package model

import (
	"context"
	"encoding/json"
	"fmt"
	"time"

	"github.com/go-redis/redis/v8"
	"gorm.io/gorm"
)

const (
	prefixCommentListKey   = "comment:list:%d:%d:%d" // postId:page:pageSize
	prefixCommentKey       = "comment:%d"            // commentId
	prefixReplyListKey     = "reply:list:%d"         // commentId
	prefixCommentUpvoteKey = "comment:upvote:%d:%d"  // userId:commentId
)

// PComment 评论
type Comment struct {
	*Model
	PostId        int64  `json:"post_id" gorm:"post_id"`                 // POST ID
	UserId        int64  `json:"user_id" gorm:"user_id"`                 // 用户ID
	Ip            string `json:"ip" gorm:"ip"`                           // IP地址
	IpLoc         string `json:"ip_loc" gorm:"ip_loc"`                   // IP城市地址
	Content       string `json:"content" gorm:"content"`                 // 评论内容
	Image         string `json:"image" gorm:"image"`                     // 评论图片
	WithUserIds   string `json:"with_user_ids" gorm:"with_user_ids"`     // 被艾特的用户
	IsEssence     int8   `json:"is_essence" gorm:"is_essence"`           // 是否精选
	ReplyCount    int64  `json:"reply_count" gorm:"reply_count"`         // 回复数
	ThumbsUpCount int64  `json:"thumbs_up_count" gorm:"thumbs_up_count"` // 点赞数
}

// TableName 表名称
func (*Comment) TableName() string {
	return "p_comment"
}

type CommentModel struct {
	conn  *gorm.DB
	redis *redis.Client
}

func NewCommentModel(conn *gorm.DB, rdb *redis.Client) *CommentModel {
	return &CommentModel{
		conn:  conn,
		redis: rdb,
	}
}

// GetCommentList 获取评论列表（带缓存）
func (m *CommentModel) GetCommentList(ctx context.Context, postId int64, page, pageSize int) ([]*Comment, error) {
	// 尝试从缓存获取
	key := fmt.Sprintf(prefixCommentListKey, postId, page, pageSize)
	data, err := m.redis.Get(ctx, key).Bytes()
	if err == nil {
		var comments []*Comment
		if err := json.Unmarshal(data, &comments); err == nil {
			return comments, nil
		}
	}

	// 从数据库获取
	var comments []*Comment
	offset := (page - 1) * pageSize
	err = m.conn.WithContext(ctx).
		Where("post_id = ? AND parent_id = 0", postId).
		Order("created_on DESC").
		Offset(offset).
		Limit(pageSize).
		Find(&comments).Error
	if err != nil {
		return nil, err
	}

	// 写入缓存
	if data, err := json.Marshal(comments); err == nil {
		m.redis.Set(ctx, key, data, 5*time.Minute) // 评论列表缓存时间较短
	}

	return comments, nil
}

// GetLatestReplies 获取最新的N条回复（带缓存）
func (m *CommentModel) GetLatestReplies(ctx context.Context, commentId int64, limit int) ([]*Comment, error) {
	// 尝试从缓存获取
	key := fmt.Sprintf(prefixReplyListKey, commentId)
	data, err := m.redis.Get(ctx, key).Bytes()
	if err == nil {
		var replies []*Comment
		if err := json.Unmarshal(data, &replies); err == nil {
			return replies, nil
		}
	}

	// 从数据库获取
	var replies []*Comment
	err = m.conn.WithContext(ctx).
		Where("parent_id = ?", commentId).
		Order("created_on DESC").
		Limit(limit).
		Find(&replies).Error
	if err != nil {
		return nil, err
	}

	// 写入缓存
	if data, err := json.Marshal(replies); err == nil {
		m.redis.Set(ctx, key, data, 5*time.Minute)
	}

	return replies, nil
}

// IsCommentUpvotedByUser 检查用户是否点赞了评论/回复（带缓存）
func (m *CommentModel) IsCommentUpvotedByUser(ctx context.Context, userId, commentId int64) (bool, error) {
	// 尝试从缓存获取
	key := fmt.Sprintf(prefixCommentUpvoteKey, userId, commentId)
	exists, err := m.redis.Exists(ctx, key).Result()
	if err == nil && exists == 1 {
		return m.redis.Get(ctx, key).Bool()
	}

	// 从数据库获取
	var count int64
	err = m.conn.WithContext(ctx).Model(&CommentUpvote{}).
		Where("user_id = ? AND comment_id = ? AND is_del = 0", userId, commentId).
		Count(&count).Error
	if err != nil {
		return false, err
	}

	// 写入缓存
	isUpvoted := count > 0
	m.redis.Set(ctx, key, isUpvoted, cacheExpiry)
	return isUpvoted, nil
}

