<?php
/**
 * TMDO_Term_Comment_Garbage_Filter — Block known-garbage writes to
 * wp_termmeta / wp_commentmeta at the metadata filter layer (v2.12.1 Phase 1).
 *
 * Phase 0 (v2.12.0) provided cleanup CLI to delete historical garbage. This
 * filter prevents the same garbage from accumulating again by intercepting
 * writes via WordPress metadata filters (`add_term_metadata`, etc.) and
 * silently dropping them — short-circuiting the database INSERT entirely.
 *
 * Targets (must align with TMDO_Termmeta_Cleaner / TMDO_Commentmeta_Cleaner):
 *
 *   wp_termmeta + wp_commentmeta:
 *     - meta_key matching `_wxr_import_*` (WordPress importer residue —
 *       written once during WXR import, never read afterward)
 *     - meta_key matching `_2meet_demo_*` (project-specific demo markers,
 *       safe to drop and re-seed)
 *
 *   wp_commentmeta only (orphan post-meta keys):
 *     - 8 hardcoded keys from TMDO_Commentmeta_Cleaner::ORPHAN_POST_META_KEYS
 *       — these are bugs / typos writing post-domain meta to comment table
 *
 * Read paths are NOT filtered. Existing rows in wp_*meta still resolve normally
 * via standard WP metadata API; once cleanup CLI runs, reads naturally return
 * empty. This minimizes risk of breaking any reader code that still expects
 * the keys (none should, but defense in depth).
 *
 * Init: hooks registered on `init` priority 5 from TMDO_Core (after
 * HivePress's plugins_loaded:5 boot, before main entity bridge filters at 10).
 *
 * Lessons applied from v2.11.7 — this class is added to
 * TMDO_Hook_Bus_Bridge::COEXIST_WHITELIST so `wp wpdo conflict-scan` does not
 * report a false positive when both Hook Bus and this filter run on the same
 * `add_term_metadata` / `add_comment_metadata` hook.
 *
 * @package WP_Data_Optimizer
 * @since   2.12.1
 */

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

/**
 * Block known-garbage writes to wp_termmeta / wp_commentmeta.
 */
final class TMDO_Term_Comment_Garbage_Filter {

	/** Option key for admin toggle. */
	public const OPT_ENABLED = 'wpdo_term_comment_garbage_filter_enabled';

	/** Telemetry option: count of garbage writes dropped (rolling 24h cumulative). */
	public const OPT_DROPPED_COUNT = 'wpdo_term_comment_garbage_drops_24h';

	/** Telemetry option: timestamp of the last reset of the 24h counter. */
	public const OPT_DROPPED_RESET_AT = 'wpdo_term_comment_garbage_drops_reset_at';

	/**
	 * Pattern prefixes that trigger a drop on writes to BOTH wp_termmeta and
	 * wp_commentmeta. Aligned with cleanup CLI `--target` buckets.
	 *
	 * @var string[]
	 */
	private const SHARED_DROP_PREFIXES = array(
		'_wxr_import_',
		'_2meet_demo_',
	);

	/**
	 * Exact meta_keys that are dropped only for wp_commentmeta writes
	 * (post-domain keys mistakenly written to comment table — always a bug).
	 *
	 * Must stay in sync with TMDO_Commentmeta_Cleaner::ORPHAN_POST_META_KEYS.
	 *
	 * @var string[]
	 */
	private const COMMENT_ONLY_ORPHAN_KEYS = array(
		'_hp_price',
		'_hp_status',
		'_hp_featured',
		'_hp_verified',
		'_hp_view_count',
		'_thumbnail_id',
		'_edit_lock',
		'_edit_last',
	);

	/**
	 * Register filters. Called from TMDO_Core::run() on init:5.
	 *
	 * Idempotent — safe to call multiple times.
	 *
	 * @return void
	 */
	public static function init(): void {
		if ( ! self::is_enabled() ) {
			return;
		}

		// Term meta writes — priority 9 (before Hook Bus at 10).
		add_filter( 'add_term_metadata', array( self::class, 'on_term_write' ), 9, 5 );
		add_filter( 'update_term_metadata', array( self::class, 'on_term_write' ), 9, 5 );

		// Comment meta writes.
		add_filter( 'add_comment_metadata', array( self::class, 'on_comment_write' ), 9, 5 );
		add_filter( 'update_comment_metadata', array( self::class, 'on_comment_write' ), 9, 5 );
	}

