using System;
using System.Collections.Generic;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Text;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Logging;
using Newtonsoft.Json;
using WebAPI.Data.Dto.OIDC;

namespace WebAPI.Data
{
    public class OIDCService
    {
        protected class IntrospectionResponse
        {
            public bool Active { get; set; }
        }
        private HttpClient _httpClient { get; set; }
        private ILogger<OIDCService> _logger { get; set; }
        public OIDCService(ILogger<OIDCService> logger)
        {
            _logger = logger;
            _httpClient = new HttpClient();
        }

        /// <summary>
        /// Simple check of an OIDC access token by attempting to hit the userinfo endpoint.
        /// </summary>
        /// <param name="accessToken">access token to check</param>
        /// <returns>success</returns>
        public async Task<bool> ValidateAccessToken(string accessToken)
        {
            Uri requestUri = new Uri($"https://{AppSettings.OIDCIntrospectionEndpoint}");
            HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Post, requestUri);
            request.Content = new FormUrlEncodedContent(new Dictionary<string, string>()
            {
                {"token", accessToken}
            });
            string encodedAuth = Convert.ToBase64String(Encoding.GetEncoding(Encoding.Latin1.CodePage)
                .GetBytes($"{AppSettings.OIDCClientId}:{AppSettings.OIDCClientSecret}"));
            request.Headers.Authorization = new AuthenticationHeaderValue("Basic", encodedAuth);
            HttpResponseMessage response = await _httpClient.SendAsync(request);
            if (!response.IsSuccessStatusCode)
            {
                return false;
            }

            var responsecontent = await response.Content.ReadAsStringAsync();
            return JsonConvert.DeserializeObject<IntrospectionResponse>(responsecontent).Active;
        }

        public async Task<OIDCUserInfoResponse> GetTokenDetails(string accessToken)
        {
            HttpRequestMessage requestMessage =
                new HttpRequestMessage(HttpMethod.Get, $"https://{AppSettings.OIDCUserInfoEndpoint}");
            requestMessage.Headers.Authorization = new AuthenticationHeaderValue("Bearer", accessToken);
            HttpResponseMessage response = await _httpClient.SendAsync(requestMessage);
            if (!response.IsSuccessStatusCode)
            {
                return null;
            }

            var responsecontent = await response.Content.ReadAsStringAsync();
            return JsonConvert.DeserializeObject<OIDCUserInfoResponse>(responsecontent);
        }
        
    }
}