From f5d9bef547f94aaf90c757ce2a25cadb1186e7e7 Mon Sep 17 00:00:00 2001
From: dal4segno <dal4segno@gmail.com>
Date: Mon, 31 Aug 2026 14:42:59 +0900
Subject: [PATCH] feat: add consent-based GA4 analytics

---
 .gitea/workflows/deploy-pages.yml          |   2 +
 UPDATES.md                                 |   6 +-
 offline/OfflineApp.svelte                  |   3 +
 offline/analytics.ts                       |   9 ++
 pages/analytics.ts                         |   3 +
 src/lib/analytics.ts                       |   4 +
 src/lib/analytics/google-analytics.ts      | 105 +++++++++++++++++++
 src/lib/analytics/types.ts                 |   9 ++
 src/lib/components/AnalyticsConsent.svelte | 111 +++++++++++++++++++++
 src/routes/+layout.svelte                  |   3 +
 vite.offline.config.ts                     |   1 +
 vite.pages.config.ts                       |   1 +
 12 files changed, 256 insertions(+), 1 deletion(-)
 create mode 100644 offline/analytics.ts
 create mode 100644 pages/analytics.ts
 create mode 100644 src/lib/analytics.ts
 create mode 100644 src/lib/analytics/google-analytics.ts
 create mode 100644 src/lib/analytics/types.ts
 create mode 100644 src/lib/components/AnalyticsConsent.svelte

diff --git a/.gitea/workflows/deploy-pages.yml b/.gitea/workflows/deploy-pages.yml
index 0b2dbb4..163a2e5 100644
--- a/.gitea/workflows/deploy-pages.yml
+++ b/.gitea/workflows/deploy-pages.yml
@@ -46,6 +46,8 @@ jobs:
 
       - name: Build public site
         if: steps.publication.outputs.ready == 'true'
+        env:
+          VITE_GA_MEASUREMENT_ID: ${{ secrets.GA_MEASUREMENT_ID }}
         run: npm run build:pages
 
       - name: Publish generated files
diff --git a/UPDATES.md b/UPDATES.md
index adff287..a4e71f5 100644
--- a/UPDATES.md
+++ b/UPDATES.md
@@ -1,9 +1,13 @@
 ---
-updatedAt: 2026-08-31T14:15:17+09:00
+updatedAt: 2026-08-31T14:45:00+09:00
 ---
 
 ## 2026년 8월 31일
 
+### 선택형 방문 통계 추가
+
+`NEW` Google Analytics 방문 통계는 사용자가 동의한 뒤에만 활성화되며, 분석 설정에서 언제든 거부할 수 있습니다. 보유 카드, 편성, 검색어와 계산값은 전송하지 않습니다.
+
 ### 업데이트 내역 탭 추가
 
 `NEW` 버전 배포를 기다리지 않고, 수시로 반영되는 기능·개선·수정·데이터 변경 내용을 한곳에서 확인할 수 있습니다.
diff --git a/offline/OfflineApp.svelte b/offline/OfflineApp.svelte
index 5801ab8..5c06066 100644
--- a/offline/OfflineApp.svelte
+++ b/offline/OfflineApp.svelte
@@ -1,5 +1,6 @@
 <script lang="ts">
   import { onMount } from 'svelte';
+  import AnalyticsConsent from '../src/lib/components/AnalyticsConsent.svelte';
   import HomePage from '../src/routes/+page.svelte';
   import CardsPage from '../src/routes/cards/+page.svelte';
   import AnalysisPage from '../src/routes/analysis/+page.svelte';
@@ -108,6 +109,8 @@
 
