Refactor Layout and improve search

.gitignore

@@ -1,5 +1,7 @@
 .claude/
+.zed/
 wiki/
+cache/
 
 # Binaries
 datascape

assets/anchors.js

@@ -0,0 +1,11 @@
+(function () {
+    document.querySelectorAll('.content h1, .content h2, .content h3, .content h4, .content h5, .content h6').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);
+    });
+}());

assets/diary/diary-day.html

@@ -1,7 +1,7 @@
 {{if .Photos}}
 <div class="photo-grid">
   {{range .Photos}}
-  <a href="{{.URL}}" target="_blank"><img src="{{.URL}}" alt="{{.Name}}" loading="lazy"></a>
+  <a href="{{.URL}}" target="_blank"><img src="{{.ThumbURL}}" alt="" loading="lazy"></a>
   {{end}}
 </div>
 {{end}}

assets/diary/diary-month.html

@@ -7,7 +7,7 @@
 {{if .Photos}}
 <div class="photo-grid">
   {{range .Photos}}
-  <a href="{{.URL}}" target="_blank"><img src="{{.URL}}" alt="{{.Name}}" loading="lazy"></a>
+  <a href="{{.URL}}" target="_blank"><img src="{{.ThumbURL}}" alt="" loading="lazy"></a>
   {{end}}
 </div>
 {{end}}

assets/diary/diary-year.html

@@ -1,7 +1,13 @@
-<h2 id="months">Months</h2>
+<h2 id="months">Monate</h2>
 {{range .Months}}
 <h3 id="{{.ID}}">
   <a href="{{.URL}}">{{.Name}}</a>
-  {{if .PhotoCount}}<span class="muted">({{.PhotoCount}} photos)</span>{{end}}
 </h3>
+{{if .Photos}}
+<div class="photo-grid">
+  {{range .Photos}}
+  <a href="{{.URL}}" target="_blank"><img src="{{.ThumbURL}}" alt="" loading="lazy"></a>
+  {{end}}
+</div>
+{{end}}
 {{end}}

assets/edit.html

@@ -0,0 +1,39 @@
+{{define "headerActions"}}
+<a class="btn" href="{{.PostURL}}">CANCEL</a>
+<button class="btn" type="submit" form="edit-form" data-action="save" data-key="S" title="Save (S)">SAVE</button>
+{{end}}
+
+{{define "content"}}
+<form id="edit-form" class="edit-form" method="POST" action="{{.PostURL}}">
+    {{if ge .SectionIndex 0}}<input type="hidden" name="section" value="{{.SectionIndex}}">{{end}}
+    <div class="editor-toolbar">
+        <button type="button" class="btn btn-tool" data-action="bold"      data-key="B" title="Bold (B)">**</button>
+        <button type="button" class="btn btn-tool" data-action="italic"    data-key="I" title="Italic (I)">*</button>
+        <span class="toolbar-sep"></span>
+        <button type="button" class="btn btn-tool" data-action="h1"        data-key="1" title="Heading 1 (1)">#</button>
+        <button type="button" class="btn btn-tool" data-action="h2"        data-key="2" title="Heading 2 (2)">##</button>
+        <button type="button" class="btn btn-tool" data-action="h3"        data-key="3" title="Heading 3 (3)">###</button>
+        <span class="toolbar-sep"></span>
+        <button type="button" class="btn btn-tool" data-action="code"      data-key="C" title="Inline code (C)">`</button>
+        <button type="button" class="btn btn-tool" data-action="codeblock" data-key="K" title="Code block (K)">```</button>
+        <span class="toolbar-sep"></span>
+        <button type="button" class="btn btn-tool" data-action="link"      data-key="L" title="Link (L)">[]</button>
+        <button type="button" class="btn btn-tool" data-action="wikilink"  data-key="P" title="Insert wiki link (P)">[[]]</button>
+        <button type="button" class="btn btn-tool" data-action="quote"     data-key="Q" title="Blockquote (Q)">&gt;</button>
+        <button type="button" class="btn btn-tool" data-action="ul"        data-key="U" title="Unordered list (U)">-</button>
+        <button type="button" class="btn btn-tool" data-action="ol"        data-key="O" title="Ordered list (O)">1.</button>
+        <button type="button" class="btn btn-tool" data-action="hr"        data-key="R" title="Horizontal rule (R)">---</button>
+        <span class="toolbar-sep"></span>
+        <button type="button" class="btn btn-tool dropdown" data-action="tbldrop" title="Table (T)">T▾</button>
+        <button type="button" class="btn btn-tool dropdown" data-action="datedrop" title="Insert date (D/W)">D▾</button>
+        <span class="toolbar-sep"></span>
+        <button type="button" class="btn btn-tool" data-action="movie" data-key="V" title="Import movie (V)">MV</button>
+    </div>
+    <textarea name="content" id="editor" autofocus>{{.RawContent}}</textarea>
+</form>
+<script src="/_/editor/lists.js"></script>
+<script src="/_/editor/tables.js"></script>
+<script src="/_/editor/dates.js"></script>
+<script src="/_/editor/movie.js"></script>
+<script src="/_/editor.js"></script>
+{{end}}

assets/editor.js

@@ -58,6 +58,7 @@
     var T = EditorTables;
     var L = EditorLists;
     var D = EditorDates;
+    var M = EditorMovie;
 
     var actions = {
         save:           function () { form.submit(); },
@@ -100,6 +101,7 @@
         tbldeleterow:   function () { applyTableOp(T.deleteRow); },
         dateiso:        function () { insertAtCursor(D.isoDate()); },
         datelong:       function () { insertAtCursor(D.longDate()); },
+        movie:          function () { M.run(textarea); },
     };
 
     // --- Keyboard shortcut registration ---
@@ -121,7 +123,10 @@
 
     document.addEventListener('keydown', function (e) {
         if (!e.altKey || !e.shiftKey) return;
-        var action = keyMap[e.key];
+        // Shift+digit produces a layout-dependent character in e.key (e.g. "!"
+        // on US, "!" on DE), so fall back to e.code for digit rows.
+        var key = /^Digit[0-9]$/.test(e.code) ? e.code.slice(5) : e.key;
+        var action = keyMap[key];
         if (action) {
             e.preventDefault();
             action();

