type UserAction struct {
    UserID    string    `json:"user_id"`     // 用户标识（可匿名）
    Action    string    `json:"action"`      // 行为类型：page_view, click, scroll 等
    Page      string    `json:"page"`        // 当前页面URL
    Element   string    `json:"element"`     // 触发元素（如按钮ID）
    Timestamp time.Time `json:"timestamp"`   // 时间戳
    IP        string    `json:"ip"`
    UA        string    `json:"ua"`          // User-Agent
}

fetch("/api/log", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    user_id: "u12345",
    action: "page_view",
    page: "/home",
    element: "",
    timestamp: new Date().toISOString(),
    ip: "", // 可由后端获取
    ua: n*igator.userAgent
  })
});

r.POST("/api/log", func(c *gin.Context) {
    var action UserAction
    if err := c.ShouldBindJSON(&action); err != nil {
        c.JSON(400, gin.H{"error": err.Error()})
        return
    }
    action.IP = c.ClientIP()
    action.UA = c.Request.UserAgent()
    action.Timestamp = time.Now()

    // 写入数据库或消息队列
    go s*eLogToDB(action)

    c.Status(200)
})

func s*eLogToDB(action UserAction) {
    _, err := db.Exec(
        "INSERT INTO user_actions(user_id, action, page, element, timestamp, ip, ua) VALUES($1,$2,$3,$4,$5,$6,$7)",
        action.UserID, action.Action, action.Page, action.Element,
        action.Timestamp, action.IP, action.UA)
    if err != nil {
        log.Printf("Failed to s*e log: %v", err)
    }
}

func GetPageViews(page string, start, end time.Time) (int, error) {
    var count int
    err := db.QueryRow(
        "SELECT COUNT(*) FROM user_actions WHERE page=$1 AND timestamp BETWEEN $2 AND $3",
        page, start, end).Scan(&count)
    return count, err
}

func GetUniqueVisitors(page string, start, end time.Time) (int, error) {
    var count int
    err := db.QueryRow(
        "SELECT COUNT(DISTINCT user_id) FROM user_actions WHERE page=$1 AND timestamp BETWEEN $2 AND $3",
        page, start, end).Scan(&count)
    return count, err
}

steps := []string{"visit_home", "click_signup", "submit_form", "complete_register"}
for _, step := range steps {
    count, _ := GetActionCount(step, period)
    fmt.Printf("%s: %d\n", step, count)
}