// Package service — Emby/Jellyfin compatibility shim.
//
// EmbyService produces JSON envelopes shaped like the most-consumed
// Emby-API endpoints so existing players (Infuse / Yamby / Hills /
// Senplayer / Kodi NextPVR extension / iOS native clients) can talk to
// MediaStationGo without a custom plugin.
//
// The shim is read-mostly: items, images, playback are fully covered;
// 播放进度上报 / 收藏切换 是写路径但走我们自己的 PlaybackHistory /
// Favorite 表，所以 Emby 客户端的"标记已看 / 收藏"也会反向同步到
// 我们自己的 React UI。
package service

import (
	"context"
	"crypto/sha1"
	"encoding/hex"
	"errors"
	"fmt"
	"path/filepath"
	"regexp"
	"sort"
	"strconv"
	"strings"
	"time"

	"go.uber.org/zap"
	"gorm.io/gorm"

	"github.com/ShukeBta/MediaStationGo/internal/config"
	"github.com/ShukeBta/MediaStationGo/internal/model"
	"github.com/ShukeBta/MediaStationGo/internal/repository"
)

// 用一个固定的 ServerId 字符串。Emby 客户端会缓存这个 id，第一次见到
// 该 id 后会把所有派生数据（cookie/收藏/历史）和它绑定。
const embyServerID = "mediastation-go-001"

// EmbyService produces Emby-shaped JSON.
type EmbyService struct {
	cfg  *config.Config
	log  *zap.Logger
	repo *repository.Container
}

// NewEmbyService is the constructor.
func NewEmbyService(cfg *config.Config, log *zap.Logger, repo *repository.Container) *EmbyService {
	return &EmbyService{cfg: cfg, log: log, repo: repo}
}

// ─── System ──────────────────────────────────────────────────────────────────

// SystemInfo returns the full Emby identity payload.
func (e *EmbyService) SystemInfo() map[string]any {
	return map[string]any{
		"Id":                     embyServerID,
		"ServerId":               embyServerID,
		"ServerName":             "MediaStationGo",
		"Version":                "10.8.13",
		"ProductName":            "Jellyfin Server",
		"OperatingSystem":        "Windows",
		"Architecture":           "X64",
		"LocalAddress":           "",
		"WanAddress":             "",
		"HasPendingRestart":      false,
		"IsShuttingDown":         false,
		"SupportsLibraryMonitor": true,
		"SupportsHttps":          false,
		"SupportsAutoDiscovery":  true,
		"HttpServerPortNumber":   e.cfg.App.Port,
		"HttpsPortNumber":        0,
		"PublishedServerUrl":     "",
		"WebSocketPortNumber":    e.cfg.App.Port,
		"CompletedInstallations": []any{},
		"CanSelfRestart":         false,
		"CanLaunchWebBrowser":    false,
		"CanRestart":             false,
	}
}

// SystemInfoPublic 是不需要认证的精简版（Emby Web 客户端登陆前会拉）。
func (e *EmbyService) SystemInfoPublic() map[string]any {
	return map[string]any{
		"Id":                     embyServerID,
		"ServerId":               embyServerID,
		"ServerName":             "MediaStationGo",
		"Version":                "10.8.13",
		"ProductName":            "Jellyfin Server",
		"OperatingSystem":        "Windows",
		"LocalAddress":           "",
		"WanAddress":             "",
		"HttpServerPortNumber":   e.cfg.App.Port,
		"HttpsPortNumber":        0,
		"SupportsHttps":          false,
		"SupportsAutoDiscovery":  true,
		"StartupWizardCompleted": true,
	}
}

// ─── Users ───────────────────────────────────────────────────────────────────

// ListUsers returns Emby-shaped users.
func (e *EmbyService) ListUsers(ctx context.Context) ([]map[string]any, error) {
	users, err := e.repo.User.List(ctx)
	if err != nil {
		return nil, err
	}
	out := make([]map[string]any, 0, len(users))
	for _, u := range users {
		out = append(out, e.userPayload(&u))
	}
	return out, nil
}

// FindUser 用 ID 查用户，用于 /Users/Me 与 /Users/{id}。
func (e *EmbyService) FindUser(ctx context.Context, id string) (map[string]any, error) {
	u, err := e.repo.User.FindByID(ctx, id)
	if err != nil || u == nil {
		return nil, err
	}
	return e.userPayload(u), nil
}

func (e *EmbyService) userPayload(u *model.User) map[string]any {
	return map[string]any{
		"Id":                        u.ID,
		"Name":                      u.Username,
		"ServerId":                  embyServerID,
		"ServerName":                "MediaStationGo",
		"HasPassword":               true,
		"HasConfiguredPassword":     true,
		"HasConfiguredEasyPassword": false,
		"EnableAutoLogin":           false,
		"LastLoginDate":             u.LastLoginAt,
		"LastActivityDate":          u.UpdatedAt,
		"Configuration": map[string]any{
			"PlayDefaultAudioTrack":      true,
			"DisplayCollectionsView":     true,
			"DisplayMissingEpisodes":     false,
			"SubtitleMode":               "Default",
			"EnableNextEpisodeAutoPlay":  true,
			"AudioLanguagePreference":    "",
			"SubtitleLanguagePreference": "",
		},
		"Policy": map[string]any{
			"IsAdministrator":                u.Role == "admin",
			"IsHidden":                       false,
			"IsDisabled":                     !u.IsActive,
			"EnableUserPreferenceAccess":     true,
			"EnableRemoteAccess":             true,
			"EnableMediaPlayback":            true,
			"EnableAudioPlaybackTranscoding": true,
			"EnableVideoPlaybackTranscoding": true,
			"EnablePlaybackRemuxing":         true,
			"EnableLiveTvAccess":             false,
			"EnableContentDownloading":       true,
			"EnableSyncTranscoding":          true,
			"EnableMediaConversion":          true,
			"EnableAllChannels":              true,
			"EnableAllFolders":               true,
			"EnableAllDevices":               true,
			"AuthenticationProviderId":       "Emby.Server.Implementations.LocalAuthenticationProvider",
			"PasswordResetProviderId":        "Emby.Server.Implementations.LocalPasswordResetProvider",
		},
	}
}