 <svelte:component this={CurrentPage} />
 
+<AnalyticsConsent pagePath={currentPath} />
+
 <style>
   :global(*) { box-sizing: border-box; }
   :global(body) { margin: 0; background: #101319; color: #e8ebf1; font-family: Pretendard, "Noto Sans KR", sans-serif; }
diff --git a/offline/analytics.ts b/offline/analytics.ts
new file mode 100644
index 0000000..4d142cf
--- /dev/null
+++ b/offline/analytics.ts
@@ -0,0 +1,9 @@
+import type { AnalyticsClient } from '../src/lib/analytics/types.ts';
+
+export const analytics: AnalyticsClient = {
+  available: false,
+  readConsent: () => null,
+  grantConsent: () => {},
+  denyConsent: () => {},
+  trackPageView: () => {}
+};
diff --git a/pages/analytics.ts b/pages/analytics.ts
new file mode 100644
index 0000000..904352a
--- /dev/null
+++ b/pages/analytics.ts
@@ -0,0 +1,3 @@
+import { createGoogleAnalytics } from '../src/lib/analytics/google-analytics.ts';
+
+export const analytics = createGoogleAnalytics(import.meta.env.VITE_GA_MEASUREMENT_ID);
diff --git a/src/lib/analytics.ts b/src/lib/analytics.ts
new file mode 100644
index 0000000..b46c133
--- /dev/null
+++ b/src/lib/analytics.ts
@@ -0,0 +1,4 @@
+import { env } from '$env/dynamic/public';
+import { createGoogleAnalytics } from '$lib/analytics/google-analytics.ts';
+
+export const analytics = createGoogleAnalytics(env.PUBLIC_GA_MEASUREMENT_ID);
diff --git a/src/lib/analytics/google-analytics.ts b/src/lib/analytics/google-analytics.ts
new file mode 100644
index 0000000..3d25633
--- /dev/null
+++ b/src/lib/analytics/google-analytics.ts
@@ -0,0 +1,105 @@
+import type { AnalyticsClient, AnalyticsConsent } from './types.ts';
+
+const CONSENT_STORAGE_KEY = 'holodori:analytics-consent';
+const MEASUREMENT_ID_PATTERN = /^G-[A-Z0-9]+$/i;
+
+type GoogleTagWindow = Window & {
+  dataLayer?: unknown[][];
+  gtag?: (...args: unknown[]) => void;
+};
+
+function browserWindow(): GoogleTagWindow | null {
+  return typeof window === 'undefined' ? null : window as GoogleTagWindow;
+}
+
+function readStoredConsent(): AnalyticsConsent {
+  const currentWindow = browserWindow();
+  if (!currentWindow) return null;
+  try {
+    const stored = currentWindow.localStorage.getItem(CONSENT_STORAGE_KEY);
+    return stored === 'granted' || stored === 'denied' ? stored : null;
+  } catch {
+    return null;
+  }
+}
+
+function writeStoredConsent(consent: Exclude<AnalyticsConsent, null>) {
+  const currentWindow = browserWindow();
+  if (!currentWindow) return;
+  try {
+    currentWindow.localStorage.setItem(CONSENT_STORAGE_KEY, consent);
+  } catch {
+    // 저장소를 사용할 수 없어도 현재 페이지의 분석 설정은 계속 적용한다.
+  }
+}
+
+function removeGoogleAnalyticsCookies() {
+  if (typeof document === 'undefined') return;
+  for (const cookie of document.cookie.split(';')) {
+    const name = cookie.split('=', 1)[0]?.trim();
+    if (name === '_ga' || name?.startsWith('_ga_')) {
+      document.cookie = `${name}=; Max-Age=0; Path=/; SameSite=Lax`;
+    }
+  }
+}
+
+export function createGoogleAnalytics(rawMeasurementId: string | undefined): AnalyticsClient {
+  const measurementId = rawMeasurementId?.trim() ?? '';
+  const available = MEASUREMENT_ID_PATTERN.test(measurementId);
+  let loaded = false;
+  let sessionConsent: AnalyticsConsent = null;
+
+  const readConsent = () => sessionConsent ?? readStoredConsent();
+
+  const load = () => {
+    const currentWindow = browserWindow();
+    if (!available || !currentWindow || loaded) return;
+
+    currentWindow.dataLayer ??= [];
+    currentWindow.gtag ??= (...args: unknown[]) => currentWindow.dataLayer?.push(args);
+    currentWindow.gtag('consent', 'default', {
+      analytics_storage: 'granted',
+      ad_storage: 'denied',
+      ad_user_data: 'denied',
+      ad_personalization: 'denied'
+    });
+    currentWindow.gtag('js', new Date());
+    currentWindow.gtag('config', measurementId, {
+      send_page_view: false,
+      allow_google_signals: false,
+      allow_ad_personalization_signals: false
+    });
+
+    const script = document.createElement('script');
+    script.async = true;
+    script.src = `https://www.googletagmanager.com/gtag/js?id=${encodeURIComponent(measurementId)}`;
+    script.dataset.holodoriAnalytics = 'true';
+    document.head.append(script);
+    loaded = true;
+  };
+
+  return {
+    available,
+    readConsent,
+    grantConsent() {
+      sessionConsent = 'granted';
+      writeStoredConsent('granted');
+      load();
+    },
+    denyConsent() {
+      sessionConsent = 'denied';
+      writeStoredConsent('denied');
+      removeGoogleAnalyticsCookies();
+    },
+    trackPageView(path: string) {
+      const currentWindow = browserWindow();
+      if (!available || !currentWindow || readConsent() !== 'granted') return;
+      load();
+      currentWindow.gtag?.('event', 'page_view', {
+        page_path: path,
