<?php

namespace StoreSuit;

defined( 'ABSPATH' ) || exit;
/**
 * Keeps a store from outgrowing its host, with nothing for the owner to set. On a live store (4 Nov 2026) the host took
 * INSERT and UPDATE away from the database user at about 3 GB and a job that could not save its place wrote 26 GB of errors.
 *
 * Hourly: the site's own PHP logs are cut back when they pass 200 MB. Daily: the database size is noted, and what is only a
 * working record goes after a stated time. What is kept and for how long:
 * - Action Scheduler's finished jobs: 7 days, by its own cleaner (20 rows at a time), for every plugin's jobs. Failed ones stay.
 * - Catalogue import changes: 30 days after the run ended; undo is only offered for 7.
 * - Finished connection jobs: 180 days.
 * - Activity log, the entries named in AUDIT_ONLY: 2 years.
 * - Everything else in the activity log stays: it also holds collections, stock moves and order history other screens read.
 * Never touched here: orders, money, stock, customers, legal records, other plugins' tables. Tables that already clear their
 * own rows (cart signals, cart reminders, email history, 404s, alerts, consent stats) keep doing so. The marketplace tables
 * look after themselves in MarketplaceV2.
 */
final class Housekeeping {
    public const HOOK = 'storeruler_housekeeping';

    public const SIZES = 'storeruler_database_days';

    private const DAY = 'storeruler_housekeeping_day';

    private const TOLD = 'storeruler_database_told';

    private const QUEUE_DAYS = 7;

    private const CATALOG_DAYS = 30;

    private const JOB_DAYS = 180;

    private const AUDIT_DAYS = 730;

    private const BATCH = 1000;

    private const BATCHES = 20;

    private const TELL_EVERY = 7 * DAY_IN_SECONDS;

    /** Size that many hosts stop at; hosts' limits cannot be read. */
    private const LIMIT_MB = 3072;

    /** Below this a store is not growing in any way that matters. */
    private const MIN_PACE_MB = 10;

    private const WARN_DAYS = 14;

    public static function hooks() : void {
        add_action( self::HOOK, array(__CLASS__, 'run') );
        add_filter( 'action_scheduler_retention_period', array(__CLASS__, 'queue_kept') );
        // Not on a shopper's page view: wp-cron's own request and the admin screens keep it scheduled.
        if ( Store::upkeep_request() ) {
            add_action( 'init', static function () {
                if ( !wp_next_scheduled( self::HOOK ) ) {
                    wp_schedule_event( time() + HOUR_IN_SECONDS, 'hourly', self::HOOK );
                }
            }, 99 );
        }
    }

    /** Shorter than the 30 days Action Scheduler keeps by default; a shorter choice made elsewhere stands. */
    public static function queue_kept( $seconds ) : int {
        return min( (int) $seconds, self::QUEUE_DAYS * DAY_IN_SECONDS );
    }

    /**
     * May run many times an hour while the database refuses writes, because WordPress cannot then move the schedule on: the
     * log check is only a stat, and nothing below it tries a write again in the same run.
     */
    public static function run() : void {
        $refused = self::writes_refused();
        if ( $refused ) {
            self::tell_refused();
            return;
        }
        $today = gmdate( 'Y-m-d' );
        // Not saved, not run: the same work must not start again on the next cron request.
        if ( get_option( self::DAY ) === $today || !update_option( self::DAY, $today, false ) ) {
            return;
        }
        self::note_size();
        self::prune();
        self::tell_growth();
    }

    /** True when the database user has lost INSERT or UPDATE. Hosts do this at their limit, and say nothing. */
    public static function writes_refused() : bool {
        global $wpdb;
        $can = '';
        foreach ( (array) $wpdb->get_col( 'SHOW GRANTS' ) as $grant ) {
            $can .= ' ' . strstr( (string) $grant . ' ON ', ' ON ', true );
        }
        return trim( $can ) !== '' && stripos( $can, 'ALL PRIVILEGES' ) === false && (stripos( $can, 'INSERT' ) === false || stripos( $can, 'UPDATE' ) === false);
    }

    /* ---------- Working records ---------- */
    private static function prune() : void {
        global $wpdb;
        $events = $wpdb->prefix . 'storesuit_events';
        if ( self::exists( $events ) ) {
            $before = gmdate( 'Y-m-d H:i:s', time() - self::AUDIT_DAYS * DAY_IN_SECONDS );
            // Only entries nothing but the activity log reads. Collections, stock moves, order and customer history stay for good.
            for ($i = 0; $i < self::BATCHES; $i++) {
                $gone = $wpdb->query( $wpdb->prepare(
                    "DELETE FROM %i WHERE event IN ('redirect_saved','quick_edited','readiness_saved','publication_changed','health_template_default','log_trimmed') AND created_at<%s LIMIT %d",
                    $events,
                    $before,
                    self::BATCH
                ) );
                if ( self::batch_ended( $gone ) ) {
                    break;
                }
            }
        }
        $runs = $wpdb->prefix . 'storesuit_catalog_runs';
        $changes = $wpdb->prefix . 'storesuit_catalog_changes';
        if ( self::exists( $runs ) && self::exists( $changes ) ) {
            $ended = (int) $wpdb->get_var( $wpdb->prepare( "SELECT MAX(id) FROM %i WHERE status IN ('done','undone','failed') AND finished<%s", $runs, gmdate( 'Y-m-d H:i:s', time() - self::CATALOG_DAYS * DAY_IN_SECONDS ) ) );
            // A run still going below that one keeps its records.
            $open = (int) $wpdb->get_var( $wpdb->prepare( "SELECT MIN(id) FROM %i WHERE status IN ('queued','running','undoing')", $runs ) );
            if ( $open && $open <= $ended ) {
                $ended = $open - 1;
            }
            for ($i = 0; $ended > 0 && $i < self::BATCHES; $i++) {
                $gone = $wpdb->query( $wpdb->prepare(
                    'DELETE FROM %i WHERE run_id<=%d LIMIT %d',
                    $changes,
                    $ended,
                    self::BATCH
                ) );
                if ( self::batch_ended( $gone ) ) {
                    break;
                }
            }
        }
        $jobs = $wpdb->prefix . 'storesuit_connection_jobs';
        if ( self::exists( $jobs ) ) {
            $before = gmdate( 'Y-m-d H:i:s', time() - self::JOB_DAYS * DAY_IN_SECONDS );
            for ($i = 0; $i < self::BATCHES; $i++) {
                $gone = $wpdb->query( $wpdb->prepare(
                    "DELETE FROM %i WHERE status IN ('complete','failed') AND updated_at<%s LIMIT %d",
                    $jobs,
                    $before,
                    self::BATCH
                ) );
                if ( self::batch_ended( $gone ) ) {
                    break;
                }
            }
        }
    }