	/**
	 * Check the admin toggle. Defaults to enabled.
	 *
	 * @return bool
	 */
	public static function is_enabled(): bool {
		return (bool) get_option( self::OPT_ENABLED, '1' );
	}

	/**
	 * Test whether a meta_key triggers the shared drop rules
	 * (applicable to both term and comment meta).
	 *
	 * @param mixed $meta_key Candidate meta_key.
	 * @return bool
	 */
	public static function is_shared_garbage_key( $meta_key ): bool {
		if ( ! is_string( $meta_key ) ) {
			return false;
		}
		foreach ( self::SHARED_DROP_PREFIXES as $prefix ) {
			if ( str_starts_with( $meta_key, $prefix ) ) {
				return true;
			}
		}
		return false;
	}

	/**
	 * Test whether a meta_key triggers the comment-only orphan post-meta drop.
	 *
	 * @param mixed $meta_key Candidate meta_key.
	 * @return bool
	 */
	public static function is_comment_orphan_key( $meta_key ): bool {
		if ( ! is_string( $meta_key ) ) {
			return false;
		}
		return in_array( $meta_key, self::COMMENT_ONLY_ORPHAN_KEYS, true );
	}

	/**
	 * Filter callback: add_term_metadata / update_term_metadata.
	 *
	 * Returns null → continue normal flow (write to wp_termmeta).
	 * Returns true → short-circuit; WP treats as success without DB write.
	 *
	 * @param mixed  $check       Filter accumulator (null at our priority).
	 * @param int    $object_id   Term ID.
	 * @param string $meta_key    Meta key being written.
	 * @param mixed  $meta_value  Value being written (unused).
	 * @param mixed  $extra       Either $unique (add) or $prev_value (update). Unused.
	 * @return mixed
	 */
	public static function on_term_write( $check, $object_id, $meta_key, $meta_value, $extra ) {
		unset( $object_id, $meta_value, $extra );
		if ( self::is_shared_garbage_key( $meta_key ) ) {
			self::increment_drop_counter();
			return true;
		}
		return $check;
	}

	/**
	 * Filter callback: add_comment_metadata / update_comment_metadata.
	 *
	 * Returns null → continue normal flow.
	 * Returns true → short-circuit (silent drop).
	 *
	 * @param mixed  $check       Filter accumulator.
	 * @param int    $object_id   Comment ID.
	 * @param string $meta_key    Meta key being written.
	 * @param mixed  $meta_value  Value being written (unused).
	 * @param mixed  $extra       Either $unique (add) or $prev_value (update). Unused.
	 * @return mixed
	 */
	public static function on_comment_write( $check, $object_id, $meta_key, $meta_value, $extra ) {
		unset( $object_id, $meta_value, $extra );
		if ( self::is_shared_garbage_key( $meta_key ) || self::is_comment_orphan_key( $meta_key ) ) {
			self::increment_drop_counter();
			return true;
		}
		return $check;
	}

	/**
	 * Increment the rolling 24h drop counter.
	 *
	 * Auto-resets every 24h based on a stored timestamp; this avoids
	 * unbounded growth and gives the admin status panel a meaningful
	 * "drops in last day" indicator.
	 *
	 * @return void
	 */
	private static function increment_drop_counter(): void {
		$now      = time();
		$reset_at = (int) get_option( self::OPT_DROPPED_RESET_AT, 0 );

		if ( 0 === $reset_at || ( $now - $reset_at ) >= DAY_IN_SECONDS ) {
			update_option( self::OPT_DROPPED_COUNT, 1, false );
			update_option( self::OPT_DROPPED_RESET_AT, $now, false );
			return;
		}

		$count = (int) get_option( self::OPT_DROPPED_COUNT, 0 );
		update_option( self::OPT_DROPPED_COUNT, $count + 1, false );
	}

	/**
	 * Get the current 24h rolling drop counter (for admin status panel).
	 *
	 * @return int
	 */
	public static function get_drop_count_24h(): int {
		$reset_at = (int) get_option( self::OPT_DROPPED_RESET_AT, 0 );
		if ( 0 === $reset_at || ( time() - $reset_at ) >= DAY_IN_SECONDS ) {
			return 0;
		}
		return (int) get_option( self::OPT_DROPPED_COUNT, 0 );
	}
}