package main

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"net/http"
	"net/url"
	"os"
	"regexp"
	"strings"
	"time"
)

// electric.go - xiaofubao 一码通电费查询链路 + shiroJID 缓存
// 对应 Python lzu_electric_full.py 的 6 步流程

// 平台常量（来自环境变量，默认值对齐 .env）
var (
	xfPlatform  = envOr("XF_PLATFORM", "QHIT_EDU")
	xfAuthAppid = envOr("XF_AUTH_APPID", "2606161276416311297")
	xfSchoolCode = envOr("XF_SCHOOL_CODE", "10730")
	xfYmAppid   = envOr("XF_YM_APPID", "1810181825222034")
	xfServiceID = envOr("LZU_SERVICE_ID", "29615")
)

var (
	browserUA = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/151.0.0.0 Safari/537.36"
	// 查询互斥锁：防止定时任务与手动刷新并发登录
	queryLock = make(chan struct{}, 1)
)

// roomInfo 绑定房间信息
type roomInfo struct {
	AreaID       string `json:"areaId"`
	BuildingCode string `json:"buildingCode"`
	FloorCode    string `json:"floorCode"`
	RoomCode     string `json:"roomCode"`
	RoomName     string `json:"roomName"`
	AreaName     string `json:"areaName"`
	BuildingName string `json:"buildingName"`
	FloorName    string `json:"floorName"`
}

// cacheData 缓存结构（shiroJID 会话 + 房间）
type cacheData struct {
	AppShiro string   `json:"app_shiro"`
	Room     roomInfo `json:"room"`
	CachedAt int64    `json:"cached_at"`
}

// electricResult 查询结果
type electricResult struct {
	OK       bool    `json:"ok"`
	Room     string  `json:"room"`
	Surplus  float64 `json:"surplus"`
	Amount   float64 `json:"amount"`
	Status   string  `json:"status"`
	Source   string  `json:"source"`
	Time     int64   `json:"time"`
	Error    string  `json:"error,omitempty"`
}

var cacheFilePath = envOr("CACHE_FILE", "data/electric_cache.json")

// ---------- 缓存 ----------
func loadCache() (*cacheData, error) {
	b, err := os.ReadFile(cacheFilePath)
	if err != nil {
		return nil, err
	}
	var c cacheData
	if err := json.Unmarshal(b, &c); err != nil {
		return nil, err
	}
	return &c, nil
}

func saveCache(c *cacheData) error {
	if err := os.MkdirAll(dirName(cacheFilePath), 0o755); err != nil {
		return err
	}
	b, _ := json.MarshalIndent(c, "", "  ")
	return os.WriteFile(cacheFilePath, b, 0o644)
}

func clearCache() {
	_ = os.Remove(cacheFilePath)
}

func dirName(p string) string {
	i := strings.LastIndexByte(p, '/')
	if i < 0 {
		i = strings.LastIndexByte(p, '\\')
	}
	if i < 0 {
		return "."
	}
	return p[:i]
}

// ---------- HTTP 辅助 ----------
type xfSession struct {
	client *http.Client
	cookie string // shiroJID
}

func newXfSession(shiroJID string) *xfSession {
	return &xfSession{client: &http.Client{}, cookie: shiroJID}
}

func (s *xfSession) postForm(urlStr, body, referer string) ([]byte, http.Header, error) {
	ctx, cancel := context.WithTimeout(context.Background(), 20*time.Second)
	defer cancel()
	req, err := http.NewRequestWithContext(ctx, "POST", urlStr, strings.NewReader(body))
	if err != nil {
		return nil, nil, err
	}
	req.Header.Set("Content-Type", "application/x-www-form-urlencoded;charset=UTF-8")
	req.Header.Set("User-Agent", browserUA)
	req.Header.Set("X-Requested-With", "XMLHttpRequest")
	req.Header.Set("Accept", "application/json, text/plain, */*")
	if referer != "" {
		req.Header.Set("Referer", referer)
	}
	if s.cookie != "" {
		req.AddCookie(&http.Cookie{Name: "shiroJID", Value: s.cookie})
	}
	resp, err := s.client.Do(req)
	if err != nil {
		return nil, nil, err
	}
	defer resp.Body.Close()
	bodyBytes, _ := io.ReadAll(resp.Body)
	return bodyBytes, resp.Header, nil
}

