commit b2ad61e3fe927a0255877b0283c0f45abed5f5d2
Author: fallensigh <fallensigh@gmail.com>
Date:   Sun Aug 23 21:29:33 2026 +0800

    feat: 核心电费查询 Go 服务
    
    - FasterLZU 登录 + xiaofubao 6 步电费链路
    
    - shiroJID 会话缓存 + 每日记录存储
    
    - 定时任务: 每天 00:00 记录, 失败重试 5 次
    
    Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)
    
    Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

diff --git a/go/crypto.go b/go/crypto.go
new file mode 100644
index 0000000..460a174
--- /dev/null
+++ b/go/crypto.go
@@ -0,0 +1,82 @@
+package main
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/md5"
+	"encoding/hex"
+	"fmt"
+	"strings"
+)
+
+// crypto.go - AES-CBC 加密/解密 + MD5 签名（与 FasterLZU APP 行为一致）
+// 密钥必须通过环境变量 LZU_AES_KEY / LZU_MD5_KEY 提供（16 字节）
+
+var (
+	aesKey = envOr("LZU_AES_KEY", "") // 16 字节，由部署环境注入
+	md5Key = envOr("LZU_MD5_KEY", "")
+)
+
+// aesEncrypt 使用 AES-CBC，IV=key，零填充，输出小写 hex
+func aesEncrypt(plaintext string) (string, error) {
+	key := []byte(aesKey)
+	if len(key) != 16 {
+		return "", fmt.Errorf("AES key 长度不是 16 字节")
+	}
+	block, err := aes.NewCipher(key)
+	if err != nil {
+		return "", err
+	}
+	data := []byte(plaintext)
+	// 零填充到 blockSize 的整数倍
+	blockSize := aes.BlockSize
+	paddedLen := len(data)
+	if paddedLen%blockSize != 0 {
+		paddedLen = len(data) + (blockSize - len(data)%blockSize)
+	}
+	padded := make([]byte, paddedLen)
+	copy(padded, data)
+	// 剩余部分保持 0x00（零填充）
+
+	iv := key
+	mode := cipher.NewCBCEncrypter(block, iv)
+	ciphertext := make([]byte, paddedLen)
+	mode.CryptBlocks(ciphertext, padded)
+	return hex.EncodeToString(ciphertext), nil
+}
+
+// aesDecrypt AES-CBC 解密，去除尾部零填充
+func aesDecrypt(hexStr string) (string, error) {
+	key := []byte(aesKey)
+	if len(key) != 16 {
+		return "", fmt.Errorf("AES key 长度不是 16 字节")
+	}
+	encrypted, err := hex.DecodeString(hexStr)
+	if err != nil {
+		return "", err
+	}
+	block, err := aes.NewCipher(key)
+	if err != nil {
+		return "", err
+	}
+	iv := key
+	mode := cipher.NewCBCDecrypter(block, iv)
+	decrypted := make([]byte, len(encrypted))
+	mode.CryptBlocks(decrypted, encrypted)
+	// 去除尾部零填充
+	validLen := len(decrypted)
+	for i := len(decrypted) - 1; i >= 0 && i >= len(decrypted)-16; i-- {
+		if decrypted[i] != 0 {
+			break
+		}
+		validLen--
+	}
+	return string(decrypted[:validLen]), nil
+}
+
+// md5Encrypt 签名: 参数值以 | 连接，末尾拼接 key，返回 MD5 hex
+func md5Encrypt(params []string, key string) string {
+	data := strings.Join(params, "|") + "|" + key
+	sum := md5.Sum([]byte(data))
+	return hex.EncodeToString(sum[:])
+}
diff --git a/go/electric.go b/go/electric.go
new file mode 100644
index 0000000..e5d65d2
--- /dev/null
+++ b/go/electric.go
@@ -0,0 +1,431 @@
+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
+}
diff --git a/go/go.mod b/go/go.mod
new file mode 100644
index 0000000..e60f602
--- /dev/null
+++ b/go/go.mod
@@ -0,0 +1,3 @@
+module electric-monitor
+
+go 1.18
diff --git a/go/history.go b/go/history.go
new file mode 100644
index 0000000..e735195
--- /dev/null
+++ b/go/history.go
@@ -0,0 +1,253 @@
