From 4c8f9bfac8d9bf7706f45bd81a679c666c6e83f1 Mon Sep 17 00:00:00 2001
From: Jake Hartnell <Jake.Hartnell@gmail.com>
Date: Tue, 9 Jun 2015 17:39:17 -0700
Subject: [PATCH] Truncate long bodies and quotes

Introduces auto-truncation of long bodies and quotes which expand when
you click on a "More" link.

Feature flagged as 'truncate_annotations'.
---
 h/features.py                                 |  1 +
 h/static/scripts/app.coffee                   |  1 +
 h/static/scripts/directive/annotation.coffee  |  7 +-
 h/static/scripts/directive/excerpt.js         | 95 +++++++++++++++++++
 .../directive/test/annotation-test.coffee     | 11 ++-
 .../scripts/directive/test/excerpt-test.js    | 86 +++++++++++++++++
 h/static/scripts/directive/test/util.js       | 18 ++--
 h/static/styles/annotations.scss              | 21 ++++
 h/static/styles/common.scss                   |  1 +
 h/static/styles/excerpt.scss                  | 31 ++++++
 h/static/styles/variables.scss                |  3 +
 h/templates/app.html.jinja2                   |  3 +
 h/templates/client/annotation.html            | 21 ++--
 h/templates/client/excerpt.html               | 12 +++
 14 files changed, 293 insertions(+), 18 deletions(-)
 create mode 100644 h/static/scripts/directive/excerpt.js
 create mode 100644 h/static/scripts/directive/test/excerpt-test.js
 create mode 100644 h/static/styles/excerpt.scss
 create mode 100644 h/templates/client/excerpt.html

diff --git a/h/features.py b/h/features.py
index 45f634fa274..8148fef04a4 100644
--- a/h/features.py
+++ b/h/features.py
@@ -14,6 +14,7 @@
     'streamer': "Enable 'live streaming' for annotations via the websocket?",
     'search_normalized': "Assume all data has normalized URI fields?",
     'show_unanchored_annotations': "Show annotations that fail to anchor?",
+    'truncate_annotations': "Truncate long quotes and bodies in annotations?",
 }
 
 
diff --git a/h/static/scripts/app.coffee b/h/static/scripts/app.coffee
index d62b960127c..262902f5efd 100644
--- a/h/static/scripts/app.coffee
+++ b/h/static/scripts/app.coffee
@@ -105,6 +105,7 @@ module.exports = angular.module('h', [
 
 .directive('annotation', require('./directive/annotation'))
 .directive('deepCount', require('./directive/deep-count'))
+.directive('excerpt', require('./directive/excerpt').directive)
 .directive('formInput', require('./directive/form-input'))
 .directive('formValidate', require('./directive/form-validate'))
 .directive('groupList', require('./directive/group-list').directive)
diff --git a/h/static/scripts/directive/annotation.coffee b/h/static/scripts/directive/annotation.coffee
index d5690fb1c37..0ecbdb56354 100644
--- a/h/static/scripts/directive/annotation.coffee
+++ b/h/static/scripts/directive/annotation.coffee
@@ -405,8 +405,8 @@ AnnotationController = [
 #
 ###
 module.exports = [
-  '$document',
-  ($document) ->
+  '$document', 'features'
+  ($document,   features) ->
     linkFn = (scope, elem, attrs, [ctrl, thread, threadFilter, counter]) ->
       # Observe the isSidebar attribute
       attrs.$observe 'isSidebar', (value) ->
@@ -419,6 +419,9 @@ module.exports = [
           scope.$evalAsync ->
             ctrl.save()
 