func (s *xfSession) get(urlStr string, allowRedirect bool) (*http.Response, error) {
	client := s.client
	if !allowRedirect {
		// 不跟随重定向
		client = &http.Client{
			CheckRedirect: func(req *http.Request, via []*http.Request) error {
				return http.ErrUseLastResponse
			},
		}
	}
	ctx, cancel := context.WithTimeout(context.Background(), 20*time.Second)
	defer cancel()
	req, err := http.NewRequestWithContext(ctx, "GET", urlStr, nil)
	if err != nil {
		return nil, err
	}
	req.Header.Set("User-Agent", browserUA)
	req.Header.Set("X-Requested-With", "XMLHttpRequest")
	if s.cookie != "" {
		req.AddCookie(&http.Cookie{Name: "shiroJID", Value: s.cookie})
	}
	return client.Do(req)
}

// ---------- 查询链路 ----------

// step1GetCodeV2 ST票据 -> ymCode（无需 cookie）
func step1GetCodeV2(startURL string) (string, error) {
	cb := url.QueryEscape(startURL)
	u := fmt.Sprintf("https://auth.xiaofubao.com/authoriz/getCodeV2?bindSkip=1&ymAppId=%s&authType=3&authAppid=%s&callbackUrl=%s",
		xfYmAppid, xfAuthAppid, cb)
	s := newXfSession("")
	resp, err := s.get(u, false)
	if err != nil {
		return "", err
	}
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusFound {
		body, _ := io.ReadAll(resp.Body)
		return "", fmt.Errorf("getCodeV2 状态码异常: %d %s", resp.StatusCode, string(body))
	}
	loc := resp.Header.Get("Location")
	re := regexp.MustCompile(`ymCode=([0-9a-f]+)`)
	m := re.FindStringSubmatch(loc)
	if len(m) < 2 {
		return "", fmt.Errorf("getCodeV2 未返回 ymCode: %s", loc)
	}
	return m[1], nil
}

// extractShiroJID 从 Set-Cookie 头提取最终生效的 shiroJID。
// 服务端可能返回多值: 设置 -> deleteMe(删除) -> 重设，须按顺序取最后一个有效值。
func extractShiroJID(hdr http.Header) (string, error) {
	found := ""
	for _, c := range hdr.Values("Set-Cookie") {
		parts := strings.Split(c, ";")
		kv := strings.SplitN(strings.TrimSpace(parts[0]), "=", 2)
		if len(kv) != 2 || kv[0] != "shiroJID" {
			continue
		}
		if kv[1] == "deleteMe" {
			found = "" // 删除之前的
			continue
		}
		found = kv[1]
	}
	if found == "" {
		return "", errors.New("未返回有效的 shiroJID cookie")
	}
	return found, nil
}

// step2GetUserByCodeV2 ymCode -> 用户信息 + webapp shiroJID
func step2GetUserByCodeV2(ymCode, startURL string) (string, error) {
	s := newXfSession("")
	body := fmt.Sprintf("code=%s&platform=%s", ymCode, xfPlatform)
	_, hdr, err := s.postForm("https://webapp.xiaofubao.com/user/getUserByCodeV2", body, startURL)
	if err != nil {
		return "", err
	}
	return extractShiroJID(hdr)
}

// flexInt 兼容 JSON 中字符串或数字的 statusCode
type flexInt int

func (f *flexInt) UnmarshalJSON(b []byte) error {
	s := strings.Trim(string(b), `"`)
	if s == "" {
		*f = 0
		return nil
	}
	var n int
	if _, err := fmt.Sscanf(s, "%d", &n); err != nil {
		return err
	}
	*f = flexInt(n)
	return nil
}

