Add task to download releases from s3

// FREEBIE

Gruntfile.js

@@ -217,6 +217,20 @@ module.exports = function(grunt) {
         cmd: 'tx pull'
       }
     },
+    release: {
+      mac: {
+        archive: 'mac/Signal.app/Contents/Resources/app.asar',
+      },
+      mas: {
+        archive: 'mas/Signal.app/Contents/Resources/app.asar',
+      },
+      linux: {
+        archive: 'linux-unpacked/resources/app.asar',
+      },
+      win: {
+        archive: 'win-unpacked/resources/app.asar',
+      }
+    },
     gitinfo: {} // to be populated by grunt gitinfo
   });
 
@@ -249,6 +263,7 @@ module.exports = function(grunt) {
   });
 
   grunt.registerTask('getExpireTime', function() {
+      grunt.task.requires('gitinfo');
       var gitinfo = grunt.config.get('gitinfo');
       var commited = gitinfo.local.branch.current.lastCommitTime;
       var time = Date.parse(commited) + 1000 * 60 * 60 * 24 * 90;
@@ -256,11 +271,108 @@ module.exports = function(grunt) {
         JSON.stringify({ buildExpiration: time }) + '\n');
   });
 
+  grunt.registerTask('clean-release', function() {
+    require('rimraf').sync('release');
+    require('mkdirp').sync('release');
+  });
+
+  grunt.registerTask('fetch-release', function() {
+    grunt.task.requires('gitinfo');
+    require('mkdirp').sync('release');
+    var fs = require('fs');
+    var done = this.async();
+    var package_json = grunt.config.get('pkg');
+    var gitinfo = grunt.config.get('gitinfo');
+    var https = require('https');
+
+    var urlBase = "https://s3-us-west-1.amazonaws.com/signal-desktop-builds";
+    var keyBase = 'liliakai/textsecure-chrome';
+    var sha = gitinfo.local.branch.current.SHA;
+    var files = [
+      'signal-desktop-' + package_json.version + '.zip',
+      'Signal-' + package_json.version + '-win.zip'
+    ];
+
+    var extract = require('extract-zip');
+    var download = function(url, dest, cb) {
+        var file = fs.createWriteStream(dest);
+        var request = https.get(url, function(response) {
+          if (response.statusCode !== 200) {
+            cb(response.statusCode);
+          } else {
+            response.pipe(file);
+            file.on('finish', function() {
+              file.close(function() {
+                extract(dest, {dir: 'release'}, cb);
+              });
+            });
+          }
+        }).on('error', function(err) { // Handle errors
+          fs.unlink(dest); // Delete the file async. (But we don't check the result)
+          if (cb) cb(err.message);
+        });
+    };
+
+    Promise.all(files.map(function(fileName) {
+      var key = [ keyBase, sha, 'dist', fileName].join('/');
+      var url = [urlBase, key].join('/');
+      var dest = 'release/' + fileName;
+      return new Promise(function(resolve) {
+        console.log(url);
+        download(url, dest, function(err) {
+          if (err) {
+            console.log('failed', dest, err);
+            resolve(err);
+          } else {
+            console.log('done', dest);
+            resolve();
+          }
+        });
+      });
+    })).then(function(results) {
+      results.forEach(function(error) {
+        if (error) {
+          grunt.fail.warn('Failed to fetch some release artifacts');
+        }
+      });
+      done();
+    });
+  });
+
+  grunt.registerMultiTask('test-release', 'Test packaged releases', function() {
+      var dir = grunt.option('dir') || 'dist';
+      var environment = grunt.option('env') || 'production';
+      var asar = require('asar');
+      var config = this.data;
+      var archive = [dir, config.archive].join('/');
+      var files = [
+        'config/default.json',
+        'config/' + environment + '.json',
+        'config/local-' + environment + '.json'
+      ];
+
+      console.log(this.target, archive);
+      var releaseFiles = files.concat(config.files || []);
+      releaseFiles.forEach(function(fileName) {
+        console.log(fileName);
+        try {
+          asar.statFile(archive, fileName);
+          return true;
+        } catch (e) {
+          console.log(e);
+          throw new Error("Missing file " + fileName);
+        }
+      });
+
+      // todo: verify package.json has `environment: <environment>`
+  });
+
   grunt.registerTask('tx', ['exec:tx-pull', 'locale-patch']);
   grunt.registerTask('dev', ['default', 'connect', 'watch']);
   grunt.registerTask('test', ['jshint', 'jscs' ]);
   grunt.registerTask('copy_dist', ['gitinfo', 'copy']);
   grunt.registerTask('date', ['gitinfo', 'getExpireTime']);
+  grunt.registerTask('prep-release', ['gitinfo', 'fetch-release', 'test-release']);
   grunt.registerTask('default', ['concat', 'sass', 'date']);
 
 };