<?php
/**
 * Layout stability and ad-slot helper.
 *
 * @package AgizoAI_Agentic
 */

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

/**
 * Layout stability scanner and optional frontend CSS helper.
 */
class AgizoAI_Agentic_Layout {

	/**
	 * Settings helper.
	 *
	 * @var AgizoAI_Agentic_Settings
	 */
	private $settings;

	/**
	 * Constructor.
	 *
	 * @param AgizoAI_Agentic_Settings $settings Settings helper.
	 */
	public function __construct( AgizoAI_Agentic_Settings $settings ) {
		$this->settings = $settings;
	}

	/**
	 * Register frontend hooks.
	 *
	 * @return void
	 */
	public function init() {
		add_action( 'wp_enqueue_scripts', array( $this, 'enqueue_frontend_helper' ), 99 );
	}

	/**
	 * Enqueue optional inline CSS helper for common ad slots.
	 *
	 * @return void
	 */
	public function enqueue_frontend_helper() {
		$options = $this->settings->get_options();

		if ( empty( $options['layout_helper_css_enabled'] ) || empty( $options['layout_reserve_ad_slots'] ) ) {
			return;
		}

		$css = $this->get_helper_css( $options );
		if ( '' === trim( $css ) ) {
			return;
		}

		wp_register_style( 'agizoai-agentic-layout-helper', false, array(), AGIZOAI_AGENTIC_VERSION );
		wp_enqueue_style( 'agizoai-agentic-layout-helper' );
		wp_add_inline_style( 'agizoai-agentic-layout-helper', $css );
	}

	/**
	 * Return generated CSS helper preview.
	 *
	 * @param array<string,mixed>|null $options Optional settings.
	 * @return string
	 */
	public function get_helper_css( $options = null ) {
		if ( null === $options || ! is_array( $options ) ) {
			$options = $this->settings->get_options();
		}

		$top     = max( 0, absint( isset( $options['layout_top_ad_min_height'] ) ? $options['layout_top_ad_min_height'] : 90 ) );
		$inline  = max( 0, absint( isset( $options['layout_inline_ad_min_height'] ) ? $options['layout_inline_ad_min_height'] : 250 ) );
		$sidebar = max( 0, absint( isset( $options['layout_sidebar_ad_min_height'] ) ? $options['layout_sidebar_ad_min_height'] : 280 ) );
		$mobile  = max( 0, absint( isset( $options['layout_mobile_ad_min_height'] ) ? $options['layout_mobile_ad_min_height'] : 250 ) );
		$header  = max( 0, absint( isset( $options['layout_sticky_header_offset'] ) ? $options['layout_sticky_header_offset'] : 0 ) );

		$css = array();
		$css[] = '/* AgizoAI Agentic Browsing Optimizer: layout stability helper. */';
		$css[] = ':root{--agizoai-agentic-top-ad-min-height:' . $top . 'px;--agizoai-agentic-inline-ad-min-height:' . $inline . 'px;--agizoai-agentic-sidebar-ad-min-height:' . $sidebar . 'px;--agizoai-agentic-mobile-ad-min-height:' . $mobile . 'px;--agizoai-agentic-sticky-header-offset:' . $header . 'px;}';
		$css[] = '.agizoai-agentic-ad-slot,.agizoai-agentic-ad-top,.agizoai-agentic-ad-inline,.agizoai-agentic-ad-sidebar,.ad-slot,.ads-slot,.adslot,.advertisement-slot,.advert-slot,ins.adsbygoogle{display:block;box-sizing:border-box;}';
		$css[] = '.agizoai-agentic-ad-top,.ad-slot-top,.ads-slot-top,.adslot-top,.advertisement-top{min-height:var(--agizoai-agentic-top-ad-min-height);}';
		$css[] = '.agizoai-agentic-ad-inline,.ad-slot-inline,.ads-slot-inline,.adslot-inline,.advertisement-inline,.entry-content ins.adsbygoogle{min-height:var(--agizoai-agentic-inline-ad-min-height);}';
		$css[] = '.agizoai-agentic-ad-sidebar,.ad-slot-sidebar,.ads-slot-sidebar,.adslot-sidebar,.widget ins.adsbygoogle{min-height:var(--agizoai-agentic-sidebar-ad-min-height);}';
		$css[] = 'html{scroll-padding-top:var(--agizoai-agentic-sticky-header-offset);}';
		$css[] = '@media (max-width: 767px){.agizoai-agentic-ad-slot,.agizoai-agentic-ad-top,.agizoai-agentic-ad-inline,.agizoai-agentic-ad-sidebar,.ad-slot,.ads-slot,.adslot,.advertisement-slot,.advert-slot,ins.adsbygoogle{min-height:var(--agizoai-agentic-mobile-ad-min-height);}}';