assets/editor/movie.js

@@ -0,0 +1,121 @@
+window.EditorMovie = (function () {
+    'use strict';
+
+    // OMDb API key. Shipped to the browser; acceptable for a single-user LAN tool.
+    var OMDB_API_KEY = 'c906744f';
+
+    var BEGIN = '<!-- BEGIN MOVIE -->';
+    var END = '<!-- END MOVIE -->';
+
+    function firstHeading(text) {
+        var m = text.match(/^#{1,6}\s+(.+?)\s*$/m);
+        return m ? m[1].trim() : '';
+    }
+
+    function parseTitleYear(raw) {
+        var m = raw.match(/^(.+?)\s*\((\d{4})\)\s*$/);
+        return m ? { title: m[1].trim(), year: m[2] } : { title: raw.trim(), year: null };
+    }
+
+    function safe(v) { return (!v || v === 'N/A') ? '' : String(v); }
+
+    function esc(s) {
+        return String(s)
+            .replace(/&/g, '&amp;')
+            .replace(/</g, '&lt;')
+            .replace(/>/g, '&gt;')
+            .replace(/"/g, '&quot;');
+    }
+
+    function buildBlock(m) {
+        var out = [BEGIN, '<aside class="movie-info">'];
+        if (m.Poster && m.Poster !== 'N/A') {
+            out.push('<img class="movie-poster" src="' + esc(m.Poster) +
+                     '" alt="' + esc(safe(m.Title)) + ' poster">');
+        }
+        out.push('<table>');
+        [
+            ['Title',    m.Title],
+            ['Year',     m.Year],
+            ['Runtime',  m.Runtime],
+            ['Genre',    m.Genre],
+            ['Director', m.Director],
+            ['Cast',     m.Actors],
+            ['Plot',     m.Plot],
+        ].forEach(function (r) {
+            out.push('<tr><th>' + r[0] + '</th><td>' + esc(safe(r[1])) + '</td></tr>');
+        });
+        out.push('</table>', '</aside>', END);
+        return out.join('\n');
+    }
+
+    function insertOrReplace(ta, markup) {
+        var t = ta.value || '';
+        var b = t.indexOf(BEGIN);
+        var e = t.indexOf(END);
+        if (b !== -1 && e !== -1 && e > b) {
+            ta.value = t.slice(0, b) + markup + t.slice(e + END.length);
+        } else {
+            var h = t.match(/^#{1,6}\s+.+?\s*$/m);
+            if (h) {
+                var idx = t.indexOf(h[0]) + h[0].length;
+                ta.value = t.slice(0, idx) + '\n\n' + markup + t.slice(idx);
+            } else {
+                ta.value = markup + (t ? '\n\n' + t : '');
+            }
+        }
+        ta.dispatchEvent(new Event('input'));
+    }
+
+    function fetchMovie(title, year) {
+        var url = 'https://www.omdbapi.com/?apikey=' + encodeURIComponent(OMDB_API_KEY) +
+                  '&type=movie&t=' + encodeURIComponent(title);
+        if (year) url += '&y=' + encodeURIComponent(year);
+        return fetch(url).then(function (r) { return r.json(); });
+    }
+
+    function showMessage(title, msg) {
+        openModal({ title: title, body: msg, confirm: { label: 'OK' } });
+    }
+
+    function run(textarea) {
+        if (!OMDB_API_KEY) {
+            showMessage('Movie import', 'OMDb API key is not set. Edit assets/editor/movie.js.');
+            return;
+        }
+
+        var input = document.createElement('input');
+        input.type = 'text';
+        input.className = 'modal-input';
+        input.placeholder = 'Title, optionally with (YYYY)';
+        input.value = firstHeading(textarea.value || '');
+
+        openModal({
+            title: 'Import movie',
+            body: input,
+            confirm: {
+                label: 'IMPORT',
+                onConfirm: function () {
+                    var raw = input.value.trim();
+                    if (!raw) return;
+                    var parsed = parseTitleYear(raw);
+                    closeModal();
+                    fetchMovie(parsed.title, parsed.year)
+                        .then(function (data) {
+                            if (!data || data.Response === 'False') {
+                                showMessage('Not found',
+                                    (data && data.Error) || 'Movie not found.');
+                                return;
+                            }
+                            insertOrReplace(textarea, buildBlock(data));
+                        })
+                        .catch(function () {
+                            showMessage('Import failed', 'OMDb lookup failed.');
+                        });
+                },
+            },
+        });
+    }
+
+    return { run: run };
+})();

assets/global-shortcuts.js

@@ -14,6 +14,13 @@
                 e.preventDefault();
                 if (window.location.pathname !== '/' && typeof movePage === 'function') movePage();
                 break;
+            case 'F':
+                var input = document.querySelector('.search-input');
+                if (!input) return;
+                e.preventDefault();
+                input.focus();
+                input.select();
+                break;
         }
     });
 })();

assets/icons/thumb-placeholder.svg

@@ -0,0 +1,6 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 16 16"
+     fill="none" stroke="#cfcfcf" stroke-width="1.5" stroke-linejoin="miter" shape-rendering="crispEdges">
+  <rect x="1" y="2" width="14" height="12"/>
+  <path d="M1 11l4-4 3 3 2-2 5 5"/>
+  <rect x="10" y="4" width="2" height="2" fill="#cfcfcf" stroke="none"/>
+</svg>

assets/layout.html

@@ -0,0 +1,37 @@
+{{define "layout"}}<!doctype html>
+<html lang="en">
+    <head>
+        <meta charset="UTF-8" />
+        <meta name="viewport" content="width=device-width, initial-scale=1" />
+        <title>{{.Title}}</title>
+        <link rel="icon" href="/_/favicon.ico" />
+        <link rel="preload" href="/_/fonts/IosevkaEtoile.woff2" as="font" type="font/woff2" crossorigin />
+        <link rel="preload" href="/_/fonts/IosevkaSlab.woff2" as="font" type="font/woff2" crossorigin />
+        <link rel="stylesheet" href="/_/style.css" />
+        <script src="/_/modal.js"></script>
+        <script src="/_/global-shortcuts.js"></script>
+        <script src="/_/tree-picker.js"></script>
+        {{block "headScripts" .}}{{end}}
+    </head>
+    <body>
+        <header>
+            <nav class="breadcrumb">
+                <a href="/"><svg class="logo" viewBox="0 0 26.052269 26.052269" xmlns="http://www.w3.org/2000/svg"><g fill="none" stroke="currentColor" stroke-linejoin="miter" transform="matrix(0.05463483,8.1519706e-6,-8.1519706e-6,0.05463483,-64.560546,-24.6949)"><rect x="1188.537" y="457.92056" width="461.87488" height="462.15189" stroke-width="20.2288"/><path d="m1348.9955 456.59572.046 309.36839" stroke-width="19.6849"/><path d="m1200.3996 765.80237 441.8362-.0659" stroke-width="19.6849"/><path d="m1648.2897 620.244-299.2012.0446" stroke-width="20.5676"/><path d="m1491.6148 909.24806-.021-136.93117" stroke-width="19.6849"/><rect x="1191.6504" y="461.66092" width="457.09634" height="457.09634" stroke-width="19.6761"/></g></svg></a>
+                {{range .Crumbs}}
+                <span class="sep">/</span><a href="{{.URL}}">{{.Name}}</a>
+                {{end}}
+            </nav>
+            {{if not .EditMode}}
+            <form class="search-form" action="/" method="get">
+                <input class="search-input" type="search" name="q" value="{{block "searchQuery" .}}{{end}}" placeholder="Search…" title="Search (F)" autocomplete="off" autocorrect="off" autocapitalize="off" spellcheck="false" />
+            </form>
+            {{end}}
+            {{block "headerActions" .}}{{end}}
+        </header>
+        <main>
+            {{block "content" .}}{{end}}
+        </main>
+        {{block "extras" .}}{{end}}
+    </body>
+</html>
+{{end}}

