using ChatBot.Services.Telegram.Commands;
using FluentAssertions;
using Xunit;

namespace ChatBot.Tests.Telegram.Commands;

public class CommandAttributeTests
{
    [Fact]
    public void CommandAttribute_ShouldHaveCorrectAttributeUsage()
    {
        // Arrange
        var attributeType = typeof(CommandAttribute);
        var attributeUsage = attributeType
            .GetCustomAttributes(typeof(AttributeUsageAttribute), false)
            .Cast<AttributeUsageAttribute>()
            .FirstOrDefault();

        // Assert
        attributeUsage.Should().NotBeNull();
        attributeUsage!.ValidOn.Should().Be(AttributeTargets.Class);
        attributeUsage.AllowMultiple.Should().BeFalse();
    }

    [Fact]
    public void CommandAttribute_ShouldSetCommandNameAndDescription()
    {
        // Arrange
        var commandName = "/test";
        var description = "Test command";

        // Act
        var attribute = new CommandAttribute(commandName, description);

        // Assert
        attribute.CommandName.Should().Be(commandName);
        attribute.Description.Should().Be(description);
        attribute.Priority.Should().Be(0); // Default value
    }

    [Fact]
    public void CommandAttribute_ShouldAllowSettingPriority()
    {
        // Arrange
        var commandName = "/test";
        var description = "Test command";
        var priority = 5;

        // Act
        var attribute = new CommandAttribute(commandName, description) { Priority = priority };

        // Assert
        attribute.CommandName.Should().Be(commandName);
        attribute.Description.Should().Be(description);
        attribute.Priority.Should().Be(priority);
    }

    [Theory]
    [InlineData("/start", "Start the bot")]
    [InlineData("/help", "Show help")]
    [InlineData("/status", "Show status")]
    [InlineData("/clear", "Clear chat history")]
    [InlineData("/settings", "Show settings")]
    public void CommandAttribute_ShouldAcceptValidCommandNames(
        string commandName,
        string description
    )
    {
        // Act
        var attribute = new CommandAttribute(commandName, description);

        // Assert
        attribute.CommandName.Should().Be(commandName);
        attribute.Description.Should().Be(description);
    }

    [Theory]
    [InlineData("")]
    [InlineData("start")]
    [InlineData("help")]
    [InlineData("status")]
    [InlineData("clear")]
    [InlineData("settings")]
    public void CommandAttribute_ShouldAcceptCommandNamesWithoutSlash(string commandName)
    {
        // Arrange
        var description = "Test command";

        // Act
        var attribute = new CommandAttribute(commandName, description);

        // Assert
        attribute.CommandName.Should().Be(commandName);
        attribute.Description.Should().Be(description);
    }

    [Theory]
    [InlineData("")]
    [InlineData("A simple description")]
    [InlineData(
        "A very long description that contains multiple words and explains what the command does in detail"
    )]
    [InlineData("Описание на русском языке")]
    [InlineData("Description with special characters: !@#$%^&*()_+-=[]{}|;':\",./<>?")]
    [InlineData("Description with unicode: 用户 ユーザー مستخدم")]
    public void CommandAttribute_ShouldAcceptVariousDescriptions(string description)
    {
        // Arrange
        var commandName = "/test";

        // Act
        var attribute = new CommandAttribute(commandName, description);

        // Assert
        attribute.CommandName.Should().Be(commandName);
        attribute.Description.Should().Be(description);
    }

    [Theory]
    [InlineData(0)]
    [InlineData(1)]
    [InlineData(10)]
    [InlineData(100)]
    [InlineData(int.MaxValue)]
    [InlineData(int.MinValue)]
    [InlineData(-1)]
    [InlineData(-100)]
    public void CommandAttribute_ShouldAcceptVariousPriorities(int priority)
    {
        // Arrange
        var commandName = "/test";
        var description = "Test command";

        // Act
        var attribute = new CommandAttribute(commandName, description) { Priority = priority };

