using System;
using System.Threading.Tasks;
using Paca.Mobile.Core;
using Paca.Server.Gateway;
using Xunit;

namespace Paca.Tests.Mobile;

/// <summary>
/// Gate 127 ~ 132: 3G/4G/5G WAN 게이트웨이 및 Wi-Fi ↔ 셀룰러 무중단 로밍 기계적 검증
/// </summary>
public class MobileWanGatewayRoamingGateTests
{
    [Fact]
    public void Gate127_ConnectCode_Generation_And_Validation()
    {
        var code = PacaConnectCodeGenerator.GenerateCode();
        Assert.NotNull(code);
        Assert.StartsWith("PACA-", code);
        Assert.True(PacaConnectCodeGenerator.IsValid(code));

        Assert.False(PacaConnectCodeGenerator.IsValid("INVALID-CODE"));
        Assert.False(PacaConnectCodeGenerator.IsValid(""));
        Assert.False(PacaConnectCodeGenerator.IsValid(null));
    }

    [Fact]
    public void Gate128_WanGatewayConfig_State_Management()
    {
        var gateway = new WanGatewayManager(deviceName: "Encep-Studio-PC", localPort: 52100);

        // 기본 상태는 비활성
        Assert.False(gateway.IsActive);
        Assert.Equal(GatewayMode.Disabled, gateway.CurrentMode);

        // 원격 릴레이/터널 활성화 시뮬레이션
        gateway.EnableCloudTunnel("https://relay.paca.app/tunnel-9876", "PACA-884123");
        Assert.True(gateway.IsActive);
        Assert.Equal(GatewayMode.CloudTunnel, gateway.CurrentMode);
        Assert.Equal("https://relay.paca.app/tunnel-9876", gateway.PublicEndpoint);
        Assert.Equal("PACA-884123", gateway.ConnectCode);
    }

    [Fact]
    public void Gate129_Upnp_Mapping_Profile_Creation()
    {
        var gateway = new WanGatewayManager(deviceName: "Encep-Studio-PC", localPort: 52100);
        gateway.EnableDirectPortMapping(publicIp: "203.0.113.50", externalPort: 52100);

        Assert.True(gateway.IsActive);
        Assert.Equal(GatewayMode.DirectPortMapping, gateway.CurrentMode);
        Assert.Equal("http://203.0.113.50:52100", gateway.PublicEndpoint);
    }

    [Fact]
    public void Gate130_RoamingProfile_Serialization()
    {
        var profile = new RoamingDeviceProfile(
            DeviceId: "device-uuid-1234",
            DeviceName: "Encep-Desktop",
            LanEndpoint: "http://192.168.0.15:52100",
            WanEndpoint: "https://relay.paca.app/tunnel-9876",
            AuthToken: "token-secret-abc",
            ConnectCode: "PACA-884123"
        );

        Assert.Equal("http://192.168.0.15:52100", profile.GetEndpointFor(NetworkEnvironment.LocalWifi));
        Assert.Equal("https://relay.paca.app/tunnel-9876", profile.GetEndpointFor(NetworkEnvironment.CellularWan));
    }

    [Fact]
    public void Gate131_RoamingConnectionManager_Auto_Failover()
    {
        var profile = new RoamingDeviceProfile(
            DeviceId: "device-uuid-1234",
            DeviceName: "Encep-Desktop",
            LanEndpoint: "http://192.168.0.15:52100",
            WanEndpoint: "https://relay.paca.app/tunnel-9876",
            AuthToken: "token-secret-abc",
            ConnectCode: "PACA-884123"
        );

        var roaming = new RoamingConnectionManager(profile);

        // 초기 Wi-Fi 상태 -> LAN 우선
        roaming.UpdateNetworkState(NetworkEnvironment.LocalWifi);
        Assert.Equal("http://192.168.0.15:52100", roaming.ActiveEndpoint);
        Assert.False(roaming.IsRoamingOnCellular);

        // LAN 연결 실패 또는 셀룰러 환경 진입 -> WAN 게이트웨이로 핫-페일오버
        roaming.RecordConnectionFailure();
        Assert.Equal("https://relay.paca.app/tunnel-9876", roaming.ActiveEndpoint);
        Assert.True(roaming.IsRoamingOnCellular);

        // Wi-Fi 재접속 및 헬스체크 복구 -> LAN 복귀
        roaming.UpdateNetworkState(NetworkEnvironment.LocalWifi);
        roaming.RecordConnectionSuccess();
        Assert.Equal("http://192.168.0.15:52100", roaming.ActiveEndpoint);
        Assert.False(roaming.IsRoamingOnCellular);
    }

    [Fact]
    public void Gate132_RoamingConnectionManager_Fallback_When_Wan_Empty()
    {
        var profile = new RoamingDeviceProfile(
            DeviceId: "dev-only-lan",
            DeviceName: "Desktop-LAN",
            LanEndpoint: "http://192.168.1.10:52100",
            WanEndpoint: null, // WAN 미설정 상태
            AuthToken: "tok",
            ConnectCode: null
        );

        var roaming = new RoamingConnectionManager(profile);
        roaming.UpdateNetworkState(NetworkEnvironment.CellularWan);

        // WAN이 없으면 LAN 주소를 유지하되 오류 상태 경고 플래그
        Assert.Equal("http://192.168.1.10:52100", roaming.ActiveEndpoint);
        Assert.True(roaming.RequiresWanSetup);
    }
}