using ECMJobRunner.Application.Common.Exceptions;
using Microsoft.AspNetCore.Mvc;
using System.Net;

namespace ECMJobRunner.WebCron.Middleware;

/// <summary>
/// Middleware for handling exceptions globally in the application.
/// Captures exceptions thrown during the request pipeline execution,
/// logs them, and returns an appropriate HTTP response with a JSON error details.
/// </summary>
/// <remarks>
/// Initializes a new instance of the <see cref="ExceptionHandlingMiddleware"/> class.
/// </remarks>
/// <param name="Next">The next middleware in the request pipeline.</param>
/// <param name="Logger">The logger instance for logging exceptions.</param>
public class ExceptionHandlingMiddleware(RequestDelegate Next, ILogger<ExceptionHandlingMiddleware> Logger)
{
    /// <summary>
    /// Invokes the middleware to handle the HTTP request.
    /// </summary>
    /// <param name="context">The HTTP context of the current request.</param>
    /// <returns>A task that represents the asynchronous operation.</returns>
    public async Task InvokeAsync(HttpContext context)
    {
        try
        {
            await Next(context); // Continue down the pipeline
        }
        catch (Exception ex)
        {
            await HandleExceptionAsync(context, ex, Logger);
        }
    }

    /// <summary>
    /// Handles exceptions by logging them and writing an appropriate JSON response.
    /// </summary>
    /// <param name="context">The HTTP context of the current request.</param>
    /// <param name="exception">The exception that occurred.</param>
    /// <param name="logger">The logger instance for logging the exception.</param>
    /// <returns>A task that represents the asynchronous operation.</returns>
    private static async Task HandleExceptionAsync(HttpContext context, Exception exception, ILogger logger)
    {
        context.Response.ContentType = "application/json";

        ValidationProblemDetails details;

        switch (exception)
        {
            case JobException jobEx:
                logger.LogWarning(jobEx, "Job exception occurred.");
                context.Response.StatusCode = (int)HttpStatusCode.BadRequest;
                details = new()
                {
                    Title = "Job Exception",
                    Detail = jobEx.Message
                };
                break;
            default:
                logger.LogError(exception, "Unhandled exception occurred.");
                context.Response.StatusCode = (int)HttpStatusCode.InternalServerError;
                details = new()
                {
                    Title = "Internal Server Error",
                    Detail = "An unexpected error occurred. Please try again later."
                };
                break;
        }

        if (details is not null)
            await context.Response.WriteAsJsonAsync(details);
    }
}