Add cookie disclaimer

src/main/resources/static/js/cookie-consent.js

@@ -0,0 +1,86 @@
+(() => {
+    const CONSENT_STORAGE_KEY = "imgfloat.cookie-consent.dismissed";
+    const COOKIE_MAX_AGE_SECONDS = 60 * 60 * 24 * 365; // 1 year
+
+    const readConsentCookie = () => {
+        return document.cookie
+            .split("; ")
+            .find((entry) => entry.startsWith(`${CONSENT_STORAGE_KEY}=`))
+            ?.split("=")[1];
+    };
+
+    const persistDismissal = () => {
+        try {
+            window.localStorage.setItem(CONSENT_STORAGE_KEY, "true");
+        } catch { }
+        document.cookie = `${CONSENT_STORAGE_KEY}=true; max-age=${COOKIE_MAX_AGE_SECONDS}; path=/; SameSite=Lax`;
+    };
+
+    const hasDismissed = () => {
+        try {
+            if (window.localStorage.getItem(CONSENT_STORAGE_KEY) === "true") {
+                return true;
+            }
+        } catch { }
+        return readConsentCookie() === "true";
+    };
+
+    const shouldShowBanner = () => {
+        if (!document.body) {
+            return false;
+        }
+        if (document.body.classList.contains("broadcast-body")) {
+            return false;
+        }
+        return !hasDismissed();
+    };
+
+    const dismissBanner = (banner) => {
+        if (!banner) {
+            return;
+        }
+        persistDismissal();
+        banner.classList.add("cookie-consent-exit");
+        window.setTimeout(() => banner.remove(), 180);
+    };
+
+    const renderBanner = () => {
+        if (!shouldShowBanner()) {
+            return;
+        }
+
+        const banner = document.createElement("section");
+        banner.className = "cookie-consent";
+        banner.setAttribute("role", "dialog");
+        banner.setAttribute("aria-live", "polite");
+        banner.setAttribute("aria-label", "Cookie usage notice");
+
+        banner.innerHTML = `
+      <div class="cookie-consent-body">
+        <p class="eyebrow subtle">Cookies & privacy</p>
+        <p class="cookie-consent-copy">
+          Imgfloat uses essential cookies to keep you signed in. By continuing to use the site, you agree to this use.
+        </p>
+      </div>
+      <div class="cookie-consent-actions">
+        <button type="button" class="button" data-consent-action="accept">Accept</button>
+        <button type="button" class="button ghost" data-consent-action="dismiss">Dismiss</button>
+      </div>
+      <button type="button" class="cookie-consent-close" aria-label="Close cookie notice" data-consent-action="dismiss">
+        &times;
+      </button>
+    `;
+
+        banner.querySelectorAll("[data-consent-action]").forEach((element) => {
+            element.addEventListener("click", () => dismissBanner(banner));
+        });
+
+        document.body.appendChild(banner);
+    };
+
+    if (document.readyState === "loading") {
+        document.addEventListener("DOMContentLoaded", renderBanner);
+    } else {
+        renderBanner();
+    }
+})();