<?php

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

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

class AIEO_Behavioural_Vector {

	const HOOK_TICK    = 'aieo_behavioural_vector_tick';
	const BATCH        = 50;     
	const MAX_ITEMS    = 200;    
	const RECO_COUNT   = 24;     
	const POOL_CAP     = 10000;  
	const POOL_CHUNK   = 500;    
	const DECAY_H      = 30.0;   
	const ACTIVE_DAYS  = 90;     
	const OBJECT_TYPE  = 'user';

	
	private static $booted = false;

	public static function bootstrap() {
		if ( self::$booted ) {
			return;
		}
		self::$booted = true;
		add_action( self::HOOK_TICK, array( __CLASS__, 'tick' ) );
		add_filter( 'pre_as_schedule_recurring_action', array( __CLASS__, 'dedup_pre_schedule' ), 5, 6 );
		add_action( 'admin_init', array( __CLASS__, 'maybe_schedule' ), 30 );
		add_action( 'init', array( __CLASS__, 'maybe_schedule' ), 30 );
	}

	public static function maybe_schedule() {
		if ( class_exists( 'AIEO_Schedule_Gate', false ) && ! AIEO_Schedule_Gate::due( __METHOD__ ) ) {
			return; 
		}
		static $checked = false;
		if ( $checked ) {
			return;
		}
		$checked = true;
		if ( get_transient( 'aieo_behvec_sched_lock' ) ) {
			return;
		}
		set_transient( 'aieo_behvec_sched_lock', 1, 5 * MINUTE_IN_SECONDS );
		if ( function_exists( 'as_next_scheduled_action' ) && function_exists( 'as_schedule_recurring_action' ) ) {
			if ( false === as_next_scheduled_action( self::HOOK_TICK, null, 'aieo' ) ) {
				as_schedule_recurring_action( time() + 2 * HOUR_IN_SECONDS, 2 * HOUR_IN_SECONDS, self::HOOK_TICK, array(), 'aieo' );
			}
		} elseif ( ! wp_next_scheduled( self::HOOK_TICK ) ) {
			wp_schedule_event( time() + 2 * HOUR_IN_SECONDS, 'twicedaily', self::HOOK_TICK );
		}
	}

	public static function dedup_pre_schedule( $pre, $timestamp, $interval, $hook, $args = array(), $group = '' ) {
		if ( self::HOOK_TICK !== $hook || 'aieo' !== $group ) {
			return $pre;
		}
		global $wpdb;
		$lk = 'aieo_behvec_sched';
		if ( 1 !== (int) $wpdb->get_var( $wpdb->prepare( 'SELECT GET_LOCK(%s, 0)', $lk ) ) ) {
			return 1;
		}
		try {
			
			$existing = (int) $wpdb->get_var( $wpdb->prepare(
				"SELECT a.action_id FROM {$wpdb->prefix}actionscheduler_actions a
				 LEFT JOIN {$wpdb->prefix}actionscheduler_groups g ON g.group_id = a.group_id
				 WHERE a.hook = %s AND a.status IN ('pending','in-progress') AND g.slug = %s
				 ORDER BY a.action_id ASC LIMIT 1",
				self::HOOK_TICK,
				'aieo'
			) );
			return $existing > 0 ? $existing : $pre;
		} finally {
			$wpdb->query( $wpdb->prepare( 'SELECT RELEASE_LOCK(%s)', $lk ) );
		}
	}

	
	
	

	public static function tick() {
		if ( ! self::ready() ) {
			return;
		}
		global $wpdb;
		$lock = 'aieo_behavioural_vector';
		if ( 1 !== (int) $wpdb->get_var( $wpdb->prepare( 'SELECT GET_LOCK(%s, 0)', $lock ) ) ) {
			return;
		}
		try {
			$subjects = self::dirty_subjects( self::BATCH );
			if ( empty( $subjects ) ) {
				return;
			}
			$built = array(); 
			foreach ( $subjects as $sid ) {
				$vec = self::build_subject_vector( (int) $sid );
				if ( is_array( $vec ) ) {
					$built[ (int) $sid ] = $vec;
				}
			}
			if ( ! empty( $built ) ) {
				self::precompute_recos( $built );
			}
			
