<?php

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

function x_pixel_get_id() {
	$pixel_id = get_option( X_PIXEL_OPTION_ID, '' );
	if ( $pixel_id === '' || ! preg_match( '/^[a-zA-Z0-9_-]+$/', $pixel_id ) ) {
		return '';
	}
	return $pixel_id;
}

function x_pixel_event_code( $pixel_id, $event_id ) {
	if ( $pixel_id === '' || $event_id === '' ) {
		return '';
	}
	if ( ! preg_match( '/^[a-zA-Z0-9_-]+$/', $event_id ) ) {
		return '';
	}
	return 'tw-' . $pixel_id . '-' . $event_id;
}

function x_pixel_conversion_id( $suffix ) {
	return substr( hash( 'sha256', home_url() ), 0, 12 ) . '-' . $suffix;
}

function x_pixel_json_flags() {
	return JSON_UNESCAPED_SLASHES | JSON_PRESERVE_ZERO_FRACTION | JSON_HEX_TAG | JSON_HEX_AMP | JSON_HEX_APOS | JSON_HEX_QUOT;
}

function x_pixel_base_code( $pixel_id ) {
	$pixel_json = wp_json_encode( (string) $pixel_id, x_pixel_json_flags() );
	if ( ! is_string( $pixel_json ) ) {
		return '';
	}
	$lines = array(
		'window.twq||(function(){',
		'var s=window.twq=function(){s.exe?s.exe.apply(s,arguments):s.queue.push(arguments);};',
		"s.version='1.1';s.queue=[];",
		'})();',
		"twq('config'," . $pixel_json . ');',
	);
	return implode( "\n", $lines );
}

function x_pixel_enqueue_tag() {
	if ( is_admin() || is_feed() ) {
		return;
	}

	$pixel_id = x_pixel_get_id();
	if ( $pixel_id === '' ) {
		return;
	}

	$base_code = x_pixel_base_code( $pixel_id );
	if ( $base_code === '' ) {
		return;
	}

	wp_enqueue_script(
		'x-pixel-uwt',
		'https://static.ads-twitter.com/uwt.js',
		array(),
		X_PIXEL_VERSION,
		array(
			'in_footer' => false,
			'strategy'  => 'async',
		)
	);
	wp_add_inline_script( 'x-pixel-uwt', $base_code, 'before' );
}
add_action( 'wp_enqueue_scripts', 'x_pixel_enqueue_tag', 1 );

function x_pixel_sessions() {
	$sessions = array();
	if ( function_exists( 'WC' ) && WC() && WC()->session ) {
		$sessions[] = WC()->session;
	}
	if ( function_exists( 'EDD' ) && EDD() && ! empty( EDD()->session ) ) {
		$sessions[] = EDD()->session;
	}
	return $sessions;
}

function x_pixel_session() {
	$sessions = x_pixel_sessions();
	return $sessions === array() ? null : $sessions[0];
}

function x_pixel_queue_browser_event( $event_id, $params, $session = null ) {
	$pixel_id = x_pixel_get_id();
	$code     = x_pixel_event_code( $pixel_id, $event_id );
	if ( ! $session ) {
		$session = x_pixel_session();
	}
	if ( $code === '' || ! $session ) {
		return false;
	}
	$queued   = array();
	$existing = $session->get( 'x_pixel_queue', array() );
	if ( is_array( $existing ) ) {
		$queued = $existing;
	}
	$queued[] = array(
		'code'   => $code,
		'params' => $params,
	);
	$session->set( 'x_pixel_queue', $queued );
	return true;
}