// ─── Views / MediaFolders ────────────────────────────────────────────────────

// Views 返回 Emby 中"虚拟根目录"——每个 library 一个条目。
func (e *EmbyService) Views(ctx context.Context) (map[string]any, error) {
	libs, err := e.repo.Library.List(ctx)
	if err != nil {
		return nil, err
	}
	items := make([]map[string]any, 0, len(libs))
	for _, l := range libs {
		items = append(items, e.libraryAsView(&l))
	}
	return map[string]any{"Items": items, "TotalRecordCount": len(items)}, nil
}

func (e *EmbyService) libraryAsView(l *model.Library) map[string]any {
	collectionType := "movies"
	switch l.Type {
	case "tv":
		collectionType = "tvshows"
	case "anime":
		collectionType = "tvshows" // Emby 没有专门的 anime CollectionType
	case "variety":
		collectionType = "tvshows"
	case "music":
		collectionType = "music"
	}
	return map[string]any{
		"Id":                l.ID,
		"Name":              l.Name,
		"CollectionType":    collectionType,
		"ServerId":          embyServerID,
		"Type":              "CollectionFolder",
		"IsFolder":          true,
		"ImageTags":         map[string]string{},
		"BackdropImageTags": []string{},
		"UserData": map[string]any{
			"PlaybackPositionTicks": 0,
			"PlayCount":             0,
			"IsFavorite":            false,
			"Played":                false,
			"UnplayedItemCount":     0,
		},
	}
}

// ─── Items ───────────────────────────────────────────────────────────────────

// ItemsParams 是 /Items 与 /Users/{uid}/Items 共用的查询参数。
type ItemsParams struct {
	UserID           string
	ParentID         string
	IDs              []string
	SearchTerm       string
	IncludeItemTypes []string
	Recursive        bool
	SortBy           string
	SortOrder        string
	Limit            int
	StartIndex       int
}

const (
	embyVirtualSeriesPrefix = "msgo-series-"
	embyVirtualSeasonPrefix = "msgo-season-"
)

var (
	embySeasonDirRE    = regexp.MustCompile(`(?i)^(season[\s._-]*\d+|s\d+|第\s*\d+\s*季)$`)
	embyYearSuffixRE   = regexp.MustCompile(`\s*[\(（\[]\d{4}[\)）\]]\s*$`)
	embyEpisodeTitleRE = regexp.MustCompile(`(?i)\s*[-_ ]*s\d{1,2}e\d{1,3}.*$`)
)

type embySeriesGroup struct {
	ID          string
	LibraryID   string
	Name        string
	PosterURL   string
	BackdropURL string
	Overview    string
	Rating      float32
	Year        int
	TMDbID      int
	BangumiID   int
	CreatedAt   time.Time
	Episodes    []model.Media
}

type embySeasonGroup struct {
	ID        string
	SeriesID  string
	LibraryID string
	Name      string
	SeasonNum int
	Series    embySeriesGroup
	Episodes  []model.Media
}

// Items paginates media in Emby's hierarchy. Episodic libraries are exposed as
// Series -> Season -> Episode so Infuse/Vidhub/SenPlayer stop treating every
// episode as a separate movie card.
func (e *EmbyService) Items(ctx context.Context, p ItemsParams) (map[string]any, error) {
	if p.Limit <= 0 || p.Limit > 500 {
		p.Limit = 50
	}
	if p.StartIndex < 0 {
		p.StartIndex = 0
	}

	if len(p.IDs) > 0 {
		items := make([]map[string]any, 0, len(p.IDs))
		for _, id := range p.IDs {
			item, err := e.Item(ctx, id, p.UserID)
			if err != nil {
				return nil, err
			}
			if item != nil {
				items = append(items, item)
			}
		}
		return map[string]any{"Items": items, "TotalRecordCount": len(items), "StartIndex": 0}, nil
	}

	if p.ParentID == "" && p.SearchTerm == "" && !p.Recursive && len(p.IncludeItemTypes) == 0 {
		return e.Views(ctx)
	}

	if season, ok, err := e.findSeasonGroup(ctx, p.ParentID); err != nil {
		return nil, err
	} else if ok {
		return e.episodeItems(ctx, season.Episodes, p)
	}

	if series, ok, err := e.findSeriesGroup(ctx, p.ParentID); err != nil {
		return nil, err
	} else if ok {
		if p.Recursive || containsItemType(p.IncludeItemTypes, "Episode") {
			return e.episodeItems(ctx, series.Episodes, p)
		}
		seasons := e.seasonsForSeries(series)
		items := make([]map[string]any, 0, len(seasons))
		for _, season := range pageSlice(seasons, p.StartIndex, p.Limit) {
			items = append(items, e.seasonPayload(season))
		}
		return map[string]any{"Items": items, "TotalRecordCount": len(seasons), "StartIndex": p.StartIndex}, nil
	}

	if p.ParentID != "" {
		if episodic, err := e.libraryIsEpisodic(ctx, p.ParentID); err != nil {
			return nil, err
		} else if episodic && !p.Recursive && !containsItemType(p.IncludeItemTypes, "Episode") {
			return e.seriesItemsForLibrary(ctx, p.ParentID, p)
		}
	}

