using KronaStaffTerminal.Models;
using KronaStaffTerminal.Services;
using KronaStaffTerminal.Tests.Mocks;
using Xunit;

namespace KronaStaffTerminal.Tests;

public class ScannerRecoveryTests
{
    [Fact]
    public void Scanner_SimulatesUsbDisconnectAndFiresConnectionLost()
    {
        using var scanner = new MockFingerprintScanner();
        scanner.Connect(0, Array.Empty<(int, string)>());
        Assert.True(scanner.IsConnected);
        Assert.Equal(ScannerState.Connected, scanner.State);

        var connectionLostFired = false;
        ScannerState? reportedState = null;

        scanner.ConnectionLost += () => connectionLostFired = true;
        scanner.StateChanged += (state, _) => reportedState = state;

        // Simulate physical USB drop
        scanner.SimulateDisconnect();

        Assert.False(scanner.IsConnected);
        Assert.Equal(ScannerState.Disconnected, scanner.State);
        Assert.True(connectionLostFired);
        Assert.Equal(ScannerState.Disconnected, reportedState);
    }

    [Fact]
    public void Scanner_SimulatesUsbReconnectAndRestoresReadyState()
    {
        using var scanner = new MockFingerprintScanner();
        scanner.Connect(0, Array.Empty<(int, string)>());
        scanner.SimulateDisconnect();
        Assert.Equal(ScannerState.Disconnected, scanner.State);

        ScannerState? reportedState = null;
        scanner.StateChanged += (state, _) => reportedState = state;

        // Simulate USB re-plug
        scanner.SimulateReconnect();

        Assert.True(scanner.IsConnected);
        Assert.Equal(ScannerState.Connected, scanner.State);
        Assert.Equal(ScannerState.Connected, reportedState);
    }

    [Fact]
    public void AdminPinVerification_OperatesNormallyWhenScannerIsDisconnected()
    {
        using var scanner = new MockFingerprintScanner();
        scanner.SimulateDisconnect();
        Assert.Equal(ScannerState.Disconnected, scanner.State);

        // Verify that AdminPinService functions 100% independently of hardware scanner state
        var (salt, hash, iterations) = AdminPinService.Hash("5555");
        var settings = new TerminalSettings
        {
            AdminPinSalt = salt,
            AdminPinHash = hash,
            AdminPinIterations = iterations
        };

        var now = DateTimeOffset.UtcNow;
        var allowed = AdminPinService.VerifyAndRecord(
            "5555", settings, now, out var error, out var rehashNeeded);

        Assert.True(allowed);
        Assert.Null(error);
        Assert.False(rehashNeeded);
    }
    
    [Fact]
    public async Task Scanner_AutoReconnectLogic_CallsConnectSuccessfully()
    {
        using var scanner = new MockFingerprintScanner();
        scanner.Connect(0, Array.Empty<(int, string)>());
        Assert.Equal(1, scanner.ConnectCallCount);

        var reconnectTcs = new TaskCompletionSource();
        scanner.ConnectionLost += async () =>
        {
            // Simulate typical application retry loop
            int retries = 0;
            while (retries < 5)
            {
                await Task.Delay(10);
                try
                {
                    scanner.Connect(0, Array.Empty<(int, string)>());
                    if (scanner.IsConnected)
                    {
                        reconnectTcs.TrySetResult();
                        return;
                    }
                }
                catch { }
                retries++;
            }
            reconnectTcs.TrySetException(new Exception("Failed to reconnect"));
        };

        scanner.SimulateDisconnect();
        // Emulate the hardware coming back after a short delay
        await Task.Delay(20);
        scanner.AddVirtualDevice(0, "SLK20R", "SERIAL"); // ensure device is discoverable if it was cleared

        await reconnectTcs.Task;
        
        Assert.True(scanner.ConnectCallCount > 1);
        Assert.Equal(ScannerState.Connected, scanner.State);
    }
}