assets/page.html

@@ -1,30 +1,7 @@
-<!doctype html>
+{{define "headScripts"}}<script src="/_/page-actions.js"></script>{{end}}
-<html lang="en">
+
-    <head>
+{{define "headerActions"}}
-        <meta charset="UTF-8" />
+{{if .CanEdit}}
-        <meta name="viewport" content="width=device-width, initial-scale=1" />
-        <title>{{.Title}}</title>
-        <link rel="icon" href="/_/favicon.ico" />
-        <link rel="preload" href="/_/fonts/IosevkaEtoile.woff2" as="font" type="font/woff2" crossorigin />
-        <link rel="preload" href="/_/fonts/IosevkaSlab.woff2" as="font" type="font/woff2" crossorigin />
-        <link rel="stylesheet" href="/_/style.css" />
-        <script src="/_/modal.js"></script>
-        <script src="/_/global-shortcuts.js"></script>
-        <script src="/_/tree-picker.js"></script>
-        <script src="/_/page-actions.js"></script>
-    </head>
-    <body>
-        <header>
-            <nav class="breadcrumb">
-                <a href="/"><svg class="logo" viewBox="0 0 26.052269 26.052269" xmlns="http://www.w3.org/2000/svg"><g fill="none" stroke="currentColor" stroke-linejoin="miter" transform="matrix(0.05463483,8.1519706e-6,-8.1519706e-6,0.05463483,-64.560546,-24.6949)"><rect x="1188.537" y="457.92056" width="461.87488" height="462.15189" stroke-width="20.2288"/><path d="m1348.9955 456.59572.046 309.36839" stroke-width="19.6849"/><path d="m1200.3996 765.80237 441.8362-.0659" stroke-width="19.6849"/><path d="m1648.2897 620.244-299.2012.0446" stroke-width="20.5676"/><path d="m1491.6148 909.24806-.021-136.93117" stroke-width="19.6849"/><rect x="1191.6504" y="461.66092" width="457.09634" height="457.09634" stroke-width="19.6761"/></g></svg></a>
-                {{range .Crumbs}}
-                <span class="sep">/</span><a href="{{.URL}}">{{.Name}}</a>
-                {{end}}
-            </nav>
-            {{if .EditMode}}
-            <a class="btn" href="{{.PostURL}}">CANCEL</a>
-            <button class="btn" type="submit" form="edit-form" data-action="save" data-key="S" title="Save (S)">SAVE</button>
-            {{else if .CanEdit}}
 <div class="dropdown">
     <button class="btn" data-action="actions-drop" title="Actions">ACTIONS ▾</button>
     <div class="dropdown-menu align-right">
@@ -37,39 +14,9 @@
     </div>
 </div>
 {{end}}
-        </header>
+{{end}}
-        <main>
+
-            {{if .EditMode}}
+{{define "content"}}
-            <form id="edit-form" class="edit-form" method="POST" action="{{.PostURL}}">
-                {{if ge .SectionIndex 0}}<input type="hidden" name="section" value="{{.SectionIndex}}">{{end}}
-                <div class="editor-toolbar">
-                    <button type="button" class="btn btn-tool" data-action="bold"      data-key="B" title="Bold (B)">**</button>
-                    <button type="button" class="btn btn-tool" data-action="italic"    data-key="I" title="Italic (I)">*</button>
-                    <span class="toolbar-sep"></span>
-                    <button type="button" class="btn btn-tool" data-action="h1"        data-key="1" title="Heading 1 (1)">#</button>
-                    <button type="button" class="btn btn-tool" data-action="h2"        data-key="2" title="Heading 2 (2)">##</button>
-                    <button type="button" class="btn btn-tool" data-action="h3"        data-key="3" title="Heading 3 (3)">###</button>
-                    <span class="toolbar-sep"></span>
-                    <button type="button" class="btn btn-tool" data-action="code"      data-key="C" title="Inline code (C)">`</button>
-                    <button type="button" class="btn btn-tool" data-action="codeblock" data-key="K" title="Code block (K)">```</button>
-                    <span class="toolbar-sep"></span>
-                    <button type="button" class="btn btn-tool" data-action="link"      data-key="L" title="Link (L)">[]</button>
-                    <button type="button" class="btn btn-tool" data-action="wikilink"  data-key="P" title="Insert wiki link (P)">[[]]</button>
-                    <button type="button" class="btn btn-tool" data-action="quote"     data-key="Q" title="Blockquote (Q)">&gt;</button>
-                    <button type="button" class="btn btn-tool" data-action="ul"        data-key="U" title="Unordered list (U)">-</button>
-                    <button type="button" class="btn btn-tool" data-action="ol"        data-key="O" title="Ordered list (O)">1.</button>
-                    <button type="button" class="btn btn-tool" data-action="hr"        data-key="R" title="Horizontal rule (R)">---</button>
-                    <span class="toolbar-sep"></span>
-                    <button type="button" class="btn btn-tool dropdown" data-action="tbldrop" title="Table (T)">T▾</button>
-                    <button type="button" class="btn btn-tool dropdown" data-action="datedrop" title="Insert date (D/W)">D▾</button>
-                </div>
-                <textarea name="content" id="editor" autofocus>{{.RawContent}}</textarea>
-            </form>
-            <script src="/_/editor/lists.js"></script>
-            <script src="/_/editor/tables.js"></script>
-            <script src="/_/editor/dates.js"></script>
-            <script src="/_/editor.js"></script>
-            {{else}}
 {{if .Content}}
 <div class="content">{{.Content}}</div>
 {{end}}
@@ -78,6 +25,7 @@
 {{end}}
 {{if or .Content .SpecialContent}}
 <script src="/_/content.js"></script>
+<script src="/_/anchors.js"></script>
 <script src="/_/toc.js"></script>
 {{end}}
 {{if .Content}}
@@ -100,7 +48,5 @@
 {{end}}
 {{end}}
 {{end}}
-        </main>
+
-        {{if .SidebarWidget}}{{.SidebarWidget}}{{end}}
+{{define "extras"}}{{if .SidebarWidget}}{{.SidebarWidget}}{{end}}{{end}}
-    </body>
-</html>

assets/search.html

@@ -0,0 +1,22 @@
+{{define "searchQuery"}}{{.Query}}{{end}}
+
+{{define "content"}}
+{{if .Query}}
+    {{if .Results}}
+    <h2 class="muted search-summary">{{len .Results}} match{{if ne (len .Results) 1}}es{{end}} for &ldquo;{{.Query}}&rdquo;</h2>
+    <div class="search-results">
+        {{range .Results}}
+        <article class="search-card">
+            <a class="search-card-name" href="{{.URL}}">{{.Name}}</a>
+            <div class="search-card-path muted">/{{.Path}}</div>
+            {{if .Snippet}}<div class="search-card-snippet">{{.Snippet}}</div>{{end}}
+        </article>
+        {{end}}
+    </div>
+    {{else}}
+    <p class="empty">No matches for &ldquo;{{.Query}}&rdquo;.</p>
+    {{end}}
+{{else}}
+<p class="empty">Enter a query above.</p>
+{{end}}
+{{end}}

assets/style.css

@@ -234,6 +234,15 @@ main {
     max-width: 100%;
 }
 
+.content a.heading-anchor {
+    color: var(--text-muted);
+    margin-right: 0.4em;
+    font-weight: normal;
+}
+.content a.heading-anchor:hover {
+    color: var(--primary-hover);
+}
+
 /* === File listing === */
 .listing {
     border: 1px solid var(--secondary);
@@ -350,6 +359,62 @@ textarea {
     box-sizing: border-box;
 }
 
