package service

import (
	"context"
	"errors"
	"strconv"
	"strings"
	"sync"
	"time"

	"github.com/truewhile/MeBox/internal/model"
)

// SetFavorite 把 mediaID 标为 userID 的收藏。只写入 MeBox 本地 favourites 表，
// 按 user_id 隔离；挂载远程 Emby 共用账号，不能再透传收藏以免串用户。
func (e *EmbyService) SetFavorite(ctx context.Context, userID, mediaID string, favorite bool) error {
	if err := SyncUserFavorite(ctx, e.repo, e.remote, userID, mediaID, favorite); err != nil {
		return err
	}
	e.invalidateEmbyItemsCache(ctx)
	return nil
}

// MarkPlayed 把 mediaID 标为已看（写一个 100% 进度的 history 行）。
// 远程挂载条目同样只落本地 PlaybackHistory，按 MeBox 用户隔离。
func (e *EmbyService) MarkPlayed(ctx context.Context, userID, mediaID string, played bool) error {
	if !played {
		err := e.repo.DB.WithContext(ctx).
			Where("user_id = ? AND media_id = ?", userID, mediaID).
			Delete(&model.PlaybackHistory{}).Error
		if err == nil {
			e.invalidateEmbyItemsCache(ctx)
		}
		return err
	}
	dur := int64(0)
	if IsEmbyRemoteID(mediaID) {
		dur = remoteItemDurationMs(ctx, e, mediaID)
	} else {
		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
	}
	err := e.repo.History.Upsert(ctx, &model.PlaybackHistory{
		UserID:     userID,
		MediaID:    mediaID,
		PositionMs: dur,
		DurationMs: dur,
		WatchedAt:  time.Now(),
		Completed:  true,
	})
	if err == nil {
		e.invalidateEmbyItemsCache(ctx)
	}
	return err
}

func remoteItemDurationMs(ctx context.Context, e *EmbyService, mediaID string) int64 {
	if e == nil || e.remote == nil || !IsEmbyRemoteID(mediaID) {
		return 0
	}
	mountID, remoteID, _ := DecodeEmbyRemoteID(mediaID)
	mount, acct, err := e.remote.ResolveMount(ctx, mountID)
	if err != nil || mount == nil || acct == nil {
		return 0
	}
	item, err := e.remote.RemoteItem(ctx, mount, acct, remoteID)
	if err != nil || item == nil {
		return 0
	}
	switch ticks := item["RunTimeTicks"].(type) {
	case float64:
		if ticks > 0 {
			return int64(ticks) / 10_000
		}
	case int64:
		if ticks > 0 {
			return ticks / 10_000
		}
	case int:
		if ticks > 0 {
			return int64(ticks) / 10_000
		}
	}
	return 0
}

// RecordProgress 记录播放进度（来自 Emby 客户端的 /Sessions/Playing/Progress）。
// 不携带 PlaySessionId 的旧调用仍保持兼容。
func (e *EmbyService) RecordProgress(ctx context.Context, userID, mediaID string, positionTicks, runtimeTicks int64) error {
	return e.RecordProgressWithSession(ctx, userID, mediaID, positionTicks, runtimeTicks, "")
}

// RecordProgressWithSession records an Emby progress update together with its
// PlaySessionId. The server-issued ID contains a millisecond timestamp, which
// lets the repository reject reports from an older playback session.
func (e *EmbyService) RecordProgressWithSession(ctx context.Context, userID, mediaID string, positionTicks, runtimeTicks int64, playSessionID string) 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
		} else if IsEmbyRemoteID(mediaID) {
			// 远程挂载条目：尝试从既有历史记录或远程详情补齐时长
			var oldHist model.PlaybackHistory
			if err := e.repo.DB.WithContext(ctx).Where("user_id = ? AND media_id = ?", userID, mediaID).First(&oldHist).Error; err == nil && oldHist.DurationMs > 0 {
				dur = oldHist.DurationMs
			} else if e.remote != nil {
				mountID, remoteID, _ := DecodeEmbyRemoteID(mediaID)
				if mount, acct, _ := e.remote.ResolveMount(ctx, mountID); mount != nil && acct != nil {
					if item, _ := e.remote.RemoteItem(ctx, mount, acct, remoteID); item != nil {
						if ticks, ok := item["RunTimeTicks"].(float64); ok && ticks > 0 {
							dur = int64(ticks) / 10_000
						} else if ticks, ok := item["RunTimeTicks"].(int64); ok && ticks > 0 {
							dur = ticks / 10_000
						}
					}
				}
			}
		}
	}
	playSessionID = strings.TrimSpace(playSessionID)
	err := e.repo.History.UpsertProgress(ctx, &model.PlaybackHistory{
		UserID:             userID,
		MediaID:            mediaID,
		PositionMs:         pos,
		DurationMs:         dur,
		WatchedAt:          time.Now(),
		Completed:          playbackProgressCompleted(pos, dur),
		SessionID:          playSessionID,
		SessionStartedAtMs: embyPlaySessionStartedAtMs(playSessionID),
	})
	if err == nil {
		e.invalidateEmbyItemsCache(ctx)
	}
	return err
}