+      # Give template access to feature flags
+      scope.feature = features.flagEnabled
+
       scope.share = (event) ->
         $container = angular.element(event.currentTarget).parent()
         $container.addClass('open').find('input').focus().select()
diff --git a/h/static/scripts/directive/excerpt.js b/h/static/scripts/directive/excerpt.js
new file mode 100644
index 00000000000..2b199c474a7
--- /dev/null
+++ b/h/static/scripts/directive/excerpt.js
@@ -0,0 +1,95 @@
+'use strict';
+
+function ExcerptController() {
+  var collapsed = true;
+
+  // Enabled is a test seam: overwritten in link function.
+  this.enabled = function () { return true; };
+
+  // Overflowing is a test seam: overwritten in link function.
+  this.overflowing = function () { return false; };
+
+  // Is the excerpt collapsed? True if no-one has toggled the excerpt open
+  // and the element is overflowing.
+  this.collapsed = function () {
+    if (!collapsed) {
+      return false;
+    }
+    return this.overflowing();
+  };
+
+  this.uncollapsed = function () {
+    return !collapsed;
+  };
+
+  this.toggle = function () {
+    collapsed = !collapsed;
+  };
+
+  return this;
+}
+
+/**
+ * @ngdoc directive
+ * @name excerpt
+ * @restrict E
+ * @description This directive truncates its contents to a height specified in
+ *              CSS, and provides controls for expanding and collapsing the
+ *              resulting truncated element. For example, with the following
+ *              template HTML:
+ *
+ *                  <article class="post">
+ *                    <excerpt>
+ *                      <div class="body" ng-model="post.body"></div>
+ *                    </excerpt>
+ *                  </article>
+ *
+ *              You would need to define the allowable height of the excerpt in
+ *              CSS:
+ *
+ *                  article.post .excerpt {
+ *                    max-height: 10em;
+ *                  }
+ *
+ *              And the excerpt directive will take care of the rest.
+ *
+ *              You can selectively disable truncation by providing a boolean
+ *              expression to the `enabled` parameter, e.g.:
+ *
+ *                  <excerpt enabled="!post.inFull">...</excerpt>
+ */
+function excerpt() {
+  return {
+    controller: ExcerptController,
+    controllerAs: 'vm',
+    link: function (scope, elem, attrs, ctrl) {
+      // Test if the transcluded element is overflowing its container. We use
+      // clientHeight rather than offsetHeight because we assume you'll be using
+      // this with "overflow: hidden;" (i.e. no scrollbars) and it's usually
+      // much faster to calculate than offsetHeight (which includes scrollbars).
+      ctrl.overflowing = function overflowing() {
+        var excerpt = elem[0].querySelector('.excerpt');
+        if (!excerpt) {
+          return false;
+        }
+        return (excerpt.scrollHeight > excerpt.clientHeight);
+      };
+
+      // If the `enabled` attr was provided, we override the enabled function.
+      if (attrs.enabled) {
+        ctrl.enabled = scope.enabled;
+      }
+    },
+    scope: {
+      enabled: '&?',
+    },
+    restrict: 'E',
+    transclude: true,
+    templateUrl: 'excerpt.html',
+  };
+}
+
+module.exports = {
+  directive: excerpt,
+  Controller: ExcerptController,
+};
diff --git a/h/static/scripts/directive/test/annotation-test.coffee b/h/static/scripts/directive/test/annotation-test.coffee
index 44e904ddf2b..e0e63260226 100644
--- a/h/static/scripts/directive/test/annotation-test.coffee
+++ b/h/static/scripts/directive/test/annotation-test.coffee
@@ -13,6 +13,7 @@ describe 'annotation', ->
   fakeAnnotationMapper = null
   fakeAnnotationUI = null
   fakeDrafts = null
+  fakeFeatures = null
   fakeFlash = null
   fakeGroups = null
   fakeMomentFilter = null
@@ -56,6 +57,9 @@ describe 'annotation', ->
       add: sandbox.stub()
       remove: sandbox.stub()
     }
+    fakeFeatures = {
+      flagEnabled: sandbox.stub().returns(true)
+    }
     fakeFlash = sandbox.stub()
 