+/* === Search === */
+.search-form {
+    display: flex;
+    gap: 0.25rem;
+}
+.search-input {
+    background: var(--bg-panel);
+    border: 1px solid var(--secondary);
+    color: var(--text);
+    font: inherit;
+    font-size: 0.9rem;
+    padding: 0.3rem 0.5rem;
+    min-width: 0;
+    width: 12rem;
+    max-width: 100%;
+    outline: none;
+}
+.search-input:focus {
+    border-color: var(--primary-hover);
+}
+.search-summary {
+    margin-bottom: 1rem;
+}
+.search-results {
+    display: flex;
+    flex-direction: column;
+    gap: 1rem;
+}
+.search-card {
+    display: flex;
+    flex-direction: column;
+    gap: 0.25rem;
+    padding-bottom: 1rem;
+    border-bottom: 1px dashed var(--secondary);
+}
+.search-card:last-child {
+    border-bottom: none;
+}
+.search-card-name {
+    color: var(--link);
+    font-size: 1.1rem;
+    word-break: break-word;
+}
+.search-card-name:hover {
+    color: var(--link-hover);
+}
+.search-card-path {
+    word-break: break-all;
+}
+.search-card-snippet {
+    font-size: 0.9rem;
+    line-height: 1.5;
+    color: var(--text-muted);
+    margin-top: 0.25rem;
+}
+
 /* === Muted text === */
 .muted {
     color: var(--text-muted);
@@ -374,6 +439,7 @@ textarea {
     height: 140px;
     object-fit: cover;
     display: block;
+    background: var(--bg-panel) url("/_/icons/thumb-placeholder.svg") center/2rem no-repeat;
 }
 
 /* === Empty state === */
@@ -584,6 +650,31 @@ hr {
     word-break: break-all;
 }
 
+/* === Movie info box === */
+.movie-info {
+    margin: 0.75rem 0;
+}
+.movie-info::after {
+    content: "";
+    display: block;
+    clear: both;
+}
+.movie-info .movie-poster {
+    float: right;
+    max-width: 200px;
+    margin: 0 0 0.75rem 1rem;
+}
+.movie-info table {
+    width: auto;
+}
+@media (max-width: 600px) {
+    .movie-info .movie-poster {
+        float: none;
+        display: block;
+        margin: 0 auto 0.75rem;
+    }
+}
+
 /* === Diary Calendar === */
 .diary-cal {
     position: fixed;

assets/toc.js

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

diary.go

@@ -286,13 +286,14 @@ type diaryPhoto struct {
 	Date     time.Time
 	Name     string
 	URL      string
+	ThumbURL string
 }
 
 type diaryMonthSummary struct {
 	ID     string
 	Name   string
 	URL    string
-	PhotoCount int
+	Photos []diaryPhoto
 }
 
 type diaryDaySection struct {
@@ -376,10 +377,16 @@ func yearPhotos(yearFsPath, yearURLPath string) []diaryPhoto {
 		if err != nil {
 			continue
 		}
+		photoURL := path.Join(yearURLPath, url.PathEscape(name))
+		thumb := photoURL
+		if hasThumbnail(name) {
+			thumb = thumbURL(photoURL, 300)
+		}
 		photos = append(photos, diaryPhoto{
 			Date:     t,
 			Name:     name,
-			URL:  path.Join(yearURLPath, url.PathEscape(name)),
+			URL:      photoURL,
+			ThumbURL: thumb,
 		})
 	}
 	return photos
@@ -394,32 +401,52 @@ func renderDiaryYear(fsPath, urlPath string) template.HTML {
 
 	photos := yearPhotos(fsPath, urlPath)
 
-	entries, err := os.ReadDir(fsPath)
+	// Collect month numbers from both subdirectories and photo filenames so
-	if err != nil {
+	// years that contain only photos (no diary entries) still list months.
-		return ""
+	monthSet := map[int]bool{}
-	}
+	monthDirs := map[int]string{}
-
+	entries, _ := os.ReadDir(fsPath)
-	var months []diaryMonthSummary
 	for _, e := range entries {
 		if !e.IsDir() {
 			continue
 		}
-		monthNum, err := strconv.Atoi(e.Name())
+		n, err := strconv.Atoi(e.Name())
-		if err != nil || monthNum < 1 || monthNum > 12 {
+		if err != nil || n < 1 || n > 12 {
 			continue
 		}
-		count := 0
+		monthSet[n] = true
+		monthDirs[n] = e.Name()
+	}
+	for _, p := range photos {
+		if p.Date.Year() == year {
+			monthSet[int(p.Date.Month())] = true
+		}
+	}
+
+	monthNums := make([]int, 0, len(monthSet))
+	for m := range monthSet {
+		monthNums = append(monthNums, m)
+	}
+	sort.Ints(monthNums)
+
+	var months []diaryMonthSummary
+	for _, monthNum := range monthNums {
+		var monthPhotos []diaryPhoto
 		for _, p := range photos {
 			if p.Date.Year() == year && int(p.Date.Month()) == monthNum {
-				count++
+				monthPhotos = append(monthPhotos, p)
 			}
 		}
 		monthDate := time.Date(year, time.Month(monthNum), 1, 0, 0, 0, 0, time.UTC)
+		dirName, ok := monthDirs[monthNum]
+		if !ok {
+			dirName = fmt.Sprintf("%02d", monthNum)
+		}
 		months = append(months, diaryMonthSummary{
 			ID:     monthDate.Format("2006-01"),
-			Name:       monthDate.Format("January 2006"),
+			Name:   fmt.Sprintf("%s %d", germanMonths[monthDate.Month()], year),
-			URL:        path.Join(urlPath, e.Name()) + "/",
+			URL:    path.Join(urlPath, dirName) + "/",
-			PhotoCount: count,
+			Photos: monthPhotos,
 		})
 	}
 

