<?php
/**
 * Works out what put a script on the page: a plugin, the theme, a page-builder
 * module in the page content, or a header/footer code snippet.
 *
 * WordPress prints enqueued scripts with id="{handle}-js". The handle usually
 * starts with the plugin's or theme's own prefix, and the same page carries that
 * plugin's local files under the same prefix, so the page itself tells us who
 * owns each handle. Scripts without a handle are placed in the content or by a
 * code-snippet plugin; the surrounding markup tells us which.
 *
 * @package GoConsent
 */

namespace GoConsent\Scanner;

defined( 'ABSPATH' ) || exit;

/**
 * Script source detector for one page.
 */
class Source {

	/**
	 * Handle prefix => [ type, slug ] learned from this page's local assets.
	 *
	 * @var array
	 */
	private $owners = array();

	/**
	 * Active plugin slugs.
	 *
	 * @var string[]
	 */
	private $plugins = array();

	/**
	 * Theme slugs (child first).
	 *
	 * @var string[]
	 */
	private $themes = array();

	/**
	 * Byte offset of </head>.
	 *
	 * @var int
	 */
	private $head_end;

	/**
	 * Page HTML.
	 *
	 * @var string
	 */
	private $html;

	/**
	 * Page URL.
	 *
	 * @var string
	 */
	private $url;

	/**
	 * Code-snippet plugins: slug => name.
	 *
	 * @return array<string,string>
	 */
	private static function snippet_plugins() {
		return array(
			'insert-headers-and-footers'  => 'WPCode',
			'wpcode-premium'              => 'WPCode',
			'header-footer-code-manager'  => 'Header Footer Code Manager',
			'code-snippets'               => 'Code Snippets',
			'code-snippets-pro'           => 'Code Snippets',
			'header-and-footer-scripts'   => 'Header and Footer Scripts',
			'insert-headers-and-footers-' => 'Insert Headers and Footers',
			'wp-headers-and-footers'      => 'Headers & Footers',
			'head-footer-code'            => 'Head & Footer Code',
			'google-site-kit'             => 'Site Kit by Google',
		);
	}

	/**
	 * Well-known handles that don't share their plugin's prefix.
	 *
	 * @return array<string,string> handle prefix => plugin slug.
	 */
	private static function aliases() {
		return array(
			'google_gtagjs'    => 'google-site-kit',
			'googlesitekit'    => 'google-site-kit',
			'gtm4wp'           => 'duracelltomi-google-tag-manager',
			'monsterinsights'  => 'google-analytics-for-wordpress',
			'exactmetrics'     => 'google-analytics-dashboard-for-wp',
			'wc'               => 'woocommerce',
			'woocommerce'      => 'woocommerce',
			'fl-builder'       => 'bb-plugin',
			'uabb'             => 'bb-ultimate-addon',
			'elementor'        => 'elementor',
			'elementor-pro'    => 'elementor-pro',
			'jetpack'          => 'jetpack',
			'facebook-for-woo' => 'facebook-for-woocommerce',
			'pys'              => 'pixelyoursite',
			'hq-rental'        => 'hq-rental-software',
		);
	}

	/**
	 * Prepare for one page.
	 *
	 * @param string $html Page HTML.
	 * @param string $url  Page URL.
	 */
	public function __construct( $html, $url ) {
		$this->html     = $html;
		$this->url      = $url;
		$end            = stripos( $html, '</head>' );
		$this->head_end = false === $end ? 0 : $end;
		foreach ( (array) get_option( 'active_plugins', array() ) as $file ) {
			$this->plugins[] = strtolower( dirname( (string) $file ) );
		}
		$this->themes = array_values( array_unique( array( get_stylesheet(), get_template() ) ) );
		$this->learn();
	}

