sequenceDiagram
    participant U as 用户浏览器
    participant G as Gin Router
    participant H as HandlerAdmin
    participant AM as AdminModel
    participant SS as SessionStore

    U->>G: GET /admin/login
    G->>H: LoginGet(c)
    H-->>U: 登录页 HTML

    U->>G: POST /admin/login {username, password}
    G->>H: LoginPost(c)
    H->>AM: VerifyPassword(username, password)
    AM->>AM: bcrypt.CompareHashAndPassword()
    AM-->>H: true/false

    alt 验证成功
        H->>SS: Create(adminID, username)
        SS-->>H: sessionID
        H->>H: c.SetCookie("session_id", sessionID, 86400, "/", "", false, true)
        H-->>U: 302 Redirect → /admin
    else 验证失败
        H-->>U: 200 + 登录页(错误提示)
    end