extlinks.go

@@ -0,0 +1,57 @@
+package main
+
+import (
+	"strings"
+
+	"github.com/yuin/goldmark"
+	"github.com/yuin/goldmark/ast"
+	"github.com/yuin/goldmark/parser"
+	"github.com/yuin/goldmark/text"
+	"github.com/yuin/goldmark/util"
+)
+
+type extLinksTransformer struct{}
+
+func (extLinksTransformer) Transform(doc *ast.Document, reader text.Reader, pc parser.Context) {
+	ast.Walk(doc, func(n ast.Node, entering bool) (ast.WalkStatus, error) {
+		if !entering {
+			return ast.WalkContinue, nil
+		}
+		link, ok := n.(*ast.Link)
+		if !ok {
+			return ast.WalkContinue, nil
+		}
+		if isExternalURL(string(link.Destination)) {
+			link.SetAttribute([]byte("target"), []byte("_blank"))
+			link.SetAttribute([]byte("rel"), []byte("noopener noreferrer"))
+		}
+		return ast.WalkContinue, nil
+	})
+}
+
+func isExternalURL(dest string) bool {
+	if strings.HasPrefix(dest, "//") {
+		return true
+	}
+	i := strings.Index(dest, ":")
+	if i <= 0 {
+		return false
+	}
+	for _, c := range dest[:i] {
+		if !(c >= 'a' && c <= 'z') && !(c >= 'A' && c <= 'Z') &&
+			!(c >= '0' && c <= '9') && c != '+' && c != '-' && c != '.' {
+			return false
+		}
+	}
+	return true
+}
+
+type extLinksExt struct{}
+
+func newExtLinksExt() goldmark.Extender { return &extLinksExt{} }
+
+func (e *extLinksExt) Extend(m goldmark.Markdown) {
+	m.Parser().AddOptions(parser.WithASTTransformers(
+		util.Prioritized(extLinksTransformer{}, 999),
+	))
+}

main.go

@@ -17,7 +17,11 @@ import (
 //go:embed assets
 var assets embed.FS
 
-var tmpl = template.Must(template.New("page.html").ParseFS(assets, "assets/page.html"))
+var (
+	pageTmpl   = template.Must(template.ParseFS(assets, "assets/layout.html", "assets/page.html"))
+	editTmpl   = template.Must(template.ParseFS(assets, "assets/layout.html", "assets/edit.html"))
+	searchTmpl = template.Must(template.ParseFS(assets, "assets/layout.html", "assets/search.html"))
+)
 
 // specialPage is the result returned by a pageTypeHandler.
 // Content is injected into the page after the standard markdown content.
@@ -41,6 +45,7 @@ var pageTypeHandlers []pageTypeHandler
 func main() {
 	addr := flag.String("addr", ":8080", "listen address")
 	wikiDir := flag.String("dir", "./wiki", "wiki root directory")
+	cacheDir := flag.String("cache", "./cache", "thumbnail cache directory")
 	user := flag.String("user", "", "basic auth username (empty = no auth)")
 	pass := flag.String("pass", "", "basic auth password")
 	flag.Parse()
@@ -53,6 +58,14 @@ func main() {
 		log.Fatal(err)
 	}
 
+	thumbCacheDir, err = filepath.Abs(*cacheDir)
+	if err != nil {
+		log.Fatal(err)
+	}
+	if err := os.MkdirAll(thumbCacheDir, 0755); err != nil {
+		log.Fatal(err)
+	}
+
 	initMarkdown(root)
 
 	authKey, err := loadOrCreateAuthKey(root)
@@ -86,6 +99,11 @@ func (h *handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	if strings.HasPrefix(r.URL.Path, thumbURLPrefix+"/") {
+		h.handleThumb(w, r)
+		return
+	}
+
 	urlPath := path.Clean("/" + r.URL.Path)
 	fsPath := filepath.Join(h.root, filepath.FromSlash(urlPath))
 
@@ -101,6 +119,11 @@ func (h *handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	if r.Method == http.MethodGet && urlPath == "/" && r.URL.Query().Has("q") {
+		h.handleSearch(w, r)
+		return
+	}
+
 	info, err := os.Stat(fsPath)
 	if err != nil {
 		if os.IsNotExist(err) {
@@ -187,6 +210,8 @@ func (h *handler) serveDir(w http.ResponseWriter, r *http.Request, urlPath, fsPa
 		if sectionIndex < len(sections) {
 			rawContent = string(sections[sectionIndex])
 		}
+	} else if editMode && rawContent == "" && urlPath != "/" {
+		rawContent = "# " + pageTitle(urlPath) + "\n\n"
 	}
 
 	data := pageData{
@@ -205,7 +230,11 @@ func (h *handler) serveDir(w http.ResponseWriter, r *http.Request, urlPath, fsPa
 	}
 
 	w.Header().Set("Content-Type", "text/html; charset=utf-8")
-	if err := tmpl.Execute(w, data); err != nil {
+	t := pageTmpl
+	if editMode {
+		t = editTmpl
+	}
+	if err := t.ExecuteTemplate(w, "layout", data); err != nil {
 		log.Printf("template error: %v", err)
 	}
 }
@@ -227,6 +256,7 @@ func (h *handler) handlePost(w http.ResponseWriter, r *http.Request, urlPath, fs
 	}
 	content := r.FormValue("content")
 	indexPath := filepath.Join(fsPath, "index.md")
+	redirectTarget := urlPath
 
 	// If a section index was submitted, splice the edited section back into
 	// the full file rather than replacing the whole document.
@@ -242,6 +272,15 @@ func (h *handler) handlePost(w http.ResponseWriter, r *http.Request, urlPath, fs
 			sections[sectionIndex] = []byte(content)
 		}
 		content = string(joinSections(sections))
+		// Section index ≥ 1 is a heading-anchored section. Redirect to its
+		// anchor so the user lands on the section they just saved, even if
+		// the heading text changed.
+		if sectionIndex >= 1 {
+			ids := headingIDs([]byte(content))
+			if sectionIndex-1 < len(ids) {
+				redirectTarget = urlPath + "#" + ids[sectionIndex-1]
+			}
+		}
 	}
 
 	if strings.TrimSpace(content) == "" {
@@ -259,7 +298,7 @@ func (h *handler) handlePost(w http.ResponseWriter, r *http.Request, urlPath, fs
 			return
 		}
 	}
-	http.Redirect(w, r, urlPath, http.StatusSeeOther)
+	http.Redirect(w, r, redirectTarget, http.StatusSeeOther)
 }
 
 // readPageSettings parses a .page-settings file in dir.

