﻿// Copyright 2017 DAIMTO ([Linda Lawton](https://twitter.com/LindaLawtonDK)) :  [www.daimto.com](http://www.daimto.com/)
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with
// the License. You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on
// an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
// specific language governing permissions and limitations under the License.
//------------------------------------------------------------------------------
// <auto-generated>
//     This code was generated by DAIMTO-Google-apis-Sample-generator 1.0.0
//     Template File Name:  ServiceAccount.tt
//     Build date: 2017-10-08
//     C# generater version: 1.0.0
//     
//     Changes to this file may cause incorrect behavior and will be lost if
//     the code is regenerated.
// </auto-generated>
//------------------------------------------------------------------------------  
// About 
// 
// Unoffical sample for the Slides v1 API for C#. 
// This sample is designed to be used with the Google .Net client library. (https://github.com/google/google-api-dotnet-client)
// 
// API Description: An API for creating and editing Google Slides presentations.
// API Documentation Link https://developers.google.com/slides/
//
// Discovery Doc  https://www.googleapis.com/discovery/v1/apis/Slides/v1/rest
//
//------------------------------------------------------------------------------
// Installation
//
// This sample code uses the Google .Net client library (https://github.com/google/google-api-dotnet-client)
//
// NuGet package:
//
// Location: https://www.nuget.org/packages/Google.Apis.Slides.v1/ 
// Install Command: PM>  Install-Package Google.Apis.Slides.v1
//
//------------------------------------------------------------------------------  
using Google.Apis.Slides.v1;
using Google.Apis.Auth.OAuth2;
using Google.Apis.Services;
using System;
using System.IO;
using System.Security.Cryptography.X509Certificates;

namespace GoogleSamplecSharpSample.Slidesv1.Auth
{

    public static class ServiceAccountExample
    {

        /// <summary>
        /// Authenticating to Google using a Service account
        /// Documentation: https://developers.google.com/accounts/docs/OAuth2#serviceaccount
        /// </summary>
        /// <param name="serviceAccountEmail">From Google Developer console https://console.developers.google.com</param>
        /// <param name="serviceAccountCredentialFilePath">Location of the .p12 or Json Service account key file downloaded from Google Developer console https://console.developers.google.com</param>
        /// <returns>AnalyticsService used to make requests against the Analytics API</returns>
        public static SlidesService AuthenticateServiceAccount(string serviceAccountEmail, string serviceAccountCredentialFilePath, string[] scopes)
		{
            try
            {
                if (string.IsNullOrEmpty(serviceAccountCredentialFilePath))
                    throw new Exception("Path to the service account credentials file is required.");
                if (!File.Exists(serviceAccountCredentialFilePath))
                    throw new Exception("The service account credentials file does not exist at: " + serviceAccountCredentialFilePath);
                if (string.IsNullOrEmpty(serviceAccountEmail))
                    throw new Exception("ServiceAccountEmail is required.");                

                // For Json file
                if (Path.GetExtension(serviceAccountCredentialFilePath).ToLower() == ".json")
                {
                    GoogleCredential credential;
                    using (var stream = new FileStream(serviceAccountCredentialFilePath, FileMode.Open, FileAccess.Read))
                    {
                        credential = GoogleCredential.FromStream(stream)
                             .CreateScoped(scopes);
                    }

                    // Create the  Analytics service.
                    return new SlidesService(new BaseClientService.Initializer()
                    {
                        HttpClientInitializer = credential,
                        ApplicationName = "Slides Service account Authentication Sample",
                    });
                }
                else if (Path.GetExtension(serviceAccountCredentialFilePath).ToLower() == ".p12")
                {   // If its a P12 file

                    var certificate = new X509Certificate2(serviceAccountCredentialFilePath, "notasecret", X509KeyStorageFlags.MachineKeySet | X509KeyStorageFlags.Exportable);
                    var credential = new ServiceAccountCredential(new ServiceAccountCredential.Initializer(serviceAccountEmail)
                    {
                        Scopes = scopes
                    }.FromCertificate(certificate));

                    // Create the  Slides service.
                    return new SlidesService(new BaseClientService.Initializer()
                    {
                        HttpClientInitializer = credential,
                        ApplicationName = "Slides Authentication Sample",
                    });
                }
                else
                {
                    throw new Exception("Unsupported Service accounts credentials.");
                }

            }
            catch (Exception ex)
            {                
                throw new Exception("CreateServiceAccountSlidesFailed", ex);
            }
        }
    }
}