package service

import (
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"net/http"
	"strings"
	"time"

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

// 微信官方 UGC 内容安全：
//   - msg_sec_check   文本，同步返回 pass/review/risky
//   - media_check_async 图片，异步：先提交拿 trace_id，结果由微信 push 回调
//
// 口径：社区所有内容默认不自动放出，只有文本检测明确 pass 且没有图片时才自动过审；
// 有图片走异步检测，结果回来再决定；检测不了（如小程序未发布、无 openid）一律转人工。

// MsgSecCheck 文本安全检测（v2）。scene: 1资料 2评论 3论坛 4日志。
// 返回 suggest: pass / review / risky
func (s *Service) MsgSecCheck(content, openid string, scene int) (string, error) {
	content = strings.TrimSpace(content)
	if content == "" {
		return "pass", nil // 没文本不用查
	}
	token, err := s.wechatAccessToken()
	if err != nil {
		return "", err
	}
	payload, _ := json.Marshal(map[string]any{
		"content": content,
		"version": 2,
		"scene":   scene,
		"openid":  openid,
	})
	var out struct {
		ErrCode int    `json:"errcode"`
		ErrMsg  string `json:"errmsg"`
		Result  struct {
			Suggest string `json:"suggest"`
			Label   int    `json:"label"`
		} `json:"result"`
	}
	if err := postJSON("https://api.weixin.qq.com/wxa/msg_sec_check?access_token="+token, payload, &out); err != nil {
		return "", err
	}
	if out.ErrCode != 0 {
		return "", fmt.Errorf("msg_sec_check(%d): %s", out.ErrCode, out.ErrMsg)
	}
	if out.Result.Suggest == "" {
		return "pass", nil
	}
	return out.Result.Suggest, nil
}

// MediaCheckAsync 提交一张图片做异步检测，返回 trace_id。mediaType 2=图片
func (s *Service) MediaCheckAsync(mediaURL, openid string, scene int) (string, error) {
	token, err := s.wechatAccessToken()
	if err != nil {
		return "", err
	}
	payload, _ := json.Marshal(map[string]any{
		"media_url":  mediaURL,
		"media_type": 2,
		"version":    2,
		"scene":      scene,
		"openid":     openid,
	})
	var out struct {
		ErrCode int    `json:"errcode"`
		ErrMsg  string `json:"errmsg"`
		TraceID string `json:"trace_id"`
	}
	if err := postJSON("https://api.weixin.qq.com/wxa/media_check_async?access_token="+token, payload, &out); err != nil {
		return "", err
	}
	if out.ErrCode != 0 {
		return "", fmt.Errorf("media_check_async(%d): %s", out.ErrCode, out.ErrMsg)
	}
	return out.TraceID, nil
}

// moderateInitial 发布前的初判：跑文本检测，决定初始状态和是否要提交图片异步检测。
// 检测不了一律转 pending 人工审核——保证「必须通过后才自动放出」。
func (s *Service) moderateInitial(content, openid string, scene int, hasImages bool) (status string, submitImages bool) {
	suggest, err := s.MsgSecCheck(content, openid, scene)
	if err != nil {
		return model.PostPending, false // 验证不了 → 人工
	}
	switch suggest {
	case "risky":
		return model.PostRejected, false
	case "review":
		return model.PostPending, false
	}
	// 文本 pass
	if hasImages {
		return model.PostPending, true // 图片还要异步查，先挂 pending
	}
	return model.PostPublished, true // 纯文本且 pass：自动过审（submitImages 无意义）
}

// submitImageChecks 逐张提交图片检测，落 trace 记录，供回调找回目标
func (s *Service) submitImageChecks(targetType, targetID, openid string, urls []string, scene int) {
	for _, u := range urls {
		if u == "" {
			continue
		}
		trace, err := s.MediaCheckAsync(u, openid, scene)
		if err != nil || trace == "" {
			continue // 提交失败的图不阻塞，靠人工兜底
		}
		s.db.Create(&model.MediaCheck{
			TraceID: trace, TargetType: targetType, TargetID: targetID, Status: model.MediaPending,
		})
	}
}

// ResolveMediaCheck 处理一条异步回调结果：更新 trace 记录，并据此决定目标状态。
// 任一张图 risky → 打回；全部 pass 且目标仍 pending → 放出。
func (s *Service) ResolveMediaCheck(traceID, suggest string) {
	var mc model.MediaCheck
	if err := s.db.Where("trace_id = ?", traceID).First(&mc).Error; err != nil {
		return // 不认识的 trace，忽略
	}
	st := model.MediaPass
	if suggest == "risky" || suggest == "review" {
		st = model.MediaRisky
	}
	s.db.Model(&model.MediaCheck{}).Where("id = ?", mc.ID).Update("status", st)

	if st == model.MediaRisky {
		s.setTargetStatus(mc.TargetType, mc.TargetID, model.PostRejected, model.PostPending)
		return
	}
	// 这张 pass 了——看这条目标是否还有没回来的图
	var pending int64
	s.db.Model(&model.MediaCheck{}).
		Where("target_type = ? AND target_id = ? AND status = ?", mc.TargetType, mc.TargetID, model.MediaPending).
		Count(&pending)
	if pending == 0 {
		s.setTargetStatus(mc.TargetType, mc.TargetID, model.PostPublished, model.PostPending)
	}
}

// setTargetStatus 把帖子/评论改成 newStatus，仅当它当前还是 onlyIf（避免覆盖人工已处理的）
func (s *Service) setTargetStatus(targetType, targetID, newStatus, onlyIf string) {
	switch targetType {
	case "post":
		s.db.Model(&model.Post{}).Where("id = ? AND status = ?", targetID, onlyIf).Update("status", newStatus)
	case "comment":
		s.db.Model(&model.Comment{}).Where("id = ? AND status = ?", targetID, onlyIf).Update("status", newStatus)
	}
}

// postJSON 一个小的 JSON POST 帮手
func postJSON(url string, body []byte, out any) error {
	ctx, cancel := context.WithTimeout(context.Background(), 12*time.Second)
	defer cancel()
	req, _ := http.NewRequestWithContext(ctx, http.MethodPost, url, bytes.NewReader(body))
	req.Header.Set("Content-Type", "application/json")
	resp, err := http.DefaultClient.Do(req)
	if err != nil {
		return err
	}
	defer resp.Body.Close()
	return json.NewDecoder(resp.Body).Decode(out)
}