	if containsItemType(p.IncludeItemTypes, "Series") && !containsItemType(p.IncludeItemTypes, "Episode") {
		return e.seriesItemsForLibrary(ctx, p.ParentID, p)
	}
	return e.mediaItems(ctx, p)
}

func (e *EmbyService) mediaItems(ctx context.Context, p ItemsParams) (map[string]any, error) {
	q := e.repo.DB.WithContext(ctx).Model(&model.Media{})
	if p.ParentID != "" {
		q = q.Where("library_id = ? OR series_id = ?", p.ParentID, p.ParentID)
	}
	if p.SearchTerm != "" {
		q = q.Where("title LIKE ? OR original_name LIKE ?", "%"+p.SearchTerm+"%", "%"+p.SearchTerm+"%")
	}
	if containsItemType(p.IncludeItemTypes, "Movie") && !containsItemType(p.IncludeItemTypes, "Episode") {
		q = q.Where("season_num = 0 AND episode_num = 0")
	}
	if containsItemType(p.IncludeItemTypes, "Episode") && !containsItemType(p.IncludeItemTypes, "Movie") {
		q = q.Where("season_num > 0 OR episode_num > 0")
	}

	var total int64
	if err := q.Count(&total).Error; err != nil {
		return nil, err
	}
	order := "created_at desc"
	switch strings.ToLower(p.SortBy) {
	case "sortname", "name":
		order = "title"
	case "premieredate", "productionyear":
		order = "year"
	case "datecreated":
		order = "created_at"
	case "communityrating":
		order = "rating"
	}
	if strings.EqualFold(p.SortOrder, "Descending") {
		if !strings.HasSuffix(order, " desc") {
			order = order + " desc"
		}
	}

	var rows []model.Media
	if err := q.Order(order).Offset(p.StartIndex).Limit(p.Limit).Find(&rows).Error; err != nil {
		return nil, err
	}
	items, err := e.payloadsForMedia(ctx, rows, p.UserID)
	if err != nil {
		return nil, err
	}
	return map[string]any{"Items": items, "TotalRecordCount": total, "StartIndex": p.StartIndex}, nil
}

func (e *EmbyService) episodeItems(ctx context.Context, rows []model.Media, p ItemsParams) (map[string]any, error) {
	if p.SearchTerm != "" {
		filtered := rows[:0]
		needle := strings.ToLower(p.SearchTerm)
		for _, row := range rows {
			if strings.Contains(strings.ToLower(row.Title), needle) || strings.Contains(strings.ToLower(row.OriginalName), needle) {
				filtered = append(filtered, row)
			}
		}
		rows = filtered
	}
	sort.SliceStable(rows, func(i, j int) bool {
		if rows[i].SeasonNum != rows[j].SeasonNum {
			return rows[i].SeasonNum < rows[j].SeasonNum
		}
		if rows[i].EpisodeNum != rows[j].EpisodeNum {
			return rows[i].EpisodeNum < rows[j].EpisodeNum
		}
		return rows[i].CreatedAt.Before(rows[j].CreatedAt)
	})
	total := len(rows)
	items, err := e.payloadsForMedia(ctx, pageSlice(rows, p.StartIndex, p.Limit), p.UserID)
	if err != nil {
		return nil, err
	}
	return map[string]any{"Items": items, "TotalRecordCount": total, "StartIndex": p.StartIndex}, nil
}

func (e *EmbyService) payloadsForMedia(ctx context.Context, rows []model.Media, userID string) ([]map[string]any, error) {
	userFavs := map[string]bool{}
	userPos := map[string]int64{}
	if userID != "" {
		var favs []model.Favorite
		_ = e.repo.DB.WithContext(ctx).Where("user_id = ?", userID).Find(&favs).Error
		for _, f := range favs {
			userFavs[f.MediaID] = true
		}
		var hist []model.PlaybackHistory
		_ = e.repo.DB.WithContext(ctx).Where("user_id = ?", userID).Find(&hist).Error
		for _, h := range hist {
			userPos[h.MediaID] = h.PositionMs
		}
	}

	items := make([]map[string]any, 0, len(rows))
	for _, m := range rows {
		items = append(items, e.itemPayload(&m, userFavs[m.ID], userPos[m.ID]))
	}
	return items, nil
}

// Item 单条目详情。
func (e *EmbyService) Item(ctx context.Context, mediaID, userID string) (map[string]any, error) {
	if strings.HasPrefix(mediaID, embyVirtualSeasonPrefix) {
		if season, ok, err := e.findSeasonGroup(ctx, mediaID); err != nil {
			return nil, err
		} else if ok {
			return e.seasonPayload(season), nil
		}
	}
	if strings.HasPrefix(mediaID, embyVirtualSeriesPrefix) {
		if series, ok, err := e.findSeriesGroup(ctx, mediaID); err != nil {
			return nil, err
		} else if ok {
			return e.seriesPayload(series), nil
		}
	}
	m, err := e.repo.Media.FindByID(ctx, mediaID)
	if err != nil {
		return nil, err
	}
	if m == nil {
		if series, ok, err := e.findSeriesGroup(ctx, mediaID); err != nil {
			return nil, err
		} else if ok {
			return e.seriesPayload(series), nil
		}
		return nil, nil
	}
	fav := false
	pos := int64(0)
	if userID != "" {
		var f model.Favorite
		ferr := e.repo.DB.WithContext(ctx).Where("user_id = ? AND media_id = ?", userID, mediaID).First(&f).Error
		if ferr == nil {
			fav = true
		}
		var h model.PlaybackHistory
		herr := e.repo.DB.WithContext(ctx).Where("user_id = ? AND media_id = ?", userID, mediaID).
			Order("watched_at desc").First(&h).Error
		if herr == nil {
			pos = h.PositionMs
		}
	}
	return e.itemPayload(m, fav, pos), nil
}