render.go

@@ -22,7 +22,7 @@ var md goldmark.Markdown
 // targets against the filesystem.
 func initMarkdown(root string) {
 	md = goldmark.New(
-		goldmark.WithExtensions(extension.GFM, extension.Table, newWikiLinkExt(root)),
+		goldmark.WithExtensions(extension.GFM, extension.Table, newWikiLinkExt(root), newExtLinksExt()),
 		goldmark.WithParserOptions(parser.WithAutoHeadingID()),
 		goldmark.WithRendererOptions(html.WithUnsafe()),
 	)

search.go

@@ -0,0 +1,327 @@
+package main
+
+import (
+	"io/fs"
+	"log"
+	"net/http"
+	"os"
+	"path/filepath"
+	"regexp"
+	"sort"
+	"strings"
+	"unicode"
+)
+
+type searchResult struct {
+	Name    string
+	URL     string
+	Path    string
+	Score   int    // number of query tokens that hit
+	NameHit bool   // at least one hit came from the folder name
+	Snippet string // ~300 chars around first body hit, or page stub for name-only hits
+}
+
+type searchPageData struct {
+	Title    string
+	Crumbs   []crumb
+	EditMode bool
+	Query    string
+	Results  []searchResult
+}
+
+// handleSearch walks the wiki root and renders a search results page for the
+// query in r.URL.Query().Get("q"). Only invoked when path is "/" and "q" is
+// present.
+func (h *handler) handleSearch(w http.ResponseWriter, r *http.Request) {
+	query := strings.TrimSpace(r.URL.Query().Get("q"))
+	results := searchWiki(h.root, query)
+
+	title := "Search"
+	if query != "" {
+		title = "Search: " + query
+	}
+	data := searchPageData{
+		Title:   title,
+		Crumbs:  []crumb{{Name: "search", URL: "/?q=" + query}},
+		Query:   query,
+		Results: results,
+	}
+	w.Header().Set("Content-Type", "text/html; charset=utf-8")
+	if err := searchTmpl.ExecuteTemplate(w, "layout", data); err != nil {
+		log.Printf("search template error: %v", err)
+	}
+}
+
+// searchWiki walks root and scores each directory by how many whitespace-split
+// query tokens hit a word in either the folder name or its index.md body.
+// A word "hits" a token via case-insensitive equality or Levenshtein ≤ 2.
+// Folder-name hits break score ties above content-only hits.
+func searchWiki(root, query string) []searchResult {
+	if query == "" {
+		return nil
+	}
+	qTokens := tokenize(query)
+	if len(qTokens) == 0 {
+		return nil
+	}
+
+	walkRoot := resolveWalkRoot(root)
+	var results []searchResult
+	_ = filepath.WalkDir(walkRoot, func(fsPath string, d fs.DirEntry, err error) error {
+		if err != nil {
+			return nil
+		}
+		if skip, walkErr := hiddenSkip(fsPath, walkRoot, d); skip {
+			return walkErr
+		}
+		if !d.IsDir() || fsPath == walkRoot {
+			return nil
+		}
+		name := d.Name()
+		body, _ := os.ReadFile(filepath.Join(fsPath, "index.md"))
+
+		nameWords := tokenize(name)
+		bodyStr := string(body)
+		bodyLower := strings.ToLower(bodyStr)
+		bodyWords := tokenize(bodyLower)
+
+		score := 0
+		nameHit := false
+		for _, qt := range qTokens {
+			inName := tokenInWords(qt, nameWords)
+			inBody := tokenInWords(qt, bodyWords)
+			if inName || inBody {
+				score++
+			}
+			if inName {
+				nameHit = true
+			}
+		}
+		if score == 0 {
+			return nil
+		}
+
+		rel, relErr := filepath.Rel(walkRoot, fsPath)
+		if relErr != nil {
+			return nil
+		}
+		results = append(results, searchResult{
+			Name:    name,
+			URL:     "/" + filepath.ToSlash(rel) + "/",
+			Path:    filepath.ToSlash(rel),
+			Score:   score,
+			NameHit: nameHit,
+			Snippet: makeSnippet(bodyStr, bodyLower, qTokens),
+		})
+		return nil
+	})
+
+	sort.SliceStable(results, func(i, j int) bool {
+		if results[i].Score != results[j].Score {
+			return results[i].Score > results[j].Score
+		}
+		if results[i].NameHit != results[j].NameHit {
+			return results[i].NameHit
+		}
+		return strings.ToLower(results[i].Name) < strings.ToLower(results[j].Name)
+	})
+	return results
+}
+
+// resolveWalkRoot resolves symlinks so WalkDir descends into the real tree
+// even when the configured wiki root is itself a symlink (as on the NAS).
+func resolveWalkRoot(root string) string {
+	if r, err := filepath.EvalSymlinks(root); err == nil {
+		return r
+	}
+	return root
+}
+
+// hiddenSkip handles dotfile/dot-dir entries during a WalkDir. It returns
+// (skipped, walkErr): skipped=true means the caller should `return walkErr`
+// to either prune the subtree (hidden dir) or move past the entry (hidden
+// file). When skipped=false the entry should be processed normally.
+func hiddenSkip(fsPath, walkRoot string, d fs.DirEntry) (bool, error) {
+	if !strings.HasPrefix(d.Name(), ".") {
+		return false, nil
+	}
+	if d.IsDir() && fsPath != walkRoot {
+		return true, filepath.SkipDir
+	}
+	return true, nil
+}
+
+// tokenize splits s into lowercase word tokens, breaking on any rune that is
+// not a letter or digit. Unicode-aware so umlauts etc. survive intact.
+func tokenize(s string) []string {
+	var tokens []string
+	var b strings.Builder
+	for _, r := range s {
+		if unicode.IsLetter(r) || unicode.IsDigit(r) {
+			b.WriteRune(unicode.ToLower(r))
+			continue
+		}
+		if b.Len() > 0 {
+			tokens = append(tokens, b.String())
+			b.Reset()
+		}
+	}
+	if b.Len() > 0 {
+		tokens = append(tokens, b.String())
+	}
+	return tokens
+}
+
+// tokenInWords reports whether qt matches any word exactly or within
+// Levenshtein distance 2. qt and words must already be lowercase.
+func tokenInWords(qt string, words []string) bool {
+	for _, w := range words {
+		if w == qt {
+			return true
+		}
+		if levenshtein(w, qt) <= 2 {
+			return true
+		}
+	}
+	return false
+}
+
+var snippetWS = regexp.MustCompile(`\s+`)
+
+const snippetWindow = 300
+
+// makeSnippet returns ~300 characters of body around the earliest substring
+// match of any query token. When no token has an exact substring span (e.g.
+// matched only via Levenshtein, or the hit was folder-name-only), it falls
+// back to the first ~300 chars of the body with the leading heading stripped.
+// Returns "" only when the body itself is empty.
+func makeSnippet(body, bodyLower string, tokens []string) string {
+	pos := -1
+	for _, t := range tokens {
+		i := strings.Index(bodyLower, t)
+		if i < 0 {
+			continue
+		}
+		if pos < 0 || i < pos {
+			pos = i
+		}
+	}
+	if pos < 0 {
+		return makeStub(body)
+	}
+
+	half := snippetWindow / 2
+	start := pos - half
+	if start < 0 {
+		start = 0
+	}
+	end := pos + half
+	if end > len(body) {
+		end = len(body)
+	}
+	start, end = expandToWordBoundaries(body, start, end)
+	out := snippetWS.ReplaceAllString(body[start:end], " ")
+	out = strings.TrimSpace(out)
+	if start > 0 {
+		out = "…" + out
+	}
+	if end < len(body) {
+		out = out + "…"
+	}
+	return out
+}
+
+// makeStub returns ~snippetWindow chars from the start of body, with the
+// leading "# Heading" line stripped. Returns "" for an empty body.
+func makeStub(body string) string {
+	stripped := string(stripFirstHeading([]byte(body)))
+	stripped = strings.TrimSpace(stripped)
+	if stripped == "" {
+		return ""
+	}
+	end := snippetWindow
+	if end > len(stripped) {
+		end = len(stripped)
+	}
+	_, end = expandToWordBoundaries(stripped, 0, end)
+	out := snippetWS.ReplaceAllString(stripped[:end], " ")
+	out = strings.TrimSpace(out)
+	if end < len(stripped) {
+		out = out + "…"
+	}
+	return out
+}
+
+// expandToWordBoundaries adjusts start/end so they don't split a word and
+// don't fall in the middle of a UTF-8 sequence. start moves forward past
+// any partial word at the beginning; end moves backward to the previous
+// word boundary.
+func expandToWordBoundaries(s string, start, end int) (int, int) {
+	for start > 0 && start < len(s) && s[start]&0xC0 == 0x80 {
+		start--
+	}
+	for end < len(s) && s[end]&0xC0 == 0x80 {
+		end++
+	}
+	if start > 0 && start < len(s) && isWordByte(s[start-1]) && isWordByte(s[start]) {
+		for start < end && isWordByte(s[start]) {
+			start++
+		}
+	}
+	if end < len(s) && isWordByte(s[end-1]) && isWordByte(s[end]) {
+		for end > start && isWordByte(s[end-1]) {
+			end--
+		}
+	}
+	return start, end
+}
+
+func isWordByte(b byte) bool {
+	if b&0x80 != 0 {
+		return true // assume any multibyte char is part of a word
+	}
+	return (b >= 'a' && b <= 'z') || (b >= 'A' && b <= 'Z') || (b >= '0' && b <= '9')
+}
+
+// levenshtein returns the edit distance between a and b. Operates on runes so
+// multi-byte characters count as one edit.
+func levenshtein(a, b string) int {
+	ar, br := []rune(a), []rune(b)
+	if len(ar) == 0 {
+		return len(br)
+	}
+	if len(br) == 0 {
+		return len(ar)
+	}
+	prev := make([]int, len(br)+1)
+	curr := make([]int, len(br)+1)
+	for j := range prev {
+		prev[j] = j
+	}
+	for i := 1; i <= len(ar); i++ {
+		curr[0] = i
+		for j := 1; j <= len(br); j++ {
+			cost := 1
+			if ar[i-1] == br[j-1] {
+				cost = 0
+			}
+			del := prev[j] + 1
+			ins := curr[j-1] + 1
+			sub := prev[j-1] + cost
+			curr[j] = min3(del, ins, sub)
+		}
+		prev, curr = curr, prev
+	}
+	return prev[len(br)]
+}
+
+func min3(a, b, c int) int {
+	m := a
+	if b < m {
+		m = b
+	}
+	if c < m {
+		m = c
+	}
+	return m
+}

