package repository

import (
	"errors"
	"time"

	"github.com/topfans/backend/pkg/models"
	"gorm.io/gorm"
)

// RankingItem 排行榜项
type RankingItem struct {
	AssetID       int64
	AssetName     string
	CoverURL      string
	OwnerUID      int64
	OwnerNickname string
	OwnerAvatar   *string
	LikeCount     int32
	IsOriginal    bool
}

// RankingRepository 排行榜Repository接口
type RankingRepository interface {
	// GetHotRankingDisplaying 获取热度排行榜-展示中
	GetHotRankingDisplaying(starID int64, limit, offset int) ([]*RankingItem, int64, error)

	// GetHotRankingMonth 获取热度排行榜-本月
	GetHotRankingMonth(starID int64, limit, offset int) ([]*RankingItem, int64, error)

	// GetHotRankingTotal 获取热度排行榜-全部
	GetHotRankingTotal(starID int64, limit, offset int) ([]*RankingItem, int64, error)

	// GetOriginalRankingDisplaying 获取自制排行榜-展示中
	GetOriginalRankingDisplaying(starID int64, limit, offset int) ([]*RankingItem, int64, error)

	// GetOriginalRankingMonth 获取自制排行榜-本月
	GetOriginalRankingMonth(starID int64, limit, offset int) ([]*RankingItem, int64, error)

	// GetOriginalRankingTotal 获取自制排行榜-全部
	GetOriginalRankingTotal(starID int64, limit, offset int) ([]*RankingItem, int64, error)

	// GetMyBestRanking 获取用户最佳的排名
	GetMyBestRanking(userID, starID int64, dimension string, isOriginalOnly bool) (*RankingItem, int32, error)
}

// rankingRepository 排行榜Repository实现
type rankingRepository struct {
	db *gorm.DB
}

// NewRankingRepository 创建排行榜Repository实例
func NewRankingRepository(db *gorm.DB) RankingRepository {
	return &rankingRepository{
		db: db,
	}
}

// GetHotRankingDisplaying 获取热度排行榜-展示中
func (r *rankingRepository) GetHotRankingDisplaying(starID int64, limit, offset int) ([]*RankingItem, int64, error) {
	return r.getHotRankingByDimension(starID, "displaying", false, limit, offset)
}

// GetHotRankingMonth 获取热度排行榜-本月
func (r *rankingRepository) GetHotRankingMonth(starID int64, limit, offset int) ([]*RankingItem, int64, error) {
	return r.getHotRankingByDimension(starID, "month", false, limit, offset)
}

// GetHotRankingTotal 获取热度排行榜-全部
func (r *rankingRepository) GetHotRankingTotal(starID int64, limit, offset int) ([]*RankingItem, int64, error) {
	return r.getHotRankingByDimension(starID, "total", false, limit, offset)
}

// GetOriginalRankingDisplaying 获取自制排行榜-展示中
func (r *rankingRepository) GetOriginalRankingDisplaying(starID int64, limit, offset int) ([]*RankingItem, int64, error) {
	return r.getHotRankingByDimension(starID, "displaying", true, limit, offset)
}

// GetOriginalRankingMonth 获取自制排行榜-本月
func (r *rankingRepository) GetOriginalRankingMonth(starID int64, limit, offset int) ([]*RankingItem, int64, error) {
	return r.getHotRankingByDimension(starID, "month", true, limit, offset)
}

// GetOriginalRankingTotal 获取自制排行榜-全部
func (r *rankingRepository) GetOriginalRankingTotal(starID int64, limit, offset int) ([]*RankingItem, int64, error) {
	return r.getHotRankingByDimension(starID, "total", true, limit, offset)
}

