<?php
/**
 * Atomic persistence operations for the Connector V2 outbox.
 */

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

class Akkedli_V2_Outbox_Repository
{
    use Akkedli_V2_Outbox_Recovery_Repository;
    const LEASE_SECONDS = 300;
    public function is_usable()
    {
        return Akkedli_V2_Outbox_Privilege_Probe::check();
    }

    public function signal_order($native_id, $event_id, $order_key, $accelerate, $now)
    {
        global $wpdb;
        $table = Akkedli_V2_Outbox_Schema::table();
        try {
            $envelope = Akkedli_V2_Outbox_Crypto::seal(
                array('native_order_id' => (string) $native_id), $event_id, 'order'
            );
        } catch (Throwable $error) {
            unset($error);
            return false;
        }
        $date = self::date($now);
        $written = $wpdb->query($wpdb->prepare(
            "INSERT INTO {$table} (event_id,order_key,operation,envelope,state,capture_attempts,attempts,
                next_attempt_gmt,created_gmt,updated_gmt) VALUES (%s,%s,'order',%s,'capture_pending',0,0,%s,%s,%s)
             ON DUPLICATE KEY UPDATE id=LAST_INSERT_ID(id),
                next_attempt_gmt=IF(state='capture_pending' AND %d=1,
                    LEAST(next_attempt_gmt,VALUES(next_attempt_gmt)),next_attempt_gmt),
                updated_gmt=IF(state='capture_pending' AND %d=1,VALUES(updated_gmt),updated_gmt)",
            $event_id, $order_key, $envelope, $date, $date, $date,
            $accelerate ? 1 : 0, $accelerate ? 1 : 0
        ));
        unset($envelope);
        return false !== $written && (int) $wpdb->insert_id > 0 ? (int) $wpdb->insert_id : false;
    }

    public function order_state($event_id)
    {
        global $wpdb;
        $table = Akkedli_V2_Outbox_Schema::table();
        $state = $wpdb->get_var($wpdb->prepare(
            "SELECT state FROM {$table} WHERE event_id=%s AND operation='order' LIMIT 1", $event_id
        ));
        return is_string($state) ? $state : '';
    }

    public function order_provenance($event_id)
    {
        global $wpdb;
        $table = Akkedli_V2_Outbox_Schema::table();
        try {
            $wpdb->flush();
            $state = $wpdb->get_var($wpdb->prepare(
                "SELECT state FROM {$table} WHERE event_id=%s
                 AND operation='order' LIMIT 1", $event_id
            ));
            if (!property_exists($wpdb, 'last_error') || '' !== (string) $wpdb->last_error)
                return null;
            return null === $state ? false : (is_string($state) ? true : null);
        } catch (Throwable $error) { unset($error); return null; }
    }

    public function insert_status($event_id, $order_key, $envelope, $now)
    {
        global $wpdb;
        $table = Akkedli_V2_Outbox_Schema::table();
        $date = self::date($now);
        $written = $wpdb->query($wpdb->prepare(
            "INSERT INTO {$table} (event_id,order_key,operation,envelope,state,capture_attempts,attempts,
                next_attempt_gmt,created_gmt,updated_gmt) VALUES (%s,%s,'status',%s,'pending',0,0,%s,%s,%s)",
            $event_id, $order_key, $envelope, $date, $date, $date
        ));
        return 1 === $written && (int) $wpdb->insert_id > 0 ? (int) $wpdb->insert_id : false;
    }

    public function claim_capture($id, $owner, $now)
    {
        global $wpdb;
        $table = Akkedli_V2_Outbox_Schema::table();
        $date = self::date($now);
        $expires = self::date($now + self::LEASE_SECONDS);
        $changed = $wpdb->query($wpdb->prepare(
            "UPDATE {$table} SET state='capture_processing',
                capture_attempts=LEAST(capture_attempts+1,255),
                lease_owner=%s,lease_expires_gmt=%s,updated_gmt=%s
             WHERE id=%d AND operation='order' AND next_attempt_gmt<=%s
               AND ((state='capture_pending' AND (lease_expires_gmt IS NULL OR lease_expires_gmt<=%s))
                 OR (state='capture_processing' AND lease_expires_gmt<=%s))",
            $owner, $expires, $date, $id, $date, $date, $date
        ));
        return 1 === $changed ? $this->claimed($id, $owner, 'capture_processing') : false;
    }

