improve task list handling

CLAUDE.md

@@ -56,6 +56,9 @@ Prefer separate, human-readable `.html` files over inlined HTML strings in Go. E
 - Editor toolbar buttons use `data-action` + `data-key`; adding `data-key` auto-registers the shortcut
 - Prefer generic, descriptive CSS classes (`btn`, `btn-small`, `muted`, `danger`) over element-specific names (`save-button`, `cancel-button`, `form-name-input`). Use a modifier + base class pattern (`btn btn-small`) rather than one-off classes that duplicate shared styles.
 - Where possible, re-use existing CSS classes
+- For mutating modals (anything that POSTs and then navigates), call `closeModal()` and then `postReplace(action, body, target)` from `page/actions.js`. Do NOT use `<form>.submit()`. Two reasons:
+  1. The modal must be removed from the DOM before navigation, or the browser's bfcache snapshots it open and back-nav restores the modal.
+  2. `postReplace` uses `window.location.replace` so the action + result occupy a single history entry. A naive POST → 303 → GET creates two entries, and back-nav lands on a stale pre-mutation snapshot of the same page.
 
 ## Development Priorities
 

assets/page/actions.js

@@ -3,6 +3,36 @@ function encodePickedPath(p) {
     return '/' + p.replace(/^\/+/, '').split('/').map(encodeURIComponent).join('/');
 }
 
+// postReplace POSTs to action with the optional form body, then loads target
+// into the current history entry — so the action and its result occupy one
+// entry instead of two, and back-navigation skips past the stale pre-mutation
+// snapshot in bfcache. body may be null for empty POSTs.
+//
+// We can't just call window.location.replace(target): when target differs from
+// the current URL only by fragment, the browser updates the URL bar without
+// re-fetching, so a server-side mutation wouldn't be reflected. Instead,
+// rewrite the current entry's URL via history.replaceState, then reload — the
+// reload always re-fetches and preserves the (new) URL including its fragment.
+function postReplace(action, body, target) {
+    var init = { method: 'POST', redirect: 'manual' };
+    if (body) {
+        init.headers = { 'Content-Type': 'application/x-www-form-urlencoded' };
+        init.body = body;
+    }
+    fetch(action, init).then(function (res) {
+        if (res.type === 'opaqueredirect' || res.ok) {
+            window.history.replaceState(null, '', target);
+            window.location.reload();
+            return;
+        }
+        return res.text().then(function (msg) {
+            alert(msg || ('Request failed (' + res.status + ')'));
+        });
+    }).catch(function () {
+        alert('Network error');
+    });
+}
+
 function promptPageName(title, initial, confirmLabel, onName) {
     var input = document.createElement('input');
     input.type = 'text';
@@ -89,11 +119,9 @@ function movePage() {
                         var action = window.location.pathname + '?move=' +
                             encodeURIComponent(dest);
                         if (linksCheckbox.checked) action += '&links=1';
-                        var form = document.createElement('form');
-                        form.method = 'POST';
-                        form.action = action;
-                        document.body.appendChild(form);
-                        form.submit();
+                        var target = encodePickedPath(dest) + '/';
+                        closeModal();
+                        postReplace(action, null, target);
                     }
                 }
             });
@@ -112,11 +140,11 @@ function deletePage() {
             danger: true,
             enterConfirms: false,
             onConfirm: function () {
-                var form = document.createElement('form');
-                form.method = 'POST';
-                form.action = window.location.pathname + '?delete=1';
-                document.body.appendChild(form);
-                form.submit();
+                var p = window.location.pathname.replace(/\/+$/, '');
+                var idx = p.lastIndexOf('/');
+                var parent = idx > 0 ? p.substring(0, idx + 1) : '/';
+                closeModal();
+                postReplace(window.location.pathname + '?delete=1', null, parent);
             }
         },
         cancel: { autofocus: true },

assets/page/anchors.js

@@ -1,17 +1,114 @@
 (function () {
-  var content = document.querySelector("main");
+  var content = document.querySelector('.content');
   if (!content) return;
 
