<?php
/**
 * Transaction_Store - the write-ahead operational store. A record is saved with
 * status 'pending' BEFORE the INSTANDA HTTP call, so a fatal or timeout can never
 * lose a submission. Powers the resubmit queue and retention.
 *
 * Retention is delivered-only: the cron purge removes confirmed-delivered records
 * past their window and NEVER deletes pending or failed records (they wait for an
 * admin to resolve them).
 *
 * @package ESP\Instanda
 */

declare(strict_types=1);

namespace ESP\Instanda;

/** Lifecycle status of a transaction. */
enum Tx_Status: string {
    case Pending   = 'pending';
    case Delivered = 'delivered';
    case Failed    = 'failed';
}

/** Hydrated transaction row. */
final class Transaction {
    public int $id = 0;
    public ?int $entry_id = null;
    public ?int $form_id = null;
    public string $status = 'pending';
    public string $environment = 'test';
    public string $dedupe_key = '';
    public bool $possible_duplicate = false;
    public string $customer_email = '';
    public string $role_label = '';
    public ?string $quote_ref = null;
    public ?string $quote_url = null;
    public string $redacted_payload = '';
    public ?int $http_status = null;
    public ?string $response_excerpt = null;
    public int $retry_count = 0;
    public ?string $error_detail = null;
    /** @var list<array{ts:string,level:string,message:string}> */
    public array $event_log = [];
    public string $created_at = '';
    public ?string $delivered_at = null;
    public ?string $expiry = null;

    /** @param array<string,mixed> $row */
    public static function from_row(array $row): self {
        $t = new self();
        $t->id                 = (int) ($row['id'] ?? 0);
        $t->entry_id           = isset($row['entry_id']) ? (int) $row['entry_id'] : null;
        $t->form_id            = isset($row['form_id']) ? (int) $row['form_id'] : null;
        $t->status             = (string) ($row['status'] ?? 'pending');
        $t->environment        = (string) ($row['environment'] ?? 'test');
        $t->dedupe_key         = (string) ($row['dedupe_key'] ?? '');
        $t->possible_duplicate = (bool) ($row['possible_duplicate'] ?? false);
        $t->customer_email     = (string) ($row['customer_email'] ?? '');
        $t->role_label         = (string) ($row['role_label'] ?? '');
        $t->quote_ref          = $row['quote_ref'] !== null ? (string) $row['quote_ref'] : null;
        $t->quote_url          = $row['quote_url'] !== null ? (string) $row['quote_url'] : null;
        $t->redacted_payload   = (string) ($row['redacted_payload'] ?? '');
        $t->http_status        = isset($row['http_status']) && $row['http_status'] !== null ? (int) $row['http_status'] : null;
        $t->response_excerpt   = $row['response_excerpt'] !== null ? (string) $row['response_excerpt'] : null;
        $t->retry_count        = (int) ($row['retry_count'] ?? 0);
        $t->error_detail       = $row['error_detail'] !== null ? (string) $row['error_detail'] : null;
        $t->event_log          = $row['event_log'] ? (array) json_decode((string) $row['event_log'], true) : [];
        $t->created_at         = (string) ($row['created_at'] ?? '');
        $t->delivered_at       = $row['delivered_at'] !== null ? (string) $row['delivered_at'] : null;
        $t->expiry             = $row['expiry'] !== null ? (string) $row['expiry'] : null;
        return $t;
    }
}

final class Transaction_Store {

    public const DB_VERSION        = '1.0.0';
    public const DB_VERSION_OPTION = 'espinstanda_db_version';
    private const TABLE            = 'esp_instanda_transactions';

    public static function table_name(): string {
        global $wpdb;
        return $wpdb->prefix . self::TABLE;
    }

    /* ----------------------------------------------------------------- schema */

    public static function install_table(): void {
        global $wpdb;
        require_once ABSPATH . 'wp-admin/includes/upgrade.php';

        $table   = self::table_name();
        $charset = $wpdb->get_charset_collate();