// LatestItems 最近添加，全库或指定库。
func (e *EmbyService) LatestItems(ctx context.Context, userID, parentID string, limit int) ([]map[string]any, error) {
	if limit <= 0 || limit > 100 {
		limit = 20
	}
	q := e.repo.DB.WithContext(ctx).Model(&model.Media{}).Where("deleted_at IS NULL")
	if parentID != "" {
		if episodic, err := e.libraryIsEpisodic(ctx, parentID); err == nil && episodic {
			resp, err := e.seriesItemsForLibrary(ctx, parentID, ItemsParams{
				UserID:     userID,
				ParentID:   parentID,
				Limit:      limit,
				StartIndex: 0,
				SortBy:     "datecreated",
				SortOrder:  "Descending",
			})
			if err != nil {
				return nil, err
			}
			items, _ := resp["Items"].([]map[string]any)
			return items, nil
		}
		q = q.Where("library_id = ?", parentID)
	}
	var rows []model.Media
	if err := q.Order("created_at desc").Limit(limit).Find(&rows).Error; err != nil {
		return nil, err
	}
	favs := map[string]bool{}
	if userID != "" {
		var fr []model.Favorite
		_ = e.repo.DB.WithContext(ctx).Where("user_id = ?", userID).Find(&fr).Error
		for _, f := range fr {
			favs[f.MediaID] = true
		}
	}
	out := make([]map[string]any, 0, len(rows))
	for _, m := range rows {
		out = append(out, e.itemPayload(&m, favs[m.ID], 0))
	}
	return out, nil
}

// ResumeItems 列出有未完成播放进度的媒体。
func (e *EmbyService) ResumeItems(ctx context.Context, userID string, limit int) (map[string]any, error) {
	if limit <= 0 || limit > 100 {
		limit = 20
	}
	type row struct {
		MediaID    string
		PositionMs int64
		DurationMs int64
	}
	var hist []model.PlaybackHistory
	if err := e.repo.DB.WithContext(ctx).
		Where("user_id = ? AND completed = ? AND position_ms > 0", userID, false).
		Order("watched_at desc").Limit(limit).Find(&hist).Error; err != nil {
		return nil, err
	}
	if len(hist) == 0 {
		return map[string]any{"Items": []any{}, "TotalRecordCount": 0}, nil
	}
	ids := make([]string, 0, len(hist))
	posByID := map[string]int64{}
	for _, h := range hist {
		ids = append(ids, h.MediaID)
		posByID[h.MediaID] = h.PositionMs
	}
	var medias []model.Media
	if err := e.repo.DB.WithContext(ctx).Where("id IN ?", ids).Find(&medias).Error; err != nil {
		return nil, err
	}
	// 维持时间倒序
	byID := map[string]*model.Media{}
	for i := range medias {
		byID[medias[i].ID] = &medias[i]
	}
	items := make([]map[string]any, 0, len(hist))
	for _, h := range hist {
		if m, ok := byID[h.MediaID]; ok {
			items = append(items, e.itemPayload(m, false, posByID[h.MediaID]))
		}
	}
	return map[string]any{"Items": items, "TotalRecordCount": len(items)}, nil
}

func (e *EmbyService) itemPayload(m *model.Media, fav bool, posMs int64) map[string]any {
	itemType := "Movie"
	name := m.Title
	parentID := m.LibraryID
	seriesID := m.SeriesID
	seriesName := ""
	seasonID := ""
	if m.SeasonNum > 0 || m.EpisodeNum > 0 {
		itemType = "Episode"
		seriesID = e.seriesIDForMedia(m)
		seriesName = e.seriesNameForMedia(m)
		seasonID = e.seasonIDForMedia(m)
		parentID = seasonID
		originalName := strings.TrimSpace(m.OriginalName)
		if originalName != "" && !strings.EqualFold(originalName, seriesName) && !strings.EqualFold(originalName, m.Title) {
			name = m.OriginalName
		} else if m.EpisodeNum > 0 {
			name = fmt.Sprintf("第 %d 集", m.EpisodeNum)
		}
	}
	imageTags := map[string]string{}
	backdropTags := []string{}
	if m.PosterURL != "" {
		imageTags["Primary"] = m.ID
	}
	if m.BackdropURL != "" {
		backdropTags = append(backdropTags, m.ID+"-bd")
	}

	runTimeTicks := int64(m.DurationSec) * 10_000_000
	durationMs := int64(m.DurationSec) * 1000
	played := posMs > 0 && durationMs > 0 && posMs >= durationMs*9/10
	pct := 0.0
	if durationMs > 0 {
		pct = float64(posMs) / float64(durationMs) * 100
	}