     fakeMomentFilter = sandbox.stub().returns('ages ago')
@@ -92,6 +96,7 @@ describe 'annotation', ->
     $provide.value 'annotationMapper', fakeAnnotationMapper
     $provide.value 'annotationUI', fakeAnnotationUI
     $provide.value 'drafts', fakeDrafts
+    $provide.value 'features', fakeFeatures
     $provide.value 'flash', fakeFlash
     $provide.value 'momentFilter', fakeMomentFilter
     $provide.value 'permissions', fakePermissions
@@ -610,7 +615,7 @@ describe("AnnotationController", ->
   Return an annotation directive instance and stub services etc.
   ###
   createAnnotationDirective = ({annotation, personaFilter, momentFilter,
-                                urlencodeFilter, drafts, flash,
+                                urlencodeFilter, drafts, features, flash,
                                 permissions, session, tags, time, annotationUI,
                                 annotationMapper, groups,
                                 documentTitleFilter, documentDomainFilter}) ->
@@ -622,6 +627,9 @@ describe("AnnotationController", ->
         add: ->
         remove: ->
       }
+      features: features or {
+        flagEnabled: -> true
+      }
       flash: flash or {
         info: ->
         error: ->
@@ -651,6 +659,7 @@ describe("AnnotationController", ->
       $provide.value("momentFilter", locals.momentFilter)
       $provide.value("urlencodeFilter", locals.urlencodeFilter)
       $provide.value("drafts", locals.drafts)
+      $provide.value("features", locals.features)
       $provide.value("flash", locals.flash)
       $provide.value("permissions", locals.permissions)
       $provide.value("session", locals.session)
diff --git a/h/static/scripts/directive/test/excerpt-test.js b/h/static/scripts/directive/test/excerpt-test.js
new file mode 100644
index 00000000000..90c0b7615b7
--- /dev/null
+++ b/h/static/scripts/directive/test/excerpt-test.js
@@ -0,0 +1,86 @@
+'use strict';
+
+var util = require('./util');
+var excerpt = require('../excerpt');
+
+
+describe('excerpt.Controller', function () {
+  var ctrl;
+
+  beforeEach(function() {
+    ctrl = new excerpt.Controller();
+    ctrl.overflowing = function () { return false; };
+  });
+
+  it('starts collapsed if the element is overflowing', function () {
+    ctrl.overflowing = function () { return true; };
+
+    assert.isTrue(ctrl.collapsed());
+  });
+
+  it('does not start collapsed if the element is not overflowing', function () {
+    assert.isFalse(ctrl.collapsed());
+  });
+
+  it('is not initially uncollapsed if the element is overflowing', function () {
+    assert.isFalse(ctrl.uncollapsed());
+  });
+
+  it('is not initially uncollapsed if the element is not overflowing', function () {
+    assert.isFalse(ctrl.uncollapsed());
+  });
+
+  describe('.toggle()', function () {
+    beforeEach(function () {
+      ctrl.overflowing = function () { return true; };
+    });
+
+    it('toggles the collapsed state', function () {
+      var a = ctrl.collapsed();
+      ctrl.toggle();
+      var b = ctrl.collapsed();
+      ctrl.toggle();
+      var c = ctrl.collapsed();
+
+      assert.notEqual(a, b);
+      assert.notEqual(b, c);
+      assert.equal(a, c);
+    });
+  });
+});
+
+
+describe('excerpt.excerpt', function () {
+  function excerptDirective(attrs, content) {
+    return util.createDirective(document, 'excerpt', attrs, {}, content);
+  }
+
+  before(function () {
+    angular.module('app', [])
+      .directive('excerpt', excerpt.directive);
+  });
+
+  beforeEach(function () {
+    angular.mock.module('app');
+    angular.mock.module('h.templates');
+  });
+
+  it('renders its contents in a .excerpt element by default', function () {
+    var element = excerptDirective({}, '<span id="foo"></span>');
+
+    assert.equal(element.find('.excerpt #foo').length, 1);
+  });
+
+  it('when enabled, renders its contents in a .excerpt element', function () {
+    var element = excerptDirective({enabled: true}, '<span id="foo"></span>');
+
+    assert.equal(element.find('.excerpt #foo').length, 1);
+  });
+
+  it('when disabled, renders its contents but not in a .excerpt element', function () {
+    var element = excerptDirective({enabled: false}, '<span id="foo"></span>');
+
+    assert.equal(element.find('.excerpt #foo').length, 0);
+    assert.equal(element.find('#foo').length, 1);
+  });
+});
diff --git a/h/static/scripts/directive/test/util.js b/h/static/scripts/directive/test/util.js
index aaba50a108b..05ca38659d3 100644
--- a/h/static/scripts/directive/test/util.js
+++ b/h/static/scripts/directive/test/util.js
@@ -15,26 +15,31 @@ function hyphenate(name) {
  *     attrA: 'initial-value'
  *   }, {
  *     scopePropery: scopeValue
- *   });
+ *   },
+ *   'Hello, world!');
  *
- * Will generate '<my-component attr-a="attrA"></my-component>' and
+ * Will generate '<my-component attr-a="attrA">Hello, world!</my-component>' and
  * compile and link it with the scope:
  *
  *  { attrA: 'initial-value', scopeProperty: scopeValue }
  *
  * @param {Document} document - The DOM Document to create the element in
  * @param {string} name - The name of the directive to instantiate
- * @param {Object} attrs - A map of attribute names (in camelCase) to initial values.
- * @param {Object} initialScope - A dictionary of properties to set on the
- *                                scope when the element is linked
+ * @param {Object} [attrs] - A map of attribute names (in camelCase) to initial
+ *                           values.
+ * @param {Object} [initialScope] - A dictionary of properties to set on the
+ *                                  scope when the element is linked
+ * @param {string} [initialHtml] - Initial inner HTML content for the directive
+ *                                 element.
  *
  * @return {DOMElement} The Angular jqLite-wrapped DOM element for the component.
  *                      The returned object has a link(scope) method which will
  *                      re-link the component with new properties.
  */
-function createDirective(document, name, attrs, initialScope) {
+function createDirective(document, name, attrs, initialScope, initialHtml) {
   attrs = attrs || {};
   initialScope = initialScope || {};
+  initialHtml = initialHtml || '';
 
