first proof of concept, security still missing

assets/javascripts/discourse/connectors/topic-after-cooked/solved-panel.hbs

@@ -1,5 +1,5 @@
 {{#if topic.accepted_answer}}
 <p class="solved">
-<i class='fa-check-square fa accepted'></i> Solved by <a data-user-card="{{topic.accepted_answer.username}}">{{topic.accepted_answer.username}}</a> in <a href="{{acceptedAnswerPath}}">post #{{topic.accepted_answer.post_number}}</a>
+{{{topic.acceptedAnswerHtml}}}
 </p>
 {{/if}}

assets/javascripts/discourse/initializers/extend-for-solved-button.js.es6

@@ -2,16 +2,31 @@ import PostMenuView from 'discourse/views/post-menu';
 import PostView from 'discourse/views/post';
 import { Button } from 'discourse/views/post-menu';
 import Topic from 'discourse/models/topic';
+import User from 'discourse/models/user';
 
 export default {
   name: 'extend-for-solved-button',
   initialize: function() {
 
     Topic.reopen({
+
       // keeping this here cause there is complex localization
       acceptedAnswerHtml: function(){
-        return I18n.t("")
-      }.property('accepted_answer')
+        var username = this.get('accepted_answer.username');
+        var postNumber = this.get('accepted_answer.post_number');
+
+        if (!username || !postNumber) {
+          return "";
+        }
+
+        return I18n.t("accepted_answer.accepted_html", {
+          username_lower: username.toLowerCase(),
+          username: username,
+          post_path: this.get('url') + "/" + postNumber,
+          post_number: postNumber,
+          user_path: User.create({username: username}).get('path')
+        });
+      }.property('accepted_answer', 'id')
     });
 
     PostView.reopen({
@@ -35,7 +50,8 @@ export default {
       clickUnacceptAnswer: function(){
         this.set('post.can_accept_answer', true);
         this.set('post.can_unaccept_answer', false);
-        this.set('post.topic.has_accepted_answer', false);
+        this.set('post.accepted_answer', false);
+        this.set('post.topic.accepted_answer', undefined);
 
         Discourse.ajax("/solution/unaccept", {
           type: 'POST',

config/locales/client.en.yml

@@ -0,0 +1,6 @@
+en:
+  js:
+    accepted_answer:
+      accept_answer: "Accept answer"
+      unaccept_answer: "Unaccept answer"
+      accepted_html: "<i class='fa-check-square fa accepted'></i> Solved by <a href data-user-card='{{username_lower}}'>{{username}}</a> in <a href='{{post_path}}'>post #{{post_number}}</a>"

plugin.rb

@@ -22,8 +22,8 @@ after_initialize do
 
       post = Post.find(params[:id].to_i)
 
-      accepted_id = post.topic.custom_fields["has_accepted_answer"].to_i
-      if accepted_id
+      accepted_id = post.topic.custom_fields["accepted_answer_post_id"].to_i
+      if accepted_id > 0
         if p2 = Post.find_by(id: accepted_id)
           p2.custom_fields["is_accepted_answer"] = nil
           p2.save!