// step3GetUserCode 生成一次性 code（必须带 referer）
func step3GetUserCode(shiroJID, startURL string) (string, error) {
	s := newXfSession(shiroJID)
	body := fmt.Sprintf("ymAppId=%s&ymAuthType=2&platform=%s", xfYmAppid, xfPlatform)
	b, _, err := s.postForm("https://webapp.xiaofubao.com/routeauth/auth/route/user/getUserCode", body, startURL)
	if err != nil {
		return "", err
	}
	var res struct {
		StatusCode flexInt `json:"statusCode"`
		Message    string  `json:"message"`
		Data       string  `json:"data"`
	}
	if err := json.Unmarshal(b, &res); err != nil {
		return "", err
	}
	if res.StatusCode != 0 {
		return "", fmt.Errorf("getUserCode 失败 %d: %s", res.StatusCode, res.Message)
	}
	return res.Data, nil
}

// step4GetUser4Authorize code -> application 域 shiroJID
func step4GetUser4Authorize(code string) (string, error) {
	s := newXfSession("")
	body := fmt.Sprintf("code=%s&authType=2&platform=%s", code, xfPlatform)
	_, hdr, err := s.postForm("https://application.xiaofubao.com/app/login/getUser4Authorize", body, "https://application.xiaofubao.com/")
	if err != nil {
		return "", err
	}
	return extractShiroJID(hdr)
}

// step5QueryBind 查询绑定房间
func step5QueryBind(shiroJID string) (*roomInfo, error) {
	s := newXfSession(shiroJID)
	body := fmt.Sprintf("bindType=3&platform=%s", xfPlatform)
	b, _, err := s.postForm("https://application.xiaofubao.com/app/electric/queryBind", body, "https://application.xiaofubao.com/")
	if err != nil {
		return nil, err
	}
	var res struct {
		StatusCode flexInt `json:"statusCode"`
		Rows       []struct {
			AreaID       string `json:"areaId"`
			BuildingCode string `json:"buildingCode"`
			FloorCode    string `json:"floorCode"`
			RoomCode     string `json:"roomCode"`
			RoomName     string `json:"roomName"`
			AreaName     string `json:"areaName"`
			BuildingName string `json:"buildingName"`
			FloorName    string `json:"floorName"`
		} `json:"rows"`
	}
	if err := json.Unmarshal(b, &res); err != nil {
		return nil, err
	}
	if res.StatusCode != 0 || len(res.Rows) == 0 {
		return nil, fmt.Errorf("queryBind 失败: %s", string(b))
	}
	r := res.Rows[0]
	return &roomInfo{
		AreaID: r.AreaID, BuildingCode: r.BuildingCode, FloorCode: r.FloorCode,
		RoomCode: r.RoomCode, RoomName: r.RoomName, AreaName: r.AreaName,
		BuildingName: r.BuildingName, FloorName: r.FloorName,
	}, nil
}

// step6QuerySurplus 查询剩余电量
func step6QuerySurplus(shiroJID string, room *roomInfo) (float64, float64, string, error) {
	s := newXfSession(shiroJID)
	body := fmt.Sprintf("areaId=%s&buildingCode=%s&floorCode=%s&roomCode=%s&platform=%s",
		room.AreaID, room.BuildingCode, room.FloorCode, room.RoomCode, xfPlatform)
	b, _, err := s.postForm("https://application.xiaofubao.com/app/electric/queryISIMSRoomSurplus", body, "https://application.xiaofubao.com/")
	if err != nil {
		return 0, 0, "", err
	}
	var res struct {
		StatusCode flexInt `json:"statusCode"`
		Data       struct {
			DisplayRoomName string `json:"displayRoomName"`
			SurplusList     []struct {
				Surplus    float64 `json:"surplus"`
				Amount     float64 `json:"amount"`
				RoomStatus string  `json:"roomStatus"`
			} `json:"surplusList"`
		} `json:"data"`
	}
	if err := json.Unmarshal(b, &res); err != nil {
		return 0, 0, "", err
	}
	if res.StatusCode != 0 || len(res.Data.SurplusList) == 0 {
		return 0, 0, "", fmt.Errorf("queryISIMSRoomSurplus 失败: %s", string(b))
	}
	item := res.Data.SurplusList[0]
	return item.Surplus, item.Amount, item.RoomStatus, nil
}