        $sql = "CREATE TABLE {$table} (
  id bigint(20) unsigned NOT NULL auto_increment,
  entry_id bigint(20) unsigned DEFAULT NULL,
  form_id bigint(20) unsigned DEFAULT NULL,
  status varchar(20) NOT NULL DEFAULT 'pending',
  environment varchar(10) NOT NULL DEFAULT 'test',
  dedupe_key varchar(64) NOT NULL DEFAULT '',
  possible_duplicate tinyint(1) NOT NULL DEFAULT 0,
  customer_email varchar(191) NOT NULL DEFAULT '',
  role_label varchar(191) NOT NULL DEFAULT '',
  quote_ref varchar(100) DEFAULT NULL,
  quote_url text DEFAULT NULL,
  redacted_payload longtext NOT NULL,
  http_status smallint(5) unsigned DEFAULT NULL,
  response_excerpt text DEFAULT NULL,
  retry_count tinyint(3) unsigned NOT NULL DEFAULT 0,
  error_detail text DEFAULT NULL,
  event_log longtext DEFAULT NULL,
  created_at datetime NOT NULL DEFAULT '0000-00-00 00:00:00',
  delivered_at datetime DEFAULT NULL,
  expiry datetime DEFAULT NULL,
  PRIMARY KEY  (id),
  KEY status (status),
  KEY environment (environment),
  KEY created_at (created_at),
  KEY expiry (expiry),
  KEY entry_id (entry_id),
  KEY dedupe_key (dedupe_key),
  KEY status_env (status,environment)
) {$charset};";

        dbDelta($sql);
        update_option(self::DB_VERSION_OPTION, self::DB_VERSION);
    }

    public static function needs_migration(): bool {
        return version_compare((string) get_option(self::DB_VERSION_OPTION, '0'), self::DB_VERSION, '<');
    }

    /* ----------------------------------------------------------------- writes */

    /** Write-ahead insert. Returns the new row id (0 on failure). */
    public function create_pending(Transaction $t): int {
        global $wpdb;
        $now = current_time('mysql');
        $t->event_log[] = self::event('Write-ahead record created (status: pending)');

        $ok = $wpdb->insert(self::table_name(), [
            'entry_id'           => $t->entry_id,
            'form_id'            => $t->form_id,
            'status'             => Tx_Status::Pending->value,
            'environment'        => $t->environment,
            'dedupe_key'         => $t->dedupe_key,
            'possible_duplicate' => 0,
            'customer_email'     => $t->customer_email,
            'role_label'         => $t->role_label,
            'redacted_payload'   => $t->redacted_payload,
            'retry_count'        => 0,
            'event_log'          => wp_json_encode($t->event_log),
            'created_at'         => $now,
        ], ['%d', '%d', '%s', '%s', '%s', '%d', '%s', '%s', '%s', '%d', '%s', '%s']);

        return $ok ? (int) $wpdb->insert_id : 0;
    }

    public function mark_success(int $id, string $quote_ref, ?string $quote_url, ?int $http_status): void {
        $delivered = current_time('mysql');
        $this->update($id, [
            'status'           => Tx_Status::Delivered->value,
            'quote_ref'        => $quote_ref,
            'quote_url'        => $quote_url,
            'http_status'      => $http_status,
            'delivered_at'     => $delivered,
            'expiry'           => $this->compute_expiry($delivered),
        ], 'Delivered - quoteRef ' . $quote_ref);
    }

    public function mark_failed(int $id, ?int $http_status, ?string $response_excerpt, string $error_detail): void {
        $this->update($id, [
            'status'           => Tx_Status::Failed->value,
            'http_status'      => $http_status,
            'response_excerpt' => $response_excerpt,
            'error_detail'     => $error_detail,
        ], 'Failed - ' . $error_detail);
    }

    public function mark_ambiguous(int $id, ?int $http_status, string $error_detail): void {
        $this->update($id, [
            'status'             => Tx_Status::Failed->value,
            'possible_duplicate' => 1,
            'http_status'        => $http_status,
            'error_detail'       => $error_detail,
        ], 'Ambiguous timeout - flagged possible duplicate');
    }

    public function increment_retry(int $id): void {
        global $wpdb;
        $table = self::table_name();
        $wpdb->query($wpdb->prepare("UPDATE {$table} SET retry_count = retry_count + 1 WHERE id = %d", $id));
    }

    public function attach_entry(int $id, int $entry_id): void {
        $this->update($id, ['entry_id' => $entry_id], null);
    }

    public function append_event(int $id, string $message, string $level = 'info'): void {
        $t = $this->find($id);
        if ($t === null) {
            return;
        }
        $t->event_log[] = self::event($message, $level);
        $this->update($id, ['event_log' => wp_json_encode($t->event_log)], null);
    }

    /* ----------------------------------------------------------------- reads */

    public function find(int $id): ?Transaction {
        global $wpdb;
        $table = self::table_name();
        $row = $wpdb->get_row($wpdb->prepare("SELECT * FROM {$table} WHERE id = %d", $id), ARRAY_A);
        return $row ? Transaction::from_row($row) : null;
    }

    public function find_by_dedupe(string $dedupe_key): ?Transaction {
        global $wpdb;
        $table = self::table_name();
        $row = $wpdb->get_row(
            $wpdb->prepare("SELECT * FROM {$table} WHERE dedupe_key = %s ORDER BY id DESC LIMIT 1", $dedupe_key),
            ARRAY_A
        );
        return $row ? Transaction::from_row($row) : null;
    }

    public function find_by_entry(int $entry_id): ?Transaction {
        global $wpdb;
        $table = self::table_name();
        $row = $wpdb->get_row(
            $wpdb->prepare("SELECT * FROM {$table} WHERE entry_id = %d ORDER BY id DESC LIMIT 1", $entry_id),
            ARRAY_A
        );
        return $row ? Transaction::from_row($row) : null;
    }

