<?php
/**
 * The chat on the site: embed.js with the agent's key, deferred in the footer, on the pages the
 * settings allow. With "Identify users" on, logged-in users are passed to replybash("identify")
 * with an HMAC of their id signed by the identity secret (docs: JavaScript API › Identity verification).
 */

defined( 'ABSPATH' ) || exit;

class ReplyBash_Frontend {
	const HANDLE       = 'replybash-widget';
	const RESET_COOKIE = 'replybash_reset';

	public static function init() {
		add_action( 'wp_enqueue_scripts', array( __CLASS__, 'enqueue' ) );
		add_filter( 'script_loader_tag', array( __CLASS__, 'agent_attribute' ), 10, 2 );
		add_action( 'wp_logout', array( __CLASS__, 'mark_logout' ) );
	}

	public static function enqueue() {
		$key = ReplyBash_Options::connection()['key'];
		$s   = ReplyBash_Options::settings();
		if ( '' === $key || ! $s['enabled'] || ! self::shows_here( $s ) ) {
			return;
		}
		// phpcs:disable WordPress.WP.EnqueuedResourceParameters.MissingVersion -- embed.js is versioned by the app.
		wp_enqueue_script(
			self::HANDLE,
			ReplyBash_Admin::app_url( '/embed.js' ),
			array(),
			null, // embed.js is versioned by the app; a ?ver= would only split its cache.
			array(
				'in_footer' => true,
				'strategy'  => 'defer',
			)
		);
		// phpcs:enable
		wp_add_inline_script( self::HANDLE, self::inline_script( $s ), 'before' );
	}

	// embed.js reads its agent from its own tag's data-agent-id.
	public static function agent_attribute( $tag, $handle ) {
		if ( self::HANDLE !== $handle ) {
			return $tag;
		}
		$key = ReplyBash_Options::connection()['key'];
		return str_replace( ' src=', ' data-agent-id="' . esc_attr( $key ) . '" src=', $tag );
	}

	/** Should the chat show on this request's page? */
	public static function shows_here( $s ) {
		if ( $s['hide_staff'] && current_user_can( 'edit_posts' ) ) {
			return false;
		}
		if ( 'all' === $s['pages_mode'] ) {
			return true;
		}
		$path    = self::current_path();
		$matched = false;
		foreach ( array_filter( explode( "\n", $s['pages'] ) ) as $pattern ) {
			if ( self::path_matches( $path, $pattern ) ) {
				$matched = true;
				break;
			}
		}
		return 'only' === $s['pages_mode'] ? $matched : ! $matched;
	}

	/** This request's path inside the site ("/pricing"), whatever folder WordPress is installed in. */
	public static function current_path() {
		$uri  = isset( $_SERVER['REQUEST_URI'] ) ? sanitize_text_field( wp_unslash( $_SERVER['REQUEST_URI'] ) ) : '/';
		$path = strtolower( (string) wp_parse_url( $uri, PHP_URL_PATH ) );
		$base = strtolower( untrailingslashit( (string) wp_parse_url( home_url(), PHP_URL_PATH ) ) );
		if ( '' !== $base && 0 === strpos( $path, $base ) ) {
			$path = substr( $path, strlen( $base ) );
		}
		return '/' . trim( $path, '/' );
	}

	/** "/blog/*" matches /blog and everything under it; "/*" matches every page; others match exactly. */
	public static function path_matches( $path, $pattern ) {
		if ( '/*' === $pattern ) {
			return true;
		}
		if ( '/*' === substr( $pattern, -2 ) ) {
			$prefix = substr( $pattern, 0, -2 );
			return $path === $prefix || 0 === strpos( $path, $prefix . '/' );
		}
		return $path === $pattern;
	}

	public static function mark_logout() {
		if ( ReplyBash_Options::settings()['identify'] ) {
			setcookie( self::RESET_COOKIE, '1', time() + HOUR_IN_SECONDS, COOKIEPATH ? COOKIEPATH : '/', COOKIE_DOMAIN, is_ssl(), false );
		}
	}

	private static function inline_script( $s ) {
		$js = 'window.replybash=window.replybash||function(){(replybash.q=replybash.q||[]).push(arguments)};';
		if ( ! $s['identify'] ) {
			return $js;
		}
		// After logging out, forget the user and their open chat once, so the next person starts fresh.
		// Read in the browser, so it works on cached pages too.
		$js .= 'if(document.cookie.indexOf("' . self::RESET_COOKIE . '=1")>-1){replybash("reset");document.cookie="' . self::RESET_COOKIE . '=; Max-Age=0; path=/"}';
		$user = wp_get_current_user();
		if ( $user->exists() && '' !== $s['identity_secret'] ) {
			$id    = 'wp-' . $user->ID;
			$data  = array(
				'userId' => $id,
				'hash'   => hash_hmac( 'sha256', $id, $s['identity_secret'] ),
				'name'   => $user->display_name,
				'email'  => $user->user_email,
			);
			$js   .= 'replybash("identify",' . wp_json_encode( $data, JSON_HEX_TAG | JSON_HEX_AMP | JSON_UNESCAPED_SLASHES ) . ');';
		}
		return $js;
	}
}