	return map[string]any{
		"Id":                m.ID,
		"Name":              name,
		"OriginalTitle":     m.OriginalName,
		"ServerId":          embyServerID,
		"Type":              itemType,
		"MediaType":         "Video",
		"IsFolder":          false,
		"ProductionYear":    m.Year,
		"ParentIndexNumber": m.SeasonNum,
		"IndexNumber":       m.EpisodeNum,
		"Overview":          m.Overview,
		"RunTimeTicks":      runTimeTicks,
		"CommunityRating":   m.Rating,
		"Container":         m.Container,
		"Width":             m.Width,
		"Height":            m.Height,
		"DateCreated":       m.CreatedAt,
		"Path":              m.Path,
		"ParentId":          parentID,
		"SeasonId":          seasonID,
		"SeasonName":        seasonName(m.SeasonNum),
		"SeriesId":          seriesID,
		"SeriesName":        seriesName,
		"ImageTags":         imageTags,
		"BackdropImageTags": backdropTags,
		"Genres":            splitCSV(m.Genres),
		"ProviderIds": map[string]string{
			"Tmdb":    intToStr(m.TMDbID),
			"Bangumi": intToStr(m.BangumiID),
		},
		"UserData": map[string]any{
			"PlaybackPositionTicks": posMs * 10_000,
			"PlayCount":             0,
			"IsFavorite":            fav,
			"Played":                played,
			"PlayedPercentage":      pct,
		},
		"MediaSources": []map[string]any{e.mediaSource(m, true)},
	}
}

func (e *EmbyService) seriesItemsForLibrary(ctx context.Context, libraryID string, p ItemsParams) (map[string]any, error) {
	q := e.repo.DB.WithContext(ctx).Model(&model.Media{}).Where("season_num > 0 OR episode_num > 0")
	if libraryID != "" {
		q = q.Where("library_id = ?", libraryID)
	}
	if p.SearchTerm != "" {
		q = q.Where("title LIKE ? OR original_name LIKE ?", "%"+p.SearchTerm+"%", "%"+p.SearchTerm+"%")
	}
	var rows []model.Media
	if err := q.Order("created_at desc").Find(&rows).Error; err != nil {
		return nil, err
	}
	groups := e.seriesGroupsFromMedia(rows)
	sortSeriesGroups(groups, p)
	total := len(groups)
	items := make([]map[string]any, 0, minInt(p.Limit, len(groups)))
	for _, group := range pageSlice(groups, p.StartIndex, p.Limit) {
		items = append(items, e.seriesPayload(group))
	}
	return map[string]any{"Items": items, "TotalRecordCount": total, "StartIndex": p.StartIndex}, nil
}

func (e *EmbyService) libraryIsEpisodic(ctx context.Context, libraryID string) (bool, error) {
	if strings.TrimSpace(libraryID) == "" {
		return false, nil
	}
	if lib, err := e.repo.Library.FindByID(ctx, libraryID); err != nil {
		return false, err
	} else if lib != nil {
		switch lib.Type {
		case "tv", "anime", "variety":
			return true, nil
		}
	}
	var count int64
	err := e.repo.DB.WithContext(ctx).Model(&model.Media{}).
		Where("library_id = ? AND (season_num > 0 OR episode_num > 0)", libraryID).
		Count(&count).Error
	return count > 0, err
}

func (e *EmbyService) findSeriesGroup(ctx context.Context, id string) (embySeriesGroup, bool, error) {
	if strings.TrimSpace(id) == "" {
		return embySeriesGroup{}, false, nil
	}
	var rows []model.Media
	q := e.repo.DB.WithContext(ctx).Model(&model.Media{}).Where("season_num > 0 OR episode_num > 0")
	if !strings.HasPrefix(id, embyVirtualSeriesPrefix) {
		q = q.Where("series_id = ?", id)
	}
	if err := q.Order("season_num asc, episode_num asc, created_at asc").Find(&rows).Error; err != nil {
		return embySeriesGroup{}, false, err
	}
	for _, group := range e.seriesGroupsFromMedia(rows) {
		if group.ID == id {
			return group, true, nil
		}
	}
	if !strings.HasPrefix(id, embyVirtualSeriesPrefix) {
		if series, err := e.repo.Series.FindByID(ctx, id); err != nil {
			return embySeriesGroup{}, false, err
		} else if series != nil {
			return embySeriesGroup{
				ID:          series.ID,
				LibraryID:   series.LibraryID,
				Name:        series.Title,
				PosterURL:   series.PosterURL,
				BackdropURL: series.BackdropURL,
				Overview:    series.Overview,
				Rating:      series.Rating,
				Year:        series.Year,
				TMDbID:      series.TMDbID,
				BangumiID:   series.BangumiID,
				CreatedAt:   series.CreatedAt,
			}, true, nil
		}
	}
	return embySeriesGroup{}, false, nil
}

func (e *EmbyService) findSeasonGroup(ctx context.Context, id string) (embySeasonGroup, bool, error) {
	if strings.TrimSpace(id) == "" || !strings.HasPrefix(id, embyVirtualSeasonPrefix) {
		return embySeasonGroup{}, false, nil
	}
	var rows []model.Media
	if err := e.repo.DB.WithContext(ctx).Model(&model.Media{}).
		Where("season_num > 0 OR episode_num > 0").
		Order("season_num asc, episode_num asc, created_at asc").
		Find(&rows).Error; err != nil {
		return embySeasonGroup{}, false, err
	}
	for _, series := range e.seriesGroupsFromMedia(rows) {
		for _, season := range e.seasonsForSeries(series) {
			if season.ID == id {
				return season, true, nil
			}
		}
	}
	return embySeasonGroup{}, false, nil
}

