feat: first take at calendar

tests/engine/BlogGenerationEngine.test.ts

@@ -336,6 +336,9 @@ describe('BlogGenerationEngine', () => {
     expect(await fileExists(path.join(tempDir, 'html', 'assets', 'lightbox.min.css'))).toBe(true);
     expect(await fileExists(path.join(tempDir, 'html', 'assets', 'lightbox.min.js'))).toBe(true);
     expect(await fileExists(path.join(tempDir, 'html', 'assets', 'tag-cloud.js'))).toBe(true);
+    expect(await fileExists(path.join(tempDir, 'html', 'assets', 'vanilla-calendar.min.css'))).toBe(true);
+    expect(await fileExists(path.join(tempDir, 'html', 'assets', 'vanilla-calendar.min.js'))).toBe(true);
+    expect(await fileExists(path.join(tempDir, 'html', 'assets', 'calendar-runtime.js'))).toBe(true);
     expect(await fileExists(path.join(tempDir, 'html', 'images', 'prev.png'))).toBe(true);
     expect(await fileExists(path.join(tempDir, 'html', 'images', 'next.png'))).toBe(true);
     expect(await fileExists(path.join(tempDir, 'html', 'images', 'close.png'))).toBe(true);
@@ -345,6 +348,60 @@ describe('BlogGenerationEngine', () => {
     expect(picoContent.length).toBeGreaterThan(0);
   });
 
+  it('writes calendar.json and wires calendar UI in generated html', async () => {
+    const posts = [
+      makePost({
+        id: '1',
+        slug: 'one',
+        title: 'One',
+        categories: ['news'],
+        createdAt: new Date('2025-03-15T10:00:00Z'),
+      }),
+      makePost({
+        id: '2',
+        slug: 'two',
+        title: 'Two',
+        categories: ['news'],
+        createdAt: new Date('2025-03-15T12:00:00Z'),
+      }),
+      makePost({
+        id: '3',
+        slug: 'three',
+        title: 'Three',
+        categories: ['news'],
+        createdAt: new Date('2025-04-01T10:00:00Z'),
+      }),
+    ];
+
+    await generate(posts, {
+      menu: {
+        items: [
+          { id: 'home', title: 'Home', kind: 'home', pageSlug: 'home', children: [] },
+        ],
+      },
+    });
+
+    const calendarJsonRaw = await readFile(path.join(tempDir, 'html', 'calendar.json'), 'utf-8');
+    const calendarJson = JSON.parse(calendarJsonRaw) as {
+      years: Record<string, number>;
+      months: Record<string, number>;
+      days: Record<string, number>;
+    };
+
+    expect(calendarJson.years['2025']).toBe(3);
+    expect(calendarJson.months['2025-03']).toBe(2);
+    expect(calendarJson.months['2025-04']).toBe(1);
+    expect(calendarJson.days['2025-03-15']).toBe(2);
+    expect(calendarJson.days['2025-04-01']).toBe(1);
+
+    const indexHtml = await readFile(path.join(tempDir, 'html', 'index.html'), 'utf-8');
+    expect(indexHtml).toContain('class="blog-menu-calendar-button"');
+    expect(indexHtml).toContain('id="blog-calendar"');
+    expect(indexHtml).toContain('href="/assets/vanilla-calendar.min.css"');
+    expect(indexHtml).toContain('src="/assets/vanilla-calendar.min.js"');
+    expect(indexHtml).toContain('src="/assets/calendar-runtime.js"');
+  });
+
   it('generates root index.html for published posts', async () => {
     const posts = [
       makePost({ id: '1', slug: 'first', title: 'First Post', createdAt: new Date('2025-01-15T10:00:00Z') }),

tests/engine/GenerationSitemapFeedService.test.ts

@@ -1,6 +1,7 @@
 import { describe, expect, it } from 'vitest';
 import type { PostData } from '../../src/main/engine/PostEngine';
 import {
+  buildCalendarArchiveData,
   buildSitemapAndFeeds,
   type GenerationPostIndexLike,
 } from '../../src/main/engine/GenerationSitemapFeedService';
@@ -71,6 +72,25 @@ function buildIndex(posts: PostData[]): GenerationPostIndexLike {
 }
 
 describe('GenerationSitemapFeedService', () => {
+  it('builds calendar archive data with year/month/day post counts', () => {
+    const publishedPosts = [
+      makePost({ id: '1', slug: 'a', createdAt: new Date('2025-01-15T10:00:00.000Z') }),
+      makePost({ id: '2', slug: 'b', createdAt: new Date('2025-01-15T12:00:00.000Z') }),
+      makePost({ id: '3', slug: 'c', createdAt: new Date('2025-02-01T08:00:00.000Z') }),
+      makePost({ id: '4', slug: 'd', createdAt: new Date('2026-01-01T08:00:00.000Z') }),
+    ];
+
+    const result = buildCalendarArchiveData(publishedPosts);
+
+    expect(result.years['2025']).toBe(3);
+    expect(result.years['2026']).toBe(1);
+    expect(result.months['2025-01']).toBe(2);
+    expect(result.months['2025-02']).toBe(1);
+    expect(result.days['2025-01-15']).toBe(2);
+    expect(result.days['2025-02-01']).toBe(1);
+    expect(result.days['2026-01-01']).toBe(1);
+  });
+
   it('builds canonical sitemap urls and paginated archive routes', () => {
     const publishedPosts = [
       makePost({

tests/engine/PreviewServer.test.ts

@@ -305,11 +305,14 @@ describe('PreviewServer', () => {
     expect(rootHtml).toContain('href="/assets/pico.min.css"');
     expect(rootHtml).toContain('href="/assets/lightbox.min.css"');
     expect(rootHtml).toContain('href="/assets/highlight.min.css"');
+    expect(rootHtml).toContain('href="/assets/vanilla-calendar.min.css"');
     expect(rootHtml).toContain('src="/assets/lightbox.min.js"');
     expect(rootHtml).toContain('src="/assets/highlight.min.js"');
     expect(rootHtml).toContain('src="/assets/code-enhancements.js"');
     expect(rootHtml).toContain('src="/assets/d3.layout.cloud.js"');
     expect(rootHtml).toContain('src="/assets/tag-cloud.js"');
+    expect(rootHtml).toContain('src="/assets/vanilla-calendar.min.js"');
+    expect(rootHtml).toContain('src="/assets/calendar-runtime.js"');
     expect(rootHtml).not.toContain('function parseWords(');
     expect(rootHtml).not.toContain('cdn.jsdelivr.net');