    /**
     * Most recent delivered transaction for a customer email within a window.
     * Self-recovery guard: do not resubmit/email if the customer already succeeded.
     */
    public function recent_success_for_email(string $email, int $within_seconds): ?Transaction {
        global $wpdb;
        $table = self::table_name();
        $cutoff = gmdate('Y-m-d H:i:s', time() - $within_seconds);
        $row = $wpdb->get_row($wpdb->prepare(
            "SELECT * FROM {$table} WHERE customer_email = %s AND status = %s AND delivered_at >= %s ORDER BY id DESC LIMIT 1",
            $email, Tx_Status::Delivered->value, $cutoff
        ), ARRAY_A);
        return $row ? Transaction::from_row($row) : null;
    }

    /**
     * Paged list for the admin browser, scoped to the active environment.
     *
     * @param array{status?:string} $filters
     * @return list<Transaction>
     */
    public function query(array $filters, int $page, int $per_page): array {
        global $wpdb;
        $table = self::table_name();
        $where = ['environment = %s'];
        $args  = [Config::environment()->value];

        if (!empty($filters['status']) && in_array($filters['status'], ['delivered', 'failed', 'pending'], true)) {
            $where[] = 'status = %s';
            $args[]  = $filters['status'];
        }

        $offset = max(0, ($page - 1) * $per_page);
        $sql = "SELECT * FROM {$table} WHERE " . implode(' AND ', $where)
            . ' ORDER BY id DESC LIMIT %d OFFSET %d';
        $args[] = $per_page;
        $args[] = $offset;

        $rows = $wpdb->get_results($wpdb->prepare($sql, $args), ARRAY_A) ?: [];
        return array_map([Transaction::class, 'from_row'], $rows);
    }

    /** Status counts for the active environment (powers the list-table views). */
    public function counts(): array {
        global $wpdb;
        $table = self::table_name();
        $env   = Config::environment()->value;
        $rows  = $wpdb->get_results($wpdb->prepare(
            "SELECT status, COUNT(*) AS n FROM {$table} WHERE environment = %s GROUP BY status", $env
        ), ARRAY_A) ?: [];

        $counts = ['all' => 0, 'delivered' => 0, 'failed' => 0, 'pending' => 0];
        foreach ($rows as $row) {
            $status = (string) $row['status'];
            $n      = (int) $row['n'];
            $counts['all'] += $n;
            if (isset($counts[$status])) {
                $counts[$status] += $n;
            }
        }
        return $counts;
    }

    /** Unresolved (failed + pending) count in the active env - powers the failure badge. */
    public function unresolved_count(): int {
        $c = $this->counts();
        return $c['failed'] + $c['pending'];
    }

    /* ----------------------------------------------------------------- retention */

    /**
     * Purge ONLY delivered records past the retention window for the given env.
     * Pending/failed are never deleted on a timer. Returns the number removed.
     */
    public function purge_delivered_older_than(int $days, Environment $env): int {
        global $wpdb;
        $table  = self::table_name();
        $cutoff = gmdate('Y-m-d H:i:s', time() - ($days * DAY_IN_SECONDS));
        return (int) $wpdb->query($wpdb->prepare(
            "DELETE FROM {$table} WHERE status = %s AND environment = %s AND delivered_at IS NOT NULL AND delivered_at < %s",
            Tx_Status::Delivered->value, $env->value, $cutoff
        ));
    }

    /* ----------------------------------------------------------------- internals */

    private function update(int $id, array $data, ?string $event): void {
        global $wpdb;
        if ($event !== null) {
            $t = $this->find($id);
            if ($t !== null) {
                $t->event_log[] = self::event($event);
                $data['event_log'] = wp_json_encode($t->event_log);
            }
        }
        $wpdb->update(self::table_name(), $data, ['id' => $id]);
    }

    private function compute_expiry(string $delivered_at): string {
        $days = (int) get_option('espinstanda_retention_days', 7);
        $ts   = strtotime($delivered_at) ?: time();
        return gmdate('Y-m-d H:i:s', $ts + ($days * DAY_IN_SECONDS));
    }

    /** @return array{ts:string,level:string,message:string} */
    private static function event(string $message, string $level = 'info'): array {
        return ['ts' => current_time('mysql'), 'level' => $level, 'message' => Logger::redact($message)];
    }
}