package repository

import (
	"carrot_bbs/internal/model"
	"fmt"

	"gorm.io/gorm"
	"gorm.io/gorm/clause"
)

// UserRepository 用户仓储
type UserRepository struct {
	db *gorm.DB
}

// NewUserRepository 创建用户仓储
func NewUserRepository(db *gorm.DB) *UserRepository {
	return &UserRepository{db: db}
}

// Create 创建用户
func (r *UserRepository) Create(user *model.User) error {
	return r.db.Create(user).Error
}

// GetByID 根据ID获取用户
func (r *UserRepository) GetByID(id string) (*model.User, error) {
	var user model.User
	err := r.db.First(&user, "id = ?", id).Error
	if err != nil {
		return nil, err
	}
	return &user, nil
}

// GetByUsername 根据用户名获取用户
func (r *UserRepository) GetByUsername(username string) (*model.User, error) {
	var user model.User
	err := r.db.First(&user, "username = ?", username).Error
	if err != nil {
		return nil, err
	}
	return &user, nil
}

// GetByEmail 根据邮箱获取用户
func (r *UserRepository) GetByEmail(email string) (*model.User, error) {
	var user model.User
	err := r.db.First(&user, "email = ?", email).Error
	if err != nil {
		return nil, err
	}
	return &user, nil
}

// GetByPhone 根据手机号获取用户
func (r *UserRepository) GetByPhone(phone string) (*model.User, error) {
	var user model.User
	err := r.db.First(&user, "phone = ?", phone).Error
	if err != nil {
		return nil, err
	}
	return &user, nil
}

// Update 更新用户
func (r *UserRepository) Update(user *model.User) error {
	return r.db.Save(user).Error
}

// Delete 删除用户
func (r *UserRepository) Delete(id string) error {
	return r.db.Delete(&model.User{}, "id = ?", id).Error
}

// List 分页获取用户列表
func (r *UserRepository) List(page, pageSize int) ([]*model.User, int64, error) {
	var users []*model.User
	var total int64

	r.db.Model(&model.User{}).Count(&total)

	offset := (page - 1) * pageSize
	err := r.db.Order("created_at DESC, id DESC").Offset(offset).Limit(pageSize).Find(&users).Error

	return users, total, err
}

// GetFollowers 获取用户粉丝
func (r *UserRepository) GetFollowers(userID string, page, pageSize int) ([]*model.User, int64, error) {
	var users []*model.User
	var total int64

	subQuery := r.db.Model(&model.Follow{}).Where("following_id = ?", userID).Select("follower_id")
	r.db.Model(&model.User{}).Where("id IN (?)", subQuery).Count(&total)

	offset := (page - 1) * pageSize
	err := r.db.Where("id IN (?)", subQuery).
		Order("created_at DESC, id DESC").
		Offset(offset).Limit(pageSize).
		Find(&users).Error

	return users, total, err
}

// GetFollowing 获取用户关注
func (r *UserRepository) GetFollowing(userID string, page, pageSize int) ([]*model.User, int64, error) {
	var users []*model.User
	var total int64

	subQuery := r.db.Model(&model.Follow{}).Where("follower_id = ?", userID).Select("following_id")
	r.db.Model(&model.User{}).Where("id IN (?)", subQuery).Count(&total)

	offset := (page - 1) * pageSize
	err := r.db.Where("id IN (?)", subQuery).
		Order("created_at DESC, id DESC").
		Offset(offset).Limit(pageSize).
		Find(&users).Error

	return users, total, err
}

// CreateFollow 创建关注关系
func (r *UserRepository) CreateFollow(follow *model.Follow) error {
	return r.db.Create(follow).Error
}

// DeleteFollow 删除关注关系
func (r *UserRepository) DeleteFollow(followerID, followingID string) error {
	return r.db.Where("follower_id = ? AND following_id = ?", followerID, followingID).Delete(&model.Follow{}).Error
}

// IsFollowing 检查是否关注了某用户
func (r *UserRepository) IsFollowing(followerID, followingID string) (bool, error) {
	var count int64
	err := r.db.Model(&model.Follow{}).Where("follower_id = ? AND following_id = ?", followerID, followingID).Count(&count).Error
	if err != nil {
		return false, err
	}
	return count > 0, nil
}

// IncrementFollowersCount 增加用户粉丝数
func (r *UserRepository) IncrementFollowersCount(userID string) error {
	return r.db.Model(&model.User{}).Where("id = ?", userID).
		UpdateColumn("followers_count", gorm.Expr("followers_count + 1")).Error
}

