/**
* ads.js — Ghost Blog Ad Injector
* Supports conditional loading, responsive ad selection, slot-based placement,
* Google Analytics 4 impression tracking, and cookie-persisted test mode.
*/
(function () {
"use strict";
// ─── Cookie Helpers ─────────────────────────────────────────────────────────
function setCookie(name, value) {
// Session-scoped (no expires), path=/ so it works across all pages
document.cookie = name + "=" + value + ";path=/;SameSite=Lax";
}
function getCookie(name) {
const match = document.cookie.match(
new RegExp("(?:^|;\\s*)" + name + "=([^;]*)"),
);
return match ? match[1] : null;
}
function deleteCookie(name) {
document.cookie =
name + "=;path=/;SameSite=Lax;expires=Thu, 01 Jan 1970 00:00:00 GMT";
}
// ─── Ad Gate ────────────────────────────────────────────────────────────────
/**
* Determine whether ads should load, and manage the show_ads cookie:
* ?show_ads=true → set cookie, load ads
* ?show_ads=false → delete cookie, skip ads
* cookie present → load ads (persisted from a previous ?show_ads=true)
* March 2026 → load ads (date-based rule, no cookie interaction)
*/
function shouldLoadAds() {
const params = new URLSearchParams(window.location.search);
const paramValue = params.get("show_ads");
if (paramValue === "true") {
setCookie("show_ads", "true");
return true;
}
if (paramValue === "false") {
deleteCookie("show_ads");
return false;
}
if (getCookie("show_ads") === "true") {
return true;
}
const now = new Date();
if (now.getFullYear() === 2026 && now.getMonth() === 2) return true; // 0-indexed; 2 = March
return false;
}
/**
* Returns true if ads are being forced via the show_ads cookie/param
* (as opposed to the date-based rule), so we know when to show the indicator.
*/
function isForced() {
const params = new URLSearchParams(window.location.search);
return (
params.get("show_ads") === "true" || getCookie("show_ads") === "true"
);
}
// ─── Force Indicator ────────────────────────────────────────────────────────
/**
* Display a small badge in the top-left corner of the page so testers
* know ads are being force-shown via the cookie.
*/
function showForceIndicator() {
const badge = document.createElement("div");
badge.textContent = "📢 Ads: forced";
badge.style.cssText = [
"position:fixed",
"top:8px",
"left:8px",
"z-index:99999",
"background:rgba(220,38,38,0.9)",
"color:#fff",
"font:bold 12px/1 system-ui,sans-serif",
"padding:5px 9px",
"border-radius:4px",
"box-shadow:0 2px 6px rgba(0,0,0,0.35)",
"pointer-events:none",
"letter-spacing:0.03em",
].join(";");
document.body.appendChild(badge);
}
// ─── Helpers ─────────────────────────────────────────────────────────────────
function isHomePage() {
return window.location.pathname === "/";
}
function getTimestamp() {
return Date.now();
}
/** Replace [timestamp] placeholder in ad src URLs */
function resolveUrl(url) {
return url.replace(/\[timestamp\]/g, getTimestamp());
}
/** Parse "WIDTHxHEIGHT" into { w, h } */
function parseSize(sizeStr) {
const [w, h] = sizeStr.split("x").map(Number);
return { w, h };
}
/**
* Fire a GA4 event for an ad impression.
* Requires gtag() to be available on the page (standard GA4 snippet).
*/
function trackImpression(adDef) {
if (typeof window.gtag !== "function") {
console.warn(
"[GhostAds] gtag() not found — skipping impression tracking for:",
adDef.slot,
);
return;
}
window.gtag("event", "ad_impression", {
advertiser: adDef.advertiser,
ad_size: adDef.size,
ad_slot: adDef.slot,
});
}
/**
* Given a list of ad definitions assigned to a slot and the current viewport width,
* pick the best fitting ad whose width <= viewport width.
* Prefers the largest ad that fits.
*/
function pickBestAd(ads, viewportWidth) {
const fitting = ads
.map((ad) => ({ ad, size: parseSize(ad.size) }))
.filter(({ size }) => size.w <= viewportWidth)
.sort((a, b) => b.size.w - a.size.w); // largest first
return fitting.length ? fitting[0].ad : null;
}
/**
* Build the wrapper div + iframe for an ad definition.
* Ad def shape: { advertiser, size, slot, iframeSrc, scriptSrc }
*/
function buildAdElement(adDef) {
const { w, h } = parseSize(adDef.size);
const iframeSrc = resolveUrl(adDef.iframeSrc);
const scriptSrc = resolveUrl(adDef.scriptSrc);
const wrapper = document.createElement("div");
wrapper.setAttribute("data-advertiser", adDef.advertiser);
wrapper.setAttribute("data-ad-size", adDef.size);
wrapper.setAttribute("data-ad-slot", adDef.slot);
wrapper.style.cssText =
"width:100%;text-align:center;overflow:hidden;margin:16px 0;";
const iframe = document.createElement("iframe");
iframe.src = iframeSrc;
iframe.width = w;
iframe.height = h;
iframe.marginWidth = 0;
iframe.marginHeight = 0;
iframe.hspace = 0;
iframe.vspace = 0;
iframe.frameBorder = 0;
iframe.scrolling = "no";
iframe.style.cssText = "display:block;margin:0 auto;border:none;";
iframe.setAttribute("bordercolor", "#000000");
const scriptTag = `