<?php

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

class AIEO_Order_Touchpoints {

	const MODELS   = array( 'last_click', 'linear', 'time_decay', 'position' );
	const MAX_ROWS = 200000; 

	
	public static function attribute( $window_days = 30, $model = 'time_decay', $lookback_days = 90 ) {
		global $wpdb;
		$window   = max( 1, min( 120, (int) $window_days ) );
		$lookback = max( 1, min( 365, (int) $lookback_days ) );
		$model    = in_array( $model, self::MODELS, true ) ? $model : 'time_decay';
		$disp     = $wpdb->prefix . 'aieo_push_dispatch';
		$blank    = array( 'available' => false, 'model' => $model, 'window_days' => $window, 'campaigns' => array(), 'note' => __( 'No attributable order paths in this window yet.', 'ai-eshop-optimizer' ) );
		if ( ! self::table_exists( $disp ) ) {
			return $blank;
		}
		$orders = self::orders_subquery();
		if ( '' === $orders ) {
			return $blank;
		}

		
		
		
		$rows = $wpdb->get_results( $wpdb->prepare(
			"SELECT o.id AS order_id, o.total_amount AS total, o.date_created_gmt AS odate,
			        d.trigger_id AS campaign, d.channel AS channel, d.sent_at AS tdate
			 FROM {$orders} o
			 JOIN `{$disp}` d
			        ON ( ( o.customer_id > 0 AND d.user_id = o.customer_id )
			             OR ( o.billing_email <> '' AND d.recipient_email = o.billing_email COLLATE utf8mb4_general_ci ) )
			       AND d.channel IN ('email','push')
			       AND ( d.state IN ('clicked','converted') OR d.opened_at IS NOT NULL )
			       AND d.sent_at IS NOT NULL
			       AND d.sent_at <= o.date_created_gmt
			       AND d.sent_at >= ( o.date_created_gmt - INTERVAL %d DAY )
			 WHERE o.date_created_gmt >= ( UTC_TIMESTAMP() - INTERVAL %d DAY )
			 ORDER BY o.id ASC, d.sent_at ASC
			 LIMIT " . (int) self::MAX_ROWS,
			$window, $lookback
		), ARRAY_A );
		if ( empty( $rows ) ) {
			return $blank;
		}

		
		$paths = array();
		foreach ( $rows as $r ) {
			$oid = (int) $r['order_id'];
			if ( ! isset( $paths[ $oid ] ) ) {
				$paths[ $oid ] = array( 'total' => (float) $r['total'], 'odate' => (string) $r['odate'], 'touches' => array() );
			}
			$paths[ $oid ]['touches'][] = array( 'campaign' => (string) $r['campaign'], 'channel' => (string) $r['channel'], 'tdate' => (string) $r['tdate'] );
		}

		
		$credit  = array(); 
		$orders_n = 0;
		$total_credited = 0.0;
		foreach ( $paths as $p ) {
			$weights = self::weights( $p['touches'], $p['odate'], $model );
			$orders_n++;
			foreach ( $p['touches'] as $i => $tp ) {
				$c = $tp['campaign'];
				if ( ! isset( $credit[ $c ] ) ) {
					$credit[ $c ] = array( 'campaign' => $c, 'credited_revenue' => 0.0, 'touches' => 0 );
				}
				$share = $p['total'] * ( isset( $weights[ $i ] ) ? $weights[ $i ] : 0 );
				$credit[ $c ]['credited_revenue'] += $share;
				$credit[ $c ]['touches']++;
				$total_credited += $share;
			}
		}
		$out = array_values( $credit );
		foreach ( $out as &$c ) {
			$c['credited_revenue'] = round( $c['credited_revenue'], 2 );
			$c['label'] = self::campaign_label( $c['campaign'] );
		}
		unset( $c );
		usort( $out, function ( $a, $b ) {
			return $b['credited_revenue'] <=> $a['credited_revenue'];
		} );

