using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.ModelBinding;

namespace HRD.WebApi.Helpers
{
    public class HttpErrorDetails : ValidationProblemDetails
    {
        public HttpErrorDetails()
        {
        }

        public HttpErrorDetails(ActionContext context)
        {
            Title = "Invalid arguments to the API";
            Detail = "The inputs supplied to the API are invalid";
            Status = StatusCodes.Status400BadRequest;
            Type = context.HttpContext.TraceIdentifier;
            URI = context.HttpContext.Request.Path.ToUriComponent();

            ConstructErrorMessages(context);
        }

        public string URI { get; init; }

        private void ConstructErrorMessages(ActionContext context)
        {
            foreach (var keyModelStatePair in context.ModelState)
            {
                var key = keyModelStatePair.Key;
                var errors = keyModelStatePair.Value.Errors;
                if (errors != null && errors.Count > 0)
                {
                    if (errors.Count == 1)
                    {
                        var errorMessage = GetErrorMessage(errors[0]);
                        base.Errors.Add(key, new[] { errorMessage });
                        Detail = errorMessage;
                    }
                    else
                    {
                        var errorMessages = new string[errors.Count];
                        for (var i = 0; i < errors.Count; i++)
                        {
                            errorMessages[i] = GetErrorMessage(errors[i]);
                            if (i == 0) { Detail = errorMessages[i]; }
                        }
                        base.Errors.Add(key, errorMessages);
                    }
                }
            }
        }

        private static string GetErrorMessage(ModelError error) => string.IsNullOrEmpty(error.ErrorMessage) ? "The input was not valid." : error.ErrorMessage;
    }
}