Display details about the search context in the placeholder

app/assets/javascripts/discourse/models/category.js

@@ -15,7 +15,7 @@ Discourse.Category = Discourse.Model.extend({
   },
 
   searchContext: function() {
-    return ({ type: 'category', id: this.get('id') });
+    return ({ type: 'category', id: this.get('id'), category: this });
   }.property('id'),
 
   url: function() {

app/assets/javascripts/discourse/models/user.js

@@ -29,7 +29,7 @@ Discourse.User = Discourse.Model.extend({
   }).property('username'),
 
   searchContext: function() {
-    return ({ type: 'user', id: this.get('username_lower') });
+    return ({ type: 'user', id: this.get('username_lower'), user: this });
   }.property('username_lower'),
 
   /**

app/assets/javascripts/discourse/routes/user_route.js

@@ -18,6 +18,9 @@ Discourse.UserRoute = Discourse.Route.extend({
 
   setupController: function(controller, user) {
     user.findDetails();
+
+    // Add a search context
+    this.controllerFor('search').set('searchContext', user.get('searchContext'));
   },
 
   activate: function() {
@@ -26,9 +29,6 @@ Discourse.UserRoute = Discourse.Route.extend({
     Discourse.MessageBus.subscribe("/users/" + user.get('username_lower'), function(data) {
       user.loadUserAction(data);
     });
-
-    // Add a search context
-    this.controllerFor('search').set('searchContext', user.get('searchContext'));
   },
 
   deactivate: function() {

app/assets/javascripts/discourse/templates/search.js.handlebars

@@ -1,4 +1,4 @@
-{{textField value=term placeholderKey="search.placeholder"}}
+{{view Discourse.SearchTextField valueBinding="term" searchContextBinding="searchContext"}}
 {{#unless loading}}
   {{#unless noResults}}
     {{#each resultType in content}}

app/assets/javascripts/discourse/views/discourse_text_field.js

@@ -9,13 +9,13 @@
 Discourse.TextField = Ember.TextField.extend({
   attributeBindings: ['autocorrect', 'autocapitalize', 'autofocus'],
 
-  placeholder: (function() {
+  placeholder: function() {
     if( this.get('placeholderKey') ) {
       return Em.String.i18n(this.get('placeholderKey'));
     } else {
       return '';
     }
-  }).property('placeholderKey')
+  }.property('placeholderKey')
 
 });
 

app/assets/javascripts/discourse/views/search/search_text_field.js

@@ -0,0 +1,33 @@
+/**
+  This is a text field that supports a dynamic placeholder based on search context.
+
+  @class SearchTextField
+  @extends Discourse.TextField
+  @namespace Discourse
+  @module Discourse
+**/
+Discourse.SearchTextField = Discourse.TextField.extend({
+
+  /**
+    A dynamic placeholder for the search field based on our context
+
+    @property placeholder
+  **/
+  placeholder: function() {
+
+    var ctx = this.get('searchContext');
+    if (ctx) {
+      switch(Em.get(ctx, 'type')) {
+        case 'user':
+          return Em.String.i18n('search.prefer.user', {username: Em.get(ctx, 'user.username')});
+        case 'category':
+          return Em.String.i18n('search.prefer.category', {category: Em.get(ctx, 'category.name')});
+      }
+    }
+
+    return Em.String.i18n('search.placeholder');
+  }.property('searchContext')
+
+});
+
+