function x_pixel_current_url() {
	$host = isset( $_SERVER['HTTP_HOST'] ) ? sanitize_text_field( wp_unslash( $_SERVER['HTTP_HOST'] ) ) : '';
	$path = isset( $_SERVER['REQUEST_URI'] ) ? esc_url_raw( wp_unslash( $_SERVER['REQUEST_URI'] ) ) : '/';
	if ( $host === '' || preg_match( '/^[A-Za-z0-9.:\[\]-]+$/', $host ) !== 1 ) {
		return home_url( '/' );
	}
	if ( $path === '' || $path[0] !== '/' ) {
		$path = '/';
	}
	return esc_url_raw( ( is_ssl() ? 'https://' : 'http://' ) . $host . $path );
}

function x_pixel_is_background_request() {
	return wp_doing_ajax() || ( defined( 'REST_REQUEST' ) && REST_REQUEST ) || ( defined( 'WC_DOING_AJAX' ) && WC_DOING_AJAX );
}

function x_pixel_is_bot_user_agent() {
	$user_agent = isset( $_SERVER['HTTP_USER_AGENT'] ) ? sanitize_text_field( wp_unslash( $_SERVER['HTTP_USER_AGENT'] ) ) : '';
	if ( $user_agent === '' ) {
		return true;
	}
	$user_agent = strtolower( $user_agent );
	$tokens     = array( 'bot', 'crawl', 'spider', 'slurp', 'facebookexternalhit', 'twitterbot', 'googlebot', 'bingbot', 'ahrefsbot', 'semrushbot', 'petalbot', 'python-requests', 'curl', 'wget', 'headlesschrome' );
	foreach ( $tokens as $token ) {
		if ( strpos( $user_agent, $token ) !== false ) {
			return true;
		}
	}
	return false;
}

function x_pixel_session_cookie_names() {
	return array( 'woocommerce_items_in_cart', 'woocommerce_cart_hash', 'edd_items_in_cart' );
}

function x_pixel_session_cookie_prefixes() {
	return array( 'wp_woocommerce_session_', 'edd_session_' );
}

function x_pixel_request_cookie_names() {
	$header = isset( $_SERVER['HTTP_COOKIE'] ) ? sanitize_text_field( wp_unslash( $_SERVER['HTTP_COOKIE'] ) ) : '';
	$names  = array();
	foreach ( explode( ';', $header ) as $pair ) {
		$parts = explode( '=', $pair, 2 );
		$name  = trim( $parts[0] );
		if ( $name !== '' ) {
			$names[] = $name;
		}
	}
	return $names;
}

function x_pixel_has_shopper_session() {
	if ( is_user_logged_in() ) {
		return true;
	}
	$names    = x_pixel_session_cookie_names();
	$prefixes = x_pixel_session_cookie_prefixes();
	foreach ( x_pixel_request_cookie_names() as $cookie ) {
		if ( in_array( $cookie, $names, true ) ) {
			return true;
		}
		foreach ( $prefixes as $prefix ) {
			if ( strpos( $cookie, $prefix ) === 0 ) {
				return true;
			}
		}
	}
	return false;
}

function x_pixel_is_untrusted_request( $is_get_add = false ) {
	if ( x_pixel_has_shopper_session() ) {
		return false;
	}
	if ( x_pixel_is_bot_user_agent() ) {
		return true;
	}
	return $is_get_add && isset( $_SERVER['REQUEST_METHOD'] ) && $_SERVER['REQUEST_METHOD'] === 'GET';
}

function x_pixel_event_source_url() {
	if ( x_pixel_is_background_request() ) {
		$referer = wp_get_raw_referer();
		if ( $referer ) {
			return esc_url_raw( $referer );
		}
	}
	return x_pixel_current_url();
}

function x_pixel_event_script( $code, $params ) {
	$code_json = wp_json_encode( (string) $code, x_pixel_json_flags() );
	$payload   = wp_json_encode( is_array( $params ) ? $params : array(), x_pixel_json_flags() );
	if ( ! is_string( $code_json ) ) {
		return '';
	}
	if ( ! is_string( $payload ) ) {
		$payload = '{}';
	}
	return "twq('event'," . $code_json . ',' . $payload . ');';
}

