﻿// 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 Cloudtrace 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: Send and retrieve trace data from Stackdriver Trace. Data is generated and available by default for all App Engine applications. Data from other applications can be written to Stackdriver Trace for display, reporting, and analysis.
// API Documentation Link https://cloud.google.com/trace
//
// Discovery Doc  https://www.googleapis.com/discovery/v1/apis/Cloudtrace/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.Cloudtrace.v1/ 
// Install Command: PM>  Install-Package Google.Apis.Cloudtrace.v1
//
//------------------------------------------------------------------------------  
using Google.Apis.Cloudtrace.v1;
using Google.Apis.Auth.OAuth2;
using Google.Apis.Services;
using System;
using System.IO;
using System.Security.Cryptography.X509Certificates;

namespace GoogleSamplecSharpSample.Cloudtracev1.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 CloudtraceService 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 CloudtraceService(new BaseClientService.Initializer()
                    {
                        HttpClientInitializer = credential,
                        ApplicationName = "Cloudtrace 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  Cloudtrace service.
                    return new CloudtraceService(new BaseClientService.Initializer()
                    {
                        HttpClientInitializer = credential,
                        ApplicationName = "Cloudtrace Authentication Sample",
                    });
                }
                else
                {
                    throw new Exception("Unsupported Service accounts credentials.");
                }

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