        // Assert
        attribute.Priority.Should().Be(priority);
    }

    [Fact]
    public void CommandAttribute_ShouldAllowNullCommandName()
    {
        // Arrange
        string? commandName = null;
        var description = "Test command";

        // Act
        var attribute = new CommandAttribute(commandName!, description);

        // Assert
        attribute.CommandName.Should().BeNull();
        attribute.Description.Should().Be(description);
    }

    [Fact]
    public void CommandAttribute_ShouldAllowNullDescription()
    {
        // Arrange
        var commandName = "/test";
        string? description = null;

        // Act
        var attribute = new CommandAttribute(commandName, description!);

        // Assert
        attribute.CommandName.Should().Be(commandName);
        attribute.Description.Should().BeNull();
    }

    [Fact]
    public void CommandAttribute_ShouldAllowBothNullValues()
    {
        // Arrange
        string? commandName = null;
        string? description = null;

        // Act
        var attribute = new CommandAttribute(commandName!, description!);

        // Assert
        attribute.CommandName.Should().BeNull();
        attribute.Description.Should().BeNull();
    }

    [Fact]
    public void CommandAttribute_ShouldBeImmutableAfterConstruction()
    {
        // Arrange
        var commandName = "/test";
        var description = "Test command";
        var attribute = new CommandAttribute(commandName, description);

        // Act & Assert
        // CommandName and Description should be read-only
        var commandNameProperty = typeof(CommandAttribute).GetProperty(
            nameof(CommandAttribute.CommandName)
        );
        var descriptionProperty = typeof(CommandAttribute).GetProperty(
            nameof(CommandAttribute.Description)
        );

        commandNameProperty!.CanWrite.Should().BeFalse();
        descriptionProperty!.CanWrite.Should().BeFalse();
    }

    [Fact]
    public void CommandAttribute_ShouldAllowPriorityModification()
    {
        // Arrange
        var commandName = "/test";
        var description = "Test command";
        var attribute = new CommandAttribute(commandName, description);

        // Act
        attribute.Priority = 42;

        // Assert
        attribute.Priority.Should().Be(42);
    }

    [Fact]
    public void CommandAttribute_ShouldInheritFromAttribute()
    {
        // Arrange & Act
        var attribute = new CommandAttribute("/test", "Test command");

        // Assert
        attribute.Should().BeAssignableTo<Attribute>();
    }

    [Fact]
    public void CommandAttribute_ShouldBeSerializable()
    {
        // Arrange
        var commandName = "/test";
        var description = "Test command";
        var priority = 5;
        var attribute = new CommandAttribute(commandName, description) { Priority = priority };

        // Act & Assert
        // Check if the attribute can be serialized (basic check)
        attribute.Should().NotBeNull();
        // Note: In .NET 5+, IsSerializable is obsolete and returns false for most types
        // This test verifies the attribute can be created and used
        attribute.GetType().Should().NotBeNull();
    }

    [Fact]
    public void CommandAttribute_ShouldHandleVeryLongCommandName()
    {
        // Arrange
        var commandName = new string('a', 1000); // Very long command name
        var description = "Test command";

        // Act
        var attribute = new CommandAttribute(commandName, description);

        // Assert
        attribute.CommandName.Should().Be(commandName);
        attribute.CommandName.Should().HaveLength(1000);
    }

    [Fact]
    public void CommandAttribute_ShouldHandleVeryLongDescription()
    {
        // Arrange
        var commandName = "/test";
        var description = new string('a', 10000); // Very long description

        // Act
        var attribute = new CommandAttribute(commandName, description);

        // Assert
        attribute.Description.Should().Be(description);
        attribute.Description.Should().HaveLength(10000);
    }

    [Fact]
    public void CommandAttribute_ShouldHandleCommandNameWithSpecialCharacters()
    {
        // Arrange
        var commandName = "/test-command_with.special@chars#123";
        var description = "Test command";

