<?php
/**
 * TMDO_Health_Cron — Daily health probe (v2.3.0 M6).
 *
 * Runs daily at 03:30 UTC. Aggregates results from:
 *   - TMDO_Site_Health 7 tests (schema_drift, error_budget, hook_conflicts,
 *     autoload_bloat, postmeta_explosion, orphan_zone_rows, missing_snapshot)
 *   - TMDO_Conflict_Monitor::get_summary()
 *   - shadow_diffs ratio per module in `verify` state
 *   - autoload size measurement
 *
 * Outputs:
 *   1. Single audit log entry: op='health_check_daily' with full payload
 *      (so admin can read history via Logs tab + `wp wpdo audit` future CLI).
 *   2. wpdo_health_alert option set when any critical found (existing
 *      TMDO_Core::render_health_alert_notice consumes this).
 *   3. wpdo_health_last_run option for SOP runbook "is health green?" question.
 *   4. action 'wpdo/health_alert_critical' fired on critical (v2.4.0 email
 *      notifier subscribes here; consumers get the full result array).
 *
 * @package WP_Data_Optimizer
 */

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

/**
 * Daily probe — stateless static API.
 */
class TMDO_Health_Cron {

	/** Option key for the most recent run summary. */
	public const OPTION_LAST_RUN = 'wpdo_health_last_run';

	/** Option key for active critical alert (consumed by Core notice). */
	public const OPTION_ALERT = 'wpdo_health_alert';

	/**
	 * Run the daily probe. Idempotent — safe to invoke ad-hoc.
	 *
	 * @return array {ok:bool, summary:array, critical_count:int, recommended_count:int, ts:string}
	 */
	public static function run(): array {
		$started_at = microtime( true );
		$results    = self::run_site_health_tests();
		$conflict   = self::summarize_conflicts();
		$shadow     = self::summarize_shadow_diffs();
		$autoload   = self::measure_autoload_size();

		$critical_count    = 0;
		$recommended_count = 0;
		foreach ( $results as $r ) {
			$status = (string) ( $r['status'] ?? 'good' );
			if ( 'critical' === $status ) {
				++$critical_count;
			} elseif ( 'recommended' === $status ) {
				++$recommended_count;
			}
		}

		$summary = array(
			'tests'             => $results,
			'critical_count'    => $critical_count,
			'recommended_count' => $recommended_count,
			'conflicts'         => $conflict,
			'shadow_diffs'      => $shadow,
			'autoload_bytes'    => $autoload,
			'ran_at'            => gmdate( 'Y-m-d H:i:s' ),
			'duration_ms'       => (int) round( ( microtime( true ) - $started_at ) * 1000 ),
		);

		// 1. Persist last-run snapshot (autoload=no, lightweight).
		update_option( self::OPTION_LAST_RUN, $summary, false );

		// 2. Set / clear alert flag.
		if ( $critical_count > 0 ) {
			$first_critical = self::first_critical_test( $results );
			update_option(
				self::OPTION_ALERT,
				array(
					'level'  => 'critical',
					'count'  => $critical_count,
					'first'  => $first_critical,
					'ran_at' => $summary['ran_at'],
				),
				false
			);
		} else {
			delete_option( self::OPTION_ALERT );
		}

		// v2.5.0 M16: refresh module suggestions cache (autoload=no).
		$module_suggestions_count = 0;
		if ( class_exists( 'TMDO_Module_Detector' ) ) {
			try {
				$detected = TMDO_Module_Detector::detect_all( true );
				foreach ( $detected as $r ) {
					if ( ! empty( $r['available'] ) && 'enable' === ( $r['recommendation'] ?? '' ) ) {
						++$module_suggestions_count;
					}
				}
			} catch ( Throwable $e ) {
				// phpcs:ignore Generic.CodeAnalysis.EmptyStatement.DetectedCatch -- detector failure must not break health check.
				error_log( '[WPDO] Module detector exception in health cron: ' . $e->getMessage() ); // phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
			}
		}

		// 3. Audit log entry.
		if ( class_exists( 'TMDO_Logger' ) ) {
			TMDO_Logger::info(
				'health_check_daily',
				array(
					'critical'                 => $critical_count,
					'recommended'              => $recommended_count,
					'duration_ms'              => $summary['duration_ms'],
					'autoload_kb'              => (int) round( $autoload / 1024 ),
					'conflicts'                => (int) ( $conflict['total'] ?? 0 ),
					'module_suggestions_count' => $module_suggestions_count,
				)
			);
		}

		// 4. Fire action for downstream subscribers (v2.4.0 email notifier).
		if ( $critical_count > 0 ) {
			do_action( 'wpdo/health_alert_critical', $summary );
		} else {
			do_action( 'wpdo/health_check_passed', $summary );
		}

		return array(
			'ok'                => true,
			'summary'           => $summary,
			'critical_count'    => $critical_count,
			'recommended_count' => $recommended_count,
			'ts'                => $summary['ran_at'],
		);
	}

	/**
	 * Read most recent run (for SOP runbook + Doctor tab streak counter).
	 *
	 * @return array|null
	 */
	public static function get_last_run(): ?array {
		$v = get_option( self::OPTION_LAST_RUN );
		return is_array( $v ) ? $v : null;
	}

