using Luna.Channels.Abstractions;
using Luna.Channels.Telegram;
using Luna.Configuration;
using Luna.Shared;
using Microsoft.Extensions.Logging;
using Moq;
using Telegram.Bot;
using Telegram.Bot.Requests;
using Telegram.Bot.Types;

namespace Luna.Channels.Tests;

[TestFixture]
[Category("Unit")]
public class TelegramChannelTests
{
    private Mock<ITelegramBotClient> _mockBotClient = null!;
    private Mock<ILogger<TelegramChannel>> _mockLogger = null!;
    private TelegramOptions _options = null!;
    private TelegramChannel _channel = null!;

    [SetUp]
    public void SetUp()
    {
        _mockBotClient = new Mock<ITelegramBotClient>();
        _mockLogger = new Mock<ILogger<TelegramChannel>>();
        _options = new TelegramOptions { BotToken = "test-bot-token:ABCDEF" };
        _channel = new TelegramChannel("100", _mockBotClient.Object, _mockLogger.Object, _options);
    }

    [TearDown]
    public void TearDown()
    {
        _channel.Dispose();
    }

    [Test]
    public void ChannelType_Returns_Telegram()
    {
        Assert.That(_channel.ChannelType, Is.EqualTo("telegram"));
    }

    [Test]
    public void ChannelId_IsSet_From_Constructor()
    {
        Assert.That(_channel.ChannelId, Is.EqualTo("100"));
    }

    [Test]
    public void ChannelId_IsUnique_Per_Instance()
    {
        var channel1 = new TelegramChannel("111", _mockBotClient.Object, _mockLogger.Object, _options);
        var channel2 = new TelegramChannel("222", _mockBotClient.Object, _mockLogger.Object, _options);

        Assert.That(channel1.ChannelId, Is.Not.EqualTo(channel2.ChannelId));

        channel1.Dispose();
        channel2.Dispose();
    }

    [Test]
    public void DisplayName_Contains_Telegram()
    {
        Assert.That(_channel.DisplayName, Does.Contain("Telegram"));
    }

    [Test]
    public void IsConnected_Is_True_Initially()
    {
        Assert.That(_channel.IsConnected, Is.True);
    }

    [Test]
    public void IsConnected_Is_False_After_Dispose()
    {
        _channel.Dispose();

        Assert.That(_channel.IsConnected, Is.False);
    }

    [Test]
    public async Task SendMessageAsync_Calls_BotClient_SendMessage()
    {
        _mockBotClient
            .Setup(c => c.SendRequest(It.IsAny<SendMessageRequest>(), It.IsAny<CancellationToken>()))
            .ReturnsAsync(new Message { Id = 1, Chat = new Chat { Id = 100 } });

        var message = new ChannelMessage(
            Guid.NewGuid().ToString(), "100", "42", "Alice", "Hello!", DateTimeOffset.UtcNow);

        await _channel.SendMessageAsync(message);

        _mockBotClient.Verify(
            c => c.SendRequest(It.IsAny<SendMessageRequest>(), It.IsAny<CancellationToken>()),
            Times.Once);
    }

    [Test]
    public async Task SendMessageAsync_Handles_Network_Error_Without_Crash()
    {
        _mockBotClient
            .Setup(c => c.SendRequest(It.IsAny<SendMessageRequest>(), It.IsAny<CancellationToken>()))
            .ThrowsAsync(new HttpRequestException("Network error"));

        var message = new ChannelMessage(
            Guid.NewGuid().ToString(), "100", "42", "Alice", "Hello!", DateTimeOffset.UtcNow);

        Assert.DoesNotThrowAsync(async () => await _channel.SendMessageAsync(message));
    }

    [Test]
    public void RaiseMessageReceived_Fires_Event_With_Correct_Mapping()
    {
        ChannelMessageReceivedEventArgs? captured = null;
        _channel.MessageReceived += (_, args) => { captured = args; return Task.CompletedTask; };

        var message = new ChannelMessage(
            Guid.NewGuid().ToString(), "999", "77", "Bob", "Hello Luna", DateTimeOffset.UtcNow);

        _channel.RaiseMessageReceived(message);

        Assert.That(captured, Is.Not.Null);
        Assert.That(captured!.Message.ConversationId, Is.EqualTo("999"));
        Assert.That(captured.Message.SenderId, Is.EqualTo("77"));
        Assert.That(captured.Message.SenderName, Is.EqualTo("Bob"));
        Assert.That(captured.Message.Content, Is.EqualTo("Hello Luna"));
        Assert.That(captured.Channel, Is.SameAs(_channel));
    }