sections.go

@@ -3,6 +3,9 @@ package main
 import (
 	"bytes"
 	"regexp"
+
+	"github.com/yuin/goldmark/ast"
+	"github.com/yuin/goldmark/text"
 )
 
 var sectionHeadingRe = regexp.MustCompile(`(?m)^#{1,6} `)
@@ -25,6 +28,29 @@ func splitSections(raw []byte) [][]byte {
 	return sections
 }
 
+// headingIDs returns the auto-generated id of every heading in raw markdown,
+// in document order. The kth heading (1-indexed) corresponds to section k from
+// splitSections. Uses the package-level goldmark parser so duplicate-id
+// numbering matches what the renderer emits.
+func headingIDs(raw []byte) []string {
+	doc := md.Parser().Parse(text.NewReader(raw))
+	var ids []string
+	ast.Walk(doc, func(n ast.Node, entering bool) (ast.WalkStatus, error) {
+		if !entering {
+			return ast.WalkContinue, nil
+		}
+		if _, ok := n.(*ast.Heading); ok {
+			if v, ok := n.AttributeString("id"); ok {
+				if b, ok := v.([]byte); ok {
+					ids = append(ids, string(b))
+				}
+			}
+		}
+		return ast.WalkContinue, nil
+	})
+	return ids
+}
+
 // joinSections reassembles sections produced by splitSections.
 // Inserts a newline between sections when a non-empty section lacks a
 // trailing newline, so an edited section cannot inline the next heading.

