<?php
// phpcs:ignore WPDO.AntiEAV -- platform diagnostic: raw meta inspection for site health
/**
 * TMDO_Site_Health — WordPress Site Health integration (v2.2.0 M3).
 *
 * Registers 7 tests under Tools → Site Health → Status:
 *   1. wpdo_schema_drift          (critical)
 *   2. wpdo_error_budget          (recommended)
 *   3. wpdo_hook_conflicts        (recommended)
 *   4. wpdo_autoload_bloat        (recommended)
 *   5. wpdo_postmeta_explosion    (recommended)
 *   6. wpdo_orphan_zone_rows      (recommended)
 *   7. wpdo_missing_snapshot      (critical)
 *
 * Each test result is cached for 5 minutes to keep Site Health responsive.
 *
 * @package WP_Data_Optimizer
 */

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

/**
 * Site Health test suite. Hook on `init` admin context.
 */
class TMDO_Site_Health {

	/** Transient cache TTL for individual checks. */
	private const CACHE_TTL = 300;

	/** Test name → callable suffix mapping. */
	private const 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',
	);

	/**
	 * Hook into Site Health.
	 *
	 * @return void
	 */
	public static function register(): void {
		add_filter( 'site_status_tests', array( __CLASS__, 'register_tests' ) );
	}

	/**
	 * Register the 7 tests with WP Site Health.
	 *
	 * @param array $tests Existing tests.
	 * @return array
	 */
	public static function register_tests( array $tests ): array {
		foreach ( self::TESTS as $key => $cb_suffix ) {
			$tests['direct'][ $key ] = array(
				'label' => self::label_for( $key ),
				'test'  => array( __CLASS__, $cb_suffix ),
			);
		}
		return $tests;
	}

	/**
	 * Human-readable label for each test.
	 *
	 * @param string $key Test slug.
	 * @return string
	 */
	private static function label_for( string $key ): string {
		$map = array(
			'wpdo_schema_drift'       => __( 'WPDO schema drift', '2meet-data-optimizer' ),
			'wpdo_error_budget'       => __( 'WPDO error budget', '2meet-data-optimizer' ),
			'wpdo_hook_conflicts'     => __( 'WPDO hook conflicts', '2meet-data-optimizer' ),
			'wpdo_autoload_bloat'     => __( 'WPDO autoload bloat', '2meet-data-optimizer' ),
			'wpdo_postmeta_explosion' => __( 'WPDO postmeta explosion', '2meet-data-optimizer' ),
			'wpdo_orphan_zone_rows'   => __( 'WPDO orphan zone rows', '2meet-data-optimizer' ),
			'wpdo_missing_snapshot'   => __( 'WPDO missing snapshot', '2meet-data-optimizer' ),
		);
		return $map[ $key ] ?? $key;
	}

	// ─── Test 1: Schema drift ─────────────────────────────────────────────

	/**
	 * Verify all expected v2 tables exist.
	 *
	 * @return array Site Health result.
	 */
	public static function check_schema_drift(): array {
		$result = self::cached(
			'wpdo_sh_schema_drift',
			static function () {
				if ( ! class_exists( 'TMDO_Installer' ) ) {
					return self::pass( __( 'WPDO installer not loaded.', '2meet-data-optimizer' ) );
				}
				if ( ! method_exists( 'TMDO_Installer', 'v2_tables_status' ) ) {
					return self::pass( __( 'Schema check unavailable on this version.', '2meet-data-optimizer' ) );
				}
				$status  = TMDO_Installer::v2_tables_status();
				$missing = array_keys( array_filter( $status, static fn( $exists ) => ! $exists ) );
				if ( empty( $missing ) ) {
					return self::pass( __( 'All WPDO v2 tables exist.', '2meet-data-optimizer' ) );
				}
				return self::fail(
					__( 'WPDO v2 tables missing', '2meet-data-optimizer' ),
					sprintf(
						/* translators: %s: comma-separated list of missing table names */
						__( 'Missing tables: %s. Run wp wpdo install or re-activate the plugin.', '2meet-data-optimizer' ),
						implode( ', ', $missing )
					),
					'critical'
				);
			}
		);
		return self::wrap( 'wpdo_schema_drift', $result );
	}