   // create a template consisting of a single element, the directive
   // we want to create and compile it
@@ -53,6 +58,7 @@ function createDirective(document, name, attrs, initialScope) {
     }
     templateElement.setAttribute(attrName, attrKey);
   });
+  templateElement.innerHTML = initialHtml;
 
   // setup initial scope
   Object.keys(attrs).forEach(function (key) {
diff --git a/h/static/styles/annotations.scss b/h/static/styles/annotations.scss
index 01959125871..1fa546778ac 100644
--- a/h/static/styles/annotations.scss
+++ b/h/static/styles/annotations.scss
@@ -37,6 +37,27 @@
 .annotation-header { margin-top: 0 }
 .annotation-footer { margin-bottom: 0 }
 
+.annotation-section {
+  .excerpt { max-height: 4.8em; }
+  .excerpt-control a {
+    font-style: italic;
+    font-family: $serif-font-family;
+    font-weight: normal;
+  }
+  .excerpt--collapsed:after {
+    height: $base-line-height;
+    @include background(linear-gradient(
+      to right,
+      $mask-start-color,
+      $mask-end-color
+    ));
+  }
+}
+
+.annotation-body {
+  .excerpt { max-height: 16.2em; }
+}
+
 .annotation-user {
   color: $text-color;
   font-weight: bold;
diff --git a/h/static/styles/common.scss b/h/static/styles/common.scss
index 5f604dd8302..797df8ea00c 100644
--- a/h/static/styles/common.scss
+++ b/h/static/styles/common.scss
@@ -5,6 +5,7 @@
 @import 'mixins/responsive';
 @import 'grid';
 @import 'annotations';
+@import 'excerpt';
 @import 'forms';
 @import 'markdown-editor';
 @import 'spinner';
diff --git a/h/static/styles/excerpt.scss b/h/static/styles/excerpt.scss
new file mode 100644
index 00000000000..5e5b0335f19
--- /dev/null
+++ b/h/static/styles/excerpt.scss
@@ -0,0 +1,31 @@
+@import "compass/css3/images";
+
+.excerpt {
+  position: relative;
+  overflow: hidden;
+}
+
+.excerpt--collapsed:after {
+  position: absolute;
+  bottom: 0;
+  height: $base-line-height * 2; // This controls the apparent height of the gradient.
+  width: 100%;
+  content: "";
+  pointer-events: none;
+  @include background(linear-gradient(
+    to bottom,
+    $mask-start-color,
+    $mask-end-color
+  ));
+}
+
+.excerpt--uncollapsed {
+  max-height: 100% !important;
+}
+
+.excerpt-control a {
+  display: block;
+  text-align: right;
+  font-weight: bold;
+  width: 100%;
+}
diff --git a/h/static/styles/variables.scss b/h/static/styles/variables.scss
index 5a052135230..c8e10079c9d 100644
--- a/h/static/styles/variables.scss
+++ b/h/static/styles/variables.scss
@@ -31,6 +31,9 @@ $button-background-gradient: top, $button-background-start, $button-background-e
 $error-color: #f0480c !default;
 $success-color: #1cbd41 !default;
 