    public function claim_delivery($id, $owner, $now)
    {
        global $wpdb;
        $table = Akkedli_V2_Outbox_Schema::table();
        $date = self::date($now);
        $expires = self::date($now + self::LEASE_SECONDS);
        $changed = $wpdb->query($wpdb->prepare(
            "UPDATE {$table} candidate LEFT JOIN {$table} earlier
              ON earlier.order_key=candidate.order_key AND earlier.id<candidate.id
              AND NOT (earlier.state='confirmed'
                OR (earlier.operation='status' AND earlier.state IN ('rejected','exhausted'))
                OR (earlier.state='rejected' AND earlier.last_outcome='authority_lost'))
             SET candidate.state='processing',candidate.attempts=LEAST(candidate.attempts+1,255),
                 candidate.lease_owner=%s,candidate.lease_expires_gmt=%s,candidate.updated_gmt=%s
             WHERE candidate.id=%d AND candidate.next_attempt_gmt<=%s AND earlier.id IS NULL
               AND ((candidate.state IN ('pending','retry')
                     AND (candidate.lease_expires_gmt IS NULL OR candidate.lease_expires_gmt<=%s))
                 OR (candidate.state='processing' AND candidate.lease_expires_gmt<=%s))",
            $owner, $expires, $date, $id, $date, $date, $date
        ));
        return 1 === $changed ? $this->claimed($id, $owner, 'processing') : false;
    }

    public function freeze($id, $owner, $envelope, $now)
    {
        return $this->transition($id, $owner, 'capture_processing', array(
            'state' => 'pending', 'envelope' => $envelope, 'next_attempt_gmt' => self::date($now),
            'last_outcome' => 'capture_ready', 'completed_gmt' => null,
        ), $now);
    }

    public function retry_capture($id, $owner, $delay, $now)
    {
        return $this->transition($id, $owner, 'capture_processing', array(
            'state' => 'capture_pending', 'next_attempt_gmt' => self::date($now + $delay),
            'last_outcome' => 'capture_incomplete', 'completed_gmt' => null,
        ), $now);
    }

    public function terminal_capture($id, $owner, $outcome, $now)
    {
        return $this->transition($id, $owner, 'capture_processing', array(
            'state' => 'capture_failed', 'envelope' => null, 'last_outcome' => $outcome,
            'completed_gmt' => self::date($now),
        ), $now);
    }

    public function retry_delivery($id, $owner, $delay, $now)
    {
        return $this->transition($id, $owner, 'processing', array(
            'state' => 'retry', 'next_attempt_gmt' => self::date($now + $delay),
            'last_outcome' => 'retryable', 'completed_gmt' => null,
        ), $now);
    }

    public function pause_delivery($id, $owner, $outcome, $now)
    {
        global $wpdb;
        $table = Akkedli_V2_Outbox_Schema::table();
        return 1 === $wpdb->query($wpdb->prepare(
            "UPDATE {$table} SET state='paused',attempts=IF(attempts>0,attempts-1,0),
                last_outcome=%s,lease_owner=NULL,lease_expires_gmt=NULL,updated_gmt=%s
             WHERE id=%d AND lease_owner=%s AND state='processing'",
            $outcome, self::date($now), $id, $owner
        ));
    }

    public function terminal_delivery($id, $owner, $state, $outcome, $now)
    {
        if (!in_array($state, array('confirmed', 'skipped', 'rejected', 'exhausted'), true)) {
            return false;
        }
        $fields = array('state' => $state, 'last_outcome' => $outcome, 'completed_gmt' => self::date($now));
        if ('exhausted' !== $state) $fields['envelope'] = null;
        return $this->transition($id, $owner, 'processing', $fields, $now);
    }
    public function quarantine_delivery(array $row, $owner, $outcome, $now)
    {
        if (!in_array($outcome, array('delivery_invalid', 'invalid_request',
            'idempotency_conflict', 'order_conflict', 'invalid_status_transition',
            'unknown_terminal'), true)) return false;
        $changed = $this->transition((int) $row['id'], $owner, 'processing', array(
            'state' => 'rejected', 'last_outcome' => $outcome,
            'completed_gmt' => self::date($now),
        ), $now);
        if ($changed && 'order' === $row['operation'])
            $this->block_dependents($row['order_key'], $now);
        return $changed;
    }