// DecrementFollowersCount 减少用户粉丝数
func (r *UserRepository) DecrementFollowersCount(userID string) error {
	return r.db.Model(&model.User{}).Where("id = ? AND followers_count > 0", userID).
		UpdateColumn("followers_count", gorm.Expr("followers_count - 1")).Error
}

// IncrementFollowingCount 增加用户关注数
func (r *UserRepository) IncrementFollowingCount(userID string) error {
	return r.db.Model(&model.User{}).Where("id = ?", userID).
		UpdateColumn("following_count", gorm.Expr("following_count + 1")).Error
}

// DecrementFollowingCount 减少用户关注数
func (r *UserRepository) DecrementFollowingCount(userID string) error {
	return r.db.Model(&model.User{}).Where("id = ? AND following_count > 0", userID).
		UpdateColumn("following_count", gorm.Expr("following_count - 1")).Error
}

// RefreshFollowersCount 刷新用户粉丝数（通过实际计数）
func (r *UserRepository) RefreshFollowersCount(userID string) error {
	var count int64
	err := r.db.Model(&model.Follow{}).Where("following_id = ?", userID).Count(&count).Error
	if err != nil {
		return err
	}
	return r.db.Model(&model.User{}).Where("id = ?", userID).
		UpdateColumn("followers_count", count).Error
}

// GetPostsCount 获取用户帖子数（实时计算）
func (r *UserRepository) GetPostsCount(userID string) (int64, error) {
	var count int64
	err := r.db.Model(&model.Post{}).Where("user_id = ?", userID).Count(&count).Error
	return count, err
}

// GetPostsCountBatch 批量获取用户帖子数（实时计算）
// 返回 map[userID]postsCount
func (r *UserRepository) GetPostsCountBatch(userIDs []string) (map[string]int64, error) {
	result := make(map[string]int64)
	if len(userIDs) == 0 {
		return result, nil
	}

	// 初始化所有用户ID的计数为0
	for _, userID := range userIDs {
		result[userID] = 0
	}

	// 使用 GROUP BY 一次性查询所有用户的帖子数
	type CountResult struct {
		UserID string
		Count  int64
	}
	var counts []CountResult
	err := r.db.Model(&model.Post{}).
		Select("user_id, count(*) as count").
		Where("user_id IN ?", userIDs).
		Group("user_id").
		Scan(&counts).Error
	if err != nil {
		return nil, err
	}

	// 更新查询结果
	for _, c := range counts {
		result[c.UserID] = c.Count
	}

	return result, nil
}

// RefreshFollowingCount 刷新用户关注数（通过实际计数）
func (r *UserRepository) RefreshFollowingCount(userID string) error {
	var count int64
	err := r.db.Model(&model.Follow{}).Where("follower_id = ?", userID).Count(&count).Error
	if err != nil {
		return err
	}
	return r.db.Model(&model.User{}).Where("id = ?", userID).
		UpdateColumn("following_count", count).Error
}

// IsBlocked 检查拉黑关系是否存在（blocker -> blocked）
func (r *UserRepository) IsBlocked(blockerID, blockedID string) (bool, error) {
	var count int64
	err := r.db.Model(&model.UserBlock{}).
		Where("blocker_id = ? AND blocked_id = ?", blockerID, blockedID).
		Count(&count).Error
	if err != nil {
		return false, err
	}
	return count > 0, nil
}

// IsBlockedEitherDirection 检查是否任一方向存在拉黑
func (r *UserRepository) IsBlockedEitherDirection(userA, userB string) (bool, error) {
	var count int64
	err := r.db.Model(&model.UserBlock{}).
		Where("(blocker_id = ? AND blocked_id = ?) OR (blocker_id = ? AND blocked_id = ?)",
			userA, userB, userB, userA).
		Count(&count).Error
	if err != nil {
		return false, err
	}
	return count > 0, nil
}

// BlockUserAndCleanupRelations 拉黑用户并清理双向关注关系（事务）
func (r *UserRepository) BlockUserAndCleanupRelations(blockerID, blockedID string) error {
	return r.db.Transaction(func(tx *gorm.DB) error {
		block := &model.UserBlock{
			BlockerID: blockerID,
			BlockedID: blockedID,
		}
		if err := tx.Clauses(clause.OnConflict{
			Columns:   []clause.Column{{Name: "blocker_id"}, {Name: "blocked_id"}},
			DoNothing: true,
		}).Create(block).Error; err != nil {
			return err
		}

		if err := tx.Where("follower_id = ? AND following_id = ?", blockerID, blockedID).
			Delete(&model.Follow{}).Error; err != nil {
			return err
		}
		if err := tx.Where("follower_id = ? AND following_id = ?", blockedID, blockerID).
			Delete(&model.Follow{}).Error; err != nil {
			return err
		}

