(function () {
	const makeStub = () => {
		const TCF_LOCATOR_NAME = "__tcfapiLocator";
		const queue = [];
		const currentWindow = window;
		let frameLocator = currentWindow;
		let cmpFrame;
		let gdprApplies;

		function addFrame() {
			const doc = currentWindow.document;
			const otherCMP = !!currentWindow.frames[TCF_LOCATOR_NAME];

			if (!otherCMP) {
				if (doc.body) {
					const iframe = doc.createElement("iframe");

					iframe.style.cssText = "display:none";
					iframe.name = TCF_LOCATOR_NAME;
					doc.body.appendChild(iframe);
				} else {
					setTimeout(addFrame, 5);
				}
			}

			return !otherCMP;
		}

		function tcfAPIHandler(...args) {
			if (!args.length) {
				/**
				 * shortcut to get the queue when the full CMP
				 * implementation loads; it can call tcfapiHandler()
				 * with no arguments to get the queued arguments
				 */

				return queue;
			} else if (args[0] === "setGdprApplies") {
				/**
				 * shortcut to set gdprApplies if the publisher
				 * knows that they apply GDPR rules to all
				 * traffic (see the section on "What does the
				 * gdprApplies value mean" for more
				 */
				if (
					args.length > 3 &&
					parseInt(args[1], 10) === 2 &&
					typeof args[3] === "boolean"
				) {
					gdprApplies = args[3];

					if (typeof args[2] === "function") {
						args[2]("set", true);
					}
				}
			} else if (args[0] === "ping") {
				/**
				 * Only supported method; give PingReturn
				 * object as response
				 */
				if (typeof args[2] === "function") {
					args[2]({
						gdprApplies: gdprApplies,
						cmpLoaded: false,
						cmpStatus: "stub",
					});
				}
			} else {
				/**
				 * some other method, just queue it for the
				 * full CMP implementation to deal with
				 */

				queue.push(args);
			}
		}

		function postMessageEventHandler(event) {
			const msgIsString = typeof event.data === "string";
			let json = {};

			if (msgIsString) {
				try {
					/**
					 * Try to parse the data from the event.  This is important
					 * to have in a try/catch because often messages may come
					 * through that are not JSON
					 */
					json = JSON.parse(event.data);
				} catch (ignore) {}
			} else {
				json = event.data;
			}

			const payload =
				typeof json === "object" && json !== null ? json.__tcfapiCall : null;

			if (payload) {
				window.__tcfapi(
					payload.command,
					payload.version,
					function (retValue, success) {
						let returnMsg = {
							__tcfapiReturn: {
								returnValue: retValue,
								success: success,
								callId: payload.callId,
							},
						};

						if (event && event.source && event.source.postMessage) {
							event.source.postMessage(
								msgIsString ? JSON.stringify(returnMsg) : returnMsg,
								"*"
							);
						}
					},
					payload.parameter
				);
			}
		}

		/**
		 * Iterate up to the top window checking for an already-created
		 * "__tcfapilLocator" frame on every level. If one exists already then we are
		 * not the master CMP and will not queue commands.
		 */
		while (frameLocator) {
			try {
				if (frameLocator.frames[TCF_LOCATOR_NAME]) {
					cmpFrame = frameLocator;
					break;
				}
			} catch (ignore) {}

			// if we're at the top and no cmpFrame
			if (frameLocator === currentWindow.top) {
				break;
			}

			// Move up
			frameLocator = frameLocator.parent;
		}

		if (!cmpFrame) {
			// we have recur'd up the windows and have found no __tcfapiLocator frame
			addFrame();
			currentWindow.__tcfapi = tcfAPIHandler;
			currentWindow.addEventListener("message", postMessageEventHandler, false);
		}
	};

	if (typeof module !== "undefined") {
		module.exports = makeStub;
	} else {
		makeStub();
	}
})();