+        page_location: new URL(path, currentWindow.location.origin).href,
+        page_title: document.title
+      });
+    }
+  };
+}
diff --git a/src/lib/analytics/types.ts b/src/lib/analytics/types.ts
new file mode 100644
index 0000000..333a325
--- /dev/null
+++ b/src/lib/analytics/types.ts
@@ -0,0 +1,9 @@
+export type AnalyticsConsent = 'granted' | 'denied' | null;
+
+export interface AnalyticsClient {
+  readonly available: boolean;
+  readConsent(): AnalyticsConsent;
+  grantConsent(): void;
+  denyConsent(): void;
+  trackPageView(path: string): void;
+}
diff --git a/src/lib/components/AnalyticsConsent.svelte b/src/lib/components/AnalyticsConsent.svelte
new file mode 100644
index 0000000..3957e90
--- /dev/null
+++ b/src/lib/components/AnalyticsConsent.svelte
@@ -0,0 +1,111 @@
+<script lang="ts">
+  import { onMount } from 'svelte';
+  import { analytics } from '$lib/analytics.ts';
+
+  export let pagePath: string;
+
+  let mounted = false;
+  let dialogOpen = false;
+  let lastTrackedPath = '';
+
+  onMount(() => {
+    mounted = true;
+    dialogOpen = analytics.available && analytics.readConsent() === null;
+  });
+
+  $: if (mounted && analytics.readConsent() === 'granted' && pagePath !== lastTrackedPath) {
+    analytics.trackPageView(pagePath);
+    lastTrackedPath = pagePath;
+  }
+
+  function grantConsent() {
+    analytics.grantConsent();
+    dialogOpen = false;
+    analytics.trackPageView(pagePath);
+    lastTrackedPath = pagePath;
+  }
+
+  function denyConsent() {
+    analytics.denyConsent();
+    dialogOpen = false;
+    lastTrackedPath = '';
+  }
+</script>
+
+{#if analytics.available}
+  {#if dialogOpen}
+    <div class="analytics-consent" role="dialog" aria-labelledby="analytics-consent-title" aria-describedby="analytics-consent-description">
+      <div class="consent-copy">
+        <strong id="analytics-consent-title">방문 통계 수집</strong>
+        <p id="analytics-consent-description">
+          서비스 개선을 위해 페이지 방문 경로와 기기·지역의 대략적인 통계를 Google Analytics로 수집합니다.
+          보유 카드, 편성, 검색어와 계산값은 전송하지 않습니다.
+        </p>
+        <a href="https://policies.google.com/privacy" target="_blank" rel="noreferrer">Google 개인정보처리방침 ↗</a>
+      </div>
+      <div class="consent-actions">
+        <button type="button" class="secondary" on:click={denyConsent}>거부</button>
+        <button type="button" class="primary" on:click={grantConsent}>동의</button>
+      </div>
+    </div>
+  {:else}
+    <button type="button" class="analytics-settings" on:click={() => dialogOpen = true}>분석 설정</button>
+  {/if}
+{/if}
+
+<style>
+  .analytics-consent {
+    position: fixed;
+    z-index: 100;
+    right: 18px;
+    bottom: 18px;
+    display: flex;
+    width: min(620px, calc(100% - 36px));
+    align-items: flex-end;
+    gap: 20px;
+    padding: 18px;
+    border: 1px solid rgb(239 139 182 / 45%);
+    border-radius: 14px;
+    background: rgb(24 28 36 / 97%);
+    box-shadow: 0 18px 50px rgb(0 0 0 / 42%);
+    color: #e8ebf1;
+  }
+
+  .consent-copy { min-width: 0; flex: 1; }
+  strong { display: block; margin-bottom: 6px; color: #f4c0d6; font-size: 15px; }
+  p { margin: 0 0 7px; color: #c3cad5; font-size: 13px; line-height: 1.55; }
+  a { color: #aeb9ca; font-size: 12px; }
+  .consent-actions { display: flex; flex: 0 0 auto; gap: 8px; }
+
+  button {
+    min-height: 38px;
+    padding: 8px 14px;
+    border: 1px solid transparent;
+    border-radius: 9px;
+    font: inherit;
+    font-size: 13px;
+    font-weight: 800;
+    cursor: pointer;
+  }
+
+  button:focus-visible { outline: 3px solid rgb(239 139 182 / 28%); outline-offset: 2px; }
+  .primary { color: #21121a; background: #ef8bb6; }
+  .secondary { border-color: #596273; color: #d4dae4; background: #303641; }
+  .analytics-settings {
+    position: fixed;
+    z-index: 90;
+    right: 12px;
+    bottom: 12px;
+    min-height: 30px;
+    padding: 5px 9px;
+    border-color: rgb(255 255 255 / 12%);
+    color: #8e98a8;
+    background: rgb(25 29 37 / 88%);
+    font-size: 11px;
+  }
+
+  @media (max-width: 560px) {
+    .analytics-consent { right: 12px; bottom: 12px; width: calc(100% - 24px); align-items: stretch; flex-direction: column; gap: 14px; }
+    .consent-actions { justify-content: flex-end; }
+  }
+</style>
diff --git a/src/routes/+layout.svelte b/src/routes/+layout.svelte
index 0fc7aa9..c04d4fc 100644
--- a/src/routes/+layout.svelte
+++ b/src/routes/+layout.svelte
@@ -1,6 +1,7 @@
 <script lang="ts">
   import { onMount } from 'svelte';
   import { page } from '$app/stores';
+  import AnalyticsConsent from '$lib/components/AnalyticsConsent.svelte';
   import { events } from '$lib/data/events.ts';
   import { createInitialReleaseClock, synchronizeReleaseClock } from '$lib/data/release-clock.ts';
   import { activeEventAt } from '$lib/engine/event-optimization.ts';
@@ -62,6 +63,8 @@
 