// embyPlaySessionStartedAtMs extracts the millisecond timestamp embedded in a
// MeBox-issued PlaySessionId. Older IDs used seconds, so normalize those too.
func embyPlaySessionStartedAtMs(playSessionID string) int64 {
	playSessionID = strings.TrimSpace(playSessionID)
	if playSessionID == "" {
		return 0
	}
	idx := strings.LastIndex(playSessionID, "-")
	if idx < 0 || idx == len(playSessionID)-1 {
		return 0
	}
	value, err := strconv.ParseInt(playSessionID[idx+1:], 10, 64)
	if err != nil || value <= 0 {
		return 0
	}
	if value >= 1_000_000_000 && value < 1_000_000_000_000 {
		value *= 1000
	}
	if value < 1_000_000_000_000 {
		return 0
	}
	return value
}

// mergeRemoteUserData overlays the current MeBox user's locally recorded
// playback and favourite state onto remote Emby payloads. Remote mounts share
// one upstream Emby account, so upstream UserData must never leak across MeBox users.
func (e *EmbyService) mergeRemoteUserData(ctx context.Context, userID string, payload any) error {
	if strings.TrimSpace(userID) == "" || payload == nil {
		return nil
	}
	items := remoteItemMaps(payload)
	ids := make([]string, 0, len(items))
	seen := make(map[string]struct{}, len(items))
	for _, item := range items {
		id, _ := item["Id"].(string)
		if !IsEmbyRemoteID(id) {
			continue
		}
		if _, ok := seen[id]; !ok {
			ids = append(ids, id)
			seen[id] = struct{}{}
		}
	}
	if len(ids) == 0 {
		return nil
	}
	var histories []model.PlaybackHistory
	if err := e.repo.DB.WithContext(ctx).Where("user_id = ? AND media_id IN ?", userID, ids).Find(&histories).Error; err != nil {
		return err
	}
	byMediaID := make(map[string]*model.PlaybackHistory, len(histories))
	for i := range histories {
		byMediaID[histories[i].MediaID] = &histories[i]
	}
	var favs []model.Favorite
	if err := e.repo.DB.WithContext(ctx).Where("user_id = ? AND media_id IN ?", userID, ids).Find(&favs).Error; err != nil {
		return err
	}
	favSet := make(map[string]bool, len(favs))
	for _, fav := range favs {
		favSet[fav.MediaID] = true
	}
	for _, item := range items {
		id, _ := item["Id"].(string)
		item["UserData"] = applyMeBoxUserData(item["UserData"], byMediaID[id], favSet[id])
	}
	return nil
}

func remoteItemMaps(payload any) []map[string]any {
	items := make([]map[string]any, 0)
	var visit func(any)
	visit = func(value any) {
		switch typed := value.(type) {
		case map[string]any:
			if _, ok := typed["Id"].(string); ok {
				items = append(items, typed)
			}
			if nested, ok := typed["Items"]; ok {
				visit(nested)
			}
		case []any:
			for _, value := range typed {
				visit(value)
			}
		case []map[string]any:
			for _, value := range typed {
				visit(value)
			}
		}
	}
	visit(payload)
	return items
}

func mergedRemoteUserData(raw any, history *model.PlaybackHistory) map[string]any {
	favorite := false
	if existing, ok := raw.(map[string]any); ok {
		if v, ok := existing["IsFavorite"].(bool); ok {
			favorite = v
		}
	}
	return applyMeBoxUserData(raw, history, favorite)
}

// applyMeBoxUserData rebuilds UserData for a remote item using only MeBox-local
// per-user state. Shared upstream Emby favourite/progress fields are discarded.
func applyMeBoxUserData(raw any, history *model.PlaybackHistory, favorite bool) map[string]any {
	userData := map[string]any{}
	if existing, ok := raw.(map[string]any); ok {
		for key, value := range existing {
			switch key {
			case "IsFavorite", "PlaybackPositionTicks", "Played", "PlayedPercentage", "PlayCount", "LastPlayedDate":
				continue
			default:
				userData[key] = value
			}
		}
	}
	userData["IsFavorite"] = favorite
	if history == nil {
		userData["PlaybackPositionTicks"] = int64(0)
		userData["Played"] = false
		userData["PlayedPercentage"] = float64(0)
		userData["PlayCount"] = 0
		return userData
	}
	duration := history.DurationMs
	position := history.PositionMs
	percentage := float64(0)
	if duration > 0 {
		percentage = float64(position) / float64(duration) * 100
	}
	userData["PlaybackPositionTicks"] = position * 10_000
	userData["Played"] = history.Completed
	userData["PlayedPercentage"] = percentage
	if history.Completed {
		userData["PlayCount"] = 1
	} else {
		userData["PlayCount"] = 0
	}
	return userData
}

// embyInvalMu 节流全量缓存失效：播放期间客户端每 5-10s 上报一次进度，
// 每次都 SCAN+DEL 全部 media:emby:* 缓存会把缓存命中率持续打穿（其他
// 客户端每次翻页都回源 SQL）。条目载荷的 UserData 在请求时动态合并，
// 进度类变更做 30s 节流即可，不影响正确性观感。
var (
	embyInvalMu   sync.Mutex
	embyInvalLast time.Time
)

func (e *EmbyService) invalidateEmbyItemsCache(ctx context.Context) {
	embyInvalMu.Lock()
	defer embyInvalMu.Unlock()
	if !embyInvalLast.IsZero() && time.Since(embyInvalLast) < 30*time.Second {
		return
	}
	embyInvalLast = time.Now()
	if e.cache != nil {
		e.cache.DeletePrefix(ctx, "media:emby:")
	}
}

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)
}