function x_pixel_printed_conversion_ids( $conversion_id = '' ) {
	static $ids = array();
	if ( is_string( $conversion_id ) && $conversion_id !== '' && ! in_array( $conversion_id, $ids, true ) ) {
		$ids[] = $conversion_id;
	}
	return $ids;
}

function x_pixel_print_event_script( $code, $params ) {
	$script = x_pixel_event_script( $code, $params );
	if ( $script === '' ) {
		return;
	}
	if ( is_array( $params ) && isset( $params['conversion_id'] ) ) {
		x_pixel_printed_conversion_ids( $params['conversion_id'] );
	}
	wp_print_inline_script_tag( $script );
}

function x_pixel_take_queued_events() {
	$events = array();
	foreach ( x_pixel_sessions() as $session ) {
		$queued = $session->get( 'x_pixel_queue', array() );
		if ( ! is_array( $queued ) || $queued === array() ) {
			continue;
		}
		$session->set( 'x_pixel_queue', array() );
		foreach ( $queued as $event ) {
			if ( empty( $event['code'] ) || ! is_string( $event['code'] ) ) {
				continue;
			}
			$events[] = array(
				'code'   => $event['code'],
				'params' => isset( $event['params'] ) && is_array( $event['params'] ) ? $event['params'] : array(),
			);
		}
	}
	return $events;
}

function x_pixel_flush_queued_events() {
	if ( is_admin() ) {
		return;
	}
	foreach ( x_pixel_take_queued_events() as $event ) {
		x_pixel_print_event_script( $event['code'], $event['params'] );
	}
}

function x_pixel_url_host( $url ) {
	$parts = wp_parse_url( (string) $url );
	if ( empty( $parts['host'] ) ) {
		return '';
	}
	$host = strtolower( $parts['host'] );
	if ( ! empty( $parts['port'] ) ) {
		$host .= ':' . (int) $parts['port'];
	}
	return $host;
}

function x_pixel_is_same_origin_request() {
	if ( ! isset( $_SERVER['REQUEST_METHOD'] ) || $_SERVER['REQUEST_METHOD'] !== 'POST' ) {
		return false;
	}
	$request_host = isset( $_SERVER['HTTP_HOST'] ) ? strtolower( sanitize_text_field( wp_unslash( $_SERVER['HTTP_HOST'] ) ) ) : '';
	if ( $request_host === '' ) {
		return false;
	}
	if ( isset( $_SERVER['HTTP_SEC_FETCH_SITE'] ) ) {
		return sanitize_text_field( wp_unslash( $_SERVER['HTTP_SEC_FETCH_SITE'] ) ) === 'same-origin';
	}
	if ( isset( $_SERVER['HTTP_ORIGIN'] ) ) {
		return x_pixel_url_host( esc_url_raw( wp_unslash( $_SERVER['HTTP_ORIGIN'] ) ) ) === $request_host;
	}
	$referer = wp_get_raw_referer();
	return $referer && x_pixel_url_host( $referer ) === $request_host;
}

function x_pixel_no_store_headers( $headers ) {
	$headers['Cache-Control'] = 'no-store, no-cache, must-revalidate, max-age=0, private';
	return $headers;
}

function x_pixel_ajax_drain() {
	add_filter( 'nocache_headers', 'x_pixel_no_store_headers', 100 );
	nocache_headers();
	if ( ! x_pixel_is_same_origin_request() ) {
		wp_send_json( array(), 403, x_pixel_json_flags() );
	}
	wp_send_json( x_pixel_take_queued_events(), 200, x_pixel_json_flags() );
}
add_action( 'wp_ajax_x_pixel_drain', 'x_pixel_ajax_drain' );
add_action( 'wp_ajax_nopriv_x_pixel_drain', 'x_pixel_ajax_drain' );

