// Package mangathemesia implements the MangaThemesia WordPress theme base.
// Pages extracted from ts_reader.run({...}) JS blob; FlareSolverr required.
package mangathemesia

import (
	"context"
	"encoding/json"
	"fmt"
	"net/http"
	"net/url"
	"regexp"
	"strings"

	"github.com/PuerkitoBio/goquery"

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

// Config holds per-source configuration.
type Config struct {
	Name             string
	BaseURL          string
	Lang             string
	MangaURLDirectory string // e.g. "/manga" or "/manhwa"

	// Overridable selectors
	SearchMangaSelector     string
	SeriesThumbSelector     string
	SeriesAuthorSelector    string
	SeriesArtistSelector    string
	SeriesDescSelector      string
	SeriesStatusSelector    string
	SeriesGenreSelector     string
	SeriesTitleSelector     string
	ChapterListSelector     string
}

func (c *Config) setDefaults() {
	if c.MangaURLDirectory == "" {
		c.MangaURLDirectory = "/manga"
	}
	if c.SearchMangaSelector == "" {
		c.SearchMangaSelector = "div.listupd div.bs, div.listupd div.bsx"
	}
	if c.SeriesThumbSelector == "" {
		c.SeriesThumbSelector = "div.thumb img, div.bigcontent img"
	}
	if c.SeriesAuthorSelector == "" {
		c.SeriesAuthorSelector = ".infotable tr:contains(Author) td:last-child, .tsinfo .imptdt:contains(Author) i"
	}
	if c.SeriesArtistSelector == "" {
		c.SeriesArtistSelector = ".infotable tr:contains(Artist) td:last-child, .tsinfo .imptdt:contains(Artist) i"
	}
	if c.SeriesDescSelector == "" {
		c.SeriesDescSelector = "div.entry-content[itemprop=description] p, div.synops"
	}
	if c.SeriesStatusSelector == "" {
		c.SeriesStatusSelector = ".infotable tr:contains(Status) td:last-child, .tsinfo .imptdt:contains(Status) i"
	}
	if c.SeriesGenreSelector == "" {
		c.SeriesGenreSelector = "div.gnr a, .mgen a, .seriestugenre a"
	}
	if c.SeriesTitleSelector == "" {
		c.SeriesTitleSelector = "h1.entry-title"
	}
	if c.ChapterListSelector == "" {
		c.ChapterListSelector = "div.bxcl li, div.cl li, #chapterlist li, ul li:has(div.chbox)"
	}
}

// Source implements source.CatalogueSource for MangaThemesia sites.
type Source struct {
	cfg    Config
	client *flare.Client
	id     int64
}

func New(cfg Config) *Source {
	cfg.setDefaults()
	opts := []flare.Option{flare.WithRateLimit(1, 2)}
	c := flare.NewClient(opts...)
	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) 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("mangathemesia: HTTP %d for %s", resp.StatusCode, rawURL)
	}
	return goquery.NewDocumentFromReader(resp.Body)
}

func (s *Source) searchURL(page int, query string, orderBy string) string {
	base := strings.TrimRight(s.cfg.BaseURL, "/")
	dir := strings.Trim(s.cfg.MangaURLDirectory, "/")
	u, _ := url.Parse(base + "/" + dir + "/")
	q := u.Query()
	q.Set("title", query)
	q.Set("page", fmt.Sprintf("%d", page))
	if orderBy != "" {
		q.Set("order", orderBy)
	}
	u.RawQuery = q.Encode()
	return u.String()
}

func (s *Source) parseMangaList(doc *goquery.Document) source.MangasPage {
	var mangas []source.SManga
	doc.Find(s.cfg.SearchMangaSelector).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 = stripDomain(href, s.cfg.BaseURL)
			}
		})
		el.Find("div.tt, div.bigor .tt").First().Each(func(_ int, e *goquery.Selection) {
			m.Title = strings.TrimSpace(e.Text())
		})
		if m.Title == "" {
			el.Find("a").First().Each(func(_ int, a *goquery.Selection) {
				m.Title = strings.TrimSpace(a.AttrOr("title", a.Text()))
			})
		}
		el.Find("img").First().Each(func(_ int, img *goquery.Selection) {
			m.ThumbnailURL = imgAttr(img, s.cfg.BaseURL)
		})
		if m.URL != "" {
			mangas = append(mangas, m)
		}
	})
	hasNext := doc.Find(".next, a.r, div.hpage a.r, .pagination .next").Length() > 0
	return source.MangasPage{Mangas: mangas, HasNextPage: hasNext}
}

func (s *Source) GetPopularManga(page int) (source.MangasPage, error) {
	doc, err := s.get(context.Background(), s.searchURL(page, "", "popular"))
	if err != nil {
		return source.MangasPage{}, err
	}
	return s.parseMangaList(doc), nil
}

func (s *Source) GetLatestUpdates(page int) (source.MangasPage, error) {
	doc, err := s.get(context.Background(), s.searchURL(page, "", "update"))
	if err != nil {
		return source.MangasPage{}, err
	}
	return s.parseMangaList(doc), nil
}

func (s *Source) GetSearchManga(page int, query string, filters []source.Filter) (source.MangasPage, error) {
	doc, err := s.get(context.Background(), s.searchURL(page, query, ""))
	if err != nil {
		return source.MangasPage{}, err
	}
	return s.parseMangaList(doc), nil
}