	/**
	 * Compute consecutive green days from audit log (best-effort for SOP UI).
	 *
	 * @return int
	 */
	public static function consecutive_green_days(): int {
		$last = self::get_last_run();
		if ( null === $last ) {
			return 0;
		}
		// If today's run is critical, streak = 0.
		if ( ( $last['critical_count'] ?? 0 ) > 0 ) {
			return 0;
		}
		// Otherwise approximate via TMDO_Logger — count distinct days with health_check_daily and 0 critical.
		// Conservative best-effort: just check today's run is green = 1 day.
		return 1;
	}

	// ─── private helpers ────────────────────────────────────────────────

	/**
	 * Run all 7 Site Health tests directly (without the WP Site Health UI loop).
	 *
	 * @return array<string,array> Test slug → result array.
	 */
	private static function run_site_health_tests(): array {
		$out = array();
		if ( ! class_exists( 'TMDO_Site_Health' ) ) {
			return $out;
		}
		$tests = array(
			'wpdo_schema_drift'       => 'check_schema_drift',
			'wpdo_error_budget'       => 'check_error_budget',
			'wpdo_hook_conflicts'     => 'check_hook_conflicts',
			'wpdo_autoload_bloat'     => 'check_autoload_bloat',
			'wpdo_postmeta_explosion' => 'check_postmeta_explosion',
			'wpdo_orphan_zone_rows'   => 'check_orphan_zone_rows',
			'wpdo_missing_snapshot'   => 'check_missing_snapshot',
		);
		foreach ( $tests as $slug => $cb ) {
			try {
				$result = call_user_func( array( 'TMDO_Site_Health', $cb ) );
				if ( is_array( $result ) ) {
					$out[ $slug ] = array(
						'status'      => (string) ( $result['status'] ?? 'good' ),
						'severity'    => (string) ( $result['severity'] ?? 'good' ),
						'label'       => (string) ( $result['label'] ?? $slug ),
						'description' => wp_strip_all_tags( (string) ( $result['description'] ?? '' ) ),
					);
				}
			} catch ( Throwable $e ) {
				$out[ $slug ] = array(
					'status'      => 'critical',
					'severity'    => 'critical',
					'label'       => $slug,
					'description' => 'test threw: ' . $e->getMessage(),
				);
			}
		}
		return $out;
	}

	/**
	 * Return a conflict summary from TMDO_Conflict_Monitor.
	 *
	 * @return array {total:int, hook_overlap:int, uaepg_overlap:int}
	 */
	private static function summarize_conflicts(): array {
		if ( ! class_exists( 'TMDO_Conflict_Monitor' ) ) {
			return array(
				'total'         => 0,
				'hook_overlap'  => 0,
				'uaepg_overlap' => 0,
			);
		}
		$summary = TMDO_Conflict_Monitor::get_summary();
		return array(
			'total'         => (int) ( $summary['total'] ?? 0 ),
			'hook_overlap'  => (int) ( $summary['hook_overlap'] ?? 0 ),
			'uaepg_overlap' => (int) ( $summary['uaepg_overlap'] ?? 0 ),
		);
	}

	/**
	 * Per-module shadow_diffs ratio (only for modules currently in `verify`).
	 * Reads wp_wpdo_shadow_diffs and bucket-counts by entity_type.
	 *
	 * @return array<string,array>
	 */
	private static function summarize_shadow_diffs(): array {
		global $wpdb;
		$out    = array();
		$table  = $wpdb->prefix . 'wpdo_shadow_diffs';
		$exists = (int) $wpdb->get_var(
			$wpdb->prepare( // phpcs:ignore WordPress.DB
				'SELECT COUNT(*) FROM information_schema.TABLES WHERE TABLE_SCHEMA = DATABASE() AND TABLE_NAME = %s',
				$table
			)
		);
		if ( 0 === $exists ) {
			return $out;
		}
		$rows = $wpdb->get_results( "SELECT entity_type, COUNT(*) AS cnt FROM `{$table}` WHERE ts >= DATE_SUB(UTC_TIMESTAMP(), INTERVAL 24 HOUR) GROUP BY entity_type", ARRAY_A ); // phpcs:ignore WordPress.DB
		if ( is_array( $rows ) ) {
			foreach ( $rows as $r ) {
				$out[ (string) $r['entity_type'] ] = array(
					'diffs_24h' => (int) $r['cnt'],
				);
			}
		}
		return $out;
	}

	/**
	 * Return the total byte size of autoloaded options.
	 *
	 * @return int Bytes in autoloaded options.
	 */
	private static function measure_autoload_size(): int {
		global $wpdb;
		return (int) $wpdb->get_var( "SELECT COALESCE(SUM(LENGTH(option_value)),0) FROM `{$wpdb->options}` WHERE autoload = 'yes'" ); // phpcs:ignore WordPress.DB
	}

	/**
	 * Return the slug of the first critical test result, or null if none.
	 *
	 * @param array $results Site Health test results map.
	 * @return string|null Slug of first critical test, or null.
	 */
	private static function first_critical_test( array $results ): ?string {
		foreach ( $results as $slug => $r ) {
			if ( 'critical' === ( $r['status'] ?? '' ) ) {
				return $slug;
			}
		}
		return null;
	}
}