		return implode( "\n", $css ) . "\n";
	}

	/**
	 * Run layout stability scan over public content.
	 *
	 * @param int $limit Number of public items to scan.
	 * @return array<string,mixed>
	 */
	public function scan( $limit = 25 ) {
		$options = $this->settings->get_options();
		$limit   = max( 1, min( 50, absint( $limit ) ) );

		$post_types = isset( $options['include_post_types'] ) && is_array( $options['include_post_types'] ) ? $options['include_post_types'] : array( 'page', 'post' );
		$post_types = array_values( array_filter( array_map( 'sanitize_key', $post_types ) ) );

		if ( empty( $post_types ) ) {
			$post_types = array( 'page', 'post' );
		}

		$metrics = $this->empty_metrics();
		$issues  = array();
		$pages   = array();

		$query = new WP_Query(
			array(
				'post_type'           => $post_types,
				'post_status'         => 'publish',
				'posts_per_page'      => $limit,
				'orderby'             => 'date',
				'order'               => 'DESC',
				'ignore_sticky_posts' => true,
				'no_found_rows'       => true,
			)
		);

		if ( $query->have_posts() ) {
			foreach ( $query->posts as $post ) {
				$html = apply_filters( 'the_content', $post->post_content );
				$page = array(
					'id'    => absint( $post->ID ),
					'title' => get_the_title( $post ),
					'url'   => get_permalink( $post ),
					'type'  => get_post_type( $post ),
				);

				$page_result = $this->analyse_html( $html, $page );
				$pages[]     = array_merge(
					$page,
					array(
						'issues' => count( $page_result['issues'] ),
					)
				);

				foreach ( $page_result['metrics'] as $key => $value ) {
					if ( isset( $metrics[ $key ] ) ) {
						$metrics[ $key ] += absint( $value );
					}
				}

				$issues = array_merge( $issues, $page_result['issues'] );
			}
			wp_reset_postdata();
		}

		$metrics['pages_scanned'] = count( $pages );

		$critical_count = count(
			array_filter(
				$issues,
				function ( $issue ) {
					return isset( $issue['severity'] ) && 'critical' === $issue['severity'];
				}
			)
		);

		$warning_count = count(
			array_filter(
				$issues,
				function ( $issue ) {
					return isset( $issue['severity'] ) && 'warning' === $issue['severity'];
				}
			)
		);

		return array(
			'enabled'        => ! empty( $options['layout_scanner_enabled'] ),
			'helper_enabled' => ! empty( $options['layout_helper_css_enabled'] ) && ! empty( $options['layout_reserve_ad_slots'] ),
			'pages'          => $pages,
			'pages_scanned'  => absint( $metrics['pages_scanned'] ),
			'metrics'        => $metrics,
			'issues'         => $issues,
			'issue_count'    => count( $issues ),
			'critical_count' => $critical_count,
			'warning_count'  => $warning_count,
			'score'          => $this->score_from_issues( $issues ),
		);
	}

