using CsharpHttpHelper;
using System;
using System.Threading.Tasks;
using System.ComponentModel.DataAnnotations;


namespace Work.Store.Api;

public sealed class LoginRequest
{
    [Required]
    public string UserName { get; set; }

    /// <summary>UTF-8 密码的 32 位大写 MD5，由调用方计算。</summary>
    [Required]
    public string Password { get; set; }

    [StringLength(100)]
    public string DeviceId { get; set; }

    [StringLength(100)]
    public string DeviceName { get; set; }
}

public sealed class LoginResult
{
    public string TokenType { get; set; } = "Bearer";
    public string Token { get; set; }
    public uint ExpiresInMinutes { get; set; }
}

public sealed class AuthApi
{
    private readonly ApiTransport _transport;
    private readonly string _deviceId;

    public AuthApi(string baseUrl) : this(new ApiTransport(baseUrl)) { }

    public AuthApi(ApiTransport transport, string deviceId = null)
    {
        _transport = transport ?? throw new ArgumentNullException(nameof(transport));
        _deviceId = deviceId;
    }

    /// <summary>同步登录，凭据快照仅存内存，供 401 时自动重登；界面调用需放在后台线程。</summary>
    public LoginResult Login(LoginRequest request)
    {
        if (request == null) throw new ArgumentNullException(nameof(request));
        var credentials = new LoginRequest
        {
            UserName = request.UserName,
            Password = request.Password,
            DeviceId = _deviceId ?? request.DeviceId,
            DeviceName = request.DeviceName
        };
        _transport.SessionGate.Wait();
        try
        {
            var result = LoginCore(_transport, credentials);
            _transport.SetSession(result.Token, credentials);
            return result;
        }
        finally { _transport.SessionGate.Release(); }
    }

    internal static LoginResult LoginCore(ApiTransport transport, LoginRequest request)
    {
        var result = transport.GetRequired<LoginResult>("Auth/Login", MethodType.Post, request, authenticated: false);
        return ValidateToken(result);
    }

    internal static async Task<LoginResult> LoginCoreAsync(ApiTransport transport, LoginRequest request)
    {
        var result = await transport.GetRequiredAsync<LoginResult>("Auth/Login", MethodType.Post, request, authenticated: false).ConfigureAwait(false);
        return ValidateToken(result);
    }

    private static LoginResult ValidateToken(LoginResult result)
    {
        if (result == null || string.IsNullOrWhiteSpace(result.Token) ||
            result.Token.IndexOfAny(new[] { '\r', '\n' }) >= 0 ||
            !string.Equals(result.TokenType, "Bearer", StringComparison.OrdinalIgnoreCase))
            throw new HttpException("登录响应缺少有效的 Bearer Token。");

        return result;
    }
}