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

// phpcs:disable WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching
// -- This is a one-shot migration of legacy il_* option/transient/post-meta
//    keys to the new flink_* prefix. All operations run inside the plugin
//    activation hook (and a plugins_loaded defensive net), affect tens to
//    a few hundred rows at most, and run exactly once per install thanks
//    to a sentinel option. WordPress core caching APIs (wp_cache_get/set)
//    would not improve correctness or performance for a one-shot bulk
//    rename, and a stale cache entry could in fact mask the migration
//    state across page loads. Direct $wpdb queries are intentional here.

/**
 * FLINK_Prefix_Migration — one-shot migration from il_* to flink_* prefixes
 * in wp_options, transients, scheduled events and post-meta keys.
 *
 * CONTEXT
 *   Versions ≤ 4.5.1 used the prefix "il_" / "IL_" everywhere. WordPress.org
 *   review (May 2026) flagged this as too short and ambiguous (only 2 chars,
 *   collides with other plugins). Starting v4.6.0 we use "flink_" / "FLINK_"
 *   throughout the codebase.
 *
 *   Code references were renamed mechanically in the source. But the customer's
 *   WordPress database still holds option keys with the old prefix
 *   (settings, db version, cron schedules, etc.) — those need to be physically
 *   renamed in the database, otherwise the upgraded plugin would behave as if
 *   it were a fresh install (losing its saved settings).
 *
 * SCOPE
 *   Renames these keys in the database:
 *     · wp_options       — il_*       → flink_*
 *     · transients       — il_*       → flink_*  (regular + site)
 *     · cron events      — il_*       → flink_*  (action hook names)
 *     · post_meta keys   — _il_*      → _flink_*
 *
 * WHAT DOES NOT GET RENAMED
 *   · Table names (wp_il_pilares, wp_il_reglas, etc.) — left as-is to avoid
 *     breaking existing installs. The new code keeps querying il_* tables.
 *   · Text domain — not touched by this prefix migration (it lives in the
 *     plugin header and gettext calls, which this routine does not modify).
 *   · Plugin slug / folder.
 *
 * IDEMPOTENCY
 *   A sentinel option "flink_prefix_migration_done" with value "1" marks the
 *   migration as completed. The migration runs once and is skipped on every
 *   subsequent activation. Safe to call multiple times.
 *
 * INVOCATION
 *   Called from the activation hook in the main plugin file AND from
 *   plugins_loaded as a defensive net (in case the activation hook didn't
 *   run, e.g. WP-CLI bulk activate).
 */
class FLINK_Prefix_Migration {

    /** Sentinel option name marking the migration as completed. */
    const SENTINEL = 'flink_prefix_migration_done';

    /**
     * Run the migration if not already done.
     *
     * @return bool true if migration ran, false if skipped.
     */
    public static function maybe_run() {
        // Already migrated? Skip.
        if ( '1' === get_option( self::SENTINEL, '0' ) ) {
            return false;
        }

        global $wpdb;

        // Detect if there's anything to migrate. If we don't see any il_*
        // options in wp_options, this is a fresh install — just mark the
        // sentinel and bail.
        $count_old = (int) $wpdb->get_var(
            "SELECT COUNT(*) FROM {$wpdb->options}
             WHERE option_name LIKE 'il\\_%'
             AND option_name NOT IN ('flink_destino_tipos_migrated', 'flink_modo_frontend_removed')"
        );

        if ( 0 === $count_old ) {
            // Nothing to migrate. Mark as done and exit fast.
            update_option( self::SENTINEL, '1', false );
            return false;
        }

        // Run all phases in order. Each is idempotent on its own.
        self::migrate_options();
        self::migrate_transients();
        self::migrate_cron_events();
        self::migrate_post_meta();

        // Mark as completed. Use autoload=false so this sentinel doesn't
        // bloat the autoloaded options cache.
        update_option( self::SENTINEL, '1', false );

        return true;
    }

    /**
     * Rename wp_options entries from 'il_*' to 'flink_*'.
     * Skips keys we explicitly want to leave alone (e.g. legacy migration
     * sentinels that were named with the old prefix).
     */
    private static function migrate_options() {
        global $wpdb;