	/**
	 * Empty metrics array.
	 *
	 * @return array<string,int>
	 */
	private function empty_metrics() {
		return array(
			'pages_scanned'                 => 0,
			'images_total'                   => 0,
			'images_missing_dimensions'      => 0,
			'iframes_total'                  => 0,
			'iframes_missing_dimensions'     => 0,
			'ad_slots_total'                 => 0,
			'ad_slots_without_reserved_space'=> 0,
			'popups_detected'                => 0,
			'sticky_or_fixed_elements'        => 0,
		);
	}

	/**
	 * Analyse HTML with DOM or regex fallback.
	 *
	 * @param string              $html Rendered HTML.
	 * @param array<string,mixed> $page Page context.
	 * @return array<string,mixed>
	 */
	private function analyse_html( $html, array $page ) {
		if ( class_exists( 'DOMDocument' ) ) {
			return $this->analyse_with_dom( $html, $page );
		}

		return $this->analyse_with_regex( $html, $page );
	}

	/**
	 * DOM-based analysis.
	 *
	 * @param string              $html Rendered HTML.
	 * @param array<string,mixed> $page Page context.
	 * @return array<string,mixed>
	 */
	private function analyse_with_dom( $html, array $page ) {
		$metrics = $this->empty_metrics();
		$issues  = array();
		$dom     = new DOMDocument();

		$previous = libxml_use_internal_errors( true );
		$encoded  = '<?xml encoding="utf-8" ?>' . (string) $html;
		$dom->loadHTML( $encoded, LIBXML_HTML_NOIMPLIED | LIBXML_HTML_NODEFDTD );
		libxml_clear_errors();
		libxml_use_internal_errors( $previous );

		$images = $dom->getElementsByTagName( 'img' );
		$metrics['images_total'] = $images->length;
		foreach ( $images as $img ) {
			if ( ! $this->node_has_box_size( $img ) ) {
				$metrics['images_missing_dimensions']++;
				$issues[] = $this->issue(
					'image_dimensions_missing',
					__( 'Image may cause layout shift', 'agizoai-agentic-browsing-optimizer' ),
					__( 'An image in public content has no explicit width and height or reserved size.', 'agizoai-agentic-browsing-optimizer' ),
					__( 'Agents may identify an element position before the image loads, then fail when the page shifts.', 'agizoai-agentic-browsing-optimizer' ),
					__( 'Add width and height attributes, use aspect-ratio CSS, or reserve the image container space.', 'agizoai-agentic-browsing-optimizer' ),
					'warning',
					$page
				);
			}
		}

		$iframes = $dom->getElementsByTagName( 'iframe' );
		$metrics['iframes_total'] = $iframes->length;
		foreach ( $iframes as $iframe ) {
			if ( ! $this->node_has_box_size( $iframe ) ) {
				$metrics['iframes_missing_dimensions']++;
				$issues[] = $this->issue(
					'iframe_dimensions_missing',
					__( 'Iframe or embed may shift layout', 'agizoai-agentic-browsing-optimizer' ),
					__( 'An iframe/embed has no explicit width and height or reserved size.', 'agizoai-agentic-browsing-optimizer' ),
					__( 'Embeds can load late and move nearby buttons, forms or links after an agent has located them.', 'agizoai-agentic-browsing-optimizer' ),
					__( 'Set width and height attributes or wrap the embed in a fixed aspect-ratio container.', 'agizoai-agentic-browsing-optimizer' ),
					'warning',
					$page
				);
			}
		}