// getHotRankingByDimension 根据维度获取排行榜
func (r *rankingRepository) getHotRankingByDimension(starID int64, dimension string, isOriginalOnly bool, limit, offset int) ([]*RankingItem, int64, error) {
	if starID <= 0 {
		return nil, 0, errors.New("star_id must be greater than 0")
	}
	if limit <= 0 {
		limit = 10
	}

	now := time.Now().UnixMilli()
	startOfMonth := time.Date(time.Now().Year(), time.Now().Month(), 1, 0, 0, 0, 0, time.Local).UnixMilli()

	// 构建基础查询，JOIN 用户表和粉丝档案表获取昵称和头像（一次查询，避免 N+1 问题）
	db := r.db.Model(&models.Asset{}).
		Select("assets.id as asset_id, assets.name as asset_name, assets.cover_url, assets.owner_uid, assets.like_count, assets.is_original, fp.nickname as owner_nickname, fp.avatar_url as owner_avatar").
		
		Joins("LEFT JOIN fan_profiles fp ON fp.user_id = assets.owner_uid AND fp.star_id = ?", starID).
		Where("assets.star_id = ? AND assets.is_active = ? AND assets.status = ?", starID, true, models.AssetStatusActive)

	if isOriginalOnly {
		db = db.Where("assets.is_original = ?", true)
	}

	// 根据维度添加条件
	switch dimension {
	case "displaying":
		// 展示中：关联 Exhibition 表，筛选未过期的，且是当前star的展馆
		db = db.Joins("INNER JOIN exhibitions ON exhibitions.asset_id = assets.id").
			Joins("INNER JOIN fan_profiles ON fan_profiles.id = exhibitions.host_profile_id").
			Where("exhibitions.expire_at > ?", now).
			Where("fan_profiles.star_id = ?", starID)
	case "month":
		// 本月：本月内开始的展览，按点赞数排序
		db = db.Joins("INNER JOIN exhibitions ON exhibitions.asset_id = assets.id").
			Where("exhibitions.start_time >= ?", startOfMonth)
	case "total":
		// 全部：直接使用 assets 表的 like_count，无需额外条件
	}

	// 统计总数
	var total int64
	countDB := r.db.Model(&models.Asset{}).
		Select("assets.id").
		Joins("LEFT JOIN fan_profiles fp ON fp.user_id = assets.owner_uid AND fp.star_id = ?", starID).
		Where("assets.star_id = ? AND assets.is_active = ? AND assets.status = ?", starID, true, models.AssetStatusActive)
	if isOriginalOnly {
		countDB = countDB.Where("assets.is_original = ?", true)
	}
	switch dimension {
	case "displaying":
		countDB = countDB.Joins("INNER JOIN exhibitions ON exhibitions.asset_id = assets.id").
			Joins("INNER JOIN fan_profiles AS host_fp ON host_fp.id = exhibitions.host_profile_id").
			Where("exhibitions.expire_at > ?", now).
			Where("host_fp.star_id = ?", starID)
	case "month":
		// 本月：本月内开始的展览
		countDB = countDB.Joins("INNER JOIN exhibitions ON exhibitions.asset_id = assets.id").
			Where("exhibitions.start_time >= ?", startOfMonth)
	}
	if err := countDB.Count(&total).Error; err != nil {
		return nil, 0, err
	}

	// 查询列表
	var results []*RankingItem
	err := db.Order("assets.like_count DESC, assets.id ASC").
		Limit(limit).
		Offset(offset).
		Scan(&results).Error

	if err != nil {
		return nil, 0, err
	}

	return results, total, nil
}



// GetMyBestRanking 获取用户最佳的排名
func (r *rankingRepository) GetMyBestRanking(userID, starID int64, dimension string, isOriginalOnly bool) (*RankingItem, int32, error) {
	if userID <= 0 || starID <= 0 {
		return nil, 0, errors.New("user_id and star_id must be greater than 0")
	}

	now := time.Now().UnixMilli()
	startOfMonth := time.Date(time.Now().Year(), time.Now().Month(), 1, 0, 0, 0, 0, time.Local).UnixMilli()

