// Package manga18 implements the Manga18 manga base.
// HTML scraping; popular: GET {base}/list-manga/{page}?order_by=views; pages via Base64-encoded URLs in inline JS.
package manga18

import (
	"context"
	"encoding/base64"
	"fmt"
	"net/http"
	"strings"
	"time"

	"github.com/PuerkitoBio/goquery"

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

type Config struct {
	Name    string
	BaseURL string
	Lang    string
}

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

func New(cfg Config) *Source {
	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) 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("manga18: HTTP %d", resp.StatusCode)
	}
	return goquery.NewDocumentFromReader(resp.Body)
}

func (s *Source) mangaFromElement(el *goquery.Selection) source.SManga {
	m := source.SManga{}
	el.Find("a").First().Each(func(_ int, a *goquery.Selection) {
		m.URL = a.AttrOr("href", "")
	})
	m.Title = strings.TrimSpace(el.Find("div.mg_info > div.mg_name a").Text())
	if thumb := el.Find("img").First().AttrOr("src", ""); thumb != "" {
		m.ThumbnailURL = util.AbsURL(s.cfg.BaseURL, thumb)
	}
	return m
}

func (s *Source) parseMangaList(doc *goquery.Document) source.MangasPage {
	var mangas []source.SManga
	doc.Find("div.story_item").Each(func(_ int, el *goquery.Selection) {
		m := s.mangaFromElement(el)
		if m.URL != "" && m.Title != "" {
			mangas = append(mangas, m)
		}
	})
	hasNext := doc.Find(".pagination > li:last-child:not(.active)").Length() > 0
	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/list-manga/%d?order_by=views", s.base(), page))
	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(), fmt.Sprintf("%s/list-manga/%d", s.base(), page))
	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) {
	u := fmt.Sprintf("%s/list-manga/%d?search=%s", s.base(), page, query)
	doc, err := s.get(context.Background(), u)
	if err != nil {
		return source.MangasPage{}, err
	}
	return s.parseMangaList(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}
	result.Title = strings.TrimSpace(doc.Find("div.detail_name > h1").Text())
	if result.Title == "" {
		result.Title = manga.Title
	}
	if thumb := doc.Find("div.detail_avatar > img").AttrOr("src", ""); thumb != "" {
		result.ThumbnailURL = util.AbsURL(s.cfg.BaseURL, thumb)
	}
	result.Description = strings.TrimSpace(doc.Find("div.detail_reviewContent").Text())

	info := doc.Find("div.detail_listInfo")
	statusText := strings.TrimSpace(info.Find("div.item div.info_value").FilterFunction(func(_ int, el *goquery.Selection) bool {
		return strings.Contains(el.Parent().Text(), "Status")
	}).Text())
	switch {
	case strings.Contains(statusText, "Ongoing"):
		result.Status = source.StatusOngoing
	case strings.Contains(statusText, "Completed"):
		result.Status = source.StatusCompleted
	default:
		result.Status = source.StatusUnknown
	}

	author := strings.TrimSpace(info.Find("div.info_value").FilterFunction(func(_ int, el *goquery.Selection) bool {
		prev := el.Prev()
		t := strings.ToLower(prev.Text())
		return strings.Contains(t, "author") || strings.Contains(t, "autor")
	}).Text())
	if author != "Updating" {
		result.Author = author
	}
	artist := strings.TrimSpace(info.Find("div.info_value").FilterFunction(func(_ int, el *goquery.Selection) bool {
		return strings.Contains(strings.ToLower(el.Prev().Text()), "artist")
	}).Text())
	if artist != "Updating" {
		result.Artist = artist
	}

	var genres []string
	info.Find("div.info_value > a[href*=/manga-list/]").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
	}
	var chapters []source.SChapter
	doc.Find("div.chapter_box .item").Each(func(_ int, el *goquery.Selection) {
		ch := source.SChapter{}
		el.Find("a").First().Each(func(_ int, a *goquery.Selection) {
			ch.URL = a.AttrOr("href", "")
			ch.Name = strings.TrimSpace(a.Text())
		})
		if dateEl := el.Find("p").First(); dateEl.Length() > 0 {
			ch.DateUpload = parseDate(strings.TrimSpace(dateEl.Text()))
		}
		if ch.URL != "" {
			chapters = append(chapters, ch)
		}
	})
	return chapters, nil
}

func parseDate(s string) int64 {
	t, err := time.Parse("02-01-2006", s)
	if err != nil {
		return 0
	}
	return t.UnixMilli()
}

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 scriptData string
	doc.Find("script").Each(func(_ int, el *goquery.Selection) {
		if scriptData != "" {
			return
		}
		html, _ := el.Html()
		if strings.Contains(html, "slides_p_path") {
			scriptData = html
		}
	})
	if scriptData == "" {
		return nil, fmt.Errorf("manga18: slides_p_path script not found")
	}

	start := strings.Index(scriptData, "[")
	end := strings.LastIndex(scriptData, "]")
	if start < 0 || end <= start {
		return nil, fmt.Errorf("manga18: image array not found")
	}
	// Trim trailing comma before closing bracket
	inner := strings.TrimRight(strings.TrimSpace(scriptData[start+1:end]), ",")
	parts := strings.Split(inner, ",")

	var pages []source.Page
	for i, part := range parts {
		encoded := strings.Trim(strings.TrimSpace(part), `"`)
		if encoded == "" {
			continue
		}
		decoded, err := base64.StdEncoding.DecodeString(encoded)
		if err != nil {
			decoded, err = base64.URLEncoding.DecodeString(encoded)
			if err != nil {
				continue
			}
		}
		imgURL := string(decoded)
		if strings.HasPrefix(imgURL, "/") {
			imgURL = s.base() + imgURL
		}
		pages = append(pages, 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               { return nil }