        // Act
        var attribute = new CommandAttribute(commandName, description);

        // Assert
        attribute.CommandName.Should().Be(commandName);
    }

    [Fact]
    public void CommandAttribute_ShouldHandleDescriptionWithNewlines()
    {
        // Arrange
        var commandName = "/test";
        var description = "Line 1\nLine 2\nLine 3";

        // Act
        var attribute = new CommandAttribute(commandName, description);

        // Assert
        attribute.Description.Should().Be(description);
    }

    [Fact]
    public void CommandAttribute_ShouldHandleDescriptionWithTabs()
    {
        // Arrange
        var commandName = "/test";
        var description = "Column1\tColumn2\tColumn3";

        // Act
        var attribute = new CommandAttribute(commandName, description);

        // Assert
        attribute.Description.Should().Be(description);
    }

    [Fact]
    public void CommandAttribute_ShouldHandleDescriptionWithCarriageReturns()
    {
        // Arrange
        var commandName = "/test";
        var description = "Line 1\r\nLine 2\r\nLine 3";

        // Act
        var attribute = new CommandAttribute(commandName, description);

        // Assert
        attribute.Description.Should().Be(description);
    }

    [Fact]
    public void CommandAttribute_ShouldHandleWhitespaceOnlyCommandName()
    {
        // Arrange
        var commandName = "   ";
        var description = "Test command";

        // Act
        var attribute = new CommandAttribute(commandName, description);

        // Assert
        attribute.CommandName.Should().Be(commandName);
    }

    [Fact]
    public void CommandAttribute_ShouldHandleWhitespaceOnlyDescription()
    {
        // Arrange
        var commandName = "/test";
        var description = "   ";

        // Act
        var attribute = new CommandAttribute(commandName, description);

        // Assert
        attribute.Description.Should().Be(description);
    }

    [Fact]
    public void CommandAttribute_ShouldHandleCommandNameWithUnicode()
    {
        // Arrange
        var commandName = "/команда_命令_コマンド_أمر";
        var description = "Test command";

        // Act
        var attribute = new CommandAttribute(commandName, description);

        // Assert
        attribute.CommandName.Should().Be(commandName);
    }

    [Fact]
    public void CommandAttribute_ShouldHandleDescriptionWithUnicode()
    {
        // Arrange
        var commandName = "/test";
        var description = "Описание команды 命令描述 コマンドの説明 وصف الأمر";

        // Act
        var attribute = new CommandAttribute(commandName, description);

        // Assert
        attribute.Description.Should().Be(description);
    }

    [Fact]
    public void CommandAttribute_ShouldHandleCommandNameWithSpaces()
    {
        // Arrange
        var commandName = "/test command with spaces";
        var description = "Test command";

        // Act
        var attribute = new CommandAttribute(commandName, description);

        // Assert
        attribute.CommandName.Should().Be(commandName);
    }

    [Fact]
    public void CommandAttribute_ShouldHandleDescriptionWithSpaces()
    {
        // Arrange
        var commandName = "/test";
        var description = "This is a test command with multiple spaces";

        // Act
        var attribute = new CommandAttribute(commandName, description);

        // Assert
        attribute.Description.Should().Be(description);
    }

    [Fact]
    public void CommandAttribute_ShouldHandleCommandNameWithNumbers()
    {
        // Arrange
        var commandName = "/test123";
        var description = "Test command";

        // Act
        var attribute = new CommandAttribute(commandName, description);

        // Assert
        attribute.CommandName.Should().Be(commandName);
    }

    [Fact]
    public void CommandAttribute_ShouldHandleDescriptionWithNumbers()
    {
        // Arrange
        var commandName = "/test";
        var description = "Test command version 1.0.0 build 123";

        // Act
        var attribute = new CommandAttribute(commandName, description);

        // Assert
        attribute.Description.Should().Be(description);
    }
}