		$all_nodes = $dom->getElementsByTagName( '*' );
		foreach ( $all_nodes as $node ) {
			if ( $this->looks_like_ad_slot( $node ) ) {
				$metrics['ad_slots_total']++;
				if ( ! $this->node_has_reserved_space( $node ) ) {
					$metrics['ad_slots_without_reserved_space']++;
					$issues[] = $this->issue(
						'ad_slot_no_reserved_space',
						__( 'Ad slot has no reserved space', 'agizoai-agentic-browsing-optimizer' ),
						__( 'A likely ad container does not declare a fixed, minimum or aspect-ratio size.', 'agizoai-agentic-browsing-optimizer' ),
						__( 'Ad scripts that inject late can push content down and make agent clicks unreliable.', 'agizoai-agentic-browsing-optimizer' ),
						__( 'Reserve ad-slot space with min-height, width/height or the v0.5.0 CSS helper.', 'agizoai-agentic-browsing-optimizer' ),
						'critical',
						$page
					);
				}
			}

			if ( $this->looks_like_popup_or_modal( $node ) ) {
				$metrics['popups_detected']++;
			}

			if ( $this->looks_like_sticky_or_fixed( $node ) ) {
				$metrics['sticky_or_fixed_elements']++;
			}
		}

		if ( $metrics['popups_detected'] > 0 ) {
			$issues[] = $this->issue(
				'popup_detected',
				__( 'Popup or modal pattern detected', 'agizoai-agentic-browsing-optimizer' ),
				__( 'Public content appears to include popup, modal or overlay markup.', 'agizoai-agentic-browsing-optimizer' ),
				__( 'Overlays can cover forms or buttons and confuse screenshot-based agents.', 'agizoai-agentic-browsing-optimizer' ),
				__( 'Ensure popups do not shift content, have clear close buttons and do not block key tasks.', 'agizoai-agentic-browsing-optimizer' ),
				'warning',
				$page
			);
		}

		if ( $metrics['sticky_or_fixed_elements'] > 0 ) {
			$issues[] = $this->issue(
				'sticky_fixed_detected',
				__( 'Sticky or fixed element pattern detected', 'agizoai-agentic-browsing-optimizer' ),
				__( 'Public content appears to include sticky/fixed element markup or inline positioning.', 'agizoai-agentic-browsing-optimizer' ),
				__( 'Sticky headers or bars can hide anchors, forms or action buttons after scrolling.', 'agizoai-agentic-browsing-optimizer' ),
				__( 'Use scroll-padding-top or the sticky header offset helper where needed.', 'agizoai-agentic-browsing-optimizer' ),
				'warning',
				$page
			);
		}

		return array(
			'metrics' => $metrics,
			'issues'  => $issues,
		);
	}

	/**
	 * Regex fallback analysis.
	 *
	 * @param string              $html Rendered HTML.
	 * @param array<string,mixed> $page Page context.
	 * @return array<string,mixed>
	 */
	private function analyse_with_regex( $html, array $page ) {
		$metrics = $this->empty_metrics();
		$issues  = array();
		$html    = (string) $html;

		if ( preg_match_all( '/<img\b[^>]*>/i', $html, $matches ) ) {
			$metrics['images_total'] = count( $matches[0] );
			foreach ( $matches[0] as $tag ) {
				if ( ! preg_match( '/\bwidth\s*=\s*["\']?\d+/i', $tag ) || ! preg_match( '/\bheight\s*=\s*["\']?\d+/i', $tag ) ) {
					$metrics['images_missing_dimensions']++;
				}
			}
		}

		if ( preg_match_all( '/<iframe\b[^>]*>/i', $html, $matches ) ) {
			$metrics['iframes_total'] = count( $matches[0] );
			foreach ( $matches[0] as $tag ) {
				if ( ! preg_match( '/\bwidth\s*=\s*["\']?\d+/i', $tag ) || ! preg_match( '/\bheight\s*=\s*["\']?\d+/i', $tag ) ) {
					$metrics['iframes_missing_dimensions']++;
				}
			}
		}

		if ( preg_match_all( '/<(div|aside|section|ins)\b[^>]*(adslot|ad-slot|adsbygoogle|advert|advertisement)[^>]*>/i', $html, $matches ) ) {
			$metrics['ad_slots_total'] = count( $matches[0] );
			foreach ( $matches[0] as $tag ) {
				if ( ! preg_match( '/(min-height|height|aspect-ratio|width)\s*:/i', $tag ) && ! preg_match( '/\bheight\s*=\s*["\']?\d+/i', $tag ) ) {
					$metrics['ad_slots_without_reserved_space']++;
				}
			}
		}