			
			if ( ! empty( $built ) && count( $subjects ) >= self::BATCH && function_exists( 'as_enqueue_async_action' ) ) {
				as_enqueue_async_action( self::HOOK_TICK, array(), 'aieo' );
			}
		} finally {
			$wpdb->query( $wpdb->prepare( 'SELECT RELEASE_LOCK(%s)', $lock ) );
		}
	}

	
	private static function dirty_subjects( $limit ) {
		global $wpdb;
		$is    = aieo_interaction_summary_table();
		$emb   = $wpdb->prefix . 'aieo_chat_embeddings';
		$subj  = $wpdb->prefix . 'aieo_subjects';
		$model = self::model();
		
		return array_map( 'intval', (array) $wpdb->get_col( $wpdb->prepare(
			"SELECT i.subject_id
			 FROM `{$is}` i
			 LEFT JOIN `{$emb}` e ON e.post_id = i.subject_id AND e.post_type = %s AND e.engine_type = %s
			 LEFT JOIN `{$subj}` s ON s.subject_id = i.subject_id
			 WHERE i.last_at > (UTC_TIMESTAMP() - INTERVAL %d DAY)
			 GROUP BY i.subject_id
			 HAVING MAX(i.last_at) > COALESCE( MAX( CONVERT_TZ( e.updated_at, @@session.time_zone, '+00:00' ) ), '1970-01-01 00:00:00' )
			    AND COALESCE( MAX(s.merged_into), 0 ) = 0
			 ORDER BY MAX(i.last_at) DESC
			 LIMIT %d",
			self::OBJECT_TYPE,
			$model,
			self::ACTIVE_DAYS,
			(int) $limit
		) ) );
	}

	
	
	

	
	public static function build_subject_vector( $subject_id ) {
		global $wpdb;
		$subject_id = (int) $subject_id;
		if ( $subject_id <= 0 || ! class_exists( 'AI_eShop_Chat_Database_Manager' ) ) {
			return null;
		}
		$is    = aieo_interaction_summary_table();
		$model = self::model();

		
		
		$rows = $wpdb->get_results( $wpdb->prepare(
			"SELECT item_id, weight, last_at,
			        ( weight * POW(2, - TIMESTAMPDIFF(HOUR, last_at, UTC_TIMESTAMP()) / (24 * %f) ) ) AS ew
			 FROM `{$is}`
			 WHERE subject_id = %d AND item_type = 'product' AND weight > 0 AND last_at IS NOT NULL
			 ORDER BY ew DESC LIMIT %d",
			self::DECAY_H,
			$subject_id,
			self::MAX_ITEMS
		), ARRAY_A );
		if ( empty( $rows ) ) {
			return null;
		}

		$item_ids = array_map( static function ( $r ) {
			return (int) $r['item_id'];
		}, $rows );

		$db = AI_eShop_Chat_Database_Manager::get_instance();
		
		
		
		$vectors = self::fetch_item_vectors( $item_ids, $model, $db );
		if ( empty( $vectors ) ) {
			return null; 
		}

		$dim  = 0;
		$acc  = null;
		$wsum = 0.0;
		$sig  = '';
		foreach ( $rows as $r ) {
			$iid = (int) $r['item_id'];
			if ( ! isset( $vectors[ $iid ] ) || ! is_array( $vectors[ $iid ] ) || empty( $vectors[ $iid ] ) ) {
				continue; 
			}
			$ew = (float) $r['ew'];
			if ( $ew < 0.0001 ) {
				continue;
			}
			$vec = $vectors[ $iid ];
			if ( null === $acc ) {
				$dim = count( $vec );
				if ( $dim <= 0 ) {
					continue;
				}
				$acc = array_fill( 0, $dim, 0.0 );
			}
			if ( count( $vec ) !== $dim ) {
				continue; 
			}
			for ( $k = 0; $k < $dim; $k++ ) {
				$acc[ $k ] += $ew * (float) $vec[ $k ];
			}
			$wsum += $ew;
			$sig  .= $iid . ':' . round( $ew, 3 ) . ';';
		}
		if ( null === $acc || $wsum <= 0.0 || $dim <= 0 ) {
			return null;
		}
		