-  var headings = content.querySelectorAll("h2, h3, h4");
-  if (!headings) return
+  var allHeadings = content.querySelectorAll('h1, h2, h3, h4, h5, h6');
+  if (!allHeadings.length) return;
 
-  headings.forEach(function (h) {
-      if (!h.id) return;
-      var a = document.createElement('a');
-      a.href = '#' + h.id;
-      a.className = 'heading-anchor';
-      a.setAttribute('aria-label', 'Link to this section');
-      a.textContent = '#';
-      h.insertBefore(a, h.firstChild);
+  function copyAnchor(id, item, label, menu) {
+    var url = window.location.origin + window.location.pathname + '#' + id;
+    function flash() {
+      item.textContent = 'Copied!';
+      setTimeout(function () {
+        item.textContent = label;
+        menu.classList.remove('is-open');
+      }, 1200);
+    }
+    function fallback() {
+      var ta = document.createElement('textarea');
+      ta.value = url;
+      ta.setAttribute('readonly', '');
+      ta.style.position = 'fixed';
+      ta.style.opacity = '0';
+      document.body.appendChild(ta);
+      ta.select();
+      var ok = false;
+      try { ok = document.execCommand('copy'); } catch (e) { ok = false; }
+      document.body.removeChild(ta);
+      if (ok) flash();
+      else openModal({
+        title: 'Copy anchor link',
+        body: 'Could not copy automatically. URL:\n' + url,
+        confirm: { label: 'OK', onConfirm: function () { closeModal(); } }
+      });
+    }
+    if (navigator.clipboard && navigator.clipboard.writeText) {
+      navigator.clipboard.writeText(url).then(flash, fallback);
+    } else {
+      fallback();
+    }
+  }
+
+  function addTask(sectionIndex, headingId) {
+    var input = document.createElement('input');
+    input.type = 'text';
+    input.className = 'modal-input';
+    input.placeholder = 'Task description';
+    var ctrl = openModal({
+      title: 'Add task',
+      body: input,
+      confirm: {
+        label: 'ADD',
+        initiallyDisabled: true,
+        onConfirm: function () {
+          var text = input.value.trim();
+          if (!text) return;
+          var action = window.location.pathname + '?addtask=' + sectionIndex;
+          var target = window.location.pathname + '#' + headingId;
+          closeModal();
+          postReplace(action, 'text=' + encodeURIComponent(text), target);
+        }
+      }
+    });
+    input.addEventListener('input', function () {
+      ctrl.setConfirmDisabled(input.value.trim() === '');
+    });
+  }
+
+  allHeadings.forEach(function (h, i) {
+    if (!h.id) return;
+    var tag = h.tagName.toLowerCase();
+    if (tag !== 'h2' && tag !== 'h3' && tag !== 'h4') return;
+
+    var sectionIndex = i + 1;
+
+    var wrap = document.createElement('span');
+    wrap.className = 'dropdown heading-anchor';
+
+    var trigger = document.createElement('button');
+    trigger.type = 'button';
+    trigger.className = 'dropdown-toggle';
+    trigger.setAttribute('aria-haspopup', 'menu');
+    trigger.setAttribute('aria-label', 'Section actions');
+    trigger.textContent = '#';
+
+    var menu = document.createElement('div');
+    menu.className = 'dropdown-menu';
+
+    var copyLabel = 'Copy anchor link';
+    var copyBtn = document.createElement('button');
+    copyBtn.type = 'button';
+    copyBtn.className = 'btn btn-tool btn-block';
+    copyBtn.dataset.action = 'copy-anchor';
+    copyBtn.textContent = copyLabel;
+    copyBtn.addEventListener('click', function (e) {
+      e.stopPropagation();
+      copyAnchor(h.id, copyBtn, copyLabel, menu);
+    });
+
+    var addBtn = document.createElement('button');
+    addBtn.type = 'button';
+    addBtn.className = 'btn btn-tool btn-block';
+    addBtn.dataset.action = 'add-task';
+    addBtn.textContent = 'Add task';
+    addBtn.addEventListener('click', function () { addTask(sectionIndex, h.id); });
+
+    menu.appendChild(copyBtn);
+    menu.appendChild(addBtn);
+    wrap.appendChild(trigger);
+    wrap.appendChild(menu);
+    h.insertBefore(wrap, h.firstChild);
+
+    wireDropdown(trigger);
   });
 }());