		if ( $metrics['images_missing_dimensions'] > 0 ) {
			$issues[] = $this->issue( 'image_dimensions_missing', __( 'Images may cause layout shift', 'agizoai-agentic-browsing-optimizer' ), __( 'One or more images lack explicit dimensions.', 'agizoai-agentic-browsing-optimizer' ), __( 'Late-loading images can move interaction targets after agents locate them.', 'agizoai-agentic-browsing-optimizer' ), __( 'Add width/height attributes or aspect-ratio CSS.', 'agizoai-agentic-browsing-optimizer' ), 'warning', $page );
		}

		if ( $metrics['iframes_missing_dimensions'] > 0 ) {
			$issues[] = $this->issue( 'iframe_dimensions_missing', __( 'Embeds may cause layout shift', 'agizoai-agentic-browsing-optimizer' ), __( 'One or more iframes lack explicit dimensions.', 'agizoai-agentic-browsing-optimizer' ), __( 'Late-loading embeds can move nearby targets.', 'agizoai-agentic-browsing-optimizer' ), __( 'Reserve iframe/embed space.', 'agizoai-agentic-browsing-optimizer' ), 'warning', $page );
		}

		if ( $metrics['ad_slots_without_reserved_space'] > 0 ) {
			$issues[] = $this->issue( 'ad_slot_no_reserved_space', __( 'Ad slots need reserved space', 'agizoai-agentic-browsing-optimizer' ), __( 'One or more likely ad slots lack reserved space.', 'agizoai-agentic-browsing-optimizer' ), __( 'Late ad injection can push content and break agent interaction.', 'agizoai-agentic-browsing-optimizer' ), __( 'Use fixed/min-height ad containers or the CSS helper.', 'agizoai-agentic-browsing-optimizer' ), 'critical', $page );
		}

		return array(
			'metrics' => $metrics,
			'issues'  => $issues,
		);
	}

	/**
	 * Check whether a DOM node has explicit box dimensions.
	 *
	 * @param DOMElement $node Node.
	 * @return bool
	 */
	private function node_has_box_size( DOMElement $node ) {
		$width  = $node->hasAttribute( 'width' ) ? trim( $node->getAttribute( 'width' ) ) : '';
		$height = $node->hasAttribute( 'height' ) ? trim( $node->getAttribute( 'height' ) ) : '';
		$style  = $node->hasAttribute( 'style' ) ? strtolower( $node->getAttribute( 'style' ) ) : '';

		if ( '' !== $width && '' !== $height ) {
			return true;
		}

		return false !== strpos( $style, 'aspect-ratio' ) || ( false !== strpos( $style, 'width:' ) && ( false !== strpos( $style, 'height:' ) || false !== strpos( $style, 'min-height:' ) ) );
	}

	/**
	 * Check reserved space on possible container.
	 *
	 * @param DOMElement $node Node.
	 * @return bool
	 */
	private function node_has_reserved_space( DOMElement $node ) {
		if ( $this->node_has_box_size( $node ) ) {
			return true;
		}

		$style = $node->hasAttribute( 'style' ) ? strtolower( $node->getAttribute( 'style' ) ) : '';

		return false !== strpos( $style, 'min-height:' ) || false !== strpos( $style, 'min-width:' ) || false !== strpos( $style, 'aspect-ratio' );
	}

