CODEX_ADK/BACKEND/Codex.CQRS/Commands/CreateConversationCommand.cs

using System;
using System.Threading;
using System.Threading.Tasks;
using Codex.Dal;
using Codex.Dal.Entities;
using FluentValidation;
using OpenHarbor.CQRS.Abstractions;

namespace Codex.CQRS.Commands;

/// <summary>
/// Creates a new conversation for grouping related messages
/// </summary>
public record CreateConversationCommand
{
    /// <summary>Conversation title</summary>
    public string Title { get; init; } = string.Empty;

    /// <summary>Optional summary or description</summary>
    public string? Summary { get; init; }
}

public class CreateConversationCommandHandler : ICommandHandler<CreateConversationCommand, Guid>
{
    private readonly CodexDbContext _dbContext;

    public CreateConversationCommandHandler(CodexDbContext dbContext)
    {
        _dbContext = dbContext;
    }

    public async Task<Guid> HandleAsync(CreateConversationCommand command, CancellationToken cancellationToken = default)
    {
        var conversation = new Conversation
        {
            Id = Guid.NewGuid(),
            Title = command.Title,
            Summary = command.Summary,
            StartedAt = DateTime.UtcNow,
            LastMessageAt = DateTime.UtcNow,
            IsActive = true,
            MessageCount = 0
        };

        _dbContext.Conversations.Add(conversation);
        await _dbContext.SaveChangesAsync(cancellationToken);

        return conversation.Id;
    }
}

public class CreateConversationCommandValidator : AbstractValidator<CreateConversationCommand>
{
    public CreateConversationCommandValidator()
    {
        RuleFor(x => x.Title)
            .NotEmpty().WithMessage("Title is required")
            .MaximumLength(500).WithMessage("Title cannot exceed 500 characters");

        RuleFor(x => x.Summary)
            .MaximumLength(2000).WithMessage("Summary cannot exceed 2000 characters")
            .When(x => !string.IsNullOrEmpty(x.Summary));
    }
}