<?php

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

require_once __DIR__ . '/dmm/sql/subjects-schema.php';

class AIEO_Behavioural_Reco {

	const LOOKALIKE_CAP = 8000;

	public static function bootstrap() {
		add_filter( 'aieo_email_digest_items', array( __CLASS__, 'digest_items' ), 10, 2 );
	}

	
	
	

	
	public static function recommend( $subject_id, $limit = 10, $args = array() ) {
		global $wpdb;
		$subject_id = (int) $subject_id;
		if ( $subject_id <= 0 || ! function_exists( 'aieo_subject_recos_table' ) ) {
			return array();
		}
		$table = aieo_subject_recos_table();
		
		$rows = $wpdb->get_results( $wpdb->prepare(
			"SELECT item_id, score FROM `{$table}` WHERE subject_id = %d ORDER BY reco_rank ASC LIMIT %d",
			$subject_id,
			max( 1, (int) $limit )
		), ARRAY_A );
		$exclude = ( isset( $args['exclude'] ) && is_array( $args['exclude'] ) )
			? array_flip( array_map( 'intval', $args['exclude'] ) )
			: array();
		$out = array();
		foreach ( (array) $rows as $r ) {
			$iid = (int) $r['item_id'];
			if ( isset( $exclude[ $iid ] ) ) {
				continue;
			}
			$out[] = array( 'item_id' => $iid, 'score' => (float) $r['score'] );
		}
		return $out;
	}

	
	
	

	
	public static function lookalikes( $subject_id, $limit = 10 ) {
		$subject_id = (int) $subject_id;
		if ( $subject_id <= 0 || ! class_exists( 'AIEO_Behavioural_Vector' ) || ! class_exists( 'AI_eShop_Chat_Database_Manager' ) ) {
			return array();
		}
		$vec = AIEO_Behavioural_Vector::get_vector( $subject_id );
		if ( empty( $vec ) ) {
			return array();
		}
		global $wpdb;
		$emb   = $wpdb->prefix . 'aieo_chat_embeddings';
		$subj  = $wpdb->prefix . 'aieo_subjects';
		$model = (string) get_option( 'aieo_chat_embedding_model', 'voyage-2' );
		$db    = AI_eShop_Chat_Database_Manager::get_instance();
		$cap   = (int) apply_filters( 'aieo_behavioural_pool_cap', self::LOOKALIKE_CAP );
		
		
		$rows = $wpdb->get_results( $wpdb->prepare(
			"SELECT e.post_id, e.embedding FROM `{$emb}` e
			 LEFT JOIN `{$subj}` s ON s.subject_id = e.post_id
			 WHERE e.post_type = 'user' AND e.engine_type = %s AND e.post_id <> %d AND e.embedding <> ''
			   AND COALESCE(s.merged_into, 0) = 0
			 ORDER BY e.updated_at DESC LIMIT %d",
			$model,
			$subject_id,
			$cap
		), ARRAY_A );
		$dim    = count( $vec );
		$scores = array();
		foreach ( (array) $rows as $r ) {
			$ov = $db->decompress_embedding( $r['embedding'] );
			if ( ! is_array( $ov ) || count( $ov ) !== $dim ) {
				continue;
			}
			$sc = self::cosine( $vec, $ov );
			if ( $sc > 0 ) {
				$scores[ (int) $r['post_id'] ] = $sc;
			}
		}
		arsort( $scores );
		$out = array();
		foreach ( $scores as $sid => $score ) {
			$out[] = array( 'subject_id' => (int) $sid, 'score' => round( (float) $score, 5 ) );
			if ( count( $out ) >= max( 1, (int) $limit ) ) {
				break;
			}
		}
		return $out;
	}

	
	
	

	
	public static function instigators( $limit = 100, $window_days = 14 ) {
		global $wpdb;
		if ( ! function_exists( 'aieo_interaction_summary_table' ) ) {
			return array();
		}
		$is = aieo_interaction_summary_table();
		
