add topic sorting & js to support it

data/static/css/style.css

@@ -859,6 +859,53 @@ a.mention {
   }
 }
 
+ol.sortable-list {
+  display: flex;
+  gap: var(--base-padding);
+  flex-direction: column;
+  list-style: none;
+  flex-grow: 1;
+  margin: 0;
+  padding-left: 0;
+
+  li {
+    display: flex;
+    gap: var(--big-padding);
+  }
+
+  li.immovable .dragger {
+    cursor: not-allowed;
+  }
+}
+
+.plank.dragger {
+  display: flex;
+  align-items: center;
+  /*background-color: var(--bg-color-tertiary);*/
+  padding: var(--base-padding);
+  cursor: move;
+}
+
+.sortable-item-inner {
+  display: flex;
+  gap: var(--base-padding);
+  flex-grow: 1;
+  flex-direction: column;
+
+  & > * {
+    flex-grow: 1;
+  }
+
+  &.row {
+    flex-direction: row;
+  }
+
+  &:not(.row) > * {
+    margin-right: auto;
+  }
+}
+
+
 @media (max-width: 768px) {
   body {
     margin-left: 0;

data/static/icons/dragger.svg

@@ -0,0 +1,46 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!-- Created with Inkscape (http://www.inkscape.org/) -->
+
+<svg
+   width="24"
+   height="24"
+   viewBox="0 0 24 24"
+   version="1.1"
+   id="svg1"
+   xmlns="http://www.w3.org/2000/svg"
+   xmlns:svg="http://www.w3.org/2000/svg">
+  <defs
+     id="defs1" />
+  <g
+     id="layer1">
+    <rect
+       style="fill:#000000;stroke:none;stroke-width:0.999996;stroke-linecap:round;stroke-linejoin:round"
+       id="rect1"
+       width="16"
+       height="2"
+       x="4"
+       y="8" />
+    <rect
+       style="fill:#000000;stroke:none;stroke-width:0.999996;stroke-linecap:round;stroke-linejoin:round"
+       id="rect2"
+       width="16"
+       height="2"
+       x="4"
+       y="11" />
+    <rect
+       style="fill:#000000;stroke:none;stroke-width:0.999996;stroke-linecap:round;stroke-linejoin:round"
+       id="rect3"
+       width="16"
+       height="2"
+       x="4"
+       y="14" />
+    <path
+       style="fill:#000000;stroke:none;stroke-linecap:round;stroke-linejoin:round"
+       d="m 6,6 6,-6 6,6 H 16 L 12,2 8,6 Z"
+       id="path3" />
+    <path
+       style="fill:#000000;stroke:none;stroke-linecap:round;stroke-linejoin:round"
+       d="m 6,18 6,6 6,-6 h -2 l -4,4 -4,-4 z"
+       id="path4" />
+  </g>
+</svg>

data/static/js/ui.js

@@ -0,0 +1,97 @@
+'use strict';
+
+{
+  function isBefore(el1, el2) {
+    if (el2.parentNode === el1.parentNode) {
+      for (let cur = el1.previousSibling; cur; cur = cur.previousSibling) {
+        if (cur === el2) return true;
+      }
+    }
+    return false;
+  }
+
+  let draggedItem = null;
+
+  function sortableItemDragStart(e, item) {
+    const box = item.getBoundingClientRect();
+    const oX = e.clientX - box.left;
+    const oY = e.clientY - box.top;
+    draggedItem = item;
+    item.classList.add('contrast-bg');
+    e.dataTransfer.setDragImage(item, oX, oY);
+    e.dataTransfer.effectAllowed = 'move';
+  }
+
+  function sortableItemDragEnd(e, item) {
+    draggedItem = null;
+    item.classList.remove('contrast-bg');
+  }
+
+  function sortableItemDragOver(e, item) {
+    const target = e.target.closest('.sortable-item');
+    if (!target || target === draggedItem) {
+      return;
+    }
+    const inSameList = draggedItem.dataset.sortableListKey === target.dataset.sortableListKey;
+    if (!inSameList) {
+      return;
+    }
+    const targetList = draggedItem.closest('.sortable-list');
+    if (isBefore(draggedItem, target)) {
+      targetList.insertBefore(draggedItem, target);
+    } else {
+      targetList.insertBefore(draggedItem, target.nextSibling);
+    }
+  }
+
+  const listItemsHandled = new Map();
+
+  const getListItemsHandled = (list) => {
+    return listItemsHandled.get(list) || new Set();
+  }
+
+  function registerSortableList(list) {
+    list.querySelectorAll('li:not(.immovable)').forEach(item => {
+      const listItems = getListItemsHandled(list);
+      listItems.add(item);
+      listItemsHandled.set(list, listItems);
+      const dragger = item.querySelector('.dragger');
+      dragger.addEventListener('dragstart', e => { sortableItemDragStart(e, item) });
+      dragger.addEventListener('dragend', e => { sortableItemDragEnd(e, item) });
+      item.addEventListener('dragover', e => { sortableItemDragOver(e, item) });
+    });
+
+    const obs = new MutationObserver(records => {
+      for (const mutation of records) {
+        mutation.addedNodes.forEach(node => {
+          if (!(node instanceof HTMLElement)) return;
+          if (!node.classList.contains('sortable-item')) return;
+          const listItems = getListItemsHandled(list);
+          if (listItems.has(node)) return;
+
+          const dragger = node.querySelector('.dragger');
+          dragger.addEventListener('dragstart', e => { sortableItemDragStart(e, item) });
+          dragger.addEventListener('dragend', e => { sortableItemDragEnd(e, item) });
+          node.addEventListener('dragover', e => { sortableItemDragOver(e, node) });
+          listItems.add(node);
+          listItemsHandled.set(list, listItems);
+        });
+      }
+    });
+    obs.observe(list, { childList: true });
+  }
+
+  document.querySelectorAll('.sortable-list').forEach(registerSortableList);
+
+  const listsObs = new MutationObserver(records => {
+    for (const mutation of records) {
+      mutation.addedNodes.forEach(node => {
+        if (!(node instanceof HTMLElement)) return;
+        if (!node.classList.contains('sortable-list')) return;
+
+        registerSortableList(node);
+      });
+    }
+  });
+  listsObs.observe(document.body, { childList: true, subtree: true })
+}