+package main
+
+import (
+	"encoding/json"
+	"os"
+	"sort"
+	"strings"
+	"sync"
+	"time"
+)
+
+// history.go - 每日电费记录存储（JSON 文件）与耗电统计
+
+type record struct {
+	Date      string  `json:"date"`   // YYYY-MM-DD
+	Surplus   float64 `json:"surplus"`
+	Amount    float64 `json:"amount"`
+	Source    string  `json:"source"` // auto / manual
+	CreatedAt int64   `json:"created_at"`
+}
+
+type dailyStat struct {
+	Date    string   `json:"date"`
+	Surplus float64  `json:"surplus"`
+	Amount  float64  `json:"amount"`
+	Usage   *float64 `json:"usage"` // nil 表示无前一天基线
+}
+
+// monthSummary 月度汇总
+type monthSummary struct {
+	Month        string   `json:"month"`          // YYYY-MM
+	RecordCount  int      `json:"record_count"`   // 记录天数
+	StartSurplus *float64 `json:"start_surplus"`  // 月初首次电量
+	EndSurplus   *float64 `json:"end_surplus"`    // 月末末次电量
+	TotalUsage   *float64 `json:"total_usage"`    // 月总耗电
+	AvgUsage     *float64 `json:"avg_usage"`      // 日均耗电
+	RechargeDays int      `json:"recharge_days"`  // 疑似充值天数（电量回升）
+	MaxUsage     *float64 `json:"max_usage"`      // 单日最大耗电
+}
+
+var (
+	historyPath   = envOr("HISTORY_FILE", "data/electric_history.json")
+	historyLock   sync.Mutex
+	historyLoaded bool
+	historyCache  []record
+)
+
+// loadHistory 读取历史记录
+func loadHistory() []record {
+	historyLock.Lock()
+	defer historyLock.Unlock()
+	if historyLoaded {
+		return historyCache
+	}
+	b, err := os.ReadFile(historyPath)
+	if err != nil {
+		historyLoaded = true
+		return nil
+	}
+	_ = json.Unmarshal(b, &historyCache)
+	historyLoaded = true
+	return historyCache
+}
+
+// saveHistory 持久化历史记录
+func saveHistory(records []record) error {
+	historyLock.Lock()
+	defer historyLock.Unlock()
+	if err := os.MkdirAll(dirName(historyPath), 0o755); err != nil {
+		return err
+	}
+	b, _ := json.MarshalIndent(records, "", "  ")
+	if err := os.WriteFile(historyPath, b, 0o644); err != nil {
+		return err
+	}
+	historyCache = records
+	return nil
+}
+
+// hasRecord 判断指定日期是否已有记录
+func hasRecord(dateStr string) bool {
+	for _, r := range loadHistory() {
+		if r.Date == dateStr {
+			return true
+		}
+	}
+	return false
+}
+
+// addRecord 写入（或覆盖）一条记录
+func addRecord(dateStr string, surplus, amount float64, source string) error {
+	records := loadHistory()
+	updated := false
+	for i, r := range records {
+		if r.Date == dateStr {
+			records[i] = record{Date: dateStr, Surplus: surplus, Amount: amount, Source: source, CreatedAt: time.Now().Unix()}
+			updated = true
+			break
+		}
+	}
+	if !updated {
+		records = append(records, record{Date: dateStr, Surplus: surplus, Amount: amount, Source: source, CreatedAt: time.Now().Unix()})
+	}
+	return saveHistory(records)
+}
+
+// getRecords 返回降序（新→旧）记录列表
+func getRecords() []record {
+	records := loadHistory()
+	sort.Slice(records, func(i, j int) bool {
+		return records[i].Date > records[j].Date
+	})
+	return records
+}
+
+// buildDailyStats 按日期升序生成每日统计（含日耗电 = 前一天剩余 - 当天剩余）
+// 注意: 耗电计算跨月时使用上月末记录作为基线（若存在）
+func buildDailyStats(records []record, month string) []dailyStat {