    /** A short delete means the table is done. A refused one ends it too: the rest waits for tomorrow. */
    private static function batch_ended( $gone ) : bool {
        return $gone === false || (int) $gone < self::BATCH;
    }

    private static function exists( string $table ) : bool {
        global $wpdb;
        return $wpdb->get_var( $wpdb->prepare( 'SHOW TABLES LIKE %s', $wpdb->esc_like( $table ) ) ) === $table;
    }

    /* ---------- Size and warnings ---------- */
    private static function note_size() : void {
        global $wpdb;
        $mb = (int) round( (float) $wpdb->get_var( $wpdb->prepare( 'SELECT SUM(data_length+index_length)/1048576 FROM information_schema.tables WHERE table_schema=%s', DB_NAME ) ) );
        if ( $mb <= 0 ) {
            return;
        }
        $days = (array) get_option( self::SIZES, array() );
        $days[gmdate( 'Y-m-d' )] = $mb;
        ksort( $days );
        update_option( self::SIZES, array_slice(
            $days,
            -15,
            null,
            true
        ), false );
    }

    /** Megabytes a day over the last week of daily sizes, or 0 before two days lie between the first and last. */
    public static function pace() : float {
        $days = array_slice(
            (array) get_option( self::SIZES, array() ),
            -8,
            null,
            true
        );
        if ( count( $days ) < 2 ) {
            return 0.0;
        }
        $dates = array_keys( $days );
        $span = (strtotime( (string) end( $dates ) . ' UTC' ) - strtotime( (string) reset( $dates ) . ' UTC' )) / DAY_IN_SECONDS;
        return ( $span >= 2 ? (float) (end( $days ) - reset( $days )) / $span : 0.0 );
    }

    public static function limit_mb() : int {
        return max( 1, (int) apply_filters( 'storeruler_database_limit_mb', self::LIMIT_MB ) );
    }

    /** Days until the size many hosts stop at, at this pace; null when the store is not growing fast enough for that to matter. */
    public static function days_left( int $total ) : ?int {
        $pace = self::pace();
        if ( $pace < self::MIN_PACE_MB ) {
            return null;
        }
        $left = (int) ceil( max( 0, self::limit_mb() - $total ) / $pace );
        return ( $left <= self::WARN_DAYS ? $left : null );
    }

    private static function tell_growth() : void {
        $room = Health::database_room();
        if ( !$room || $room['status'] !== 'attention' || time() - (int) get_option( self::TOLD, 0 ) < self::TELL_EVERY ) {
            return;
        }
        // Not saved, not sent: a message must not go out again with every run.
        if ( update_option( self::TOLD, time(), false ) ) {
            self::mail( (string) $room['summary'], (string) $room['detail'] );
        }
    }

    /**
     * The database can't remember a message was sent, so a small file in the temporary folder does. No file, no message.
     */
    private static function tell_refused() : void {
        $stamp = trailingslashit( get_temp_dir() ) . 'storeruler-db-refused-' . md5( ABSPATH );
        if ( file_exists( $stamp ) && time() - (int) filemtime( $stamp ) < DAY_IN_SECONDS ) {
            return;
        }
        // phpcs:disable WordPress.PHP.NoSilencedErrors.Discouraged,WordPress.WP.AlternativeFunctions.file_system_operations_touch -- Remembers that the message went out while the database refuses writes; a folder that refuses it just means no message.
        if ( !@touch( $stamp ) ) {
            return;
        }
        // phpcs:enable WordPress.PHP.NoSilencedErrors.Discouraged,WordPress.WP.AlternativeFunctions.file_system_operations_touch
        self::mail( I18n::t( 'The database refuses new records.' ), I18n::t( 'New orders, stock changes and settings cannot be saved. This usually means the database reached the hosting limit: ask your host to give the database user its write permissions back.' ) );
    }

    private static function mail( string $summary, string $detail ) : void {
        if ( !apply_filters( 'storeruler_database_mail', true ) ) {
            return;
        }
        wp_mail( (string) get_option( 'admin_email' ), sprintf( '[%1$s] %2$s', wp_specialchars_decode( (string) get_option( 'blogname' ), ENT_QUOTES ), $summary ), $detail . "\n\n" . admin_url( 'admin.php?page=storesuit-settings#ss-health' ) );
    }

}