	/**
	 * Learn handle prefixes from local plugin/theme assets on this page.
	 */
	private function learn() {
		if ( ! preg_match_all( '#<(?:script|link)\b[^>]*\bid\s*=\s*["\']([a-z0-9_.-]+?)-(?:js|css)["\'][^>]*>#i', $this->html, $m, PREG_SET_ORDER ) ) {
			return;
		}
		foreach ( $m as $tag ) {
			if ( ! preg_match( '#/wp-content/(plugins|mu-plugins|themes)/([a-z0-9_.-]+)/#i', $tag[0], $p ) ) {
				continue;
			}
			$owner = array( 'themes' === strtolower( $p[1] ) ? 'theme' : 'plugin', strtolower( $p[2] ) );
			foreach ( self::prefixes( strtolower( $tag[1] ) ) as $prefix ) {
				if ( ! isset( $this->owners[ $prefix ] ) ) {
					$this->owners[ $prefix ] = $owner;
				}
			}
		}
	}

	/**
	 * Full handle, then its first two tokens, then its first token.
	 *
	 * @param string $handle Handle.
	 * @return string[]
	 */
	private static function prefixes( $handle ) {
		$parts = preg_split( '/[-_.]/', $handle );
		$out   = array( $handle );
		if ( count( $parts ) > 2 ) {
			$out[] = $parts[0] . '-' . $parts[1];
		}
		if ( strlen( $parts[0] ) >= 2 ) {
			$out[] = $parts[0];
		}
		return array_values( array_unique( $out ) );
	}

	/**
	 * Source of one script tag.
	 *
	 * @param string $attrs  Tag attributes.
	 * @param int    $offset Byte offset of the tag in the page.
	 * @return array{type:string,slug:string,name:string,detail:string,post:int}
	 */
	public function detect( $attrs, $offset ) {
		$out = array(
			'type'   => 'unknown',
			'slug'   => '',
			'name'   => '',
			'detail' => '',
			'post'   => 0,
		);

		// Enqueued: id="{handle}-js" (or -js-extra / -js-before / -js-after for its inline parts).
		if ( preg_match( '#\bid\s*=\s*["\']([a-z0-9_.-]+?)-js(?:-extra|-before|-after)?["\']#i', $attrs, $hm ) ) {
			$handle        = strtolower( $hm[1] );
			$out['detail'] = $handle;
			$owner         = $this->owner_of( $handle );
			if ( $owner ) {
				$out['type'] = $owner[0];
				$out['slug'] = $owner[1];
				$out['name'] = self::name_of( $owner[0], $owner[1] );
				return $out;
			}
			$out['type'] = 'handle';
			return $out;
		}

		// No handle: placed in the page content or by a header/footer code tool.
		$before = substr( $this->html, max( 0, $offset - 8000 ), min( 8000, $offset ) );
		$module = $offset > $this->head_end ? self::builder_module( $before ) : '';
		if ( $module ) {
			$out['type']   = 'content';
			$out['name']   = $module;
			$out['detail'] = self::section_name( $before );
			$out['post']   = (int) url_to_postid( $this->url );
			if ( ! $out['post'] && untrailingslashit( (string) wp_parse_url( $this->url, PHP_URL_PATH ) ) === untrailingslashit( (string) wp_parse_url( home_url( '/' ), PHP_URL_PATH ) ) ) {
				$out['post'] = (int) get_option( 'page_on_front' );
			}
			return $out;
		}
		foreach ( self::snippet_plugins() as $slug => $name ) {
			if ( in_array( $slug, $this->plugins, true ) ) {
				$out['type']   = 'snippet';
				$out['slug']   = $slug;
				$out['name']   = $name;
				$out['detail'] = $offset < $this->head_end ? 'head' : 'footer';
				return $out;
			}
		}
		$out['detail'] = $offset < $this->head_end ? 'head' : 'body';
		return $out;
	}

