using System.Net;
using KronaStaffTerminal.Models;
using KronaStaffTerminal.Services;
using Xunit;

namespace KronaStaffTerminal.Tests;

public class AttendanceSyncTests
{
    private sealed class MockHttpMessageHandler : HttpMessageHandler
    {
        public Func<HttpRequestMessage, HttpResponseMessage> HandlerFunc { get; set; } =
            _ => new HttpResponseMessage(HttpStatusCode.OK);

        public List<HttpRequestMessage> CapturedRequests { get; } = new();

        protected override Task<HttpResponseMessage> SendAsync(
            HttpRequestMessage request,
            CancellationToken cancellationToken)
        {
            CapturedRequests.Add(request);
            return Task.FromResult(HandlerFunc(request));
        }
    }

    private static TerminalState CreateConfiguredState()
    {
        return new TerminalState
        {
            Settings = new TerminalSettings
            {
                StaffServerUrl = "https://staff.krona.internal:8453",
                StaffServerToken = "test_token_secret_123",
                TerminalDeviceId = "TERM-TEST-01"
            }
        };
    }

    [Fact]
    public async Task SyncPending_With200Ok_MarksRecordsAsSyncedAndSendsHeaders()
    {
        var mockHandler = new MockHttpMessageHandler
        {
            HandlerFunc = _ => new HttpResponseMessage(HttpStatusCode.OK)
        };
        var httpClient = new HttpClient(mockHandler);
        var syncService = new AttendanceSyncService(httpClient);
        var state = CreateConfiguredState();

        var record1 = new AttendanceRecord
        {
            Id = UlidGenerator.New(),
            EmployeeId = "emp-10",
            EventType = "Приход",
            OccurredAtUtc = DateTimeOffset.UtcNow.AddMinutes(-5),
            ServerSynced = false
        };
        var record2 = new AttendanceRecord
        {
            Id = UlidGenerator.New(),
            EmployeeId = "emp-10",
            EventType = "Уход",
            OccurredAtUtc = DateTimeOffset.UtcNow,
            ServerSynced = false
        };

        state.Attendance.Add(record1);
        state.Attendance.Add(record2);

        var result = await syncService.SyncPendingAsync(state, TestContext.Current.CancellationToken);

        Assert.Equal(2, result.ProcessedCount);
        Assert.Equal(2, result.SuccessCount);
        Assert.Equal(0, result.FailedCount);
        Assert.True(record1.ServerSynced);
        Assert.True(record2.ServerSynced);

        // Verify headers
        Assert.Equal(2, mockHandler.CapturedRequests.Count);
        var req = mockHandler.CapturedRequests[0];
        Assert.Equal("Bearer test_token_secret_123", req.Headers.Authorization?.ToString());
        Assert.True(req.Headers.Contains("Idempotency-Key"));
        Assert.True(req.Headers.Contains("X-Request-Id"));
    }

    [Fact]
    public async Task SyncPending_With409Conflict_TreatedAsIdempotentSuccess()
    {
        var mockHandler = new MockHttpMessageHandler
        {
            HandlerFunc = _ => new HttpResponseMessage(HttpStatusCode.Conflict)
        };
        var httpClient = new HttpClient(mockHandler);
        var syncService = new AttendanceSyncService(httpClient);
        var state = CreateConfiguredState();

        var record = new AttendanceRecord
        {
            Id = UlidGenerator.New(),
            EmployeeId = "emp-15",
            EventType = "Приход",
            OccurredAtUtc = DateTimeOffset.UtcNow,
            ServerSynced = false
        };
        state.Attendance.Add(record);

        var result = await syncService.SyncPendingAsync(state, TestContext.Current.CancellationToken);

        Assert.Equal(1, result.ProcessedCount);
        Assert.Equal(1, result.SuccessCount);
        Assert.Equal(0, result.FailedCount);
        Assert.True(record.ServerSynced);
        Assert.Null(record.ServerSyncError);
    }

    [Fact]
    public async Task SyncPending_With500Error_RetainsRecordForRetry()
    {
        var mockHandler = new MockHttpMessageHandler
        {
            HandlerFunc = _ => new HttpResponseMessage(HttpStatusCode.InternalServerError)
        };
        var httpClient = new HttpClient(mockHandler);
        var syncService = new AttendanceSyncService(httpClient);
        var state = CreateConfiguredState();

        var record = new AttendanceRecord
        {
            Id = UlidGenerator.New(),
            EmployeeId = "emp-20",
            EventType = "Приход",
            OccurredAtUtc = DateTimeOffset.UtcNow,
            ServerSynced = false
        };
        state.Attendance.Add(record);

        var result = await syncService.SyncPendingAsync(state, TestContext.Current.CancellationToken);

        Assert.Equal(1, result.ProcessedCount);
        Assert.Equal(0, result.SuccessCount);
        Assert.Equal(1, result.FailedCount);
        Assert.False(record.ServerSynced);
        Assert.Equal("HTTP 500", record.ServerSyncError);
    }

    [Fact]
    public async Task SyncPending_WithNetworkException_HaltsCurrentCycle()
    {
        var mockHandler = new MockHttpMessageHandler
        {
            HandlerFunc = _ => throw new HttpRequestException("Connection refused")
        };
        var httpClient = new HttpClient(mockHandler);
        var syncService = new AttendanceSyncService(httpClient);
        var state = CreateConfiguredState();

        var record1 = new AttendanceRecord
        {
            Id = UlidGenerator.New(),
            EmployeeId = "emp-1",
            EventType = "Приход",
            OccurredAtUtc = DateTimeOffset.UtcNow.AddMinutes(-2),
            ServerSynced = false
        };
        var record2 = new AttendanceRecord
        {
            Id = UlidGenerator.New(),
            EmployeeId = "emp-2",
            EventType = "Приход",
            OccurredAtUtc = DateTimeOffset.UtcNow.AddMinutes(-1),
            ServerSynced = false
        };
        state.Attendance.Add(record1);
        state.Attendance.Add(record2);

        var result = await syncService.SyncPendingAsync(state, TestContext.Current.CancellationToken);

        Assert.Equal(2, result.ProcessedCount);
        Assert.Equal(1, result.FailedCount);
        Assert.True(result.HasNetworkError);
        Assert.False(record1.ServerSynced);
        Assert.False(record2.ServerSynced);
        // Only first was attempted because loop broke on network drop
        Assert.Single(mockHandler.CapturedRequests);
    }
}