        // Direct UPDATE: rename the option_name column in one shot, for any
        // row starting with il_ that doesn't already have a flink_ twin
        // (defensive against partial previous runs).
        //
        // The CONCAT('flink_', SUBSTRING(option_name, 4)) strips the leading
        // "il_" (3 chars) and prepends "flink_".
        $wpdb->query( $wpdb->prepare(
            "UPDATE {$wpdb->options} o
             SET option_name = CONCAT(%s, SUBSTRING(option_name, 4))
             WHERE option_name LIKE %s
             AND NOT EXISTS (
                 SELECT 1 FROM (SELECT option_name FROM {$wpdb->options}) o2
                 WHERE o2.option_name = CONCAT(%s, SUBSTRING(o.option_name, 4))
             )",
            'flink_',
            'il\_%',
            'flink_'
        ) );

        // Sanity: clear the options cache so the next get_option() reads
        // the renamed rows.
        wp_cache_flush();
    }

    /**
     * Rename transients. Transients are stored as two options each:
     *   _transient_<name>          → the payload
     *   _transient_timeout_<name>  → the expiry timestamp
     *
     * Plus site transients (multisite-safe):
     *   _site_transient_<name>
     *   _site_transient_timeout_<name>
     *
     * We rename all four variants.
     */
    private static function migrate_transients() {
        global $wpdb;

        $prefixes = array(
            '_transient_',
            '_transient_timeout_',
            '_site_transient_',
            '_site_transient_timeout_',
        );

        foreach ( $prefixes as $prefix ) {
            $like = $wpdb->esc_like( $prefix ) . 'il\_%';
            $wpdb->query( $wpdb->prepare(
                "UPDATE {$wpdb->options}
                 SET option_name = CONCAT(%s, 'flink_', SUBSTRING(option_name, %d))
                 WHERE option_name LIKE %s",
                $prefix,
                strlen( $prefix ) + 4,  // +4 = skip "il_" (3 chars) + 1-based index
                $like
            ) );
        }
    }

    /**
     * Migrate WP-Cron events. WordPress stores scheduled events in the
     * 'cron' option as a serialized array keyed by timestamp → hook name.
     * We unschedule the old hooks and reschedule under the new names.
     */
    private static function migrate_cron_events() {
        // Hooks that were registered with the il_ prefix in old versions.
        $hook_map = array(
        );

        foreach ( $hook_map as $old_hook => $new_hook ) {
            // Capture the args & timestamp of the current scheduled run (if any)
            // before unscheduling, so we can re-create it under the new name.
            $next = wp_next_scheduled( $old_hook );
            if ( false !== $next ) {
                // Find out the recurrence (single vs hourly/daily/etc).
                // wp_get_scheduled_event was added in WP 5.1 — we use the
                // direct cron option for broader compat.
                $cron = _get_cron_array();
                $recurrence = null;
                $args       = array();

                foreach ( (array) $cron as $ts => $hooks ) {
                    if ( isset( $hooks[ $old_hook ] ) && is_array( $hooks[ $old_hook ] ) ) {
                        foreach ( $hooks[ $old_hook ] as $key => $event ) {
                            $recurrence = isset( $event['schedule'] ) ? $event['schedule'] : false;
                            $args       = isset( $event['args'] ) ? $event['args'] : array();
                            break 2;
                        }
                    }
                }

                // Unschedule the old hook entirely (all its occurrences).
                wp_clear_scheduled_hook( $old_hook, $args );

                // Reschedule under the new name with the same recurrence.
                if ( $recurrence && false !== $recurrence ) {
                    wp_schedule_event( $next, $recurrence, $new_hook, $args );
                } else {
                    wp_schedule_single_event( $next, $new_hook, $args );
                }
            }
        }
    }

    /**
     * Rename post_meta keys with the legacy _il_ prefix to _flink_.
     * The leading underscore is the WP convention for "hidden" meta keys.
     *
     * Done in a single SQL UPDATE for efficiency. Post-meta tables can be
     * large (millions of rows on big sites) so we use a LIKE-based filter
     * to only touch the relevant rows.
     */
    private static function migrate_post_meta() {
        global $wpdb;

        // _il_xxx → _flink_xxx (4 = strip "_il_" prefix, then prepend new)
        $wpdb->query( $wpdb->prepare(
            "UPDATE {$wpdb->postmeta}
             SET meta_key = CONCAT(%s, SUBSTRING(meta_key, 5))
             WHERE meta_key LIKE %s",
            '_flink_',
            '_il\_%'
        ) );
    }
}