using ChatBot.Data;
using ChatBot.Services;
using ChatBot.Tests.TestUtilities;
using FluentAssertions;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using Moq;

namespace ChatBot.Tests.Services;

public class DatabaseInitializationServiceTests : UnitTestBase
{
    [Fact]
    public void DatabaseInitializationService_ShouldCreateInstance()
    {
        // Arrange
        var serviceProviderMock = new Mock<IServiceProvider>();
        var loggerMock = new Mock<ILogger<DatabaseInitializationService>>();

        // Act
        var service = new DatabaseInitializationService(
            serviceProviderMock.Object,
            loggerMock.Object
        );

        // Assert
        Assert.NotNull(service);
    }

    [Fact]
    public async Task DatabaseInitializationService_StopAsync_ShouldComplete()
    {
        // Arrange
        var serviceProviderMock = new Mock<IServiceProvider>();
        var loggerMock = new Mock<ILogger<DatabaseInitializationService>>();
        var service = new DatabaseInitializationService(
            serviceProviderMock.Object,
            loggerMock.Object
        );

        // Act & Assert
        await service.StopAsync(CancellationToken.None);

        // If we reach here, the method completed successfully
        Assert.True(true);
    }

    [Fact]
    public async Task StartAsync_ShouldLogCorrectInformation_WhenStopping()
    {
        // Arrange
        var serviceProviderMock = new Mock<IServiceProvider>();
        var loggerMock = new Mock<ILogger<DatabaseInitializationService>>();
        var service = new DatabaseInitializationService(
            serviceProviderMock.Object,
            loggerMock.Object
        );

        // Act
        await service.StopAsync(CancellationToken.None);

        // Assert
        loggerMock.Verify(
            x =>
                x.Log(
                    LogLevel.Information,
                    It.IsAny<EventId>(),
                    It.Is<It.IsAnyType>(
                        (v, t) => v.ToString()!.Contains("Database initialization service stopped")
                    ),
                    It.IsAny<Exception>(),
                    It.IsAny<Func<It.IsAnyType, Exception?, string>>()
                ),
            Times.Once
        );
    }

    [Fact]
    public async Task StartAsync_ShouldHandleCancellationToken()
    {
        // Arrange
        var serviceProviderMock = new Mock<IServiceProvider>();
        var loggerMock = new Mock<ILogger<DatabaseInitializationService>>();
        var cts = new CancellationTokenSource();
        cts.Cancel(); // Cancel immediately

        // Setup service provider to throw when CreateScope is called
        serviceProviderMock
            .Setup(x => x.GetService(typeof(IServiceScopeFactory)))
            .Returns((IServiceScopeFactory)null!);

        var service = new DatabaseInitializationService(
            serviceProviderMock.Object,
            loggerMock.Object
        );

        // Act & Assert
        var act = async () => await service.StartAsync(cts.Token);
        await act.Should().ThrowAsync<InvalidOperationException>();
    }

    [Fact]
    public async Task StartAsync_ShouldLogStartingMessage()
    {
        // Arrange
        var serviceProviderMock = new Mock<IServiceProvider>();
        var loggerMock = new Mock<ILogger<DatabaseInitializationService>>();

        // Setup service provider to throw when CreateScope is called
        serviceProviderMock
            .Setup(x => x.GetService(typeof(IServiceScopeFactory)))
            .Returns((IServiceScopeFactory)null!);

        var service = new DatabaseInitializationService(
            serviceProviderMock.Object,
            loggerMock.Object
        );

        // Act & Assert
        var act = async () => await service.StartAsync(CancellationToken.None);
        await act.Should().ThrowAsync<InvalidOperationException>();

        loggerMock.Verify(
            x =>
                x.Log(
                    LogLevel.Information,
                    It.IsAny<EventId>(),
                    It.Is<It.IsAnyType>(
                        (v, t) => v.ToString()!.Contains("Starting database initialization...")
                    ),
                    It.IsAny<Exception>(),
                    It.IsAny<Func<It.IsAnyType, Exception?, string>>()
                ),
            Times.Once
        );
    }

