csharp/src/Api/Middleware/ErrorHandlingMiddleware.cs

using System.Net;
using System.Text.Json;
using AiDevProject.Core.Exceptions;

namespace AiDevProject.Api.Middleware;

/// <summary>
/// Global error handling middleware.
/// </summary>
public class ErrorHandlingMiddleware
{
    private readonly RequestDelegate _next;
    private readonly ILogger<ErrorHandlingMiddleware> _logger;

    public ErrorHandlingMiddleware(RequestDelegate next, ILogger<ErrorHandlingMiddleware> logger)
    {
        _next = next;
        _logger = logger;
    }

    public async Task InvokeAsync(HttpContext context)
    {
        try
        {
            await _next(context);
        }
        catch (AppException ex) when (ex.IsOperational)
        {
            _logger.LogWarning("Operational error: {Message}", ex.Message);
            await HandleExceptionAsync(context, ex.StatusCode, ex.Message);
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Unexpected error: {Message}", ex.Message);
            await HandleExceptionAsync(context, 500, "Internal server error");
        }
    }

    private static async Task HandleExceptionAsync(HttpContext context, int statusCode, string message)
    {
        context.Response.StatusCode = statusCode;
        context.Response.ContentType = "application/json";

        var response = new { status = "error", message };
        await context.Response.WriteAsync(JsonSerializer.Serialize(response));
    }
}