// ---------- 完整登录流程 ----------
func fullLoginFlow() (string, *roomInfo, *electricResult, error) {
	lzu := newLzuClient(envOr("LZU_USERNAME", ""), envOr("LZU_PASSWORD", ""))
	if lzu.username == "" || lzu.password == "" {
		return "", nil, nil, errors.New("缺少 LZU_USERNAME / LZU_PASSWORD 配置")
	}
	if _, _, err := lzu.Login(); err != nil {
		return "", nil, nil, err
	}
	st, err := lzu.GetSt(xfServiceID)
	if err != nil {
		return "", nil, nil, err
	}
	startURL := fmt.Sprintf("https://webapp.xiaofubao.com/card/apps_all.shtml?authAppid=%s&platform=%s&schoolCode=%s&PersonID=%s&st=%s&ticket=%s",
		xfAuthAppid, xfPlatform, xfSchoolCode, lzu.username, st, st)

	ymCode, err := step1GetCodeV2(startURL)
	if err != nil {
		return "", nil, nil, err
	}
	webappShiro, err := step2GetUserByCodeV2(ymCode, startURL)
	if err != nil {
		return "", nil, nil, err
	}
	code, err := step3GetUserCode(webappShiro, startURL)
	if err != nil {
		return "", nil, nil, err
	}
	appShiro, err := step4GetUser4Authorize(code)
	if err != nil {
		return "", nil, nil, err
	}
	room, err := step5QueryBind(appShiro)
	if err != nil {
		return "", nil, nil, err
	}
	surplus, amount, status, err := step6QuerySurplus(appShiro, room)
	if err != nil {
		return "", nil, nil, err
	}
	result := &electricResult{
		OK: true, Room: displayRoomName(room), Surplus: round2(surplus),
		Amount: round2(amount), Status: status, Source: "login", Time: time.Now().Unix(),
	}
	return appShiro, room, result, nil
}

// ---------- 查询入口（缓存优先） ----------
func queryElectric() *electricResult {
	queryLock <- struct{}{}
	defer func() { <-queryLock }()

	// 1. 尝试缓存
	if c, err := loadCache(); err == nil {
		if time.Now().Unix()-c.CachedAt < cacheTTL() {
			surplus, amount, status, err := step6QuerySurplus(c.AppShiro, &c.Room)
			if err == nil {
				return &electricResult{
					OK: true, Room: displayRoomName(&c.Room), Surplus: round2(surplus),
					Amount: round2(amount), Status: status, Source: "cache", Time: time.Now().Unix(),
				}
			}
			fmt.Println("[缓存] 会话失效:", err)
		}
	}

	// 2. 完整登录
	appShiro, room, result, err := fullLoginFlow()
	if err != nil {
		clearCache()
		return &electricResult{OK: false, Error: err.Error()}
	}
	_ = saveCache(&cacheData{AppShiro: appShiro, Room: *room, CachedAt: time.Now().Unix()})
	return result
}

func displayRoomName(r *roomInfo) string {
	return fmt.Sprintf("%s%s%s%s", r.AreaName, r.BuildingName, r.FloorName, r.RoomName)
}

func round2(f float64) float64 {
	return float64(int(f*100+0.5)) / 100
}

func cacheTTL() int64 {
	ttl := int64(6 * 24 * 3600)
	if v := envOr("XF_CACHE_TTL", ""); v != "" {
		var n int64
		if _, err := fmt.Sscanf(v, "%d", &n); err == nil && n > 0 {
			ttl = n
		}
	}
	return ttl
}