	// 构建基础查询，与 getHotRankingByDimension 保持一致
	db := r.db.Model(&models.Asset{}).
		Select("assets.id as asset_id, assets.name as asset_name, assets.cover_url, assets.owner_uid, assets.like_count, assets.is_original, fp.nickname as owner_nickname, fp.avatar_url as owner_avatar").
		Joins("LEFT JOIN fan_profiles fp ON fp.user_id = assets.owner_uid AND fp.star_id = ?", starID).
		Where("assets.owner_uid = ? AND assets.star_id = ? AND assets.is_active = ? AND assets.status = ?", userID, starID, true, models.AssetStatusActive)

	if isOriginalOnly {
		db = db.Where("assets.is_original = ?", true)
	}

	// 根据维度添加条件，与 getHotRankingByDimension 保持一致
	switch dimension {
	case "displaying":
		// 展示中：关联 Exhibition 表，筛选未过期的，且是当前star的展馆
		db = db.Joins("INNER JOIN exhibitions ON exhibitions.asset_id = assets.id").
			Joins("INNER JOIN fan_profiles AS host_fp ON host_fp.id = exhibitions.host_profile_id").
			Where("exhibitions.expire_at > ?", now).
			Where("host_fp.star_id = ?", starID)
	case "month":
		// 本月：本月内开始的展览
		db = db.Joins("INNER JOIN exhibitions ON exhibitions.asset_id = assets.id").
			Where("exhibitions.start_time >= ?", startOfMonth)
	}

	// 获取用户在该star下点赞数最高的藏品
	var result struct {
		AssetID       int64
		AssetName     string
		CoverURL      string
		OwnerUID      int64
		LikeCount     int32
		IsOriginal    bool
		OwnerNickname string
		OwnerAvatar   *string
	}

	if err := db.Order("assets.like_count DESC, assets.id ASC").First(&result).Error; err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return nil, 0, nil
		}
		return nil, 0, err
	}

	// 计算该藏品的排名（与 getHotRankingByDimension 的排序逻辑一致：like_count DESC, id ASC）
	var rank int64
	rankingDB := r.db.Model(&models.Asset{}).
		Select("assets.id").
		Joins("LEFT JOIN fan_profiles fp ON fp.user_id = assets.owner_uid AND fp.star_id = ?", starID).
		Where("assets.star_id = ? AND assets.is_active = ? AND assets.status = ?", starID, true, models.AssetStatusActive).
		Where("assets.like_count > ? OR (assets.like_count = ? AND assets.id < ?)", result.LikeCount, result.LikeCount, result.AssetID)

	if isOriginalOnly {
		rankingDB = rankingDB.Where("assets.is_original = ?", true)
	}

	switch dimension {
	case "displaying":
		rankingDB = rankingDB.Joins("INNER JOIN exhibitions ON exhibitions.asset_id = assets.id").
			Joins("INNER JOIN fan_profiles AS host_fp ON host_fp.id = exhibitions.host_profile_id").
			Where("exhibitions.expire_at > ?", now).
			Where("host_fp.star_id = ?", starID)
	case "month":
		// 本月：本月内开始的展览
		rankingDB = rankingDB.Joins("INNER JOIN exhibitions ON exhibitions.asset_id = assets.id").
			Where("exhibitions.start_time >= ?", startOfMonth)
	}

	if err := rankingDB.Count(&rank).Error; err != nil {
		return nil, 0, err
	}

	return &RankingItem{
		AssetID:       result.AssetID,
		AssetName:     result.AssetName,
		CoverURL:      result.CoverURL,
		OwnerUID:      result.OwnerUID,
		LikeCount:     result.LikeCount,
		IsOriginal:    result.IsOriginal,
		OwnerNickname: result.OwnerNickname,
		OwnerAvatar:   result.OwnerAvatar,
	}, int32(rank + 1), nil
}