+	all := loadHistory()
+	// 若指定月份，额外包含上一月最后一条记录作为基线（不计入本月输出）
+	var prevMonthLast *record
+	if month != "" {
+		prevPrefix := prevMonth(month) + "-"
+		var last *record
+		for i := range all {
+			if strings.HasPrefix(all[i].Date, prevPrefix) {
+				if last == nil || all[i].Date > last.Date {
+					last = &all[i]
+				}
+			}
+		}
+		prevMonthLast = last
+	}
+
+	// 筛选目标记录
+	var target []record
+	if month != "" {
+		target = filterByMonth(records, month)
+	} else {
+		target = records
+	}
+	sort.Slice(target, func(i, j int) bool {
+		return target[i].Date < target[j].Date
+	})
+
+	var daily []dailyStat
+	var prevSurplus *float64
+	if prevMonthLast != nil {
+		prevSurplus = &prevMonthLast.Surplus
+	}
+	for _, r := range target {
+		var usage *float64
+		if prevSurplus != nil {
+			u := round2(*prevSurplus - r.Surplus)
+			if u < 0 {
+				u = 0 // 充值/异常归零
+			}
+			usage = &u
+		}
+		daily = append(daily, dailyStat{Date: r.Date, Surplus: r.Surplus, Amount: r.Amount, Usage: usage})
+		s := r.Surplus
+		prevSurplus = &s
+	}
+	return daily
+}
+
+// prevMonth 返回上个月的 YYYY-MM
+func prevMonth(month string) string {
+	t, err := time.Parse("2006-01", month)
+	if err != nil {
+		return ""
+	}
+	return t.AddDate(0, -1, 0).Format("2006-01")
+}
+
+// filterByMonth 按月份(YYYY-MM)筛选记录
+func filterByMonth(records []record, month string) []record {
+	if month == "" {
+		return records
+	}
+	prefix := month + "-"
+	var out []record
+	for _, r := range records {
+		if strings.HasPrefix(r.Date, prefix) {
+			out = append(out, r)
+		}
+	}
+	return out
+}
+
+// buildMonthSummary 生成某月的月度汇总
+func buildMonthSummary(daily []dailyStat, month string) *monthSummary {
+	if len(daily) == 0 {
+		return &monthSummary{Month: month, RecordCount: 0}
+	}
+	// daily 已是升序
+	m := month
+	if m == "" {
+		m = daily[0].Date[:7]
+	}
+	start := daily[0].Surplus
+	end := daily[len(daily)-1].Surplus
+
+	var total float64
+	var max float64
+	rechargeDays := 0
+	countWithUsage := 0
+	for _, d := range daily {
+		if d.Usage != nil {
+			total += *d.Usage
+			if *d.Usage > max {
+				max = *d.Usage
+			}
+			countWithUsage++
+		}
+		// 疑似充值：当天剩余比前一天高
+	}
+	// 充值与最大耗电基于原始升序记录重新精确计算
+	if len(daily) >= 2 {
+		rechargeDays = countRecharges(daily)
+	}
+
+	var totalP, avgP, maxP, startP, endP *float64
+	startP, endP = &start, &end
+	totalP = &total
+	if countWithUsage > 0 {
+		avg := round2(total / float64(countWithUsage))
+		avgP = &avg
+	}
+	maxP = &max
+
+	return &monthSummary{
+		Month:        m,
+		RecordCount:  len(daily),
+		StartSurplus: startP,
+		EndSurplus:   endP,
+		TotalUsage:   totalP,
+		AvgUsage:     avgP,
+		RechargeDays: rechargeDays,
+		MaxUsage:     maxP,
+	}
+}
+
+// countRecharges 统计疑似充值天数（当天剩余较前一天回升）
+func countRecharges(daily []dailyStat) int {
+	n := 0
+	for i := 1; i < len(daily); i++ {
+		if daily[i].Surplus > daily[i-1].Surplus {
+			n++
+		}
+	}
+	return n
+}
diff --git a/go/lzuapi.go b/go/lzuapi.go
new file mode 100644
index 0000000..4f2ae2e
--- /dev/null
+++ b/go/lzuapi.go
@@ -0,0 +1,130 @@
+package main