	// ─── Test 2: Error budget (last 7 days) ──────────────────────────────

	/**
	 * Count errors in wp_wpdo_errors over the last 7 days.
	 *
	 * @return array Site Health result.
	 */
	public static function check_error_budget(): array {
		$result = self::cached(
			'wpdo_sh_error_budget',
			static function () {
				global $wpdb;
				$table  = $wpdb->prefix . 'wpdo_errors';
				$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 self::pass( __( 'Error log not present (yet) — clean.', '2meet-data-optimizer' ) );
				}
				$threshold = (int) apply_filters( 'wpdo/site_health/error_budget_threshold', 100 );
				$count     = (int) $wpdb->get_var( "SELECT COUNT(*) FROM `{$table}` WHERE created_at >= DATE_SUB(UTC_TIMESTAMP(), INTERVAL 7 DAY)" ); // phpcs:ignore WordPress.DB
				if ( $count <= $threshold ) {
					return self::pass(
						sprintf(
						/* translators: %d: error count */
							__( '%d errors in the last 7 days (within budget).', '2meet-data-optimizer' ),
							$count
						)
					);
				}
				return self::fail(
					__( 'WPDO error budget exceeded', '2meet-data-optimizer' ),
					sprintf(
						/* translators: 1: error count, 2: threshold */
						__( '%1$d errors in the last 7 days (threshold %2$d). Inspect under Tools → WP Data Optimizer → Logs.', '2meet-data-optimizer' ),
						$count,
						$threshold
					),
					'recommended'
				);
			}
		);
		return self::wrap( 'wpdo_error_budget', $result );
	}

	// ─── Test 3: Hook conflicts ──────────────────────────────────────────

	/**
	 * Check for interceptor or hook conflicts via TMDO_Conflict_Monitor.
	 *
	 * @return array Site Health result.
	 */
	public static function check_hook_conflicts(): array {
		$result = self::cached(
			'wpdo_sh_hook_conflicts',
			static function () {
				if ( ! class_exists( 'TMDO_Conflict_Monitor' ) ) {
					return self::pass( __( 'Conflict monitor not loaded.', '2meet-data-optimizer' ) );
				}
				$summary = TMDO_Conflict_Monitor::get_summary();
				$total   = (int) ( $summary['total'] ?? 0 );
				if ( 0 === $total ) {
					return self::pass( __( 'No interceptor / hook conflicts detected.', '2meet-data-optimizer' ) );
				}
				return self::fail(
					__( 'WPDO hook conflicts detected', '2meet-data-optimizer' ),
					sprintf(
						/* translators: %d: number of conflicts */
						__( '%d interceptor/hook conflicts detected. Run wp wpdo conflict-scan for details.', '2meet-data-optimizer' ),
						$total
					),
					'recommended'
				);
			}
		);
		return self::wrap( 'wpdo_hook_conflicts', $result );
	}

	// ─── Test 4: Autoload bloat ──────────────────────────────────────────

	/**
	 * Check total autoloaded options size against a configurable threshold.
	 *
	 * @return array Site Health result.
	 */
	public static function check_autoload_bloat(): array {
		$result = self::cached(
			'wpdo_sh_autoload_bloat',
			static function () {
				global $wpdb;
				$threshold_mb = (int) apply_filters( 'wpdo/site_health/autoload_threshold_mb', 5 );
				$bytes        = (int) $wpdb->get_var( "SELECT SUM(LENGTH(option_value)) FROM `{$wpdb->options}` WHERE autoload = 'yes'" ); // phpcs:ignore WordPress.DB
				$mb           = $bytes / 1024 / 1024;
				if ( $mb < $threshold_mb ) {
					return self::pass(
						sprintf(
						/* translators: 1: actual size in MB */
							__( 'Autoload total %1$0.2f MB (under %2$d MB threshold).', '2meet-data-optimizer' ),
							$mb,
							$threshold_mb
						)
					);
				}
				return self::fail(
					__( 'Autoload size large', '2meet-data-optimizer' ),
					sprintf(
						/* translators: 1: actual size in MB, 2: threshold in MB */
						__( 'Autoload total %1$0.2f MB exceeds %2$d MB threshold. Consider migrating large autoloaded options to wp_wpdo_uni_options.', '2meet-data-optimizer' ),
						$mb,
						$threshold_mb
					),
					'recommended'
				);
			}
		);
		return self::wrap( 'wpdo_autoload_bloat', $result );
	}