function x_pixel_print_drain_script() {
	if ( is_admin() || x_pixel_get_id() === '' ) {
		return;
	}
	$woocommerce = class_exists( 'WooCommerce' );
	$edd         = function_exists( 'EDD' );
	if ( ! $woocommerce && ! $edd ) {
		return;
	}
	$config = wp_json_encode(
		array(
			'url'      => admin_url( 'admin-ajax.php', 'relative' ),
			'wc'       => $woocommerce,
			'edd'      => $edd,
			'atc'      => get_option( X_PIXEL_OPTION_EVENT_ATC, '' ) !== '',
			'fired'    => x_pixel_printed_conversion_ids(),
			'cookies'  => x_pixel_session_cookie_names(),
			'prefixes' => x_pixel_session_cookie_prefixes(),
		),
		x_pixel_json_flags()
	);
	if ( ! is_string( $config ) ) {
		return;
	}
	$listener = <<<'JS'
(function (c) {
	var timer = null;
	var fired = window.__xPixelFired = window.__xPixelFired || new Set();
	for (var f = 0; f < c.fired.length; f++) {
		fired.add(c.fired[f]);
	}
	function fire(events) {
		if (!window.twq || !Array.isArray(events)) {
			return;
		}
		for (var i = 0; i < events.length; i++) {
			var event = events[i] || {};
			var params = event.params && typeof event.params === 'object' ? event.params : {};
			var id = params.conversion_id;
			if (typeof id === 'string' && id !== '') {
				if (fired.has(id)) {
					continue;
				}
				fired.add(id);
			}
			twq('event', event.code, params);
		}
	}
	function hasSession() {
		var cookies = [];
		try {
			cookies = document.cookie ? document.cookie.split(';') : [];
		} catch (e) {
			return false;
		}
		for (var i = 0; i < cookies.length; i++) {
			var name = cookies[i].replace(/^\s+/, '').split('=')[0];
			if (c.cookies.indexOf(name) !== -1) {
				return true;
			}
			for (var p = 0; p < c.prefixes.length; p++) {
				if (name.indexOf(c.prefixes[p]) === 0) {
					return true;
				}
			}
		}
		return false;
	}
	function drain() {
		if (!window.fetch) {
			return;
		}
		clearTimeout(timer);
		timer = setTimeout(function () {
			fetch(c.url, {
				method: 'POST',
				credentials: 'same-origin',
				headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
				body: 'action=x_pixel_drain'
			}).then(function (r) {
				return r.ok ? r.json() : [];
			}).then(fire).catch(function () {});
		}, 250);
	}
	function ready(fn) {
		if (document.readyState === 'loading') {
			document.addEventListener('DOMContentLoaded', fn);
		} else {
			fn();
		}
	}
	ready(function () {
		if (hasSession()) {
			drain();
		}
	});
	if (!c.atc) {
		return;
	}
	if (c.wc) {
		document.addEventListener('wc-blocks_added_to_cart', drain);
		ready(function () {
			if (window.jQuery) {
				jQuery(document.body).on('added_to_cart', function (e, fragments) {
					var events = fragments && fragments.x_pixel_events;
					if (Array.isArray(events) && events.length) {
						fire(events);
					} else {
						drain();
					}
				});
			}
			if (!window.wp || !wp.data || !wp.data.subscribe) {
				return;
			}
			var lastCount = null;
			wp.data.subscribe(function () {
				var store = wp.data.select('wc/store/cart');
				if (!store || !store.getCartData) {
					return;
				}
				if (store.hasFinishedResolution && !store.hasFinishedResolution('getCartData')) {
					return;
				}
				var data = store.getCartData();
				var count = data && data.itemsCount;
				if (typeof count !== 'number') {
					return;
				}
				if (lastCount !== null && count > lastCount) {
					drain();
				}
				lastCount = count;
			}, 'wc/store/cart');
		});
	}
	if (c.edd) {
		ready(function () {
			if (window.jQuery) {
				jQuery(document.body).on('edd_cart_item_added', drain);
			}
		});
	}
})
JS;
	wp_print_inline_script_tag( $listener . '(' . $config . ');' );
}