		return array(
			'available'       => true,
			'model'           => $model,
			'models'          => self::MODELS,
			'window_days'     => $window,
			'lookback_days'   => $lookback,
			'orders_with_path' => $orders_n,
			'total_credited'  => round( $total_credited, 2 ),
			'campaigns'       => $out,
			'note'            => __( 'Credit is spread across every OWNED message the customer engaged with before buying. last_click = 100% to the final touch; linear = equal; time_decay = more to recent touches (7-day half-life); position = 40/40 first+last, 20% shared between. Compare models to see which campaigns last-click under-credits.', 'ai-eshop-optimizer' ),
		);
	}

	
	private static function weights( $touches, $order_date, $model ) {
		$n = count( $touches );
		if ( $n <= 0 ) {
			return array();
		}
		if ( 1 === $n ) {
			return array( 1.0 );
		}
		switch ( $model ) {
			case 'last_click':
				$w = array_fill( 0, $n, 0.0 );
				$w[ $n - 1 ] = 1.0;
				return $w;

			case 'linear':
				return array_fill( 0, $n, 1.0 / $n );

			case 'position':
				
				
				
				if ( 2 === $n ) {
					return array( 0.5, 0.5 );
				}
				$w = array_fill( 0, $n, 0.0 );
				$w[0]        = 0.4;
				$w[ $n - 1 ] = 0.4;
				$mid = $n - 2;
				for ( $i = 1; $i < $n - 1; $i++ ) {
					$w[ $i ] = 0.2 / $mid;
				}
				return $w;

			case 'time_decay':
			default:
				$ot = strtotime( (string) $order_date . ' UTC' );
				$raw = array();
				$sum = 0.0;
				foreach ( $touches as $tp ) {
					$tt   = strtotime( (string) $tp['tdate'] . ' UTC' );
					$days = max( 0, ( $ot - $tt ) / DAY_IN_SECONDS );
					$wt   = pow( 2, - $days / 7.0 ); 
					$raw[] = $wt;
					$sum  += $wt;
				}
				if ( $sum <= 0 ) {
					return array_fill( 0, $n, 1.0 / $n );
				}
				return array_map( function ( $x ) use ( $sum ) {
					return $x / $sum;
				}, $raw );
		}
	}

	private static function campaign_label( $campaign ) {
		if ( 0 === strpos( $campaign, 'wf_' ) && class_exists( 'AIEO_Workflows' ) ) {
			$wf = AIEO_Workflows::get( (int) substr( $campaign, 3 ) );
			if ( $wf ) {
				return (string) $wf['name'];
			}
		}
		if ( 0 === strpos( $campaign, 'campaign:' ) ) {
			return __( 'Broadcast', 'ai-eshop-optimizer' ) . ' #' . substr( $campaign, 9 );
		}
		return $campaign;
	}

	
	private static function orders_subquery() {
		global $wpdb;
		$hpos = $wpdb->prefix . 'wc_orders';
		if ( self::table_exists( $hpos ) ) {
			return "(SELECT id, customer_id, billing_email, date_created_gmt, total_amount
			         FROM `{$hpos}`
			         WHERE type = 'shop_order' AND status IN ('wc-completed','wc-processing'))";
		}
		$posts = $wpdb->posts;
		$meta  = $wpdb->postmeta;
		if ( ! self::table_exists( $posts ) ) {
			return '';
		}
		return "(SELECT p.ID AS id,
		                CAST(COALESCE(cu.meta_value, 0) AS UNSIGNED) AS customer_id,
		                COALESCE(be.meta_value, '') AS billing_email,
		                p.post_date_gmt AS date_created_gmt,
		                CAST(COALESCE(tot.meta_value, 0) AS DECIMAL(14,2)) AS total_amount
		         FROM `{$posts}` p
		         LEFT JOIN `{$meta}` cu  ON cu.post_id = p.ID AND cu.meta_key = '_customer_user'
		         LEFT JOIN `{$meta}` be  ON be.post_id = p.ID AND be.meta_key = '_billing_email'
		         LEFT JOIN `{$meta}` tot ON tot.post_id = p.ID AND tot.meta_key = '_order_total'
		         WHERE p.post_type = 'shop_order' AND p.post_status IN ('wc-completed','wc-processing'))";
	}

	private static function table_exists( $t ) {
		global $wpdb;
		return (string) $wpdb->get_var( $wpdb->prepare( 'SHOW TABLES LIKE %s', $t ) ) === $t;
	}
}