using Microsoft.AspNetCore.Http;
using System.Net;
using System.Text;
using System.Text.Json;

namespace Library;

public class ExceptionMiddleware
{
	private readonly RequestDelegate _next;

	public ExceptionMiddleware( RequestDelegate next )
	{
		_next = next;
	}

	public async Task InvokeAsync( HttpContext httpContext )
	{
		try
		{
			await _next( httpContext );
		}
		catch ( RedirectException exception )
		{
			HandleExceptionAsync( httpContext , exception );
		}
		catch ( ErrorException exception )
		{
			await HandleErrorAsync( httpContext , exception );
		}
		catch ( APIErrorException exception )
		{
			await HandleApiErrorAsync( httpContext , exception );
		}
		catch ( Exception exception )
		{
			await HandleExceptionAsync( httpContext , exception );
		}
	}

	private void HandleExceptionAsync( HttpContext context , RedirectException exception )
	{
		context.Response.Redirect( exception.Destination );
	}

	private static Task HandleErrorAsync( HttpContext context , ErrorException exception )
	{
		context.Response.StatusCode = 500;
		return context.Response.WriteAsync( exception.ErrorMessage );
	}
	private static Task HandleApiErrorAsync( HttpContext context , APIErrorException exception )
	{
		using MemoryStream stream = new( );

		using Utf8JsonWriter writer = new( stream );
		writer.WriteStartObject( );
		writer.WriteBoolean( "Success" , false );
		writer.WriteString( "ErrorMessage" , exception.ErrorMessage );
		writer.WriteEndObject( );
		writer.Dispose( );

		context.Response.ContentType = System.Net.Mime.MediaTypeNames.Application.Json;
		return context.Response.WriteAsync( Encoding.UTF8.GetString( stream.ToArray( ) ) );
	}

	private static Task HandleExceptionAsync( HttpContext context , Exception exception )
	{
		context.Response.ContentType = System.Net.Mime.MediaTypeNames.Text.Plain;
		context.Response.StatusCode = (int)HttpStatusCode.InternalServerError;
		return context.Response.WriteAsync( exception.ToString( ) );
	}
}