// GetReplyList 获取回复列表（带缓存）
func (m *CommentModel) GetReplyList(ctx context.Context, commentId int64, page, pageSize int) ([]*Comment, error) {
	// 尝试从缓存获取
	key := fmt.Sprintf(prefixReplyListKey+":%d:%d", commentId, page, pageSize)
	data, err := m.redis.Get(ctx, key).Bytes()
	if err == nil {
		var replies []*Comment
		if err := json.Unmarshal(data, &replies); err == nil {
			return replies, nil
		}
	}

	// 从数据库获取
	var replies []*Comment
	offset := (page - 1) * pageSize
	err = m.conn.WithContext(ctx).
		Where("parent_id = ?", commentId).
		Order("created_on DESC").
		Offset(offset).
		Limit(pageSize).
		Find(&replies).Error
	if err != nil {
		return nil, err
	}

	// 写入缓存
	if data, err := json.Marshal(replies); err == nil {
		m.redis.Set(ctx, key, data, 5*time.Minute) // 回复列表缓存时间较短
	}

	return replies, nil
}

// Create 创建评论
func (m *CommentModel) Create(ctx context.Context, comment *Comment) error {
	err := m.conn.WithContext(ctx).Create(comment).Error
	if err != nil {
		return err
	}

	// 删除相关缓存
	m.ClearCommentListCache(ctx, comment.PostId)
	return nil
}

// ClearCommentListCache 清除评论列表缓存
func (m *CommentModel) ClearCommentListCache(ctx context.Context, postId int64) error {
	// 清除评论列表缓存
	pattern := fmt.Sprintf("comment:list:%d*", postId)
	keys, err := m.redis.Keys(ctx, pattern).Result()
	if err != nil {
		return err
	}
	if len(keys) > 0 {
		m.redis.Del(ctx, keys...)
	}

	// 清除回复列表缓存
	pattern = fmt.Sprintf(prefixReplyListKey+"*", postId)
	keys, err = m.redis.Keys(ctx, pattern).Result()
	if err != nil {
		return err
	}
	if len(keys) > 0 {
		m.redis.Del(ctx, keys...)
	}

	return nil
}

// IncrementUpvoteCount 增加点赞数
func (m *CommentModel) IncrementUpvoteCount(ctx context.Context, commentId int64, increment int) error {
	err := m.conn.WithContext(ctx).Model(&Comment{}).
		Where("id = ?", commentId).
		UpdateColumn("thumbs_up_count", gorm.Expr("thumbs_up_count + ?", increment)).Error
	if err != nil {
		return err
	}

	// 删除评论缓存
	key := fmt.Sprintf(prefixCommentKey, commentId)
	m.redis.Del(ctx, key)
	return nil
}

// CreateCommentUpvote 创建评论点赞记录
func (m *CommentModel) CreateCommentUpvote(ctx context.Context, upvote *CommentUpvote) error {
	err := m.conn.WithContext(ctx).Create(upvote).Error
	if err != nil {
		return err
	}

	// 删除点赞状态缓存
	key := fmt.Sprintf(prefixCommentUpvoteKey, upvote.UserId, upvote.CommentId)
	m.redis.Del(ctx, key)
	return nil
}

// DeleteCommentUpvote 删除评论点赞记录
func (m *CommentModel) DeleteCommentUpvote(ctx context.Context, userId, commentId int64) error {
	err := m.conn.WithContext(ctx).Model(&CommentUpvote{}).
		Where("user_id = ? AND comment_id = ?", userId, commentId).
		Update("is_del", 1).Error
	if err != nil {
		return err
	}

	// 删除点赞状态缓存
	key := fmt.Sprintf(prefixCommentUpvoteKey, userId, commentId)
	m.redis.Del(ctx, key)
	return nil
}

// 获取评论
func (m *CommentModel) GetComment(ctx context.Context, commentId int64) (*Comment, error) {
	var comment Comment
	err := m.conn.WithContext(ctx).Where("id = ?", commentId).First(&comment).Error
	if err != nil {
		return nil, err
	}
	return &comment, nil
}

// IncrementReplyCount 增加回复数
func (m *CommentModel) IncrementReplyCount(ctx context.Context, commentId int64, increment int) error {
	err := m.conn.WithContext(ctx).Model(&Comment{}).
		Where("id = ?", commentId).
		UpdateColumn("reply_count", gorm.Expr("reply_count + ?", increment)).Error
	if err != nil {
		return err
	}

	// 删除评论缓存
	key := fmt.Sprintf(prefixCommentKey, commentId)
	m.redis.Del(ctx, key)
	return nil
}

// Delete 删除评论
func (m *CommentModel) Delete(ctx context.Context, commentId int64) error {
	return m.conn.WithContext(ctx).Model(&Comment{}).
		Where("id = ?", commentId).
		Updates(map[string]interface{}{
			"is_del":      1,
			"deleted_on":  time.Now().Unix(),
			"modified_on": time.Now().Unix(),
		}).Error
}