    public function block_dependents($order_key, $now)
    {
        global $wpdb;
        $table = Akkedli_V2_Outbox_Schema::table();
        return $wpdb->query($wpdb->prepare(
            "UPDATE {$table} SET state='rejected',envelope=NULL,last_outcome='order_blocked',
                lease_owner=NULL,lease_expires_gmt=NULL,completed_gmt=%s,updated_gmt=%s
             WHERE order_key=%s AND operation='status' AND (state IN ('pending','retry')
                OR (state='processing' AND lease_expires_gmt<=%s))",
            self::date($now), self::date($now), $order_key, self::date($now)
        ));
    }

    public function recoverable($now, $limit)
    {
        global $wpdb;
        $table = Akkedli_V2_Outbox_Schema::table();
        return $wpdb->get_results($wpdb->prepare(
            "SELECT id,operation,state FROM {$table}
             WHERE ((state IN ('capture_pending','pending','retry') AND next_attempt_gmt<=%s
                    AND NOT (state='retry' AND last_outcome IN
                        ('local_not_ready','connector_disabled') AND updated_gmt>%s))
                OR (state IN ('capture_processing','processing') AND lease_expires_gmt<=%s))
             ORDER BY id ASC LIMIT %d", self::date($now),
            self::date($now - self::LEASE_SECONDS), self::date($now), $limit
        ), ARRAY_A);
    }

    public function block_orphans($now, $limit)
    {
        global $wpdb;
        $table = Akkedli_V2_Outbox_Schema::table();
        $ids = $wpdb->get_col($wpdb->prepare(
            "SELECT child.id FROM {$table} child INNER JOIN {$table} parent
               ON parent.order_key=child.order_key AND parent.operation='order'
              AND parent.state IN ('skipped','rejected','exhausted','capture_failed')
             WHERE child.operation='status' AND (child.state IN ('pending','retry')
                OR (child.state='processing' AND child.lease_expires_gmt<=%s))
             ORDER BY child.id ASC LIMIT %d", self::date($now), $limit
        ));
        $blocked = 0;
        foreach (is_array($ids) ? $ids : array() as $id) {
            $changed = $wpdb->query($wpdb->prepare(
                "UPDATE {$table} SET state='rejected',envelope=NULL,last_outcome='order_blocked',
                    lease_owner=NULL,lease_expires_gmt=NULL,completed_gmt=%s,updated_gmt=%s
                 WHERE id=%d AND operation='status' AND (state IN ('pending','retry')
                    OR (state='processing' AND lease_expires_gmt<=%s))",
                self::date($now), self::date($now), $id, self::date($now)
            ));
            $blocked += 1 === $changed ? 1 : 0;
        }
        return $blocked;
    }

    public function cleanup($cutoff, $limit)
    {
        global $wpdb;
        $table = Akkedli_V2_Outbox_Schema::table();
        return $wpdb->query($wpdb->prepare(
            "DELETE FROM {$table} WHERE operation='status' AND envelope IS NULL
             AND state IN ('confirmed','rejected','exhausted') AND completed_gmt<%s LIMIT %d",
            self::date($cutoff), $limit
        ));
    }

    private function claimed($id, $owner, $state)
    {
        global $wpdb;
        $table = Akkedli_V2_Outbox_Schema::table();
        return $wpdb->get_row($wpdb->prepare(
            "SELECT id,event_id,order_key,operation,envelope,state,capture_attempts,attempts,
                last_outcome,created_gmt
             FROM {$table} WHERE id=%d AND lease_owner=%s AND state=%s LIMIT 1",
            $id, $owner, $state
        ), ARRAY_A);
    }

    private function transition($id, $owner, $expected, array $fields, $now)
    {
        global $wpdb;
        $table = Akkedli_V2_Outbox_Schema::table();
        $sets = array();
        $values = array();
        foreach ($fields as $field => $value) {
            $sets[] = "{$field}=" . (null === $value ? 'NULL' : '%s');
            if (null !== $value) {
                $values[] = $value;
            }
        }
        $sets[] = 'lease_owner=NULL';
        $sets[] = 'lease_expires_gmt=NULL';
        $sets[] = 'updated_gmt=%s';
        $values[] = self::date($now);
        $values[] = $id;
        $values[] = $owner;
        $values[] = $expected;
        $query = "UPDATE {$table} SET " . implode(',', $sets)
            . ' WHERE id=%d AND lease_owner=%s AND state=%s';
        return 1 === $wpdb->query($wpdb->prepare($query, $values));
    }

    private static function date($timestamp)
    {
        return gmdate('Y-m-d H:i:s', (int) $timestamp);
    }
}