+$mask-start-color: rgba($white, 0) !default;
+$mask-end-color: $white !default;
+
 @function color-weight($c, $n: 500) {
   @if $n == 50 {
     @return tint($c, 85%);
diff --git a/h/templates/app.html.jinja2 b/h/templates/app.html.jinja2
index c9703f95d5f..63dd6420054 100644
--- a/h/templates/app.html.jinja2
+++ b/h/templates/app.html.jinja2
@@ -93,6 +93,9 @@
   <script type="text/ng-template" id="annotation.html">
     {{ include_raw("h:templates/client/annotation.html") }}
   </script>
+  <script type="text/ng-template" id="excerpt.html">
+    {{ include_raw("h:templates/client/excerpt.html") }}
+  </script>
   <script type="text/ng-template" id="group_list.html">
     {{ include_raw("h:templates/client/group_list.html") }}
   </script>
diff --git a/h/templates/client/annotation.html b/h/templates/client/annotation.html
index 2c2137f8988..4ecbf59ba33 100644
--- a/h/templates/client/annotation.html
+++ b/h/templates/client/annotation.html
@@ -56,12 +56,14 @@
   <!-- Excerpts -->
   <section class="annotation-section"
            ng-repeat="target in vm.annotation.target track by $index">
-    <blockquote class="annotation-quote"
-                ng-hide="target.diffHTML && vm.showDiff"
-                ng-bind-html="selector.exact"
-                ng-repeat="selector in target.selector
-                           | filter : {'type': 'TextQuoteSelector'}
-                           track by $index"></blockquote>
+    <excerpt enabled="feature('truncate_annotations')">
+      <blockquote class="annotation-quote"
+                  ng-hide="target.diffHTML && vm.showDiff"
+                  ng-bind-html="selector.exact"
+                  ng-repeat="selector in target.selector
+                             | filter : {'type': 'TextQuoteSelector'}
+                             track by $index"></blockquote>
+    </excerpt>
     <blockquote class="annotation-quote"
                 ng-bind-html="target.diffHTML"
                 ng-show="target.diffHTML && vm.showDiff"></blockquote>
@@ -76,11 +78,12 @@
   <!-- / Excerpts -- >
 
   <!-- Body -->
-  <section name="text"
-           class="annotation-body"
-           ng-model="vm.annotation.text"
+  <section name="text" class="annotation-body">
+    <excerpt enabled="feature('truncate_annotations') && !vm.editing">
+      <div ng-model="vm.annotation.text"
            ng-readonly="!vm.editing"
            markdown>
+    </excerpt>
   </section>
   <!-- / Body -->
 
diff --git a/h/templates/client/excerpt.html b/h/templates/client/excerpt.html
new file mode 100644
index 00000000000..c6171ae15f8
--- /dev/null
+++ b/h/templates/client/excerpt.html
@@ -0,0 +1,12 @@
+<div ng-transclude ng-if="!vm.enabled()"></div>
+<div ng-if="vm.enabled()">
+  <div class="excerpt"
+       ng-class="{'excerpt--uncollapsed': vm.uncollapsed(),
+                  'excerpt--collapsed': vm.collapsed()}"
+       ng-transclude></div>
+
+  <div class="excerpt-control">
+    <a ng-if="vm.collapsed()" ng-click="vm.toggle()">More</a>
+    <a ng-if="vm.uncollapsed()" ng-click="vm.toggle()">Less</a>
+  </div>
+</div>