<?php
if ( ! defined( 'ABSPATH' ) ) {
    exit;
}

/**
 * Polls the ACH Processing API for payment status updates on pending/on-hold
 * orders and transitions WooCommerce order status accordingly.
 *
 * Replaces the legacy check-status.php direct-URL cron endpoint. Runs under
 * Action Scheduler so it survives low-traffic sites and deduplicates with
 * other WooCommerce scheduled work.
 */
class ACHP_Status_Poller {
    const HOOK            = 'achp_poll_payment_status';
    const INTERVAL        = 300;   // 5 minutes between polls.
    const BATCH_SIZE      = 10;    // Max refs per upstream status-check call.
    const MAX_ORDERS      = 200;   // Cap per poll tick to avoid memory blowups.
    const LOOKBACK_DAYS   = 90;    // Don't poll orders older than this.

    public function __construct() {
        add_action( 'init', [ $this, 'schedule' ] );
        add_action( self::HOOK, [ __CLASS__, 'run' ] );
    }

    public function schedule() {
        if ( ! function_exists( 'as_next_scheduled_action' ) ) {
            return;
        }
        if ( false === as_next_scheduled_action( self::HOOK ) ) {
            as_schedule_recurring_action(
                time(),
                self::INTERVAL,
                self::HOOK,
                [],
                'ACH Processing'
            );
        }
    }

    /**
     * Returns diagnostic counts so the manual-trigger AJAX path can show
     * ops what the poll actually did. The recurring Action Scheduler call
     * ignores the return value.
     *
     * @return array{candidates:int,refs:int,rows:int,updated:int,unchanged:int,unmapped:int,no_match:int,update_failed:int,empty_ref:int}
     */
    public static function run() {
        $logger = wc_get_logger();
        $ctx    = [ 'source' => 'ach-processing' ];
        $stats  = [
            'candidates'     => 0,
            'refs'           => 0,
            'rows'           => 0,
            'updated'        => 0,
            'unchanged'      => 0,
            'unmapped'       => 0,
            'no_match'       => 0,
            'update_failed'  => 0,
            'empty_ref'      => 0,
        ];

        $orders = wc_get_orders( [
            'limit'        => self::MAX_ORDERS,
            'status'       => [ 'pending', 'on-hold' ],
            'meta_key'     => 'custom_transaction_id',
            'meta_compare' => 'EXISTS',
            'date_created' => '>' . ( time() - ( self::LOOKBACK_DAYS * DAY_IN_SECONDS ) ),
            'orderby'      => 'date',
            'order'        => 'DESC',
        ] );

        $stats['candidates'] = is_array( $orders ) ? count( $orders ) : 0;

        $refs = [];
        foreach ( (array) $orders as $order ) {
            $ref = $order->get_meta( 'custom_transaction_id', true );
            if ( '' !== $ref ) {
                $refs[ $ref ] = $order;
            }
        }
        $stats['refs'] = count( $refs );

        $logger->info(
            sprintf( 'Status poll start: %d candidate orders, %d with non-empty refs.', $stats['candidates'], $stats['refs'] ),
            $ctx
        );

        if ( empty( $refs ) ) {
            return $stats;
        }

        foreach ( array_chunk( array_keys( $refs ), self::BATCH_SIZE ) as $batch ) {
            $remoteData = ACHP_Main_Class::curlStatusPost( $batch );
            $rowCount   = is_array( $remoteData ) ? count( $remoteData ) : 0;
            $stats['rows'] += $rowCount;

            $logger->info(
                sprintf( 'Status poll batch: sent %d refs, received %d rows.', count( $batch ), $rowCount ),
                $ctx
            );

            foreach ( (array) $remoteData as $row ) {
                // Normalize key case at both levels — the API has been seen
                // to flip between camelCase and PascalCase across endpoints
                // (`curlPost` already does this for its `status` subkeys).
                // Without this, `paymentRefID` lookups would silently miss
                // when the API ships `PaymentRefID`.
                if ( is_array( $row ) ) {
                    $row = array_change_key_case( $row, CASE_LOWER );
                    if ( isset( $row['status'] ) && is_array( $row['status'] ) ) {
                        $row['status'] = array_change_key_case( $row['status'], CASE_LOWER );
                    }
                }

