add reply button functionality

js/thread.js

@@ -0,0 +1,8 @@
+const ta = document.getElementById("post_content");
+
+for (let button of document.querySelectorAll(".reply-button")) {
+  button.addEventListener("click", (e) => {
+    ta.value += button.value;
+    ta.scrollIntoView()
+  })
+}

views/threads/post.etlua

@@ -43,8 +43,10 @@
             show_reply = false
           end
           if show_reply then
+            local d = post.created_at < post.edited_at and post.edited_at or post.created_at
+            local reply_text = ("On %s, %s said:\n%s\n\n---\n\n"):format(os.date("%c", d), post.username, post.original_markup)
           %>
-            <button>Reply</button>
+            <button value="<%= reply_text %>" class="reply-button">Reply</button>
           <% end %>
         </span>
     </div>

views/threads/thread.etlua

@@ -1,4 +1,11 @@
-<% local is_locked = ntob(thread.is_locked) %>
+<%
+  local is_locked = ntob(thread.is_locked)
+  local can_post = (not is_locked and not me:is_guest()) or me:is_mod()
+  -- not locked, not guest, not mod = not false and not false or false = true and true or false = true
+  -- locked, not guest, not mod = not true and not false or false = false and true or false = false
+  -- not locked, guest, not mod = not false and not true or false = true and false or false = false
+  -- not locked, not guest, mod = not false and not false or true = true and true and true
+%>
 <main>
   <nav class="darkbg">
     <h1 class="thread-title"><%= thread.title %></h1>
@@ -16,10 +23,11 @@
 <% if is_locked then -%>
   <% render("views.common.infobox", {kind = constants.InfoboxKind.LOCK, msg = "This thread is locked."}) %>
 <% end -%>
-<% if not me:is_guest() and not is_locked then %>
+<% if can_post then %>
 <h1>Respond to "<%= thread.title %>"</h1>
 <form method="post">
-  <textarea id="post_content" name="post_content" placeholder="Response body" required></textarea><br>
+  <textarea id="post_content" name="post_content" placeholder="Response body" rows=7 required></textarea><br>
   <input type="submit" value="Post reply">
 </form>
+<script src="/static/js/thread.js"></script>
 <% end %>