func (e *EmbyService) seriesGroupsFromMedia(rows []model.Media) []embySeriesGroup {
	byID := map[string]*embySeriesGroup{}
	order := []string{}
	for _, row := range rows {
		row := row
		seriesID := e.seriesIDForMedia(&row)
		group, ok := byID[seriesID]
		if !ok {
			group = &embySeriesGroup{
				ID:        seriesID,
				LibraryID: row.LibraryID,
				Name:      e.seriesNameForMedia(&row),
				Year:      row.Year,
				TMDbID:    row.TMDbID,
				BangumiID: row.BangumiID,
				CreatedAt: row.CreatedAt,
			}
			byID[seriesID] = group
			order = append(order, seriesID)
		}
		if row.CreatedAt.After(group.CreatedAt) {
			group.CreatedAt = row.CreatedAt
		}
		if group.PosterURL == "" && row.PosterURL != "" {
			group.PosterURL = row.PosterURL
		}
		if group.BackdropURL == "" && row.BackdropURL != "" {
			group.BackdropURL = row.BackdropURL
		}
		if group.Overview == "" && row.Overview != "" {
			group.Overview = row.Overview
		}
		if group.Rating == 0 && row.Rating > 0 {
			group.Rating = row.Rating
		}
		if group.Year == 0 && row.Year > 0 {
			group.Year = row.Year
		}
		group.Episodes = append(group.Episodes, row)
	}
	groups := make([]embySeriesGroup, 0, len(order))
	for _, id := range order {
		group := *byID[id]
		sort.SliceStable(group.Episodes, func(i, j int) bool {
			if group.Episodes[i].SeasonNum != group.Episodes[j].SeasonNum {
				return group.Episodes[i].SeasonNum < group.Episodes[j].SeasonNum
			}
			if group.Episodes[i].EpisodeNum != group.Episodes[j].EpisodeNum {
				return group.Episodes[i].EpisodeNum < group.Episodes[j].EpisodeNum
			}
			return group.Episodes[i].CreatedAt.Before(group.Episodes[j].CreatedAt)
		})
		groups = append(groups, group)
	}
	return groups
}

func (e *EmbyService) seasonsForSeries(series embySeriesGroup) []embySeasonGroup {
	bySeason := map[int]*embySeasonGroup{}
	order := []int{}
	for _, episode := range series.Episodes {
		seasonNum := episode.SeasonNum
		if seasonNum <= 0 {
			seasonNum = 1
		}
		season, ok := bySeason[seasonNum]
		if !ok {
			season = &embySeasonGroup{
				ID:        seasonID(series.ID, seasonNum),
				SeriesID:  series.ID,
				LibraryID: series.LibraryID,
				Name:      seasonName(seasonNum),
				SeasonNum: seasonNum,
				Series:    series,
			}
			bySeason[seasonNum] = season
			order = append(order, seasonNum)
		}
		season.Episodes = append(season.Episodes, episode)
	}
	sort.Ints(order)
	out := make([]embySeasonGroup, 0, len(order))
	for _, seasonNum := range order {
		out = append(out, *bySeason[seasonNum])
	}
	return out
}

func (e *EmbyService) seriesPayload(group embySeriesGroup) map[string]any {
	imageTags := map[string]string{}
	backdropTags := []string{}
	if group.PosterURL != "" {
		imageTags["Primary"] = group.ID
	}
	if group.BackdropURL != "" {
		backdropTags = append(backdropTags, group.ID+"-bd")
	}
	return map[string]any{
		"Id":                 group.ID,
		"Name":               group.Name,
		"ServerId":           embyServerID,
		"Type":               "Series",
		"MediaType":          "Video",
		"IsFolder":           true,
		"ParentId":           group.LibraryID,
		"ProductionYear":     group.Year,
		"Overview":           group.Overview,
		"CommunityRating":    group.Rating,
		"RecursiveItemCount": len(group.Episodes),
		"ChildCount":         len(e.seasonsForSeries(group)),
		"DateCreated":        group.CreatedAt,
		"ImageTags":          imageTags,
		"BackdropImageTags":  backdropTags,
		"ProviderIds": map[string]string{
			"Tmdb":    intToStr(group.TMDbID),
			"Bangumi": intToStr(group.BangumiID),
		},
		"UserData": emptyUserData(),
	}
}

func (e *EmbyService) seasonPayload(season embySeasonGroup) map[string]any {
	imageTags := map[string]string{}
	backdropTags := []string{}
	if season.Series.PosterURL != "" {
		imageTags["Primary"] = season.ID
	}
	if season.Series.BackdropURL != "" {
		backdropTags = append(backdropTags, season.ID+"-bd")
	}
	return map[string]any{
		"Id":                season.ID,
		"Name":              season.Name,
		"ServerId":          embyServerID,
		"Type":              "Season",
		"MediaType":         "Video",
		"IsFolder":          true,
		"ParentId":          season.SeriesID,
		"SeriesId":          season.SeriesID,
		"SeriesName":        season.Series.Name,
		"IndexNumber":       season.SeasonNum,
		"ChildCount":        len(season.Episodes),
		"ImageTags":         imageTags,
		"BackdropImageTags": backdropTags,
		"UserData":          emptyUserData(),
	}
}

// ImageURL returns artwork for a media/series/season item id.
func (e *EmbyService) ImageURL(ctx context.Context, id, imageType string) (string, error) {
	pick := func(primary, backdrop string) string {
		switch strings.ToLower(imageType) {
		case "backdrop", "art":
			if backdrop != "" {
				return backdrop
			}
		}
		if primary != "" {
			return primary
		}
		return backdrop
	}
	if strings.HasPrefix(id, embyVirtualSeasonPrefix) {
		if season, ok, err := e.findSeasonGroup(ctx, id); err != nil {
			return "", err
		} else if ok {
			return pick(season.Series.PosterURL, season.Series.BackdropURL), nil
		}
	}
	if strings.HasPrefix(id, embyVirtualSeriesPrefix) {
		if series, ok, err := e.findSeriesGroup(ctx, id); err != nil {
			return "", err
		} else if ok {
			return pick(series.PosterURL, series.BackdropURL), nil
		}
	}
	m, err := e.repo.Media.FindByID(ctx, id)
	if err == nil && m != nil {
		return pick(m.PosterURL, m.BackdropURL), nil
	}
	if err != nil {
		return "", err
	}
	if series, ok, err := e.findSeriesGroup(ctx, id); err != nil {
		return "", err
	} else if ok {
		return pick(series.PosterURL, series.BackdropURL), nil
	}
	return "", nil
}

