package redis

import (
	"context"
	"encoding/json"
	"fwh-toolbox-server/cache"
	"time"

	"go.uber.org/zap"
)

var (
	aiChatCtx            = context.Background()
	aiChatSessionKey     = "fwhtoolbox:aiChat:session:"     // {prefix}{userId} → sessionId
	aiChatSessionListKey = "fwhtoolbox:aiChat:sessionList:" // {prefix}{userId} → JSON array
	aiChatTTL            = 7 * 24 * time.Hour
)

// AiSessionItem 会话列表项（Redis 存储结构）
type AiSessionItem struct {
	SessionId  string `json:"sessionId"`
	Title      string `json:"title"`
	CreatedAt  int64  `json:"createdAt"`
	LastActive int64  `json:"lastActive"`
}

// ============ 当前活跃会话 ============

// AiActiveSession 当前活跃会话信息（Redis 存储结构）
type AiActiveSession struct {
	SessionId  string `json:"sessionId"`
	Title      string `json:"title"`
	CreatedAt  int64  `json:"createdAt"`
	LastActive int64  `json:"lastActive"`
}

// SaveAiSession 保存用户当前活跃会话完整信息
func SaveAiSession(userId string, sess AiActiveSession) error {
	key := aiChatSessionKey + userId
	data, err := json.Marshal(sess)
	if err != nil {
		return err
	}
	return cache.Set(aiChatCtx, key, string(data), aiChatTTL)
}

// GetAiSession 获取用户保存的活跃会话信息
func GetAiSession(userId string) (*AiActiveSession, error) {
	key := aiChatSessionKey + userId
	raw, err := cache.Get(aiChatCtx, key)
	if err != nil {
		return nil, err
	}
	var sess AiActiveSession
	if err := json.Unmarshal([]byte(raw), &sess); err != nil {
		return nil, err
	}
	return &sess, nil
}

// DeleteAiSession 删除用户保存的活跃会话信息
func DeleteAiSession(userId string) {
	key := aiChatSessionKey + userId
	cache.Delete(aiChatCtx, key)
}

// ============ 会话历史列表 ============

// SaveAiSessionList 保存用户完整会话历史列表
func SaveAiSessionList(userId string, list []AiSessionItem) error {
	key := aiChatSessionListKey + userId
	data, err := json.Marshal(list)
	if err != nil {
		return err
	}
	return cache.Set(aiChatCtx, key, string(data), aiChatTTL)
}

// GetAiSessionList 获取用户完整会话历史列表
func GetAiSessionList(userId string) ([]AiSessionItem, error) {
	key := aiChatSessionListKey + userId
	raw, err := cache.Get(aiChatCtx, key)
	if err != nil {
		return nil, err
	}
	var list []AiSessionItem
	if err := json.Unmarshal([]byte(raw), &list); err != nil {
		return nil, err
	}
	return list, nil
}

// DeleteAiSessionList 删除用户会话历史列表
func DeleteAiSessionList(userId string) {
	key := aiChatSessionListKey + userId
	cache.Delete(aiChatCtx, key)
}

// UpdateAiSessionTitle 更新列表中指定会话的标题
func UpdateAiSessionTitle(userId string, sessionId string, title string) {
	list, err := GetAiSessionList(userId)
	if err != nil {
		return
	}
	for i := range list {
		if list[i].SessionId == sessionId {
			list[i].Title = title
			break
		}
	}
	if err := SaveAiSessionList(userId, list); err != nil {
		zap.L().Warn("[AIChat] 更新会话标题到Redis失败", zap.Error(err))
	}
}