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"strings"
+	"time"
+)
+
+// lzuapi.go - FasterLZU (appservice.lzu.edu.cn) 登录客户端
+// 对应 Python lzuapi.py 中的 login() 与 get_st()
+
+const (
+	appServiceBase = "https://appservice.lzu.edu.cn"
+	lzuUserAgent   = "Mozilla/5.0 (Linux; Android 12; SM-S7110 Build/V417IR; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/101.0.4951.61 Mobile Safari/537.36 lzdx_ua JHZF_LZDXAPP"
+)
+
+// lzuClient FasterLZU API 客户端
+type lzuClient struct {
+	http         *http.Client
+	username     string
+	password     string
+	loginToken   string
+	gatewayToken string
+}
+
+func newLzuClient(username, password string) *lzuClient {
+	return &lzuClient{
+		http:     &http.Client{},
+		username: username,
+		password: password,
+	}
+}
+
+// encryptedHeaders 加密请求头
+func encryptedHeaders() http.Header {
+	h := http.Header{}
+	h.Set("Content-Type", "application/json;charset=UTF-8")
+	h.Set("Transfer-Encrypt", "true")
+	h.Set("User-Agent", lzuUserAgent)
+	return h
+}
+
+// Login 登录，返回 (loginToken, gatewayToken)
+func (c *lzuClient) Login() (string, string, error) {
+	url := appServiceBase + "/api/eusp-unify-terminal/app-user/login"
+	data := map[string]any{
+		"app_os": 2,
+		"name":   c.username,
+		"pwd":    c.password,
+	}
+	plaintext, _ := json.Marshal(data) // 无空格，与 Python separators=(",",":") 一致
+	ciphertext, err := aesEncrypt(string(plaintext))
+	if err != nil {
+		return "", "", err
+	}
+	ctx, cancel := context.WithTimeout(context.Background(), 20*time.Second)
+	defer cancel()
+	req, err := http.NewRequestWithContext(ctx, "POST", url, bytes.NewBufferString(ciphertext))
+	if err != nil {
+		return "", "", err
+	}
+	req.Header = encryptedHeaders()
+	resp, err := c.http.Do(req)
+	if err != nil {
+		return "", "", err
+	}
+	defer resp.Body.Close()
+	body, _ := io.ReadAll(resp.Body)
+
+	decrypted, err := aesDecrypt(strings.TrimSpace(string(body)))
+	if err != nil {
+		return "", "", fmt.Errorf("登录响应解密失败: %w", err)
+	}
+	var res struct {
+		Code int `json:"code"`
+		Data struct {
+			LoginToken   string `json:"login_token"`
+			GatewayToken string `json:"gateway_token"`
+		} `json:"data"`
+	}
+	if err := json.Unmarshal([]byte(decrypted), &res); err != nil {
+		return "", "", fmt.Errorf("登录响应解析失败: %w", err)
+	}
+	if res.Code != 1 {
+		return "", "", fmt.Errorf("登录失败 code=%d", res.Code)
+	}
+	c.loginToken = res.Data.LoginToken
+	c.gatewayToken = res.Data.GatewayToken
+	return c.loginToken, c.gatewayToken, nil
+}
+
+// GetSt 获取服务令牌 ST
+func (c *lzuClient) GetSt(serviceID string) (string, error) {
+	url := fmt.Sprintf("%s/api/eusp-unify-terminal/app-user/getSt?loginToken=%s&serviceId=%s&service=",
+		appServiceBase, c.loginToken, serviceID)
+	ctx, cancel := context.WithTimeout(context.Background(), 20*time.Second)
+	defer cancel()
+	req, err := http.NewRequestWithContext(ctx, "GET", url, nil)
+	if err != nil {
+		return "", err
+	}
+	req.Header = encryptedHeaders()
+	resp, err := c.http.Do(req)
+	if err != nil {
+		return "", err
+	}
+	defer resp.Body.Close()
