using System;
using System.Net.Http;
using System.Threading.Tasks;
using PepperDash.Core;

namespace PepperDash.Essentials.Services
{

    /// <summary>
    /// Service for interacting with a Mobile Control Edge server instance
    /// </summary>
    public class MobileControlApiService
    {
        private readonly HttpClient _client;

        /// <summary>
        /// Create an instance of the <see cref="MobileControlApiService"/> class.
        /// </summary>
        /// <param name="apiUrl">Mobile Control Edge API URL</param>
        public MobileControlApiService(string apiUrl)
        {
            var handler = new HttpClientHandler
            {
                AllowAutoRedirect = false,
                ServerCertificateCustomValidationCallback = (req, cert, certChain, errors) => true
            };

            _client = new HttpClient(handler);
        }

        /// <summary>
        /// Send authorization request to Mobile Control Edge Server
        /// </summary>
        /// <param name="apiUrl">Mobile Control Edge API URL</param>
        /// <param name="grantCode">Grant code for authorization</param>
        /// <param name="systemUuid">System UUID for authorization</param>
        /// <returns>Authorization response</returns>
        public async Task<AuthorizationResponse> SendAuthorizationRequest(string apiUrl, string grantCode, string systemUuid)
        {
            try
            {
                var request = new HttpRequestMessage(HttpMethod.Get, $"{apiUrl}/system/{systemUuid}/authorize?grantCode={grantCode}");

                Debug.LogMessage(Serilog.Events.LogEventLevel.Debug, "Sending authorization request to {host}", null, request.RequestUri);

                var response = await _client.SendAsync(request);

                var authResponse = new AuthorizationResponse
                {
                    Authorized = response.StatusCode == System.Net.HttpStatusCode.OK
                };

                if (authResponse.Authorized)
                {
                    return authResponse;
                }

                if (response.StatusCode == System.Net.HttpStatusCode.Moved)
                {
                    var location = response.Headers.Location;

                    authResponse.Reason = $"ERROR: Mobile Control API has moved. Please adjust configuration to \"{location}\"";

                    return authResponse;
                }

                var responseString = await response.Content.ReadAsStringAsync();

                switch (responseString)
                {
                    case "codeNotFound":
                        authResponse.Reason = $"Authorization failed. Code not found for system UUID {systemUuid}";
                        break;
                    case "uuidNotFound":
                        authResponse.Reason = $"Authorization failed. System UUID {systemUuid} not found. Check Essentials configuration.";
                        break;
                    default:
                        authResponse.Reason = $"Authorization failed. Response {response.StatusCode}: {responseString}";
                        break;
                }

                return authResponse;
            }
            catch (Exception ex)
            {
                Debug.LogMessage(ex, "Error authorizing with Mobile Control");
                return new AuthorizationResponse { Authorized = false, Reason = ex.Message };
            }
        }
    }
}