add previews to babycode editor component

data/static/style.css

@@ -26,7 +26,7 @@
   font-weight: bold;
   font-style: italic;
 }
-.currentpage, .pagebutton, input[type=file]::file-selector-button, button.warn, input[type=submit].warn, .linkbutton.warn, button.critical, input[type=submit].critical, .linkbutton.critical, button, input[type=submit], .linkbutton {
+.tab-button, .currentpage, .pagebutton, input[type=file]::file-selector-button, button.warn, input[type=submit].warn, .linkbutton.warn, button.critical, input[type=submit].critical, .linkbutton.critical, button, input[type=submit], .linkbutton {
   cursor: default;
   color: black;
   font-size: 0.9em;
@@ -511,6 +511,50 @@ input[type=text]:focus, input[type=password]:focus, textarea:focus, select:focus
 
 .babycode-editor {
   height: 150px;
+  font-size: 1rem;
+}
+
+.babycode-editor-container {
+  width: 100%;
+}
+
+.babycode-preview-errors-container {
+  font-size: 0.8rem;
+}
+
+.tab-button {
+  background-color: rgb(177, 206, 204.5);
+  border-bottom: none;
+  border-bottom-left-radius: 0;
+  border-bottom-right-radius: 0;
+  margin-bottom: 0;
+}
+.tab-button:hover {
+  background-color: rgb(192.6, 215.8, 214.6);
+}
+.tab-button:active {
+  background-color: rgb(166.6881496063, 178.0118503937, 177.4261417323);
+}
+.tab-button:disabled {
+  background-color: rgb(209.535, 211.565, 211.46);
+}
+.tab-button.active {
+  background-color: #beb1ce;
+  padding-top: 8px;
+}
+
+.tab-content {
+  display: none;
+}
+.tab-content.active {
+  min-height: 250px;
+  display: block;
+  background-color: rgb(191.3137931034, 189.7, 193.3);
+  border: 1px solid black;
+  padding: 10px;
+  border-top-right-radius: 3px;
+  border-bottom-right-radius: 3px;
+  border-bottom-left-radius: 3px;
 }
 
 ul, ol {

js/babycode-editor.js

@@ -59,4 +59,48 @@
     e.preventDefault();
     insertTag("code", true)
   })
+  
+  const previewEndpoint = "/api/babycode-preview";
+  let previousMarkup = "";
+  const previewTab = document.getElementById("tab-preview");
+  previewTab.addEventListener("tab-activated", async () => {
+    const previewContainer = document.getElementById("babycode-preview-container");
+    const previewErrorsContainer = document.getElementById("babycode-preview-errors-container");
+    // previewErrorsContainer.textContent = "";
+    const markup = ta.value.trim();
+    if (markup === "" || markup === previousMarkup) {
+      return;
+    }
+    previousMarkup = markup;
+      const req = await fetch(previewEndpoint, {
+        method: "POST",
+        headers: {
+          "Content-Type": "application/json",
+        },
+        body: JSON.stringify({markup: markup})
+      })
+      if (!req.ok) {
+        switch (req.status) {
+          case 429:
+            previewErrorsContainer.textContent = "(Old preview, try again in a few seconds.)"
+            previousMarkup = "";
+            break;
+          case 400:
+            previewErrorsContainer.textContent = "(Request got malformed.)"
+            break;
+          case 401:
+            previewErrorsContainer.textContent = "(You are not logged in.)"
+            break;
+          default:
+            previewErrorsContainer.textContent = "(Error. Check console.)"
+            console.error(req.error);
+            break;
+        }
+        return;
+      }
+      
+      const json_resp = await req.json();
+      previewContainer.innerHTML = json_resp.html;
+      previewErrorsContainer.textContent = "";
+  });
 }

js/tabs.js

@@ -0,0 +1,30 @@
+function activateSelfDeactivateSibs(button) {
+  if (button.classList.contains("active")) return;
+  
+  Array.from(button.parentNode.children).forEach(s => {
+    if (s === button){
+      button.classList.add('active');
+    } else {
+      s.classList.remove('active');
+    }
+    const targetId = s.dataset.targetId;
+    const target = document.getElementById(targetId);
+    
+    if (!target) return;
+    
+    if (s.classList.contains('active')) {
+      target.classList.add('active');
+      target.dispatchEvent(new CustomEvent("tab-activated", {bubbles: false}))
+    } else {
+      target.classList.remove('active');
+    }
+  });
+}
+
+document.addEventListener("DOMContentLoaded", () => {
+  document.querySelectorAll(".tab-button").forEach(button => {
+    button.addEventListener("click", () => {
+      activateSelfDeactivateSibs(button);
+    });
+  });
+});

sass/style.scss

@@ -45,6 +45,7 @@ $lighter: color.scale($accent_color, $lightness: 60%, $saturation: -60%);
 
 $main_bg: color.scale($accent_color, $lightness: -10%, $saturation: -40%);
 $button_color: color.adjust($accent_color, $hue: 90);
+$button_color2: color.adjust($accent_color, $hue: 180);
 
 %button-base {
   cursor: default;
@@ -524,8 +525,44 @@ input[type="text"], input[type="password"], textarea, select {
 
 .babycode-editor {
   height: 150px;
+  font-size: 1rem;
 }
 
+.babycode-editor-container {
+  width: 100%;
+}
+
+.babycode-preview-errors-container {
+  font-size: 0.8rem;
+}
+
+.tab-button {
+  @include button($button_color);
+  border-bottom: none;
+  border-bottom-left-radius: 0;
+  border-bottom-right-radius: 0;
+  margin-bottom: 0;
+  
+  &.active {
+    background-color: $button_color2;
+    padding-top: 8px;
+  }
+}
+
+.tab-content {
+  display: none;
+  
+  &.active {
+    min-height: 250px;
+    display: block;
+    background-color: color.adjust($button_color2, $saturation: -20%);
+    border: 1px solid black;
+    padding: 10px;
+    border-top-right-radius: 3px;
+    border-bottom-right-radius: 3px;
+    border-bottom-left-radius: 3px;
+  }
+}
 
 ul, ol {
   margin: 10px 0 10px 30px;

views/base.etlua

@@ -18,5 +18,6 @@
   </footer>
   <script src="/static/js/copy-code.js"></script>
   <script src="/static/js/date-fmt.js"></script>
+  <script src="/static/js/tabs.js"></script>
 </body>
 </html>

views/common/babycode-editor-component.etlua

@@ -1,3 +1,9 @@
+<div class="babycode-editor-container">
+  <div class="tab-buttons">
+    <button type=button class="tab-button active" data-target-id="tab-edit">Write</button>
+    <button type=button class="tab-button" data-target-id="tab-preview">Preview</button>
+  </div>
+  <div class="tab-content active" id="tab-edit">
     <span>
       <button type=button id="post-editor-bold" title="Insert Bold">B</button>
       <button type=button id="post-editor-italics" title="Insert Italics">I</button>
@@ -5,4 +11,10 @@
       <button type=button id="post-editor-code" title="Insert Code block">Code</button>
     </span>
     <textarea class="babycode-editor" name="<%= ta_name %>" id="babycode-content" placeholder="<%= ta_placeholder or "Post body"%>" <%= not optional and "required" or "" %>><%- prefill or "" %></textarea>
-<script src="/static/js/babycode-editor.js"></script>
+  </div>
+  <div class="tab-content" id="tab-preview">
+    <div id="babycode-preview-errors-container">Type something!</div>
+    <div id="babycode-preview-container"></div>
+  </div>
+</div>
+<script src="/static/js/babycode-editor.js?v=1"></script>