawQuery = q.Encode()
				u = parsed.String()
			} else {
				u = raw
			}
		}
	})
	if u != "" {
		return util.AbsURL(baseURL, u)
	}
	return ""
}

func relURL(raw, baseURL string) string {
	u, err := url.Parse(raw)
	if err != nil {
		return raw
	}
	base, err := url.Parse(baseURL)
	if err != nil {
		return raw
	}
	if u.Host == base.Host {
		return u.Path
	}
	return raw
}

func (s *Source) mangaFromElement(el *goquery.Selection) source.SManga {
	m := source.SManga{}
	m.ThumbnailURL = getImageURL(el, s.cfg.BaseURL)
	el.Find("a[href]").First().Each(func(_ int, a *goquery.Selection) {
		m.Title = a.AttrOr("title", "")
		href := a.AttrOr("href", "")
		m.URL = relURL(href, s.cfg.BaseURL)
	})
	return m
}

func (s *Source) popularSelector() string {
	if s.cfg.PopularSelector != "" {
		return s.cfg.PopularSelector
	}
	var parts []string
	for _, label := range []string{"Popular", "Popularie", "Trending"} {
		parts = append(parts, fmt.Sprintf("div:contains(%s) + div .group.overflow-hidden.grid", label))
	}
	return strings.Join(parts, ", ")
}

func (s *Source) GetPopularManga(page int) (source.MangasPage, error) {
	doc, err := s.get(context.Background(), s.base())
	if err != nil {
		return source.MangasPage{}, err
	}
	var mangas []source.SManga
	doc.Find(s.popularSelector()).Each(func(_ int, el *goquery.Selection) {
		m := s.mangaFromElement(el)
		if m.URL != "" && m.Title != "" {
			mangas = append(mangas, m)
		}
	})
	return source.MangasPage{Mangas: mangas, HasNextPage: false}, nil
}

func (s *Source) GetLatestUpdates(page int) (source.MangasPage, error) {
	doc, err := s.get(context.Background(), s.base()+"/latest/")
	if err != nil {
		return source.MangasPage{}, err
	}
	var mangas []source.SManga
	doc.Find("div.grid > div.group").Each(func(_ int, el *goquery.Selection) {
		m := s.mangaFromElement(el)
		if m.URL != "" && m.Title != "" {
			mangas = append(mangas, m)
		}
	})
	return source.MangasPage{Mangas: mangas, HasNextPage: false}, nil
}

func (s *Source) GetSearchManga(page int, query string, filters []source.Filter) (source.MangasPage, error) {
	u := fmt.Sprintf("%s/series/?q=%s", s.base(), query)
	doc, err := s.get(context.Background(), u)
	if err != nil {
		return source.MangasPage{}, err
	}
	var mangas []source.SManga
	// Filter client-side by title
	doc.Find("#searched_series_page > button").Each(func(_ int, el *goquery.Selection) {
		title := el.AttrOr("title", "")
		if query != "" && !strings.Contains(strings.ToLower(title), strings.ToLower(query)) {
			return
		}
		m := s.mangaFromElement(el)
		if m.URL == "" {
			el.Find("a[href]").First().Each(func(_ int, a *goquery.Selection) {
				m.URL = relURL(a.AttrOr("href", ""), s.cfg.BaseURL)
				m.Title = a.AttrOr("title", strings.TrimSpace(a.Text()))
			})
		}
		if m.Title == "" {
			m.Title = title
		}
		if m.URL != "" {
			mangas = append(mangas, m)
		}
	})
	return source.MangasPage{Mangas: mangas, HasNextPage: false}, nil
}

func parseStatus(s *goquery.Selection) int {
	if s == nil || s.Length() == 0 {
		return source.StatusUnknown
	}
	switch strings.ToLower(strings.TrimSpace(s.Text())) {
	case "ongoing":
		return source.StatusOngoing
	case "dropped":
		return source.StatusCancelled
	case "paused":
		return source.StatusHiatus
	case "completed":
		return source.StatusCompleted
	default:
		return source.StatusUnknown
	}
}