		$mag = 0.0;
		for ( $k = 0; $k < $dim; $k++ ) {
			$acc[ $k ] /= $wsum;
			$mag       += $acc[ $k ] * $acc[ $k ];
		}
		$mag = sqrt( $mag );
		if ( $mag <= 0.0 ) {
			return null;
		}
		for ( $k = 0; $k < $dim; $k++ ) {
			$acc[ $k ] /= $mag;
		}
		$db->store_embedding( $subject_id, $acc, md5( $sig ), self::OBJECT_TYPE, $model, 0 );
		return $acc;
	}

	
	
	

	private static function precompute_recos( array $built ) {
		global $wpdb;
		if ( ! class_exists( 'AI_eShop_Chat_Database_Manager' ) ) {
			return;
		}
		$emb   = $wpdb->prefix . 'aieo_chat_embeddings';
		$model = self::model();
		$cap   = (int) apply_filters( 'aieo_behavioural_pool_cap', self::POOL_CAP );
		$topN  = (int) apply_filters( 'aieo_behavioural_reco_count', self::RECO_COUNT );
		$db    = AI_eShop_Chat_Database_Manager::get_instance();

		$excl  = array();
		$heaps = array();
		foreach ( $built as $sid => $v ) {
			$excl[ $sid ]  = self::converted_items( (int) $sid );
			$heaps[ $sid ] = array(); 
		}

		$cursor = 0;
		$seen   = 0;
		while ( $seen < $cap ) {
			
			$rows = $wpdb->get_results( $wpdb->prepare(
				"SELECT post_id, embedding FROM `{$emb}`
				 WHERE post_type = 'product' AND engine_type = %s AND deduplicated = 0
				   AND embedding <> '' AND post_id > %d
				 ORDER BY post_id ASC LIMIT %d",
				$model,
				$cursor,
				self::POOL_CHUNK
			), ARRAY_A );
			if ( empty( $rows ) ) {
				break;
			}
			foreach ( $rows as $r ) {
				$pid    = (int) $r['post_id'];
				$cursor = $pid;
				$seen++;
				$ivec = $db->decompress_embedding( $r['embedding'] );
				if ( ! is_array( $ivec ) || empty( $ivec ) ) {
					continue;
				}
				$idim = count( $ivec );
				foreach ( $built as $sid => $sv ) {
					if ( isset( $excl[ $sid ][ $pid ] ) || count( $sv ) !== $idim ) {
						continue;
					}
					$score = self::cosine( $sv, $ivec );
					if ( $score <= 0 ) {
						continue;
					}
					self::heap_push( $heaps[ $sid ], $pid, $score, $topN );
				}
				if ( $seen >= $cap ) {
					break;
				}
			}
		}
		if ( $seen >= $cap ) {
			self::log( "reco pool capped at {$cap} — catalog tail excluded from recommendations" );
		}

		
		$now   = gmdate( 'Y-m-d H:i:s' );
		$table = aieo_subject_recos_table();
		foreach ( $heaps as $sid => $heap ) {
			arsort( $heap );
			$wpdb->delete( $table, array( 'subject_id' => (int) $sid ), array( '%d' ) );
			$rank = 1;
			foreach ( $heap as $item_id => $score ) {
				$wpdb->insert( $table, array(
					'subject_id'  => (int) $sid,
					'reco_rank'   => $rank,
					'item_id'     => (int) $item_id,
					'item_type'   => 'product',
					'score'       => round( (float) $score, 6 ),
					'computed_at' => $now,
				), array( '%d', '%d', '%d', '%s', '%f', '%s' ) );
				if ( ++$rank > $topN ) {
					break;
				}
			}
		}
	}

	
	private static function heap_push( &$heap, $item_id, $score, $n ) {
		if ( count( $heap ) < $n ) {
			$heap[ $item_id ] = $score;
			return;
		}
		$min = min( $heap );
		if ( $score <= $min ) {
			return;
		}
		$heap[ $item_id ] = $score;
		