assets/page/main.html

@@ -42,6 +42,9 @@
     <button class="btn btn-block" data-companion-reveal hidden title="Reveal in file manager">REVEAL ON CLIENT</button>
     {{if not .IsRoot}}
     <button class="btn btn-block" onclick="movePage()" title="Move page (M)">MOVE PAGE</button>
+    {{end}}
+    <button class="btn btn-block" data-action="clean-tasks" onclick="cleanUpTasks()" title="Clean up finished tasks" hidden>CLEAN UP TASKS</button>
+    {{if not .IsRoot}}
     <button class="btn btn-block danger" onclick="deletePage()" title="Delete page">DELETE PAGE</button>
     {{end}}
 </nav>{{end}}{{if .SidebarWidget}}{{.SidebarWidget}}{{end}}{{end}}

assets/page/tasks.js

@@ -21,4 +21,25 @@
             });
         });
     });
+
+    var hasChecked = !!document.querySelector('input.task-checkbox:checked');
+    if (hasChecked) {
+        var btn = document.querySelector('[data-action="clean-tasks"]');
+        if (btn) btn.hidden = false;
+    }
 })();
+
+function cleanUpTasks() {
+    openModal({
+        title: 'Clean up tasks',
+        body: 'Remove all completed tasks from this page?',
+        confirm: {
+            label: 'CLEAN UP',
+            danger: true,
+            onConfirm: function () {
+                closeModal();
+                postReplace(window.location.pathname + '?cleantasks=1', null, window.location.pathname);
+            }
+        }
+    });
+}

assets/page/toc.js

@@ -21,7 +21,7 @@ document.addEventListener("DOMContentLoaded", function () {
     var a = document.createElement("a");
     a.href = "#" + h.id;
     var clone = h.cloneNode(true);
-    clone.querySelectorAll(".btn, .muted, .heading-anchor").forEach(function (el) { el.remove(); });
+    clone.querySelectorAll(".btn, .muted, .heading-anchor, .dropdown").forEach(function (el) { el.remove(); });
     a.textContent = clone.textContent.trim();
     li.appendChild(a);
     list.appendChild(li);

assets/style.css

@@ -273,12 +273,20 @@ main {
     max-width: 100%;
 }
 
-a.heading-anchor {
-    color: var(--text-muted);
+.dropdown.heading-anchor {
     margin-right: 0.4em;
     font-weight: normal;
 }
-a.heading-anchor:hover {
+.heading-anchor .dropdown-toggle {
+    background: none;
+    border: none;
+    padding: 0;
+    cursor: pointer;
+    color: var(--text-muted);
+    font: inherit;
+    font-weight: normal;
+}
+.heading-anchor .dropdown-toggle:hover {
     color: var(--primary-hover);
 }
 

main.go

@@ -333,6 +333,14 @@ func (h *handler) handlePost(w http.ResponseWriter, r *http.Request, urlPath, fs
 		h.handleAppend(w, r, urlPath, fsPath)
 		return
 	}
+	if query.Has("cleantasks") {
+		h.handleCleanTasks(w, r, urlPath, fsPath)
+		return
+	}
+	if query.Has("addtask") {
+		h.handleAddTask(w, r, urlPath, fsPath)
+		return
+	}
 
 	if err := r.ParseForm(); err != nil {
 		http.Error(w, "bad request", http.StatusBadRequest)

tasks.go

@@ -7,6 +7,7 @@ import (
 	"path/filepath"
 	"regexp"
 	"strconv"
+	"strings"
 )
 