                $ref     = $row['paymentrefid'] ?? '';
                $message = $row['status']['message'] ?? '';

                if ( '' === (string) $ref ) {
                    $stats['empty_ref']++;
                    $logger->warning(
                        sprintf( 'Row missing paymentRefID after normalization: %s', wp_json_encode( $row ) ),
                        $ctx
                    );
                    continue;
                }

                $order = $refs[ $ref ] ?? null;
                if ( ! $order ) {
                    $stats['no_match']++;
                    $logger->warning(
                        sprintf( 'Row ref=%s did not match any candidate order. Row: %s', $ref, wp_json_encode( $row ) ),
                        $ctx
                    );
                    continue;
                }

                $outcome = self::apply_status( $order, $message );
                if ( isset( $stats[ $outcome ] ) ) {
                    $stats[ $outcome ]++;
                }
                $logger->info(
                    sprintf(
                        'Row: ref=%s order=#%d current=%s msg=%s -> %s',
                        $ref, $order->get_id(), $order->get_status(),
                        '' === (string) $message ? '(empty)' : $message, $outcome
                    ),
                    $ctx
                );
            }
        }

        $logger->info(
            sprintf(
                'Status poll done: candidates=%d refs=%d rows=%d updated=%d unchanged=%d unmapped=%d no_match=%d update_failed=%d empty_ref=%d',
                $stats['candidates'], $stats['refs'], $stats['rows'],
                $stats['updated'], $stats['unchanged'], $stats['unmapped'],
                $stats['no_match'], $stats['update_failed'], $stats['empty_ref']
            ),
            $ctx
        );

        return $stats;
    }

    /**
     * @return string 'updated'|'unchanged'|'unmapped'|'update_failed'
     */
    private static function apply_status( WC_Order $order, $message ) {
        $message = (string) $message;
        $map     = [
            'New'              => 'pending',
            'Pending'          => 'on-hold',
            'Hold'             => 'on-hold',
            'SB Hold'          => 'on-hold',
            'At SB'            => 'processing',
            'File Transmitted' => 'processing',
            'SB Remit'         => 'processing',
            'Returned'         => 'failed',
            'Deleted'          => 'cancelled',
            'SB Void'          => 'cancelled',
        ];

        // Unknown upstream statuses must not transition the order — silently
        // demoting a 'processing' order to 'on-hold' on an unrecognised
        // message would mask real bugs. Log once for ops to investigate.
        if ( ! isset( $map[ $message ] ) ) {
            wc_get_logger()->warning(
                sprintf( 'Unmapped ACH status "%s" for order #%d.', $message, $order->get_id() ),
                [ 'source' => 'ach-processing' ]
            );
            return 'unmapped';
        }

        $target = $map[ $message ];
        if ( $order->get_status() === $target ) {
            return 'unchanged';
        }

        $order->update_status( $target, sprintf( 'ACH Processing status: %s', $message ) );

        // Re-read the order to confirm the transition actually persisted —
        // catches silent failures from filters that veto the change or from
        // HPOS/data-store misconfiguration.
        $reloaded = wc_get_order( $order->get_id() );
        if ( ! $reloaded || $reloaded->get_status() !== $target ) {
            wc_get_logger()->error(
                sprintf(
                    'Status update did not persist for order #%d: expected "%s", still "%s" after update_status().',
                    $order->get_id(), $target, $reloaded ? $reloaded->get_status() : '(no order)'
                ),
                [ 'source' => 'ach-processing' ]
            );
            return 'update_failed';
        }
        return 'updated';
    }
}