 <slot />
 
+<AnalyticsConsent pagePath={`${$page.url.pathname}${$page.url.search}`} />
+
 <style>
   :global(*) { box-sizing: border-box; }
   :global(body) { margin: 0; background: #101319; color: #e8ebf1; font-family: Pretendard, "Noto Sans KR", sans-serif; }
diff --git a/vite.offline.config.ts b/vite.offline.config.ts
index aaf31a8..482972a 100644
--- a/vite.offline.config.ts
+++ b/vite.offline.config.ts
@@ -12,6 +12,7 @@ export default defineConfig({
   plugins: [svelte()],
   resolve: {
     alias: [
+      { find: '$lib/analytics.ts', replacement: path.join(root, 'offline/analytics.ts') },
       { find: '$app/stores', replacement: path.join(root, 'offline/page-store.ts') },
       { find: '$app/environment', replacement: path.join(root, 'offline/app-environment.ts') },
       { find: '$lib/data/chart-loader.ts', replacement: path.join(root, 'offline/chart-loader.ts') },
diff --git a/vite.pages.config.ts b/vite.pages.config.ts
index ff43917..6a9d0ed 100644
--- a/vite.pages.config.ts
+++ b/vite.pages.config.ts
@@ -12,6 +12,7 @@ export default defineConfig({
   plugins: [svelte()],
   resolve: {
     alias: [
+      { find: '$lib/analytics.ts', replacement: path.join(root, 'pages/analytics.ts') },
       { find: '$app/stores', replacement: path.join(root, 'offline/page-store.ts') },
       { find: '$app/environment', replacement: path.join(root, 'offline/app-environment.ts') },
       { find: '$lib/data/chart-loader.ts', replacement: path.join(root, 'offline/chart-loader.ts') },