	/**
	 * Return whether a node looks like an ad container.
	 *
	 * @param DOMElement $node Node.
	 * @return bool
	 */
	private function looks_like_ad_slot( DOMElement $node ) {
		$name = strtolower( $node->nodeName );
		$id   = $node->hasAttribute( 'id' ) ? strtolower( $node->getAttribute( 'id' ) ) : '';
		$cls  = $node->hasAttribute( 'class' ) ? strtolower( $node->getAttribute( 'class' ) ) : '';
		$text = $id . ' ' . $cls;

		if ( 'ins' === $name && false !== strpos( $cls, 'adsbygoogle' ) ) {
			return true;
		}

		if ( false !== strpos( $text, 'adslot' ) || false !== strpos( $text, 'ad-slot' ) || false !== strpos( $text, 'ads-slot' ) || false !== strpos( $text, 'advertisement' ) || false !== strpos( $text, 'advert-slot' ) ) {
			return true;
		}

		return ( false !== strpos( $text, 'google-auto-placed' ) || false !== strpos( $text, 'adsbygoogle' ) );
	}

	/**
	 * Return whether a node looks like popup/modal markup.
	 *
	 * @param DOMElement $node Node.
	 * @return bool
	 */
	private function looks_like_popup_or_modal( DOMElement $node ) {
		$id    = $node->hasAttribute( 'id' ) ? strtolower( $node->getAttribute( 'id' ) ) : '';
		$cls   = $node->hasAttribute( 'class' ) ? strtolower( $node->getAttribute( 'class' ) ) : '';
		$role  = $node->hasAttribute( 'role' ) ? strtolower( $node->getAttribute( 'role' ) ) : '';
		$text  = $id . ' ' . $cls . ' ' . $role;

		return false !== strpos( $text, 'modal' ) || false !== strpos( $text, 'popup' ) || false !== strpos( $text, 'overlay' ) || false !== strpos( $text, 'dialog' );
	}

	/**
	 * Return whether a node looks fixed/sticky.
	 *
	 * @param DOMElement $node Node.
	 * @return bool
	 */
	private function looks_like_sticky_or_fixed( DOMElement $node ) {
		$id    = $node->hasAttribute( 'id' ) ? strtolower( $node->getAttribute( 'id' ) ) : '';
		$cls   = $node->hasAttribute( 'class' ) ? strtolower( $node->getAttribute( 'class' ) ) : '';
		$style = $node->hasAttribute( 'style' ) ? strtolower( $node->getAttribute( 'style' ) ) : '';
		$text  = $id . ' ' . $cls . ' ' . $style;

		return false !== strpos( $text, 'position:fixed' ) || false !== strpos( $text, 'position: sticky' ) || false !== strpos( $text, 'position:sticky' ) || false !== strpos( $text, 'sticky' ) || false !== strpos( $text, 'fixed-bar' );
	}

	/**
	 * Build issue array.
	 *
	 * @param string              $id ID.
	 * @param string              $title Title.
	 * @param string              $problem Problem.
	 * @param string              $why Why.
	 * @param string              $fix Fix.
	 * @param string              $severity Severity.
	 * @param array<string,mixed> $page Page context.
	 * @return array<string,mixed>
	 */
	private function issue( $id, $title, $problem, $why, $fix, $severity, array $page ) {
		return array(
			'id'         => sanitize_key( $id ),
			'title'      => $title,
			'problem'    => $problem,
			'why'        => $why,
			'fix'        => $fix,
			'severity'   => sanitize_key( $severity ),
			'page_id'    => isset( $page['id'] ) ? absint( $page['id'] ) : 0,
			'page_title' => isset( $page['title'] ) ? wp_strip_all_tags( (string) $page['title'] ) : '',
			'page_url'   => isset( $page['url'] ) ? esc_url_raw( (string) $page['url'] ) : '',
			'page_type'  => isset( $page['type'] ) ? sanitize_key( (string) $page['type'] ) : '',
		);
	}

	/**
	 * Convert issues into score.
	 *
	 * @param array<int,array<string,mixed>> $issues Issues.
	 * @return int
	 */
	private function score_from_issues( array $issues ) {
		$score = 100;

		foreach ( $issues as $issue ) {
			$score -= isset( $issue['severity'] ) && 'critical' === $issue['severity'] ? 12 : 6;
		}

		return max( 0, min( 100, absint( $score ) ) );
	}
}