		$min_key = array_search( $min, $heap, true );
		if ( false !== $min_key ) {
			unset( $heap[ $min_key ] );
		}
	}

	
	private static function fetch_item_vectors( array $item_ids, $model, $db ) {
		global $wpdb;
		$item_ids = array_values( array_unique( array_map( 'intval', $item_ids ) ) );
		if ( empty( $item_ids ) ) {
			return array();
		}
		$emb = $wpdb->prefix . 'aieo_chat_embeddings';
		$in  = implode( ',', $item_ids );
		
		$rows = $wpdb->get_results( $wpdb->prepare(
			"SELECT post_id, embedding FROM `{$emb}`
			 WHERE post_type = 'product' AND engine_type = %s AND deduplicated = 0
			   AND embedding <> '' AND post_id IN ({$in})",
			$model
		), ARRAY_A );
		$out = array();
		foreach ( (array) $rows as $r ) {
			$v = $db->decompress_embedding( $r['embedding'] );
			if ( is_array( $v ) && ! empty( $v ) ) {
				$out[ (int) $r['post_id'] ] = $v;
			}
		}
		return $out;
	}

	private static function converted_items( $subject_id ) {
		global $wpdb;
		$is = aieo_interaction_summary_table();
		
		$ids = $wpdb->get_col( $wpdb->prepare(
			"SELECT item_id FROM `{$is}` WHERE subject_id = %d AND item_type = 'product' AND conversions > 0",
			(int) $subject_id
		) );
		return array_flip( array_map( 'intval', (array) $ids ) );
	}

	private static function cosine( array $a, array $b ) {
		$dot = 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;
			$nb  += $y * $y;
		}
		
		if ( $nb <= 0.0 ) {
			return 0.0;
		}
		return $dot / sqrt( $nb );
	}

	
	
	

	
	public static function get_vector( $subject_id ) {
		global $wpdb;
		$subject_id = (int) $subject_id;
		if ( $subject_id <= 0 || ! class_exists( 'AI_eShop_Chat_Database_Manager' ) ) {
			return null;
		}
		$emb   = $wpdb->prefix . 'aieo_chat_embeddings';
		$model = self::model();
		
		$blob = $wpdb->get_var( $wpdb->prepare(
			"SELECT embedding FROM `{$emb}` WHERE post_id = %d AND post_type = %s AND engine_type = %s LIMIT 1",
			$subject_id,
			self::OBJECT_TYPE,
			$model
		) );
		if ( ! $blob ) {
			return null;
		}
		$db  = AI_eShop_Chat_Database_Manager::get_instance();
		$vec = $db->decompress_embedding( $blob );
		return is_array( $vec ) && ! empty( $vec ) ? $vec : null;
	}

	
	private static function model() {
		$provider = (string) get_option( 'aieo_embedding_provider', 'voyage' );
		if ( 'openai' === $provider ) {
			return (string) get_option( 'aieo_chat_openai_embedding_model', 'text-embedding-3-large' );
		}
		return (string) get_option( 'aieo_chat_embedding_model', 'voyage-2' );
	}

	private static function log( $msg ) {
		if ( function_exists( 'aieo_debug_log' ) ) {
			aieo_debug_log( 'AIEO_Behavioural_Vector: ' . $msg );
		}
	}

	private static function ready() {
		if ( ! function_exists( 'aieo_interaction_summary_table' ) || ! function_exists( 'aieo_subject_recos_table' ) ) {
			return false;
		}
		global $wpdb;
		$is = aieo_interaction_summary_table();
		
		return (string) $wpdb->get_var( $wpdb->prepare( 'SHOW TABLES LIKE %s', $is ) ) === $is
			&& class_exists( 'AI_eShop_Chat_Database_Manager' );
	}
}