// Copyright (C) 2021-present sam (starshines.gay)
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published
// by the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.

using System.Net;
using System.Text.Json.Serialization;

namespace Catalogger.Backend.Api.Middleware;

public class ErrorMiddleware(ILogger baseLogger) : IMiddleware
{
    public async Task InvokeAsync(HttpContext context, RequestDelegate next)
    {
        try
        {
            await next(context);
        }
        catch (ApiError ae)
        {
            context.Response.StatusCode = (int)ae.StatusCode;
            await context.Response.WriteAsJsonAsync(ae.ToJson());
        }
        catch (Exception e)
        {
            var type = e.TargetSite?.DeclaringType ?? typeof(ErrorMiddleware);
            var typeName = e.TargetSite?.DeclaringType?.FullName ?? "<unknown>";
            var logger = baseLogger.ForContext(type);

            logger.Error(e, "Error in {ClassName} ({Path})", typeName, context.Request.Path);

            context.Response.StatusCode = StatusCodes.Status500InternalServerError;
            await context.Response.WriteAsJsonAsync(
                new ApiError(
                    HttpStatusCode.InternalServerError,
                    ErrorCode.InternalServerError,
                    "Internal server error"
                ).ToJson()
            );
        }
    }
}

public class ApiError(HttpStatusCode statusCode, ErrorCode errorCode, string message)
    : Exception(message)
{
    public HttpStatusCode StatusCode { get; init; } = statusCode;
    public ErrorCode ErrorCode { get; init; } = errorCode;

    private record Json(ErrorCode ErrorCode, string Message);

    public object ToJson() => new Json(ErrorCode, Message);
}

[JsonConverter(typeof(JsonStringEnumConverter))]
public enum ErrorCode
{
    InternalServerError,
    BadRequest,
    AuthRequired,
    UnknownGuild,
}