function createMenuItem() {
	browser.contextMenus.create({
		id: "copy-image-as-link",
		title: "Copy Image As Link",
		contexts: ["image"]
	});
}
createMenuItem();
browser.runtime.onMessage.addListener(notify);
let lastMessage = {};
function notify(message) {
	lastMessage = message;
	// TODO - this only works the next time :-(
	//browser.contextMenus.update("copy-image-as-link", {'enabled': message['showImageAsLinkMenuItem']});
	/*browser.contextMenus.remove("copy-image-as-link").then(() => {
		if (message['showImageAsLinkMenuItem']) {
			createMenuItem();
		}
	});*/
}
browser.contextMenus.onClicked.addListener((info, tab) => {
	if (info.menuItemId == "copy-image-as-link" && lastMessage.altText !== undefined && lastMessage.altText != "") {
		let imgSrc = info.srcUrl;
		let linkUrl = info.linkUrl;
		let safeImgSrc = escapeHTML(imgSrc);
		let safeLinkUrl = escapeHTML(linkUrl);
		let altText = escapeHTML(lastMessage.altText);
		let height = lastMessage.height;
		let width = lastMessage.width;
		const html = `<a href="${safeLinkUrl}"><img src="${safeImgSrc}" alt="${altText}" height="${height}" width="${width}"></a>`;
		
		// https://github.com/mdn/webextensions-examples/blob/master/context-menu-copy-link-with-types/background.js
		// The example will show how data can be copied, but since background
		// pages cannot directly write to the clipboard, we will run a content
		// script that copies the actual content.

		// clipboard-helper.js defines function copyToClipboard.
		const code = "copyToClipboard(" +
		    JSON.stringify(html) + ");";

		browser.tabs.executeScript({
		    code: "typeof copyToClipboard === 'function';",
		}).then((results) => {
		    // The content script's last expression will be true if the function
		    // has been defined. If this is not the case, then we need to run
		    // clipboard-helper.js to define function copyToClipboard.
		    if (!results || results[0] !== true) {
			return browser.tabs.executeScript(tab.id, {
			    file: "clipboard-helper.js",
			});
		    }
		}).then(() => {
		    return browser.tabs.executeScript(tab.id, {
			code,
		    });
		}).catch((error) => {
		    // This could happen if the extension is not allowed to run code in
		    // the page, for example if the tab is a privileged page.
		    console.error("Failed to copy text: " + error);
		});
	}
});

// https://gist.github.com/Rob--W/ec23b9d6db9e56b7e4563f1544e0d546
function escapeHTML(str) {
    // Note: string cast using String; may throw if `str` is non-serializable, e.g. a Symbol.
    // Most often this is not the case though.
    return String(str)
        .replace(/&/g, "&amp;")
        .replace(/"/g, "&quot;").replace(/'/g, "&#39;")
        .replace(/</g, "&lt;").replace(/>/g, "&gt;");
}