		$rows = $wpdb->get_results( $wpdb->prepare(
			"SELECT subject_id, item_id, weight AS intent, last_at
			 FROM `{$is}`
			 WHERE item_type = 'product' AND conversions = 0
			   AND ( carts > 0 OR wishlists > 0 OR weight >= 4 )
			   AND last_at >= (UTC_TIMESTAMP() - INTERVAL %d DAY)
			 ORDER BY weight DESC LIMIT %d",
			(int) $window_days,
			(int) $limit
		), ARRAY_A );
		$out = array();
		foreach ( (array) $rows as $r ) {
			$out[] = array(
				'subject_id' => (int) $r['subject_id'],
				'item_id'    => (int) $r['item_id'],
				'intent'     => (float) $r['intent'],
				'last_at'    => (string) $r['last_at'],
			);
		}
		return $out;
	}

	
	
	

	
	public static function digest_items( $default, $ctx ) {
		$user_id    = (int) ( $ctx['user_id'] ?? 0 );
		$subject_id = (int) ( $ctx['subject_id'] ?? 0 );
		$count      = max( 1, (int) ( $ctx['count'] ?? 6 ) );
		if ( $subject_id <= 0 && $user_id > 0 && class_exists( 'AIEO_Subject_Resolver' ) ) {
			$subject_id = (int) AIEO_Subject_Resolver::subject_for_user( $user_id );
		}
		if ( $subject_id <= 0 ) {
			return $default;
		}
		
		$recs = self::recommend( $subject_id, $count * 3 );
		if ( empty( $recs ) ) {
			return $default;
		}
		$items = array();
		foreach ( $recs as $rec ) {
			if ( count( $items ) >= $count ) {
				break;
			}
			$pid  = (int) $rec['item_id'];
			$card = self::product_card( $pid );
			if ( $card ) {
				$items[] = $card;
			}
		}
		
		if ( count( $items ) < $count && is_array( $default ) ) {
			$have = array();
			foreach ( $items as $it ) {
				$have[ $it['url'] ] = true;
			}
			foreach ( $default as $d ) {
				if ( count( $items ) >= $count ) {
					break;
				}
				if ( empty( $have[ $d['url'] ] ) ) {
					$items[]            = $d;
					$have[ $d['url'] ] = true;
				}
			}
		}
		return ! empty( $items ) ? $items : $default;
	}

	
	private static function product_card( $pid ) {
		if ( function_exists( 'wc_get_product' ) ) {
			$p = wc_get_product( $pid );
			if ( ! $p || ! is_object( $p ) ) {
				return null;
			}
			if ( 'publish' !== $p->get_status() || ! $p->is_visible() || ! $p->is_in_stock() ) {
				return null;
			}
			$img = $p->get_image_id();
			return array(
				'title' => (string) $p->get_name(),
				'url'   => (string) get_permalink( $pid ),
				'image' => $img ? (string) wp_get_attachment_image_url( $img, 'medium' ) : '',
				
				'meta'  => class_exists( 'AIEO_Catalogue_Mode' ) && AIEO_Catalogue_Mode::prices_off( $p ) ? '' : (string) wp_strip_all_tags( wc_price( $p->get_price() ) ),
			);
		}
		if ( 'publish' !== get_post_status( $pid ) ) {
			return null;
		}
		return array(
			'title' => (string) get_the_title( $pid ),
			'url'   => (string) get_permalink( $pid ),
			'image' => (string) get_the_post_thumbnail_url( $pid, 'medium' ),
			'meta'  => '',
		);
	}

	private static function cosine( array $a, array $b ) {
		$dot = 0.0;
		$na  = 0.0;
		$nb  = 0.0;
		$n   = count( $a );
		for ( $i = 0; $i < $n; $i++ ) {
			$x    = (float) $a[ $i ];
			$y    = (float) $b[ $i ];
			$dot += $x * $y;
			$na  += $x * $x;
			$nb  += $y * $y;
		}
		if ( $na <= 0.0 || $nb <= 0.0 ) {
			return 0.0;
		}
		return $dot / ( sqrt( $na ) * sqrt( $nb ) );
	}
}