    [Test]
    public void RaiseMessageReceived_Maps_SenderName_And_Timestamp()
    {
        var sentAt = new DateTimeOffset(2025, 6, 1, 12, 0, 0, TimeSpan.Zero);

        ChannelMessageReceivedEventArgs? captured = null;
        _channel.MessageReceived += (_, args) => { captured = args; return Task.CompletedTask; };

        var message = new ChannelMessage(
            Guid.NewGuid().ToString(), "123", "55", "Carol", "Hi", sentAt);

        _channel.RaiseMessageReceived(message);

        Assert.That(captured, Is.Not.Null);
        Assert.That(captured!.Message.SenderName, Is.EqualTo("Carol"));
        Assert.That(captured.Message.Timestamp, Is.EqualTo(sentAt));
    }

    [Test]
    public async Task SendStreamingMessageAsync_Sends_Initial_Then_Edits_In_Place()
    {
        _mockBotClient
            .Setup(c => c.SendRequest(It.IsAny<SendMessageRequest>(), It.IsAny<CancellationToken>()))
            .ReturnsAsync(new Message { Id = 10, Chat = new Chat { Id = 100 } });

        _mockBotClient
            .Setup(c => c.SendRequest(It.IsAny<EditMessageTextRequest>(), It.IsAny<CancellationToken>()))
            .ReturnsAsync(new Message { Id = 10, Chat = new Chat { Id = 100 } });

        var updates = new List<ChatStreamUpdate>
        {
            new(ChatStreamUpdateType.Text, "Hello ", null, false),
            new(ChatStreamUpdateType.Text, "World", null, false),
            new(ChatStreamUpdateType.Complete, null, null, true),
        };

        await _channel.SendStreamingMessageAsync(updates.ToAsyncEnumerable());

        // First chunk sends a message, second chunk edits it
        _mockBotClient.Verify(
            c => c.SendRequest(It.IsAny<SendMessageRequest>(), It.IsAny<CancellationToken>()),
            Times.Once);

        _mockBotClient.Verify(
            c => c.SendRequest(It.IsAny<EditMessageTextRequest>(), It.IsAny<CancellationToken>()),
            Times.AtLeastOnce);
    }

    [Test]
    public async Task SendStreamingMessageAsync_Handles_4096_Char_Limit_By_Chunking()
    {
        var longContent = new string('A', 4097);
        var updates = new List<ChatStreamUpdate>
        {
            new(ChatStreamUpdateType.Text, longContent, null, false),
            new(ChatStreamUpdateType.Complete, null, null, true),
        };

        _mockBotClient
            .Setup(c => c.SendRequest(It.IsAny<SendMessageRequest>(), It.IsAny<CancellationToken>()))
            .ReturnsAsync(new Message { Id = 20, Chat = new Chat { Id = 100 } });

        _mockBotClient
            .Setup(c => c.SendRequest(It.IsAny<EditMessageTextRequest>(), It.IsAny<CancellationToken>()))
            .ReturnsAsync(new Message { Id = 20, Chat = new Chat { Id = 100 } });

        await _channel.SendStreamingMessageAsync(updates.ToAsyncEnumerable());

        // Content exceeds 4096 — needs at least 2 SendMessage calls (initial + overflow)
        _mockBotClient.Verify(
            c => c.SendRequest(It.IsAny<SendMessageRequest>(), It.IsAny<CancellationToken>()),
            Times.AtLeast(2));
    }

    [Test]
    public async Task SendStreamingMessageAsync_Handles_IsComplete_True_With_Final_Edit()
    {
        _mockBotClient
            .Setup(c => c.SendRequest(It.IsAny<SendMessageRequest>(), It.IsAny<CancellationToken>()))
            .ReturnsAsync(new Message { Id = 30, Chat = new Chat { Id = 100 } });

        _mockBotClient
            .Setup(c => c.SendRequest(It.IsAny<EditMessageTextRequest>(), It.IsAny<CancellationToken>()))
            .ReturnsAsync(new Message { Id = 30, Chat = new Chat { Id = 100 } });

        var updates = new List<ChatStreamUpdate>
        {
            new(ChatStreamUpdateType.Text, "Final answer", null, false),
            new(ChatStreamUpdateType.Complete, null, null, true),
        };

        await _channel.SendStreamingMessageAsync(updates.ToAsyncEnumerable());