+	body, _ := io.ReadAll(resp.Body)
+
+	decrypted, err := aesDecrypt(strings.TrimSpace(string(body)))
+	if err != nil {
+		return "", fmt.Errorf("getSt 响应解密失败: %w", err)
+	}
+	var res struct {
+		Code int    `json:"code"`
+		Data string `json:"data"`
+	}
+	if err := json.Unmarshal([]byte(decrypted), &res); err != nil {
+		return "", fmt.Errorf("getSt 响应解析失败: %w", err)
+	}
+	if res.Code != 1 {
+		return "", fmt.Errorf("getSt 失败 code=%d", res.Code)
+	}
+	return res.Data, nil
+}
diff --git a/go/main.go b/go/main.go
new file mode 100644
index 0000000..3304249
--- /dev/null
+++ b/go/main.go
@@ -0,0 +1,223 @@
+package main
+
+import (
+	"embed"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"os"
+	"sort"
+	"strings"
+	"time"
+)
+
+// main.go - 宿舍电费监控 Web 服务（零第三方依赖，单二进制）
+// 路由:
+//   GET /              -> 静态前端
+//   GET /api/electric  -> 实时电费
+//   GET /api/history   -> 历史记录 + 每日耗电统计
+// 定时任务: 每天 00:00 记录电费，失败重试 5 次（间隔 60s）
+
+//go:embed static
+var staticFS embed.FS
+
+const (
+	retryTimes    = 5
+	retryInterval = 60 * time.Second
+	checkInterval = 30 * time.Second
+)
+
+var (
+	host = envOr("HOST", "0.0.0.0")
+	port = envOr("PORT", "8000")
+)
+
+// envOr 读取环境变量，为空时返回默认值
+func envOr(key, def string) string {
+	if v := os.Getenv(key); v != "" {
+		return v
+	}
+	return def
+}
+
+// ---------- 定时任务 ----------
+func schedulerLoop() {
+	lastTryDate := ""
+	for {
+		now := time.Now()
+		today := now.Format("2006-01-02")
+		// 00:00~00:05 窗口触发
+		if now.Hour() == 0 && now.Minute() < 5 && lastTryDate != today {
+			lastTryDate = today
+			if !hasRecord(today) {
+				fmt.Printf("[定时] %s 00:00 触发每日电费记录\n", today)
+				runDailyRecordWithRetry()
+				time.Sleep(checkInterval * 2)
+			}
+		} else if now.Hour() == 0 && !hasRecord(today) && lastTryDate != today {
+			// 失败补记
+			lastTryDate = today
+			fmt.Println("[补记] 今日无记录，尝试补记")
+			runDailyRecordWithRetry()
+		}
+		time.Sleep(checkInterval)
+	}
+}
+
+func runDailyRecordWithRetry() {
+	for i := 1; i <= retryTimes; i++ {
+		if recordAndLog() {
+			return
+		}
+		fmt.Printf("[定时] 第 %d 次尝试失败，%d 秒后重试\n", i, retryInterval/time.Second)
+		time.Sleep(retryInterval)
+	}
+	fmt.Printf("[定时] %d 次重试均失败，等待下轮\n", retryTimes)
+}
+
+func recordAndLog() bool {
+	res := queryElectric()
+	if !res.OK {
+		return false
+	}
+	today := time.Now().Format("2006-01-02")
+	if err := addRecord(today, res.Surplus, res.Amount, "auto"); err != nil {
+		fmt.Println("[记录] 写入失败:", err)
+		return false
+	}
+	fmt.Printf("[记录] %s 剩余 %.2f 度 (%.2f 元) [auto]\n", today, res.Surplus, res.Amount)
+	return true
+}
+
+// ---------- HTTP 处理 ----------
+func apiElectric(w http.ResponseWriter, r *http.Request) {
+	res := queryElectric()
+	writeJSON(w, res)
+}
+
+func apiHistory(w http.ResponseWriter, r *http.Request) {
+	q := r.URL.Query()
+	month := q.Get("month") // YYYY-MM，空=全部
+
+	records := getRecords()
+	allDaily := buildDailyStats(records, "") // 全量（用于可用月份列表）
+	monthDaily := buildDailyStats(records, month)
+
+	// 可用月份列表（降序）
+	months := availableMonths(records)
+