		for _, uid := range []string{blockerID, blockedID} {
			var followersCount int64
			if err := tx.Model(&model.Follow{}).Where("following_id = ?", uid).Count(&followersCount).Error; err != nil {
				return err
			}
			if err := tx.Model(&model.User{}).Where("id = ?", uid).
				UpdateColumn("followers_count", followersCount).Error; err != nil {
				return err
			}

			var followingCount int64
			if err := tx.Model(&model.Follow{}).Where("follower_id = ?", uid).Count(&followingCount).Error; err != nil {
				return err
			}
			if err := tx.Model(&model.User{}).Where("id = ?", uid).
				UpdateColumn("following_count", followingCount).Error; err != nil {
				return err
			}
		}

		return nil
	})
}

// UnblockUser 取消拉黑
func (r *UserRepository) UnblockUser(blockerID, blockedID string) error {
	return r.db.Where("blocker_id = ? AND blocked_id = ?", blockerID, blockedID).
		Delete(&model.UserBlock{}).Error
}

// GetBlockedUsers 获取用户黑名单列表
func (r *UserRepository) GetBlockedUsers(blockerID string, page, pageSize int) ([]*model.User, int64, error) {
	var users []*model.User
	var total int64

	subQuery := r.db.Model(&model.UserBlock{}).Where("blocker_id = ?", blockerID).Select("blocked_id")
	r.db.Model(&model.User{}).Where("id IN (?)", subQuery).Count(&total)

	offset := (page - 1) * pageSize
	err := r.db.Where("id IN (?)", subQuery).
		Order("created_at DESC, id DESC").
		Offset(offset).
		Limit(pageSize).
		Find(&users).Error

	return users, total, err
}

// Search 搜索用户
func (r *UserRepository) Search(keyword string, page, pageSize int) ([]*model.User, int64, error) {
	var users []*model.User
	var total int64

	query := r.db.Model(&model.User{})

	// 搜索用户名、昵称、简介
	if keyword != "" {
		if r.db.Dialector.Name() == "postgres" {
			query = query.Where(
				"to_tsvector('simple', COALESCE(username, '') || ' ' || COALESCE(nickname, '') || ' ' || COALESCE(bio, '')) @@ plainto_tsquery('simple', ?)",
				keyword,
			)
		} else {
			searchPattern := "%" + keyword + "%"
			query = query.Where("username LIKE ? OR nickname LIKE ? OR bio LIKE ?", searchPattern, searchPattern, searchPattern)
		}
	}

	query.Count(&total)

	offset := (page - 1) * pageSize
	err := query.Offset(offset).Limit(pageSize).Order("created_at DESC").Find(&users).Error

	return users, total, err
}

// GetMutualFollowStatus 批量获取双向关注状态
// 返回 map[userID][isFollowing, isFollowingMe]
func (r *UserRepository) GetMutualFollowStatus(currentUserID string, targetUserIDs []string) (map[string][2]bool, error) {
	result := make(map[string][2]bool)

	if len(targetUserIDs) == 0 {
		return result, nil
	}

	fmt.Printf("[DEBUG] GetMutualFollowStatus: currentUserID=%s, targetUserIDs=%v\n", currentUserID, targetUserIDs)

	// 初始化所有目标用户为未关注状态
	for _, userID := range targetUserIDs {
		result[userID] = [2]bool{false, false}
	}

	// 查询当前用户关注了哪些目标用户 (isFollowing)
	var followingIDs []string
	err := r.db.Model(&model.Follow{}).
		Where("follower_id = ? AND following_id IN ?", currentUserID, targetUserIDs).
		Pluck("following_id", &followingIDs).Error
	if err != nil {
		return nil, err
	}
	fmt.Printf("[DEBUG] GetMutualFollowStatus: currentUser follows these targets: %v\n", followingIDs)
	for _, id := range followingIDs {
		status := result[id]
		status[0] = true
		result[id] = status
	}

	// 查询哪些目标用户关注了当前用户 (isFollowingMe)
	var followerIDs []string
	err = r.db.Model(&model.Follow{}).
		Where("follower_id IN ? AND following_id = ?", targetUserIDs, currentUserID).
		Pluck("follower_id", &followerIDs).Error
	if err != nil {
		return nil, err
	}
	fmt.Printf("[DEBUG] GetMutualFollowStatus: these targets follow currentUser: %v\n", followerIDs)
	for _, id := range followerIDs {
		status := result[id]
		status[1] = true
		result[id] = status
	}

	fmt.Printf("[DEBUG] GetMutualFollowStatus: final result=%v\n", result)
	return result, nil
}