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}

	// Thumbnail from div[class*=photoURL] background-image style
	result.ThumbnailURL = getImageURL(doc.Find("div[class*=photoURL]").First(), s.cfg.BaseURL)
	descSel := "div:containsOwn(Synopsis) ~ div"
	if s.cfg.DescriptionSelector != "" {
		descSel = s.cfg.DescriptionSelector
	}
	result.Description = strings.TrimSpace(doc.Find(descSel).First().Text())

	statusSel := "div:has(span:containsOwn(Status)) ~ div"
	if s.cfg.StatusSelector != "" {
		statusSel = s.cfg.StatusSelector
	}
	result.Status = parseStatus(doc.Find(statusSel).First())

	authorSel := "div:has(span:containsOwn(Author)) ~ div"
	if s.cfg.AuthorSelector != "" {
		authorSel = s.cfg.AuthorSelector
	}
	result.Author = strings.TrimSpace(doc.Find(authorSel).First().Text())

	artistSel := "div:has(span:containsOwn(Artist)) ~ div"
	if s.cfg.ArtistSelector != "" {
		artistSel = s.cfg.ArtistSelector
	}
	result.Artist = strings.TrimSpace(doc.Find(artistSel).First().Text())

	// Title from h1 inside the series header
	result.Title = strings.TrimSpace(doc.Find("h1").First().Text())
	if result.Title == "" {
		result.Title = manga.Title
	}

	// Genres from grid links
	var genres []string
	doc.Find("div.grid:has(>h1) > div > a:not([title='Status'])").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 (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
	}
	// Exclude upcoming and (optionally) paid chapters
	sel := "#chapters > a:not(:has(.text-sm span))"
	var chapters []source.SChapter
	doc.Find(sel).Each(func(_ int, el *goquery.Selection) {
		ch := source.SChapter{}
		el.Find("a[href]").First().Each(func(_ int, a *goquery.Selection) {
			href := a.AttrOr("href", "")
			ch.URL = relURL(href, s.cfg.BaseURL)
		})
		if ch.URL == "" {
			href := el.AttrOr("href", "")
			ch.URL = relURL(href, s.cfg.BaseURL)
		}
		ch.Name = strings.TrimSpace(el.Find(".text-sm").Text())
		if dateEl := el.Find(".text-xs").First(); dateEl.Length() > 0 {
			ch.DateUpload = util.ParseRelativeDate(strings.TrimSpace(dateEl.Text()))
			if ch.DateUpload == 0 {
				ch.DateUpload = util.ParseAbsoluteDate(strings.TrimSpace(dateEl.Text()), "Jan 2, 2006")
			}
		}
		if ch.URL != "" {
			chapters = append(chapters, ch)
		}
	})
	return chapters, nil
}

var (
	cdnHostRe  = regexp.MustCompile("realUrl\\s*=\\s*`[^`]+//([^/`]+)")
	cdnCleanRe = regexp.MustCompile(`\$\{[^}]*\}`)
)

func getCdnURL(doc *goquery.Document) string {
	var cdnURL string
	doc.Find("script").Each(func(_ int, el *goquery.Selection) {
		if cdnURL != "" {
			return
		}
		html, _ := el.Html()
		if m := cdnHostRe.FindStringSubmatch(html); len(m) > 1 {
			host := cdnCleanRe.ReplaceAllString(m[1], "")
			cdnURL = "https://" + host + "/uploads"
		}
	})
	return cdnURL
}

var oldCdnRe = regexp.MustCompile(`^(https?:)?//cdn\d*\.keyoapp\.com`)

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
	}
	cdnURL := getCdnURL(doc)
	// Primary: #pages > img[uid] with CDN URL
	var pages []source.Page
	if cdnURL != "" {
		doc.Find("#pages > img[uid]").Each(func(i int, img *goquery.Selection) {
			uid := img.AttrOr("uid", "")
			if uid != "" {
				pages = append(pages, source.Page{Index: i, ImageURL: cdnURL + "/" + uid})
			}
		})
	}
	if len(pages) > 0 {
		return pages, nil
	}
	// Fallback: old CDN direct src
	doc.Find("#pages > img").Each(func(i int, img *goquery.Selection) {
		src := img.AttrOr("src", "")
		if src == "" {
			src = img.AttrOr("data-src", "")
		}
		if oldCdnRe.MatchString(src) {
			pages = append(pages, source.Page{Index: i, ImageURL: src})
		}
	})
	return pages, nil
}

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