var browser = browser || chrome;

chrome.runtime.onMessage.addListener(function(message, sender, sendResponse) {

    let value = message.value;

    switch (message.subject) {
        case "tabsUpdated":
            setTimeout(function(blacklist) {
                hideVideo(blacklist);
            }, 2000, value);
            break;
        case "updateBlacklist":
            hideVideo(value);
        default:

    }
});

/**
* Hide video in feed matching keywords
* @param array blacklist
*/
function hideVideo(blacklist) {
    console.debug("Hidding video");
	blacklist = blacklist || [];

	let regex = new RegExp(blacklist.join('|'), "i");
	let shelves = document.getElementsByClassName("item-section");

    // Don't match anything
    if (blacklist.length < 1) {
        regex = new RegExp('$^', 'i');
    }

	Array.from(shelves).forEach(function(shelf) {

		let xpathReturn = document.evaluate('.//div[1]/div[2]/ul/li/div/div/div[1]/div[2]/h3/a/text()', shelf, null, XPathResult.FIRST_ORDERED_NODE_TYPE, null);

		if (xpathReturn.singleNodeValue !== undefined) {

			let title = xpathReturn.singleNodeValue.nodeValue;
			if (regex.exec(title) !== null) {
			    // Thhis is necessary to avoid infinite loops with zero-width matches
				shelf.style.display = 'none';
			} else {
				shelf.style.display = 'block';
			}
		}

	});

}