thumb.go

@@ -0,0 +1,224 @@
+package main
+
+import (
+	"bytes"
+	"crypto/sha256"
+	"encoding/hex"
+	"fmt"
+	"io"
+	"log"
+	"net/http"
+	"net/url"
+	"os"
+	"path"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+)
+
+// Thumbnailer produces a thumbnail of a source file. Implementations register
+// themselves in init() by appending to thumbnailers. The first registered
+// handler whose CanHandle returns true is used.
+type Thumbnailer interface {
+	CanHandle(ext string) bool
+	Generate(src io.Reader, dst io.Writer, width int) error
+}
+
+var thumbnailers []Thumbnailer
+
+// thumbCacheDir is set from the -cache flag at startup.
+var thumbCacheDir string
+
+const thumbURLPrefix = "/_thumb"
+
+// Cache is content-addressed: the cache path is derived from the SHA-256 of
+// the source file. Renames and moves reuse the same cache entry; overwriting
+// a file with new content produces a new digest and regenerates.
+var (
+	thumbLocks   = map[string]*sync.Mutex{}
+	thumbLocksMu sync.Mutex
+
+	digestCache  = map[string]digestEntry{}
+	digestCacheMu sync.Mutex
+)
+
+// digestEntry remembers the digest of a source file so repeated requests do
+// not re-hash the whole file. The (mtime, size) pair invalidates the cache
+// when the file is overwritten in place.
+type digestEntry struct {
+	mtime time.Time
+	size  int64
+	hex   string
+}
+
+func findThumbnailer(name string) Thumbnailer {
+	ext := strings.ToLower(filepath.Ext(name))
+	if ext == "" {
+		return nil
+	}
+	for _, t := range thumbnailers {
+		if t.CanHandle(ext) {
+			return t
+		}
+	}
+	return nil
+}
+
+// hasThumbnail reports whether a file name has a registered thumbnailer.
+func hasThumbnail(name string) bool {
+	return findThumbnailer(name) != nil
+}
+
+// thumbURL builds a thumbnail URL for a wiki file. filePath must be URL-style
+// (slash-separated, leading slash), as already used on page links.
+func thumbURL(filePath string, width int) string {
+	return thumbURLPrefix + filePath + "?w=" + strconv.Itoa(width)
+}
+
+func (h *handler) handleThumb(w http.ResponseWriter, r *http.Request) {
+	raw := strings.TrimPrefix(r.URL.Path, thumbURLPrefix)
+	if raw == "" || raw == "/" {
+		http.NotFound(w, r)
+		return
+	}
+	decoded, err := url.PathUnescape(raw)
+	if err != nil {
+		http.Error(w, "bad path", http.StatusBadRequest)
+		return
+	}
+	cleanPath := path.Clean(decoded)
+
+	srcFS := filepath.Join(h.root, filepath.FromSlash(cleanPath))
+	rel, err := filepath.Rel(h.root, srcFS)
+	if err != nil || strings.HasPrefix(rel, "..") {
+		http.Error(w, "Forbidden", http.StatusForbidden)
+		return
+	}
+
+	srcInfo, err := os.Stat(srcFS)
+	if err != nil || srcInfo.IsDir() {
+		http.NotFound(w, r)
+		return
+	}
+
+	t := findThumbnailer(srcFS)
+	if t == nil {
+		http.NotFound(w, r)
+		return
+	}
+
+	width := 300
+	if s := r.URL.Query().Get("w"); s != "" {
+		if n, err := strconv.Atoi(s); err == nil && n > 0 && n <= 2000 {
+			width = n
+		}
+	}
+
+	digest, data, err := sourceDigest(srcFS, srcInfo)
+	if err != nil {
+		log.Printf("thumb digest %s: %v", rel, err)
+		http.Error(w, "thumbnail failed", http.StatusInternalServerError)
+		return
+	}
+
+	cacheFS := filepath.Join(thumbCacheDir, digest[:2], fmt.Sprintf("%s.%d.jpg", digest, width))
+	if _, err := os.Stat(cacheFS); err == nil {
+		serveThumb(w, r, cacheFS)
+		return
+	}
+
+	lock := thumbLock(cacheFS)
+	lock.Lock()
+	defer lock.Unlock()
+
+	if _, err := os.Stat(cacheFS); err == nil {
+		serveThumb(w, r, cacheFS)
+		return
+	}
+
+	var src io.Reader
+	if data != nil {
+		src = bytes.NewReader(data)
+	} else {
+		f, err := os.Open(srcFS)
+		if err != nil {
+			log.Printf("thumb open %s: %v", rel, err)
+			http.Error(w, "thumbnail failed", http.StatusInternalServerError)
+			return
+		}
+		defer f.Close()
+		src = f
+	}
+
+	if err := generateThumb(t, src, cacheFS, width); err != nil {
+		log.Printf("thumb %s: %v", rel, err)
+		http.Error(w, "thumbnail failed", http.StatusInternalServerError)
+		return
+	}
+	serveThumb(w, r, cacheFS)
+}
+
+// sourceDigest returns the SHA-256 hex digest of a source file's content.
+// On a cache hit (path + mtime + size unchanged) the returned data is nil,
+// so the caller knows to open the file itself. On a miss the file is read
+// once and the contents are returned for the caller to reuse.
+func sourceDigest(srcFS string, info os.FileInfo) (string, []byte, error) {
+	digestCacheMu.Lock()
+	d, ok := digestCache[srcFS]
+	digestCacheMu.Unlock()
+	if ok && d.mtime.Equal(info.ModTime()) && d.size == info.Size() {
+		return d.hex, nil, nil
+	}
+
+	data, err := os.ReadFile(srcFS)
+	if err != nil {
+		return "", nil, err
+	}
+	sum := sha256.Sum256(data)
+	h := hex.EncodeToString(sum[:])
+
+	digestCacheMu.Lock()
+	digestCache[srcFS] = digestEntry{mtime: info.ModTime(), size: info.Size(), hex: h}
+	digestCacheMu.Unlock()
+
+	return h, data, nil
+}
+
+func serveThumb(w http.ResponseWriter, r *http.Request, cacheFS string) {
+	w.Header().Set("Cache-Control", "public, max-age=86400")
+	http.ServeFile(w, r, cacheFS)
+}
+
+func generateThumb(t Thumbnailer, src io.Reader, cacheFS string, width int) error {
+	if err := os.MkdirAll(filepath.Dir(cacheFS), 0755); err != nil {
+		return err
+	}
+	tmp, err := os.CreateTemp(filepath.Dir(cacheFS), ".thumb-*")
+	if err != nil {
+		return err
+	}
+	tmpName := tmp.Name()
+	if err := t.Generate(src, tmp, width); err != nil {
+		tmp.Close()
+		os.Remove(tmpName)
+		return err
+	}
+	if err := tmp.Close(); err != nil {
+		os.Remove(tmpName)
+		return err
+	}
+	return os.Rename(tmpName, cacheFS)
+}
+
+func thumbLock(key string) *sync.Mutex {
+	thumbLocksMu.Lock()
+	defer thumbLocksMu.Unlock()
+	m, ok := thumbLocks[key]
+	if !ok {
+		m = &sync.Mutex{}
+		thumbLocks[key] = m
+	}
+	return m
+}

thumb_image.go

@@ -0,0 +1,81 @@
+package main
+
+import (
+	"image"
+	"image/color"
+	_ "image/gif"
+	"image/jpeg"
+	_ "image/png"
+	"io"
+)
+
+func init() {
+	thumbnailers = append(thumbnailers, &imageThumbnailer{})
+}
+
+type imageThumbnailer struct{}
+
+func (it *imageThumbnailer) CanHandle(ext string) bool {
+	switch ext {
+	case ".jpg", ".jpeg", ".png", ".gif":
+		return true
+	}
+	return false
+}
+
+func (it *imageThumbnailer) Generate(src io.Reader, dst io.Writer, width int) error {
+	img, _, err := image.Decode(src)
+	if err != nil {
+		return err
+	}
+	return jpeg.Encode(dst, resizeBox(img, width), &jpeg.Options{Quality: 80})
+}
+
+// resizeBox downsamples src to the requested width using a box filter.
+// Aspect ratio is preserved. Upscaling is a no-op (returns src unchanged).
+// Each source pixel is visited exactly once; alpha is discarded.
+func resizeBox(src image.Image, width int) image.Image {
+	b := src.Bounds()
+	srcW, srcH := b.Dx(), b.Dy()
+	if srcW <= width {
+		return src
+	}
+	dstW := width
+	dstH := srcH * width / srcW
+	if dstH < 1 {
+		dstH = 1
+	}
+	dst := image.NewRGBA(image.Rect(0, 0, dstW, dstH))
+
+	for y := 0; y < dstH; y++ {
+		sy0 := y * srcH / dstH
+		sy1 := (y + 1) * srcH / dstH
+		if sy1 == sy0 {
+			sy1 = sy0 + 1
+		}
+		for x := 0; x < dstW; x++ {
+			sx0 := x * srcW / dstW
+			sx1 := (x + 1) * srcW / dstW
+			if sx1 == sx0 {
+				sx1 = sx0 + 1
+			}
+			var r, g, bl, n uint64
+			for sy := sy0; sy < sy1; sy++ {
+				for sx := sx0; sx < sx1; sx++ {
+					sr, sg, sb, _ := src.At(b.Min.X+sx, b.Min.Y+sy).RGBA()
+					r += uint64(sr >> 8)
+					g += uint64(sg >> 8)
+					bl += uint64(sb >> 8)
+					n++
+				}
+			}
+			dst.SetRGBA(x, y, color.RGBA{
+				R: uint8(r / n),
+				G: uint8(g / n),
+				B: uint8(bl / n),
+				A: 255,
+			})
+		}
+	}
+	return dst
+}