// Package gmanga implements the GManga Arabic manga base.
// GET {base}/api/releases?page={n}; POST search.
package gmanga

import (
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"strings"

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

type Config struct {
	Name    string
	BaseURL string
	Lang    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, "/") }

type releaseDTO struct {
	Manga struct {
		ID        int    `json:"id"`
		Slug      string `json:"slug"`
		Title     string `json:"title"`
		ArTitle   string `json:"arabic_title"`
		Thumbnail string `json:"thumbnail"`
	} `json:"manga"`
}

type releasesDTO struct {
	Data []releaseDTO `json:"data"`
	Meta struct {
		LastPage int `json:"last_page"`
		CurrentPage int `json:"current_page"`
	} `json:"meta"`
}

func (s *Source) getJSON(ctx context.Context, rawURL string, out any) error {
	req, err := http.NewRequestWithContext(ctx, http.MethodGet, rawURL, nil)
	if err != nil {
		return err
	}
	req.Header.Set("Accept", "application/json")
	resp, err := s.client.Do(req)
	if err != nil {
		return err
	}
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusOK {
		return fmt.Errorf("gmanga: HTTP %d", resp.StatusCode)
	}
	body, _ := io.ReadAll(resp.Body)
	return json.Unmarshal(body, out)
}

func (s *Source) GetPopularManga(page int) (source.MangasPage, error) {
	var result releasesDTO
	if err := s.getJSON(context.Background(), fmt.Sprintf("%s/api/releases?page=%d", s.base(), page), &result); err != nil {
		return source.MangasPage{}, err
	}
	seen := map[int]bool{}
	var mangas []source.SManga
	for _, r := range result.Data {
		if seen[r.Manga.ID] {
			continue
		}
		seen[r.Manga.ID] = true
		title := r.Manga.Title
		if title == "" {
			title = r.Manga.ArTitle
		}
		mangas = append(mangas, source.SManga{
			URL:          fmt.Sprintf("/mangas/%s", r.Manga.Slug),
			Title:        title,
			ThumbnailURL: util.AbsURL(s.cfg.BaseURL, r.Manga.Thumbnail),
		})
	}
	hasNext := result.Meta.CurrentPage < result.Meta.LastPage
	return source.MangasPage{Mangas: mangas, HasNextPage: hasNext}, 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) {
	body, _ := json.Marshal(map[string]any{"q": query, "page": page})
	req, _ := http.NewRequestWithContext(context.Background(), http.MethodPost,
		s.base()+"/api/mangas/search", bytes.NewReader(body))
	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("Accept", "application/json")
	resp, err := s.client.Do(req)
	if err != nil {
		return source.MangasPage{}, err
	}
	defer resp.Body.Close()
	raw, _ := io.ReadAll(resp.Body)
	var result struct {
		Data []struct {
			ID        int    `json:"id"`
			Slug      string `json:"slug"`
			Title     string `json:"title"`
			Thumbnail string `json:"thumbnail"`
		} `json:"data"`
		HasMore bool `json:"has_more"`
	}
	if err := json.Unmarshal(raw, &result); err != nil {
		return source.MangasPage{}, err
	}
	mangas := make([]source.SManga, len(result.Data))
	for i, m := range result.Data {
		mangas[i] = source.SManga{
			URL:          fmt.Sprintf("/mangas/%s", m.Slug),
			Title:        m.Title,
			ThumbnailURL: util.AbsURL(s.cfg.BaseURL, m.Thumbnail),
		}
	}
	return source.MangasPage{Mangas: mangas, HasNextPage: result.HasMore}, nil
}

func (s *Source) GetMangaDetails(manga source.SManga) (source.SManga, error) {
	slug := util.SlugFromURL(manga.URL)
	var result struct {
		Manga struct {
			Title       string   `json:"title"`
			ArTitle     string   `json:"arabic_title"`
			Thumbnail   string   `json:"thumbnail"`
			Description string   `json:"description"`
			Authors     []string `json:"authors"`
			Status      string   `json:"status"`
			Tags        []struct{ Name string `json:"name"` } `json:"tags"`
		} `json:"manga"`
	}
	if err := s.getJSON(context.Background(), fmt.Sprintf("%s/api/mangas/%s", s.base(), slug), &result); err != nil {
		return manga, err
	}
	title := result.Manga.Title
	if title == "" {
		title = result.Manga.ArTitle
	}
	genres := make([]string, len(result.Manga.Tags))
	for i, t := range result.Manga.Tags {
		genres[i] = t.Name
	}
	return source.SManga{
		URL:          manga.URL,
		Title:        title,
		Author:       strings.Join(result.Manga.Authors, ", "),
		Description:  result.Manga.Description,
		Genre:        strings.Join(genres, ", "),
		Status:       util.StatusFromString(result.Manga.Status),
		ThumbnailURL: util.AbsURL(s.cfg.BaseURL, result.Manga.Thumbnail),
	}, nil
}

func (s *Source) GetChapterList(manga source.SManga) ([]source.SChapter, error) {
	slug := util.SlugFromURL(manga.URL)
	var result struct {
		Chapters []struct {
			ID        int     `json:"id"`
			Number    float32 `json:"number"`
			Title     string  `json:"title"`
			CreatedAt string  `json:"created_at"`
		} `json:"chapters"`
	}
	if err := s.getJSON(context.Background(), fmt.Sprintf("%s/api/mangas/%s/chapters", s.base(), slug), &result); err != nil {
		return nil, err
	}
	chapters := make([]source.SChapter, len(result.Chapters))
	for i, ch := range result.Chapters {
		name := fmt.Sprintf("Chapter %.1f", ch.Number)
		if ch.Title != "" {
			name += " - " + ch.Title
		}
		chapters[i] = source.SChapter{
			URL:        fmt.Sprintf("/mangas/%s/%d", slug, ch.ID),
			Name:       name,
			DateUpload: util.ParseAbsoluteDate(ch.CreatedAt, "2006-01-02T15:04:05Z"),
		}
	}
	return chapters, nil
}

func (s *Source) GetPageList(chapter source.SChapter) ([]source.Page, error) {
	chID := util.SlugFromURL(chapter.URL)
	var result struct {
		Pages []struct {
			URL string `json:"url"`
		} `json:"chapter_data"`
	}
	if err := s.getJSON(context.Background(), fmt.Sprintf("%s/api/chapters/%s", s.base(), chID), &result); err != nil {
		return nil, err
	}
	pages := make([]source.Page, len(result.Pages))
	for i, p := range result.Pages {
		pages[i] = source.Page{Index: i, ImageURL: util.AbsURL(s.cfg.BaseURL, p.URL)}
	}
	return pages, nil
}

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