package gallery

import (
	"crypto/md5"
	"encoding/json"
	"fmt"
	"io/fs"
	"os"
	"path/filepath"
	"strings"
	"time"
)

type Gallery struct {
	images   []string
	uuid     string
	title    string
	jpTitle  string
	tags     []Tag
	source   Source
	CTime    time.Time
	artists  []string
	groups   []string
	parodies []string
}

func (g *Gallery) Name() string       { return g.title }
func (g *Gallery) JpName() string     { return g.jpTitle }
func (g *Gallery) Uuid() string       { return g.uuid }
func (g *Gallery) Images() []string   { return g.images }
func (g *Gallery) Tags() []Tag        { return g.tags }
func (g *Gallery) Source() Source     { return g.source }
func (g *Gallery) Artists() []string  { return g.artists }
func (g *Gallery) Groups() []string   { return g.groups }
func (g *Gallery) Parodies() []string { return g.parodies }

func newGallery(
	images []string, uuid string, title string, jpTitle string, tags []Tag,
	source Source, CTime time.Time, artists []string, groups []string, parodies []string,
) Gallery {
	return Gallery{
		images:   images,
		uuid:     uuid,
		title:    title,
		jpTitle:  jpTitle,
		tags:     tags,
		source:   source,
		CTime:    CTime,
		artists:  artists,
		groups:   groups,
		parodies: parodies,
	}
}

type Source string

const (
	Nhentai  Source = "nhentai"
	Exhentai        = "exhentai"
	Hitomi          = "hitomi"
)

type Gender string

const (
	Male   Gender = "male"
	Female Gender = "female"
	Any    Gender = "any"
)

type Tag struct {
	Name string
	Sex  Gender
}

func newTag(name string, sex Gender) Tag {
	return Tag{
		Name: strings.ToLower(name),
		Sex:  sex,
	}
}

func genUuid(title string) string {
	return fmt.Sprintf("%x", md5.Sum([]byte(title)))
}

func filterImages(root string, galleryDir []fs.DirEntry) []string {
	var paths []string
	for _, file := range galleryDir {
		if file.IsDir() {
			continue
		}
		name := file.Name()

		// fixme
		isJpeg := strings.HasSuffix(name, ".jpeg") || strings.HasSuffix(name, ".jpg")
		isPng := strings.HasSuffix(name, ".png")
		isWebp := strings.HasSuffix(name, ".webp")
		isJson := strings.HasSuffix(name, ".json")

		if isJson {
			continue
		}
		if isJpeg || isPng || isWebp {
			paths = append(paths, filepath.Join(root, name))
		}
	}
	return paths
}

func NewNhentaiGallery(infoBinary []byte, root string, galleryDir []fs.DirEntry) (Gallery, error) {
	var data struct {
		Title    string
		Title_en string `json:"title_en"`
		Title_ja string
		// Gallery_id string `json:"gallery_id"` // troublesome
		Media_id                                    int
		Date                                        int64
		Scanlator                                   string
		Artist, Group, Parody, Characters, Tags     []string
		Type, Lang, Language, Category, Subcategory string
		Count                                       int
	}
	err := json.Unmarshal(infoBinary, &data)
	if err != nil {
		return Gallery{}, err
	}
	var tags []Tag
	for _, t := range data.Tags {
		tags = append(tags, newTag(t, Any))
	}
	images := filterImages(root, galleryDir)
	d, err := os.Stat(root)
	if err != nil {
		return Gallery{}, err
	}
	g := newGallery(
		images, genUuid(data.Title), data.Title, data.Title_ja, tags,
		Nhentai, d.ModTime(), data.Artist, data.Group, data.Parody,
	)
	return g, nil
}

func NewExhentaiGallery(infoBinary []byte, root string, galleryDir []fs.DirEntry) (Gallery, error) {
	var data struct {
		Gid          int
		Token        string
		Thumb        string
		Title        string
		Title_jpn    string
		Eh_category  string
		Uploader     string
		Date         string
		Parent       string
		Language     string
		Filecount    string
		Favorites    string
		Rating       string
		Torrentcount string
		Lang         string
		Category     string
		Subcategory  string
		Expunged     bool
		Filesize     int
		Tags         []string
	}
	err := json.Unmarshal(infoBinary, &data)
	if err != nil {
		return Gallery{}, err
	}
	var (
		tags     []Tag
		artists  []string
		groups   []string
		parodies []string
	)
	for _, t := range data.Tags {
		switch {
		case strings.HasPrefix(t, "female:"):
			tags = append(tags, newTag(t[7:], Female))
		case strings.HasPrefix(t, "male:"):
			tags = append(tags, newTag(t[5:], Male))
		case strings.HasPrefix(t, "artist:"):
			artists = append(artists, t[7:])
		case strings.HasPrefix(t, "group:"):
			groups = append(groups, t[6:])
		case strings.HasPrefix(t, "parody:"):
			parodies = append(parodies, t[7:])
		}
	}
	d, err := os.Stat(root)
	if err != nil {
		return Gallery{}, err
	}
	g := newGallery(
		filterImages(root, galleryDir), genUuid(data.Title), data.Title, data.Title_jpn,
		tags, Exhentai, d.ModTime(), artists, groups, parodies,
	)
	return g, nil
}

func NewHitomiGallery(infoBinary []byte, root string, galleryDir []fs.DirEntry) (Gallery, error) {
	var data struct {
		Gallery_id  int
		Title       string
		Title_jpn   string
		Type        string
		Language    string
		Lang        string
		Date        string
		Tags        []string
		Artist      []string
		Group       []string
		Parody      []string
		Characters  []string
		Count       int
		Category    string
		Subcategory string
	}
	err := json.Unmarshal(infoBinary, &data)
	if err != nil {
		return Gallery{}, err
	}
	var tags []Tag
	for _, t := range data.Tags {
		sex := Any
		name := t
		if strings.HasSuffix(t, "♀") {
			sex = Female
			name = t[:len(t)-3]
		} else if strings.HasSuffix(t, "♂") {
			sex = Male
			name = t[:len(t)-3]
		}
		tags = append(tags, newTag(name, sex))
	}
	d, err := os.Stat(root)
	if err != nil {
		return Gallery{}, err
	}
	g := newGallery(
		filterImages(root, galleryDir), genUuid(data.Title), data.Title, data.Title_jpn,
		tags, Hitomi, d.ModTime(), data.Artist, data.Group, data.Parody,
	)
	return g, nil
}

func NewGallery(source Source, infoBinary []byte, root string, galleryDir []fs.DirEntry) (Gallery, error) {
	switch source {
	case Nhentai:
		return NewNhentaiGallery(infoBinary, root, galleryDir)
	case Exhentai:
		return NewExhentaiGallery(infoBinary, root, galleryDir)
	case Hitomi:
		return NewHitomiGallery(infoBinary, root, galleryDir)
	}
	panic(source)
}