    [Fact]
    public async Task StartAsync_ShouldThrowExceptionWhenServiceProviderFails()
    {
        // Arrange
        var serviceProviderMock = new Mock<IServiceProvider>();
        var loggerMock = new Mock<ILogger<DatabaseInitializationService>>();

        // Setup service provider to throw when CreateScope is called
        serviceProviderMock
            .Setup(x => x.GetService(typeof(IServiceScopeFactory)))
            .Returns((IServiceScopeFactory)null!);

        var service = new DatabaseInitializationService(
            serviceProviderMock.Object,
            loggerMock.Object
        );

        // Act & Assert
        var act = async () => await service.StartAsync(CancellationToken.None);
        await act.Should().ThrowAsync<InvalidOperationException>();

        // Verify that starting message was logged
        loggerMock.Verify(
            x =>
                x.Log(
                    LogLevel.Information,
                    It.IsAny<EventId>(),
                    It.Is<It.IsAnyType>(
                        (v, t) => v.ToString()!.Contains("Starting database initialization...")
                    ),
                    It.IsAny<Exception>(),
                    It.IsAny<Func<It.IsAnyType, Exception?, string>>()
                ),
            Times.Once
        );
    }

    [Fact]
    public async Task StartAsync_ShouldHandleOperationCanceledException()
    {
        // Arrange
        var serviceProviderMock = new Mock<IServiceProvider>();
        var loggerMock = new Mock<ILogger<DatabaseInitializationService>>();
        var cts = new CancellationTokenSource();
        cts.Cancel(); // Cancel immediately

        // Setup service provider to throw when CreateScope is called
        serviceProviderMock
            .Setup(x => x.GetService(typeof(IServiceScopeFactory)))
            .Returns((IServiceScopeFactory)null!);

        var service = new DatabaseInitializationService(
            serviceProviderMock.Object,
            loggerMock.Object
        );

        // Act & Assert
        var act = async () => await service.StartAsync(cts.Token);
        await act.Should().ThrowAsync<InvalidOperationException>();
    }

    [Fact]
    public async Task StartAsync_ShouldHandleGeneralException()
    {
        // Arrange
        var serviceProviderMock = new Mock<IServiceProvider>();
        var loggerMock = new Mock<ILogger<DatabaseInitializationService>>();

        // Setup service provider to throw when CreateScope is called
        serviceProviderMock
            .Setup(x => x.GetService(typeof(IServiceScopeFactory)))
            .Returns((IServiceScopeFactory)null!);

        var service = new DatabaseInitializationService(
            serviceProviderMock.Object,
            loggerMock.Object
        );

        // Act & Assert
        var act = async () => await service.StartAsync(CancellationToken.None);
        await act.Should().ThrowAsync<InvalidOperationException>();
    }

    [Fact]
    public async Task StartAsync_ShouldThrowExceptionWithServiceProviderError()
    {
        // Arrange
        var serviceProviderMock = new Mock<IServiceProvider>();
        var loggerMock = new Mock<ILogger<DatabaseInitializationService>>();

        // Setup service provider to throw when CreateScope is called
        serviceProviderMock
            .Setup(x => x.GetService(typeof(IServiceScopeFactory)))
            .Returns((IServiceScopeFactory)null!);

        var service = new DatabaseInitializationService(
            serviceProviderMock.Object,
            loggerMock.Object
        );

        // Act & Assert
        var act = async () => await service.StartAsync(CancellationToken.None);
        await act.Should().ThrowAsync<InvalidOperationException>();

        // Verify that starting message was logged
        loggerMock.Verify(
            x =>
                x.Log(
                    LogLevel.Information,
                    It.IsAny<EventId>(),
                    It.Is<It.IsAnyType>(
                        (v, t) => v.ToString()!.Contains("Starting database initialization...")
                    ),
                    It.IsAny<Exception>(),
                    It.IsAny<Func<It.IsAnyType, Exception?, string>>()
                ),
            Times.Once
        );
    }
}