func (e *EmbyService) seriesIDForMedia(m *model.Media) string {
	if strings.TrimSpace(m.SeriesID) != "" {
		return m.SeriesID
	}
	return stableEmbyID(embyVirtualSeriesPrefix, m.LibraryID, e.seriesNameForMedia(m))
}

func (e *EmbyService) seasonIDForMedia(m *model.Media) string {
	return seasonID(e.seriesIDForMedia(m), maxInt(m.SeasonNum, 1))
}

func (e *EmbyService) seriesNameForMedia(m *model.Media) string {
	if strings.TrimSpace(m.SeriesID) != "" {
		if series, err := e.repo.Series.FindByID(context.Background(), m.SeriesID); err == nil && series != nil && strings.TrimSpace(series.Title) != "" {
			return series.Title
		}
	}
	if name := inferSeriesNameFromPath(m.Path); name != "" {
		return name
	}
	name := strings.TrimSpace(m.Title)
	name = embyEpisodeTitleRE.ReplaceAllString(name, "")
	name = embyYearSuffixRE.ReplaceAllString(name, "")
	if name == "" {
		name = strings.TrimSpace(m.OriginalName)
	}
	return name
}

func inferSeriesNameFromPath(path string) string {
	path = strings.TrimSpace(path)
	if path == "" {
		return ""
	}
	dir := filepath.Dir(path)
	base := filepath.Base(dir)
	if embySeasonDirRE.MatchString(base) {
		dir = filepath.Dir(dir)
		base = filepath.Base(dir)
	}
	base = strings.TrimSpace(embyYearSuffixRE.ReplaceAllString(base, ""))
	if base == "." || base == string(filepath.Separator) {
		return ""
	}
	return base
}

func stableEmbyID(prefix string, parts ...string) string {
	h := sha1.New()
	for _, part := range parts {
		_, _ = h.Write([]byte(strings.ToLower(strings.TrimSpace(part))))
		_, _ = h.Write([]byte{0})
	}
	return prefix + hex.EncodeToString(h.Sum(nil))[:32]
}

func seasonID(seriesID string, seasonNum int) string {
	return stableEmbyID(embyVirtualSeasonPrefix, seriesID, strconv.Itoa(maxInt(seasonNum, 1)))
}

func seasonName(seasonNum int) string {
	if seasonNum <= 0 {
		seasonNum = 1
	}
	return fmt.Sprintf("第 %d 季", seasonNum)
}

func sortSeriesGroups(groups []embySeriesGroup, p ItemsParams) {
	switch strings.ToLower(p.SortBy) {
	case "sortname", "name":
		sort.SliceStable(groups, func(i, j int) bool {
			if strings.EqualFold(p.SortOrder, "Descending") {
				return groups[i].Name > groups[j].Name
			}
			return groups[i].Name < groups[j].Name
		})
	default:
		sort.SliceStable(groups, func(i, j int) bool {
			if strings.EqualFold(p.SortOrder, "Ascending") {
				return groups[i].CreatedAt.Before(groups[j].CreatedAt)
			}
			return groups[i].CreatedAt.After(groups[j].CreatedAt)
		})
	}
}

func containsItemType(types []string, want string) bool {
	for _, t := range types {
		if strings.EqualFold(strings.TrimSpace(t), want) {
			return true
		}
	}
	return false
}

func pageSlice[T any](items []T, start, limit int) []T {
	if start < 0 {
		start = 0
	}
	if limit <= 0 {
		limit = len(items)
	}
	if start >= len(items) {
		return []T{}
	}
	end := start + limit
	if end > len(items) {
		end = len(items)
	}
	return items[start:end]
}

func emptyUserData() map[string]any {
	return map[string]any{
		"PlaybackPositionTicks": 0,
		"PlayCount":             0,
		"IsFavorite":            false,
		"Played":                false,
		"PlayedPercentage":      0,
	}
}

func minInt(a, b int) int {
	if a < b {
		return a
	}
	return b
}

func maxInt(a, b int) int {
	if a > b {
		return a
	}
	return b
}

// ─── Playback ────────────────────────────────────────────────────────────────

// PlaybackInfo returns a PlaybackInfoResponse usable by Emby clients.
func (e *EmbyService) PlaybackInfo(ctx context.Context, mediaID string) (map[string]any, error) {
	m, err := e.playableMedia(ctx, mediaID)
	if err != nil || m == nil {
		return nil, err
	}
	return map[string]any{
		"MediaSources":  []map[string]any{e.mediaSource(m, false)},
		"PlaySessionId": fmt.Sprintf("%s-%d", m.ID, time.Now().Unix()),
	}, nil
}

func (e *EmbyService) playableMedia(ctx context.Context, id string) (*model.Media, error) {
	if season, ok, err := e.findSeasonGroup(ctx, id); err != nil {
		return nil, err
	} else if ok && len(season.Episodes) > 0 {
		return &season.Episodes[0], nil
	}
	if series, ok, err := e.findSeriesGroup(ctx, id); err != nil {
		return nil, err
	} else if ok && len(series.Episodes) > 0 {
		return &series.Episodes[0], nil
	}
	return e.repo.Media.FindByID(ctx, id)
}

