package service

import (
	"encoding/json"
	"fmt"
	"math/rand"
	"time"

	"gorm.io/datatypes"

	"github.com/sundynix/pets-be/internal/ai"
	"github.com/sundynix/pets-be/internal/model"
)

const botTickMinutes = 15

// 话题种子，增加生成多样性
var botTopics = []string{
	"新手第一次给猫换粮的经历和注意点",
	"幼犬疫苗期间的日常照护",
	"猫咪软便观察和调理的经验",
	"遛狗时防止捡食的小技巧",
	"换季掉毛严重怎么护理",
	"刚到家的猫如何度过应激期",
	"给狗狗刷牙、清口腔的经验",
	"记录体重时发现的小变化",
	"驱虫到期提醒和实操",
	"多猫家庭的相处磨合",
	"老年猫饮水和肾脏健康关注点",
	"幼猫社会化和玩耍引导",
}

// 默认虚拟宠友账号池（昵称 + emoji 头像）
var botSeeds = []struct{ Name, Emoji string }{
	{"团子的日常", "🐱"}, {"布丁妈妈", "🐶"}, {"三花小报告", "🐱"},
	{"柯基屁股蛋", "🐶"}, {"橘座驾到", "🐱"}, {"奶牛猫饲养员", "🐮"},
	{"金毛暖暖", "🦮"}, {"布偶少爷", "😺"}, {"英短小灰灰", "🐱"},
	{"泰迪不乖", "🐩"}, {"狸花猫巡逻队", "🐈"}, {"雪纳瑞老张", "🐶"},
	{"银渐层日记", "😸"}, {"哈士奇拆家现场", "🐺"}, {"暹罗小王子", "🐱"},
	{"边牧上学记", "🐕"}, {"美短起司", "🧀"}, {"柴犬麻薯", "🐕"},
	{"无毛猫斯芬克斯", "🐱"}, {"比熊棉花糖", "🐶"}, {"缅因大橘", "🦁"},
	{"腊肠一米五", "🌭"}, {"加菲脸圆圆", "😻"}, {"萨摩耶微笑", "🐻‍❄️"},
	{"蓝猫布加迪", "🐱"}, {"法斗打呼噜", "🐶"}, {"折耳软软", "🐱"},
	{"阿拉斯加大脸", "🐺"},
}

// 兜底文案（AI 未开启/失败时用）
var fallbackPosts = []string{
	"换粮第3天，软便基本好了，7天过渡法真的有用，分享给同样在换粮的姐妹～",
	"幼猫社会化真的重要，每天陪玩20分钟，现在一点都不怕生人了🐱",
	"提醒大家驱虫别忘记，我差点漏了，手机日历设个提醒最保险。",
	"金毛换季掉毛太夸张了，每天梳一次+补点卵磷脂，情况好多了。",
}

// getBotConfig 取单例配置（不存在返回内置默认，不写库）
func (s *Service) getBotConfig() model.CommunityBotConfig {
	var c model.CommunityBotConfig
	if err := s.db.First(&c, "1").Error; err != nil {
		return model.CommunityBotConfig{Enabled: true, DailyCount: 3, StartHour: 9, EndHour: 21}
	}
	return c
}

// GetCommunityBotConfig 后台读取配置
func (s *Service) GetCommunityBotConfig() model.CommunityBotConfig {
	return s.getBotConfig()
}

// SaveCommunityBotConfig 后台保存配置（固定 id=1 upsert）
func (s *Service) SaveCommunityBotConfig(in model.CommunityBotConfig) (model.CommunityBotConfig, error) {
	if in.DailyCount < 0 {
		in.DailyCount = 0
	}
	if in.StartHour < 0 || in.StartHour > 23 {
		in.StartHour = 9
	}
	if in.EndHour < 1 || in.EndHour > 24 {
		in.EndHour = 21
	}
	if in.EndHour <= in.StartHour {
		in.EndHour = in.StartHour + 1
	}
	in.ID = "1"
	if err := s.db.Save(&in).Error; err != nil {
		return in, err
	}
	return in, nil
}

// SeedCommunityBot 启动幂等 seed：虚拟账号池（按昵称补齐新增账号）+ 配置单例
func (s *Service) SeedCommunityBot() error {
	// 迁移前的旧用户 is_bot 为 NULL，回填为 false 便于筛选
	if err := s.db.Model(&model.User{}).Where("is_bot IS NULL").Update("is_bot", false).Error; err != nil {
		return err
	}
	for _, b := range botSeeds {
		var n int64
		if err := s.db.Model(&model.User{}).Where("nickname = ? AND is_bot = ?", b.Name, true).Count(&n).Error; err != nil {
			return err
		}
		if n == 0 {
			u := model.User{Nickname: b.Name, Avatar: b.Emoji, IsBot: true, Onboarded: true}
			if err := s.db.Create(&u).Error; err != nil {
				return err
			}
		}
	}
	var cfgCount int64
	if err := s.db.Model(&model.CommunityBotConfig{}).Count(&cfgCount).Error; err != nil {
		return err
	}
	if cfgCount == 0 {
		c := model.CommunityBotConfig{Enabled: true, DailyCount: 3, StartHour: 9, EndHour: 21}
		c.ID = "1"
		if err := s.db.Create(&c).Error; err != nil {
			return err
		}
	}
	return nil
}

