<?php
/**
 * Core analyzer — inspects post fields and emits normalized signals 0..1
 */
class AIT_AIPSEO_Analyzer {

	public function __construct() {
		add_action( 'save_post', [ $this, 'maybe_analyze_on_save' ], 20, 2 );
	}

	public function maybe_analyze_on_save( $post_id, $post ) {

		if ( wp_is_post_autosave( $post_id ) || wp_is_post_revision( $post_id ) ) { return; }

		$disabled = AIT_AIPSEO_Settings::get('disabled');
		$analysis_trigger = AIT_AIPSEO_Settings::get('analysis_trigger');
		$post_types = AIT_AIPSEO_Settings::get('post_types');
		$analyze_only_with_keyword = AIT_AIPSEO_Settings::get('analyze_only_with_keyword');
		
		if ( ! empty( $disabled ) ) { return; }

		if ( 'manual' === $analysis_trigger ) { return; }

		if ( ! in_array( $post->post_type, (array) ( $post_types ?? [] ), true ) ) { return; }

		if ( ! empty( $analyze_only_with_keyword ) ) {
			$kws = AIT_AIPSEO_Keyword_Density::get_target_keywords( $post_id );
			if ( empty( $kws ) ) { return; }
		}

		$this->analyze_and_store( $post_id );
	}

	public function analyze_and_store( int $post_id ): array {
		$result = $this->analyze( $post_id );
		update_post_meta( $post_id, '_ait_aipseo_score', $result );
		$this->update_recent_activity( $post_id, $result['score'] ?? 0 );
		AIT_AIPSEO_Dashboard::update_seo_score();
		return $result;
	}

	public function analyze( int $post_id ): array {
		$post = get_post( $post_id );
		if ( ! $post ) { return [ 'score' => 0, 'signals' => [] ]; }

		$title = (string) get_the_title( $post );
		$meta_title = get_post_meta( $post_id, '_yoast_wpseo_title', true );
		$meta_desc  = get_post_meta( $post_id, '_yoast_wpseo_metadesc', true );
		if ( '' === $meta_title ) { $meta_title = get_post_meta( $post_id, '_seopress_titles_title', true ); }
		if ( '' === $meta_desc )  { $meta_desc  = get_post_meta( $post_id, '_seopress_titles_desc', true ); }
		if ( '' === $meta_title ) { $meta_title = get_post_meta( $post_id, '_aioseo_title', true ); }
		if ( '' === $meta_desc )  { $meta_desc  = get_post_meta( $post_id, '_aioseo_description', true ); }
		if ( '' === $meta_title ) { $meta_title = $title; }
		if ( '' === $meta_desc )  { $meta_desc  = wp_trim_words( $post->post_excerpt ?: wp_strip_all_tags( $post->post_content ), 30, '' ); }

		$content = wp_strip_all_tags( (string) $post->post_content );
		$keywords = class_exists( 'AIT_AIPSEO_Keyword_Density' ) ? ( new AIT_AIPSEO_Keyword_Density() )->get_target_keywords( $post_id ) : [];

		$signals = [
			'title'       => $this->signal_title( $title, $keywords ),
			'meta'        => $this->signal_meta( $meta_title, $meta_desc, $keywords ),
			'headings'    => $this->signal_headings( $post_id, $keywords ),
			'readability' => $this->signal_readability( $content ),
			'links'       => $this->signal_links( $post_id ),
			'images'      => $this->signal_images( $post_id ),
		];

		$score = class_exists( 'AIT_AIPSEO_Score' ) ? ( new AIT_AIPSEO_Score() )->calculate( $signals ) : [ 'score' => 0, 'breakdown' => [] ];
		return array_merge( $score, [ 'signals' => $signals ] );
	}

	private function signal_title( string $title, array $keywords ): float {
		$len_ok = ( strlen( $title ) >= 30 && strlen( $title ) <= 60 );
		$kw_ok  = empty( $keywords ) ? true : ( false !== stripos( $title, $keywords[0] ) );
		return ( $len_ok ? 0.6 : 0.3 ) + ( $kw_ok ? 0.4 : 0.0 );
	}

	private function signal_meta( string $title, string $desc, array $keywords ): float {
		$len  = strlen( $desc );
		$ok   = ( $len >= 120 && $len <= 160 );
		$kwok = empty( $keywords ) ? true : ( false !== stripos( $desc, $keywords[0] ) );
		return ( $ok ? 0.6 : 0.3 ) + ( $kwok ? 0.4 : 0.0 );
	}

	private function signal_headings( int $post_id, array $keywords ): float {
		$content = get_post_field( 'post_content', $post_id );
		preg_match_all( '/<h[1-3][^>]*>(.*?)<\/h[1-3]>/', $content, $m );
		$has_h1 = (bool) preg_match( '/<h1[\s>]/i', $content );
		$k = empty( $keywords ) ? '' : preg_quote( $keywords[0], '/' );
		$kw_in_h = ( $k && preg_match( '/<h[1-3][^>]*>[^<]*' . $k . '[^<]*<\/h[1-3]>/i', $content ) ) ? 1 : 0;
		$base = $has_h1 ? 0.6 : 0.3;
		return $base + ( $kw_in_h ? 0.4 : 0 );
	}

	private function signal_readability( string $content ): float {
		$words = str_word_count( $content );
		$sent  = max( 1, substr_count( $content, '.' ) + substr_count( $content, '!' ) + substr_count( $content, '?' ) );
		$avg   = $words / $sent;
		if ( $avg >= 12 && $avg <= 25 ) { return 1.0; }
		if ( $avg >= 8 && $avg <= 30 ) { return 0.7; }
		return 0.4;
	}

	private function signal_links( int $post_id ): float {
		$content = get_post_field( 'post_content', $post_id );
		$internal = preg_match_all( '/<a[^>]+href=\"(?!https?:\\/\\/)([^\"#]+)\"/i', $content );
		$external = preg_match_all( '/<a[^>]+href=\"https?:\\/\\//i', $content );
		return ( $internal > 0 ? 0.5 : 0.2 ) + ( $external > 0 ? 0.5 : 0.2 );
	}

	private function signal_images( int $post_id ): float {
		$content = get_post_field( 'post_content', $post_id );
		$imgs = preg_match_all( '/<img\\b/i', $content );
		$alts = preg_match_all( '/<img[^>]+alt=\"[^\"]+\"/i', $content );
		if ( $imgs == 0 ) { return 0.6; } // not image-heavy content: neutral
		$ratio = $alts > 0 ? min( 1, $alts / max( 1, $imgs ) ) : 0;
		return 0.3 + 0.7 * $ratio;
	}

	private function update_recent_activity( int $post_id, $score ) {
		$recent = get_option( 'ait_aipseo_recent', [] );
		if ( ! is_array( $recent ) ) { $recent = []; }
		array_unshift( $recent, [ 'post_id' => $post_id, 'score' => (float) $score, 'time' => current_time( 'timestamp' ) ] );
		$recent = array_slice( $recent, 0, 10 );
		update_option( 'ait_aipseo_recent', $recent );
	}
}