replace leading space to emsp

journal/templates/review_edit.html

@@ -44,7 +44,14 @@
                 <div id="rawContent">
                   {{ form.body }}
                 </div>
-                <div class="review-form__fyi">{% trans '不知道什么是Markdown？可以参考' %}<a target="_blank" href="https://www.markdownguide.org/">{% trans '这里' %}</a></div>
+                <div>
+                <label for="leading_space" style="display: inline;">
+                  <input type="checkbox" name="leading_space" value="1" id="leading_space" checked> 保留行首空格（替换为全角）
+                </label>
+                <span class="review-form__fyi">
+                  {% trans '不知道什么是Markdown？可以参考' %}<a target="_blank" href="https://www.markdownguide.org/">{% trans '这里' %}</a>
+                </span>
+                </div>
                 <div class="review-form__option">
                   <div class="review-form__visibility-radio">
 

journal/views.py

@@ -436,6 +436,13 @@ def review_edit(request, item_uuid, review_uuid=None):
                     mark_date = None
             if mark_date:
                 form.instance.created_time = mark_date
+            if request.POST.get("leading_space"):
+                form.instance.body = re.sub(
+                    r"^(\u2003*)( +)",
+                    lambda s: "\u2003" * ((len(s[2]) + 1) // 2 + len(s[1])),
+                    form.instance.body,
+                    flags=re.MULTILINE,
+                )
             form.save()
             if form.cleaned_data["share_to_mastodon"]:
                 form.instance.save = lambda **args: None