+	summary := buildMonthSummary(monthDaily, month)
+	writeJSON(w, map[string]any{
+		"ok":        true,
+		"month":     month,
+		"months":    months,
+		"records":   monthDaily, // 升序每日统计（含 usage）
+		"daily":     monthDaily,
+		"summary":   summary,
+		"all_count": len(allDaily),
+	})
+}
+
+// availableMonths 返回所有有记录的月份（YYYY-MM，降序）
+func availableMonths(records []record) []string {
+	seen := map[string]bool{}
+	var months []string
+	for _, r := range records {
+		if len(r.Date) >= 7 {
+			m := r.Date[:7]
+			if !seen[m] {
+				seen[m] = true
+				months = append(months, m)
+			}
+		}
+	}
+	sort.Sort(sort.Reverse(sort.StringSlice(months)))
+	return months
+}
+
+func writeJSON(w http.ResponseWriter, v any) {
+	w.Header().Set("Content-Type", "application/json; charset=utf-8")
+	w.Header().Set("Cache-Control", "no-store")
+	_ = json.NewEncoder(w).Encode(v)
+}
+
+// ---------- 静态文件 ----------
+// 直接从 embed FS 读取并写出，避免 http.FileServer 的目录重定向问题
+func serveStatic(w http.ResponseWriter, r *http.Request) {
+	p := r.URL.Path
+	orig := p
+	if strings.HasPrefix(p, "/static/") {
+		p = strings.TrimPrefix(p, "/static/")
+	}
+	if p == "/" {
+		p = "/index.html"
+	}
+	if p == "" {
+		p = "/index.html"
+	}
+
+	// 规范化为以 / 开头的 embed 路径
+	if !strings.HasPrefix(p, "/") {
+		p = "/" + p
+	}
+	full := "static" + p
+	data, err := staticFS.ReadFile(full)
+	if err != nil {
+		fmt.Printf("[静态] %s -> %s: 读取失败 %v\n", orig, full, err)
+		http.NotFound(w, r)
+		return
+	}
+	// 设置 Content-Type
+	switch {
+	case strings.HasSuffix(p, ".html"):
+		w.Header().Set("Content-Type", "text/html; charset=utf-8")
+	case strings.HasSuffix(p, ".css"):
+		w.Header().Set("Content-Type", "text/css; charset=utf-8")
+	case strings.HasSuffix(p, ".js"):
+		w.Header().Set("Content-Type", "text/javascript; charset=utf-8")
+	case strings.HasSuffix(p, ".png"):
+		w.Header().Set("Content-Type", "image/png")
+	default:
+		w.Header().Set("Content-Type", "application/octet-stream")
+	}
+	w.Header().Set("Cache-Control", "no-cache")
+	_, _ = w.Write(data)
+}
+
+func main() {
+	// 启动定时任务
+	go schedulerLoop()
+
+	// 启动时若今日无记录，立即查询建立基线
+	today := time.Now().Format("2006-01-02")
+	if !hasRecord(today) {
+		fmt.Println("[启动] 今日无记录，立即查询并记录")
+		go runDailyRecordWithRetry()
+	}
+
+	mux := http.NewServeMux()
+	mux.HandleFunc("/api/electric", apiElectric)
+	mux.HandleFunc("/api/history", apiHistory)
+	mux.HandleFunc("/", serveStatic)
+
+	addr := fmt.Sprintf("%s:%s", host, port)
+	fmt.Println("=" + strings.Repeat("=", 49))
+	fmt.Println("宿舍电费监控服务已启动")
+	fmt.Println("  访问地址: http://" + addr)
+	fmt.Println("  定时记录: 每天 00:00，失败重试", retryTimes, "次")
+	fmt.Println("=" + strings.Repeat("=", 49))
+
+	// 带超时的 HTTP 服务器：防止慢速/空闲连接堆积 goroutine
+	srv := &http.Server{
+		Addr:              addr,
+		Handler:           mux,
+		ReadHeaderTimeout: 10 * time.Second,
+		ReadTimeout:       30 * time.Second,
+		WriteTimeout:      60 * time.Second,
+		IdleTimeout:       90 * time.Second,
+	}
+	if err := srv.ListenAndServe(); err != nil {
+		fmt.Println("服务启动失败:", err)
+		os.Exit(1)
+	}
+}