// countAIPostsToday 今天已生成的 AI 帖数
func (s *Service) countAIPostsToday() int64 {
	now := time.Now()
	start := time.Date(now.Year(), now.Month(), now.Day(), 0, 0, 0, 0, now.Location())
	var n int64
	s.db.Model(&model.Post{}).Where("is_ai = ? AND created_at >= ?", true, start).Count(&n)
	return n
}

// GenerateCommunityPosts 生成 n 条 AI 帖并入库，返回实际生成数
func (s *Service) GenerateCommunityPosts(n int) (int, error) {
	if n <= 0 {
		return 0, nil
	}
	var bots []model.User
	if err := s.db.Where("is_bot = ?", true).Find(&bots).Error; err != nil {
		return 0, err
	}
	if len(bots) == 0 {
		return 0, nil
	}
	made := 0
	for i := 0; i < n; i++ {
		bot := bots[rand.Intn(len(bots))]
		content, tag := s.genOnePostContent()
		if content == "" {
			continue
		}
		tagsJSON, _ := json.Marshal([]string{tag})
		imagesJSON, _ := json.Marshal(pickPhotos())
		p := model.Post{
			UserID: bot.ID, AuthorName: bot.Nickname, AuthorEmoji: bot.Avatar,
			Identity: "petName", Content: content, Tags: datatypes.JSON(tagsJSON),
			Images:    datatypes.JSON(imagesJSON),
			LikeCount: rand.Intn(40), Status: model.PostPublished, IsAI: true,
		}
		if err := s.db.Create(&p).Error; err != nil {
			return made, err
		}
		made++
	}
	return made, nil
}

// 配图 emoji 池（App 用 emoji 当照片渲染），当作帖子的「图」
var photoPool = []string{"🐱", "🐶", "🐈", "🐕", "🍚", "🦴", "🧶", "🪀", "🏠", "🌿", "🛁", "💊", "🐾", "🍗", "🥩", "🧸", "☀️", "🛏️"}

// pickPhotos ~65% 概率随机贴 1-3 张配图，其余纯文字（更自然）
func pickPhotos() []string {
	if rand.Float64() > 0.65 {
		return []string{}
	}
	n := 1 + rand.Intn(3)
	out := make([]string, 0, n)
	for i := 0; i < n; i++ {
		out = append(out, photoPool[rand.Intn(len(photoPool))])
	}
	return out
}

// genOnePostContent 生成一条文案 + 标签；AI 不可用/失败回退内置文案
func (s *Service) genOnePostContent() (string, string) {
	tags := []string{"晒宠", "求助", "经验", "避坑"}
	tag := tags[rand.Intn(len(tags))]
	if !s.ai.Enabled() {
		return fallbackPosts[rand.Intn(len(fallbackPosts))], tag
	}
	topic := botTopics[rand.Intn(len(botTopics))]
	system := aiSafetyPrompt + `

你在为宠物社区「宠友圈」生成一条真实、口语化的养宠动态，像普通铲屎官发的朋友圈。
要求：40-120 字；真实有细节，可带 1-2 个 emoji；涉及异常要顺带提醒何时就医；不要标题、不要话题标签、不要营销口吻。
只输出 JSON：{"content":"","tag":"晒宠|求助|经验|避坑"}`
	user := fmt.Sprintf("主题：%s。请生成一条。", topic)
	out, err := s.ai.Complete(system, []ai.Message{{Role: "user", Content: user}}, ai.Options{JSON: true, Temperature: -1})
	if err != nil {
		return fallbackPosts[rand.Intn(len(fallbackPosts))], tag
	}
	var r struct {
		Content string `json:"content"`
		Tag     string `json:"tag"`
	}
	if err := json.Unmarshal([]byte(extractJSON(out)), &r); err != nil || r.Content == "" {
		return fallbackPosts[rand.Intn(len(fallbackPosts))], tag
	}
	if r.Tag != "" {
		tag = r.Tag
	}
	return r.Content, tag
}

// RunCommunityBotTick 定时器每次调用：白天窗口内按剩余名额概率投放，天然打散在白天
func (s *Service) RunCommunityBotTick() {
	cfg := s.getBotConfig()
	if !cfg.Enabled || cfg.DailyCount <= 0 {
		return
	}
	now := time.Now()
	h := now.Hour()
	if h < cfg.StartHour || h >= cfg.EndHour {
		return
	}
	today := s.countAIPostsToday()
	if today >= int64(cfg.DailyCount) {
		return
	}
	remaining := cfg.DailyCount - int(today)
	minsLeft := (cfg.EndHour-h)*60 - now.Minute()
	ticksLeft := minsLeft / botTickMinutes
	if ticksLeft < 1 {
		ticksLeft = 1
	}
	if rand.Float64() <= float64(remaining)/float64(ticksLeft) {
		_, _ = s.GenerateCommunityPosts(1)
	}
}

// StartCommunityBot 启动后台定时投放协程
func (s *Service) StartCommunityBot() {
	go func() {
		for {
			s.RunCommunityBotTick()
			time.Sleep(botTickMinutes * time.Minute)
		}
	}()
}