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

	doc.Find(s.cfg.SeriesTitleSelector).First().Each(func(_ int, el *goquery.Selection) {
		result.Title = strings.TrimSpace(el.Text())
	})
	doc.Find(s.cfg.SeriesThumbSelector).First().Each(func(_ int, img *goquery.Selection) {
		result.ThumbnailURL = imgAttr(img, s.cfg.BaseURL)
	})
	doc.Find(s.cfg.SeriesAuthorSelector).First().Each(func(_ int, el *goquery.Selection) {
		result.Author = strings.TrimSpace(el.Text())
	})
	doc.Find(s.cfg.SeriesArtistSelector).First().Each(func(_ int, el *goquery.Selection) {
		result.Artist = strings.TrimSpace(el.Text())
	})
	var descParts []string
	doc.Find(s.cfg.SeriesDescSelector).Each(func(_ int, el *goquery.Selection) {
		if t := strings.TrimSpace(el.Text()); t != "" {
			descParts = append(descParts, t)
		}
	})
	result.Description = strings.Join(descParts, "\n\n")
	doc.Find(s.cfg.SeriesStatusSelector).First().Each(func(_ int, el *goquery.Selection) {
		result.Status = util.StatusFromString(el.Text())
	})
	var genres []string
	doc.Find(s.cfg.SeriesGenreSelector).Each(func(_ int, el *goquery.Selection) {
		if t := strings.TrimSpace(el.Text()); t != "" {
			genres = append(genres, t)
		}
	})
	result.Genre = strings.Join(genres, ", ")
	return result, nil
}

func (s *Source) GetChapterList(manga source.SManga) ([]source.SChapter, error) {
	rawURL := util.AbsURL(s.cfg.BaseURL, manga.URL)
	doc, err := s.get(context.Background(), rawURL)
	if err != nil {
		return nil, err
	}
	var chapters []source.SChapter
	doc.Find(s.cfg.ChapterListSelector).Each(func(i int, el *goquery.Selection) {
		ch := source.SChapter{}
		el.Find("a").First().Each(func(_ int, a *goquery.Selection) {
			if href, ok := a.Attr("href"); ok {
				ch.URL = stripDomain(href, s.cfg.BaseURL)
			}
			el.Find(".chnum").First().Each(func(_ int, e *goquery.Selection) {
				ch.Name = strings.TrimSpace(e.Text())
			})
			if ch.Name == "" {
				ch.Name = strings.TrimSpace(a.Text())
			}
		})
		el.Find(".chapterdate").First().Each(func(_ int, e *goquery.Selection) {
			ch.DateUpload = util.ParseAbsoluteDate(strings.TrimSpace(e.Text()), "January 02, 2006")
			if ch.DateUpload == 0 {
				ch.DateUpload = util.ParseRelativeDate(e.Text())
			}
		})
		if ch.URL != "" {
			chapters = append(chapters, ch)
		}
	})
	return chapters, nil
}

// jsonImageListRe extracts the images array from ts_reader.run({..., "images": [...], ...}).
var jsonImageListRe = regexp.MustCompile(`"images"\s*:\s*(\[.*?])`)

func (s *Source) GetPageList(chapter source.SChapter) ([]source.Page, error) {
	rawURL := util.AbsURL(s.cfg.BaseURL, chapter.URL)
	doc, err := s.get(context.Background(), rawURL)
	if err != nil {
		return nil, err
	}

	// Find ts_reader.run({...}) script
	var imageListJSON string
	doc.Find("script").Each(func(_ int, script *goquery.Selection) {
		text := script.Text()
		if strings.Contains(text, "ts_reader.run") {
			if m := jsonImageListRe.FindStringSubmatch(text); len(m) > 1 {
				imageListJSON = m[1]
			}
		}
	})

	if imageListJSON == "" {
		return nil, fmt.Errorf("mangathemesia: could not find ts_reader image list")
	}

	var images []string
	if err := json.Unmarshal([]byte(imageListJSON), &images); err != nil {
		return nil, fmt.Errorf("mangathemesia: parse images: %w", err)
	}

	pages := make([]source.Page, len(images))
	for i, img := range images {
		pages[i] = source.Page{Index: i, URL: rawURL, ImageURL: util.AbsURL(s.cfg.BaseURL, img)}
	}
	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 stripDomain(href, baseURL string) string {
	parsed, err := url.Parse(href)
	if err != nil || !parsed.IsAbs() {
		return href
	}
	base, err := url.Parse(baseURL)
	if err != nil {
		return href
	}
	if parsed.Host != base.Host {
		return href
	}
	return parsed.RequestURI()
}

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 ""
}