        // Initial message sent
        _mockBotClient.Verify(
            c => c.SendRequest(It.IsAny<SendMessageRequest>(), It.IsAny<CancellationToken>()),
            Times.Once);
    }

    [Test]
    public void AllowedUserIds_Non_Empty_Blocks_Unauthorized_User()
    {
        var restrictedOptions = new TelegramOptions
        {
            BotToken = "test-token",
            AllowedUserIds = ["111", "222"]
        };
        var restrictedChannel = new TelegramChannel(
            "500", _mockBotClient.Object, _mockLogger.Object, restrictedOptions);

        ChannelMessageReceivedEventArgs? captured = null;
        restrictedChannel.MessageReceived += (_, args) => { captured = args; return Task.CompletedTask; };

        var message = new ChannelMessage(
            Guid.NewGuid().ToString(), "500", "999", "Hacker", "attack", DateTimeOffset.UtcNow);

        restrictedChannel.RaiseMessageReceived(message);

        Assert.That(captured, Is.Null, "Message from unauthorized user should be silently ignored");

        restrictedChannel.Dispose();
    }

    [Test]
    public void AllowedUserIds_Non_Empty_Allows_Authorized_User()
    {
        var restrictedOptions = new TelegramOptions
        {
            BotToken = "test-token",
            AllowedUserIds = ["111", "222"]
        };
        var restrictedChannel = new TelegramChannel(
            "500", _mockBotClient.Object, _mockLogger.Object, restrictedOptions);

        ChannelMessageReceivedEventArgs? captured = null;
        restrictedChannel.MessageReceived += (_, args) => { captured = args; return Task.CompletedTask; };

        var message = new ChannelMessage(
            Guid.NewGuid().ToString(), "500", "111", "TrustedUser", "hello", DateTimeOffset.UtcNow);

        restrictedChannel.RaiseMessageReceived(message);

        Assert.That(captured, Is.Not.Null, "Message from authorized user should be accepted");

        restrictedChannel.Dispose();
    }

    [Test]
    public void AllowedUserIds_Empty_Accepts_All_Users()
    {
        var openOptions = new TelegramOptions
        {
            BotToken = "test-token",
            AllowedUserIds = []
        };
        var openChannel = new TelegramChannel(
            "600", _mockBotClient.Object, _mockLogger.Object, openOptions);

        ChannelMessageReceivedEventArgs? captured = null;
        openChannel.MessageReceived += (_, args) => { captured = args; return Task.CompletedTask; };

        var message = new ChannelMessage(
            Guid.NewGuid().ToString(), "600", "12345", "Anyone", "hello", DateTimeOffset.UtcNow);

        openChannel.RaiseMessageReceived(message);

        Assert.That(captured, Is.Not.Null, "Message should be accepted when AllowedUserIds is empty");

        openChannel.Dispose();
    }

    [Test]
    public void Malformed_Message_With_Null_Text_Is_Skipped()
    {
        ChannelMessageReceivedEventArgs? captured = null;
        _channel.MessageReceived += (_, args) => { captured = args; return Task.CompletedTask; };

        var message = new ChannelMessage(
            Guid.NewGuid().ToString(), "700", "88", "Ghost", null!, DateTimeOffset.UtcNow);

        _channel.RaiseMessageReceived(message);

        Assert.That(captured, Is.Null, "Message with null text should be silently skipped");
    }

    [Test]
    public void Malformed_Message_With_Empty_Text_Is_Skipped()
    {
        ChannelMessageReceivedEventArgs? captured = null;
        _channel.MessageReceived += (_, args) => { captured = args; return Task.CompletedTask; };

        var message = new ChannelMessage(
            Guid.NewGuid().ToString(), "700", "88", "Ghost", "", DateTimeOffset.UtcNow);

        _channel.RaiseMessageReceived(message);

        Assert.That(captured, Is.Null, "Message with empty text should be silently skipped");
    }

    [Test]
    public void Dispose_Fires_ConnectionStateChanged()
    {
        ChannelConnectionEventArgs? captured = null;
        _channel.ConnectionStateChanged += (_, args) =>
        {
            captured = args;
            return Task.CompletedTask;
        };

        _channel.Dispose();

        Assert.That(captured, Is.Not.Null);
        Assert.That(captured!.IsConnected, Is.False);
        Assert.That(captured.Channel, Is.SameAs(_channel));
    }
}