// mediaSource 是 /Items 与 /PlaybackInfo 共享的 MediaSource 结构。
//
// asEmbedded=true：嵌在 /Items 列表里，不包含完整 stream URL（避免暴露
// 直链给搜索接口）。/PlaybackInfo 走 false 路径，URL 指向 Emby 兼容
// /Videos/{id}/stream（客户端会继续携带 X-Emby-Token 或 append api_key）。
func (e *EmbyService) mediaSource(m *model.Media, asEmbedded bool) map[string]any {
	src := map[string]any{
		"Id":                   m.ID,
		"Name":                 m.Title,
		"Path":                 m.Path,
		"Container":            m.Container,
		"Size":                 m.SizeBytes,
		"Protocol":             "Http",
		"Type":                 "Default",
		"IsRemote":             false,
		"SupportsTranscoding":  true,
		"SupportsDirectStream": true,
		"SupportsDirectPlay":   true,
		"SupportsProbing":      true,
		"RunTimeTicks":         int64(m.DurationSec) * 10_000_000,
		"MediaStreams":         e.mediaStreams(m),
	}
	if !asEmbedded {
		src["DirectStreamUrl"] = "/Videos/" + m.ID + "/stream"
		src["TranscodingUrl"] = "/Videos/" + m.ID + "/stream"
	}
	if strings.TrimSpace(m.STRMURL) != "" {
		// STRM 重定向：客户端直接拉远端，跳过我们这一层。
		src["IsRemote"] = true
		src["DirectStreamUrl"] = m.STRMURL
		src["Path"] = m.STRMURL
	}
	return src
}

func (e *EmbyService) mediaStreams(m *model.Media) []map[string]any {
	streams := []map[string]any{}
	if m.VideoCodec != "" || m.Width > 0 {
		streams = append(streams, map[string]any{
			"Codec":        m.VideoCodec,
			"Type":         "Video",
			"Index":        0,
			"Width":        m.Width,
			"Height":       m.Height,
			"AspectRatio":  "",
			"IsDefault":    true,
			"IsForced":     false,
			"IsExternal":   false,
			"DisplayTitle": fmt.Sprintf("%dx%d %s", m.Width, m.Height, m.VideoCodec),
		})
	}
	if m.AudioCodec != "" {
		streams = append(streams, map[string]any{
			"Codec":      m.AudioCodec,
			"Type":       "Audio",
			"Index":      1,
			"IsDefault":  true,
			"IsForced":   false,
			"IsExternal": false,
		})
	}
	return streams
}

// ─── 收藏 / 已看（Emby 客户端写路径） ──────────────────────────────────────

// SetFavorite 把 mediaID 标为 userID 的收藏。
func (e *EmbyService) SetFavorite(ctx context.Context, userID, mediaID string, favorite bool) error {
	if favorite {
		var f model.Favorite
		err := e.repo.DB.WithContext(ctx).
			Where("user_id = ? AND media_id = ?", userID, mediaID).First(&f).Error
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return e.repo.DB.WithContext(ctx).Create(&model.Favorite{
				UserID: userID, MediaID: mediaID,
			}).Error
		}
		return err
	}
	return e.repo.DB.WithContext(ctx).
		Where("user_id = ? AND media_id = ?", userID, mediaID).
		Delete(&model.Favorite{}).Error
}

// MarkPlayed 把 mediaID 标为已看（写一个 100% 进度的 history 行）。
func (e *EmbyService) MarkPlayed(ctx context.Context, userID, mediaID string, played bool) error {
	if !played {
		return e.repo.DB.WithContext(ctx).
			Where("user_id = ? AND media_id = ?", userID, mediaID).
			Delete(&model.PlaybackHistory{}).Error
	}
	m, err := e.repo.Media.FindByID(ctx, mediaID)
	if err != nil || m == nil {
		return errors.New("media not found")
	}
	dur := int64(m.DurationSec) * 1000
	if dur <= 0 {
		dur = 1
	}
	return e.repo.History.Upsert(ctx, &model.PlaybackHistory{
		UserID:     userID,
		MediaID:    mediaID,
		PositionMs: dur,
		DurationMs: dur,
		WatchedAt:  time.Now(),
		Completed:  true,
	})
}

// RecordProgress 记录播放进度（来自 Emby 客户端的 /Sessions/Playing/Progress）。
func (e *EmbyService) RecordProgress(ctx context.Context, userID, mediaID string, positionTicks, runtimeTicks int64) error {
	pos := positionTicks / 10_000
	dur := runtimeTicks / 10_000
	if dur <= 0 {
		// runtimeTicks 缺失时回退到 media.DurationSec
		if m, _ := e.repo.Media.FindByID(ctx, mediaID); m != nil {
			dur = int64(m.DurationSec) * 1000
		}
	}
	completed := dur > 0 && pos >= dur*9/10
	return e.repo.History.Upsert(ctx, &model.PlaybackHistory{
		UserID:     userID,
		MediaID:    mediaID,
		PositionMs: pos,
		DurationMs: dur,
		WatchedAt:  time.Now(),
		Completed:  completed,
	})
}

// ─── Helpers ─────────────────────────────────────────────────────────────────

func splitCSV(s string) []string {
	if strings.TrimSpace(s) == "" {
		return []string{}
	}
	parts := strings.Split(s, ",")
	out := make([]string, 0, len(parts))
	for _, p := range parts {
		p = strings.TrimSpace(p)
		if p != "" {
			out = append(out, p)
		}
	}
	return out
}

func intToStr(v int) string {
	if v == 0 {
		return ""
	}
	return strconv.Itoa(v)
}