	/**
	 * Owner of a handle.
	 *
	 * @param string $handle Handle.
	 * @return array|null [ type, slug ].
	 */
	private function owner_of( $handle ) {
		foreach ( self::prefixes( $handle ) as $prefix ) {
			if ( isset( $this->owners[ $prefix ] ) ) {
				return $this->owners[ $prefix ];
			}
		}
		foreach ( self::aliases() as $prefix => $slug ) {
			if ( ( $handle === $prefix || 0 === strpos( $handle, $prefix . '-' ) || 0 === strpos( $handle, $prefix . '_' ) ) && in_array( $slug, $this->plugins, true ) ) {
				return array( 'plugin', $slug );
			}
		}
		foreach ( $this->themes as $slug ) {
			if ( 0 === strpos( $handle, strtolower( $slug ) ) ) {
				return array( 'theme', $slug );
			}
		}
		foreach ( $this->plugins as $slug ) {
			$flat = str_replace( '-', '', $slug );
			if ( strlen( $slug ) >= 3 && ( 0 === strpos( $handle, $slug ) || 0 === strpos( str_replace( array( '-', '_' ), '', $handle ), $flat ) ) ) {
				return array( 'plugin', $slug );
			}
		}
		return null;
	}

	/**
	 * Page-builder module wrapping a script, from the markup just before it.
	 *
	 * @param string $before Preceding HTML.
	 * @return string Module name or ''.
	 */
	private static function builder_module( $before ) {
		$tail = substr( $before, -3000 );
		$map  = array(
			'fl-module-html'        => __( 'Beaver Builder HTML module', 'goconsent' ),
			'fl-html'               => __( 'Beaver Builder HTML module', 'goconsent' ),
			'elementor-widget-html' => __( 'Elementor HTML widget', 'goconsent' ),
			'elementor-shortcode'   => __( 'Elementor shortcode widget', 'goconsent' ),
			'et_pb_code'            => __( 'Divi Code module', 'goconsent' ),
			'wp-block-html'         => __( 'Custom HTML block', 'goconsent' ),
			'widget_custom_html'    => __( 'Custom HTML widget', 'goconsent' ),
			'vc_raw_html'           => __( 'WPBakery Raw HTML element', 'goconsent' ),
			'brxe-code'             => __( 'Bricks Code element', 'goconsent' ),
			'oxy-code-block'        => __( 'Oxygen Code Block', 'goconsent' ),
		);
		$best = '';
		$pos  = -1;
		foreach ( $map as $needle => $name ) {
			$p = strripos( $tail, $needle );
			if ( false !== $p && $p > $pos ) {
				$pos  = $p;
				$best = $name;
			}
		}
		return $best;
	}

	/**
	 * Nearest human-named section id before the script ("BUSINESS REPORT FORM").
	 *
	 * @param string $before Preceding HTML.
	 * @return string
	 */
	private static function section_name( $before ) {
		if ( ! preg_match_all( '#\bid\s*=\s*["\']([^"\']{2,80})["\']#i', $before, $m ) ) {
			return '';
		}
		foreach ( array_reverse( $m[1] ) as $id ) {
			if ( preg_match( '#^(fl-|elementor-|et_pb|wp-|vc_|brxe-|oxy-|post-|menu-|page-)|^[a-f0-9]{6,}$|-js$|-css$#i', $id ) ) {
				continue;
			}
			return $id;
		}
		return '';
	}

	/**
	 * Display name of a plugin or theme.
	 *
	 * @param string $type plugin|theme.
	 * @param string $slug Slug.
	 * @return string
	 */
	public static function name_of( $type, $slug ) {
		if ( 'theme' === $type ) {
			$t = wp_get_theme( $slug );
			return $t->exists() ? (string) $t->get( 'Name' ) : $slug;
		}
		if ( ! function_exists( 'get_plugins' ) ) {
			require_once ABSPATH . 'wp-admin/includes/plugin.php';
		}
		foreach ( get_plugins() as $file => $data ) {
			if ( strtolower( dirname( $file ) ) === $slug && ! empty( $data['Name'] ) ) {
				return (string) $data['Name'];
			}
		}
		return $slug;
	}
}