 // taskCheckboxRe matches the <input> tag goldmark's GFM extension emits for a
@@ -110,3 +111,201 @@ func flipTaskLine(raw []byte, n int, checked bool) ([]byte, bool) {
 	lines[target] = taskLineRe.ReplaceAll(lines[target], replacement)
 	return bytes.Join(lines, []byte("\n")), true
 }
+
+// handleCleanTasks rewrites index.md with every completed task line — and its
+// continuation lines — removed. Triggered by POST /{path}?cleantasks=1.
+func (h *handler) handleCleanTasks(w http.ResponseWriter, r *http.Request, urlPath, fsPath string) {
+	indexPath := filepath.Join(fsPath, "index.md")
+	raw, err := os.ReadFile(indexPath)
+	if err != nil {
+		http.Error(w, "read failed: "+err.Error(), http.StatusInternalServerError)
+		return
+	}
+	updated := stripCompletedTasks(raw)
+	if !bytes.Equal(updated, raw) {
+		if err := writeFileAtomic(indexPath, updated, 0644); err != nil {
+			http.Error(w, "write failed: "+err.Error(), http.StatusInternalServerError)
+			return
+		}
+	}
+	http.Redirect(w, r, urlPath, http.StatusSeeOther)
+}
+
+// handleAddTask appends a single `- [ ] text` task to the last task list in
+// the selected section, or creates a new list at the end of the section if
+// none exists. Triggered by POST /{path}?addtask=<section-index> with form
+// field `text`.
+func (h *handler) handleAddTask(w http.ResponseWriter, r *http.Request, urlPath, fsPath string) {
+	sectionIndex, err := strconv.Atoi(r.URL.Query().Get("addtask"))
+	if err != nil || sectionIndex < 1 {
+		http.Error(w, "bad section index", http.StatusBadRequest)
+		return
+	}
+	if err := r.ParseForm(); err != nil {
+		http.Error(w, "bad request", http.StatusBadRequest)
+		return
+	}
+	text := r.FormValue("text")
+	if strings.ContainsAny(text, "\r\n") {
+		http.Error(w, "text must be single-line", http.StatusBadRequest)
+		return
+	}
+	text = strings.TrimSpace(text)
+	if text == "" {
+		http.Error(w, "empty text", http.StatusBadRequest)
+		return
+	}
+
+	indexPath := filepath.Join(fsPath, "index.md")
+	raw, err := os.ReadFile(indexPath)
+	if err != nil {
+		http.Error(w, "read failed: "+err.Error(), http.StatusInternalServerError)
+		return
+	}
+	sections := splitSections(raw)
+	if sectionIndex >= len(sections) {
+		http.Error(w, "section out of range", http.StatusBadRequest)
+		return
+	}
+
+	sections[sectionIndex] = appendToLastTaskList(sections[sectionIndex], text)
+	updated := joinSections(sections)
+	if err := writeFileAtomic(indexPath, updated, 0644); err != nil {
+		http.Error(w, "write failed: "+err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	target := urlPath
+	ids := headingIDs(updated)
+	if sectionIndex-1 < len(ids) {
+		target = urlPath + "#" + ids[sectionIndex-1]
+	}
+	http.Redirect(w, r, target, http.StatusSeeOther)
+}
+
+// splitLines returns raw split on '\n', dropping the trailing empty element
+// produced when raw ends in '\n', and reports whether that newline was there.
+// reassemble undoes the split with the matching trailing-newline state.
+func splitLines(raw []byte) (lines [][]byte, trailingNewline bool) {
+	trailingNewline = len(raw) > 0 && raw[len(raw)-1] == '\n'
+	lines = bytes.Split(raw, []byte("\n"))
+	if trailingNewline && len(lines) > 0 && len(lines[len(lines)-1]) == 0 {
+		lines = lines[:len(lines)-1]
+	}
+	return lines, trailingNewline
+}
+
+func reassemble(lines [][]byte, trailingNewline bool) []byte {
+	out := bytes.Join(lines, []byte("\n"))
+	if trailingNewline && len(out) > 0 {
+		out = append(out, '\n')
+	}
+	return out
+}
+
+// isFence reports whether line opens or closes a fenced code block.
+func isFence(line []byte) bool {
+	t := bytes.TrimLeft(line, " \t")
+	return bytes.HasPrefix(t, []byte("```")) || bytes.HasPrefix(t, []byte("~~~"))
+}
+
+// indentWidth counts leading-whitespace columns, tabs and spaces equally.
+// Adequate for the user's own wiki text, where mixed tab/space indents are rare.
+func indentWidth(line []byte) int {
+	n := 0
+	for n < len(line) && (line[n] == ' ' || line[n] == '\t') {
+		n++
+	}
+	return n
+}
+
+// stripCompletedTasks removes every `[x]`/`[X]` task line and its continuation
+// lines (blank, or indented strictly more than the bullet) from raw. Lines
+// inside fenced code blocks are ignored, matching flipTaskLine's contract.
+func stripCompletedTasks(raw []byte) []byte {
+	lines, trailing := splitLines(raw)
+	out := make([][]byte, 0, len(lines))
+	inFence := false
+	for i := 0; i < len(lines); i++ {
+		line := lines[i]
+		if isFence(line) {
+			inFence = !inFence
+			out = append(out, line)
+			continue
+		}
+		if !inFence {
+			if m := taskLineRe.FindSubmatch(line); m != nil && (m[2][0] == 'x' || m[2][0] == 'X') {
+				bulletIndent := indentWidth(line)
+				j := i + 1
+				for j < len(lines) {
+					next := lines[j]
+					if len(bytes.TrimSpace(next)) > 0 && indentWidth(next) <= bulletIndent {
+						break
+					}
+					j++
+				}
+				i = j - 1
+				continue
+			}
+		}
+		out = append(out, line)
+	}
+	return reassemble(out, trailing)
+}
+
+// appendToLastTaskList inserts `- [ ] text` after the last task list item in
+// sectionBytes. If no task list exists in the section, it appends a new list
+// at the end, separated by a blank line. Bullet character and indent are
+// inherited from the existing last item when present.
+func appendToLastTaskList(sectionBytes []byte, text string) []byte {
+	lines, trailing := splitLines(sectionBytes)
+
+	// Forward scan: track fence state and remember the last non-fenced task line.
+	lastTask, lastPrefix, lastIndent := -1, "", 0
+	inFence := false
+	for i, line := range lines {
+		if isFence(line) {
+			inFence = !inFence
+			continue
+		}
+		if inFence {
+			continue
+		}
+		if m := taskLineRe.FindSubmatch(line); m != nil {
+			lastTask = i
+			lastPrefix = string(m[1])
+			lastIndent = indentWidth(line)
+		}
+	}
+
+	if lastTask >= 0 {
+		// Walk forward over continuation lines (blank or more-indented), then
+		// back over trailing blanks so the new task slots in after the last
+		// real content line of the item.
+		end := lastTask + 1
+		for end < len(lines) {
+			next := lines[end]
+			if len(bytes.TrimSpace(next)) > 0 && indentWidth(next) <= lastIndent {
+				break
+			}
+			end++
+		}
+		for end > lastTask+1 && len(bytes.TrimSpace(lines[end-1])) == 0 {
+			end--
+		}
+		newLine := []byte(lastPrefix + "[ ] " + text)
+		out := append(append(append([][]byte{}, lines[:end]...), newLine), lines[end:]...)
+		return reassemble(out, trailing)
+	}
+
+	// No task list — append one at section end, blank-line-separated from any
+	// preceding content. Trim trailing blanks first to control spacing exactly.
+	for len(lines) > 0 && len(bytes.TrimSpace(lines[len(lines)-1])) == 0 {
+		lines = lines[:len(lines)-1]
+	}
+	if len(lines) > 0 {
+		lines = append(lines, nil)
+	}
+	lines = append(lines, []byte("- [ ] "+text))
+	return reassemble(lines, trailing)
+}