	// ─── Test 5: Postmeta explosion ──────────────────────────────────────

	/**
	 * Check whether wp_postmeta row count exceeds the explosion threshold.
	 *
	 * @return array Site Health result.
	 */
	public static function check_postmeta_explosion(): array {
		$result = self::cached(
			'wpdo_sh_postmeta_explosion',
			static function () {
				global $wpdb;
				$threshold = (int) apply_filters( 'wpdo/site_health/postmeta_threshold', 5_000_000 );
				$count     = (int) $wpdb->get_var( "SELECT COUNT(*) FROM `{$wpdb->postmeta}`" ); // phpcs:ignore WordPress.DB
				if ( $count < $threshold ) {
					return self::pass(
						sprintf(
						/* translators: %s: row count */
							__( 'wp_postmeta has %s rows (under threshold).', '2meet-data-optimizer' ),
							number_format_i18n( $count )
						)
					);
				}
				// Also check if any zone module is active.
				$any_active = false;
				if ( class_exists( 'TMDO_Feature_Flags' ) ) {
					foreach ( TMDO_Feature_Flags::all() as $state ) {
						if ( 'idle' !== $state ) {
							$any_active = true;
							break;
						}
					}
				}
				$severity = $any_active ? 'recommended' : 'critical';
				return self::fail(
					__( 'wp_postmeta is large', '2meet-data-optimizer' ),
					sprintf(
						/* translators: %s: row count */
						__( 'wp_postmeta has %s rows. Run the Classifier to identify candidates for migration into Hot/Warm/Cold/Archive zones.', '2meet-data-optimizer' ),
						number_format_i18n( $count )
					),
					$severity
				);
			}
		);
		return self::wrap( 'wpdo_postmeta_explosion', $result );
	}

	// ─── Test 6: Orphan zone rows ────────────────────────────────────────

	/**
	 * Detect zone table rows that belong to modules currently in idle state.
	 *
	 * @return array Site Health result.
	 */
	public static function check_orphan_zone_rows(): array {
		$result = self::cached(
			'wpdo_sh_orphan_zone',
			static function () {
				global $wpdb;
				if ( ! class_exists( 'TMDO_Feature_Flags' ) ) {
					return self::pass( __( 'Feature flags not loaded.', '2meet-data-optimizer' ) );
				}
				$idle_modules = array_keys( array_filter( TMDO_Feature_Flags::all(), static fn( $state ) => 'idle' === $state ) );
				$orphans      = array();
				foreach ( $idle_modules as $module ) {
					// Best-effort: zone tables for hot_*/cold_* are dynamically named.
					$candidates = array(
						$wpdb->prefix . 'wpdo_warm',
						$wpdb->prefix . 'wpdo_archive',
					);
					foreach ( $candidates as $table ) {
						$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 ) {
							continue;
						}
						$count = (int) $wpdb->get_var( "SELECT COUNT(*) FROM `{$table}`" ); // phpcs:ignore WordPress.DB
						if ( $count > 0 ) {
							$orphans[ $table ] = $count;
						}
					}
				}
				if ( empty( $orphans ) ) {
					return self::pass( __( 'No orphan zone rows from idle modules.', '2meet-data-optimizer' ) );
				}
				$lines = array();
				foreach ( $orphans as $t => $n ) {
					$lines[] = sprintf( '%s (%s rows)', $t, number_format_i18n( $n ) );
				}
				return self::fail(
					__( 'Orphan zone rows detected', '2meet-data-optimizer' ),
					sprintf(
						/* translators: %s: list of tables and row counts */
						__( 'Modules in idle state but zone tables still hold data: %s. These rows are typically cleanup leftovers — verify before truncating.', '2meet-data-optimizer' ),
						implode( ', ', $lines )
					),
					'recommended'
				);
			}
		);
		return self::wrap( 'wpdo_orphan_zone_rows', $result );
	}

	// ─── Test 7: Missing snapshot ────────────────────────────────────────

	/**
	 * Verify that a recent snapshot exists when modules are in risk states.
	 *
	 * @return array Site Health result.
	 */
	public static function check_missing_snapshot(): array {
		$result = self::cached(
			'wpdo_sh_missing_snapshot',
			static function () {
				global $wpdb;
				if ( ! class_exists( 'TMDO_Snapshot_Manager' ) || ! class_exists( 'TMDO_Feature_Flags' ) ) {
					return self::pass( __( 'Snapshot system not yet available.', '2meet-data-optimizer' ) );
				}
				// Risk only applies to modules in cutover/cleanup/complete (data is in custom tables).
				$risk_modules = array_keys(
					array_filter(
						TMDO_Feature_Flags::all(),
						static fn( $state ) => in_array( $state, array( 'cutover', 'cleanup', 'complete' ), true )
					)
				);
				if ( empty( $risk_modules ) ) {
					return self::pass( __( 'No modules in risk state — snapshot not required.', '2meet-data-optimizer' ) );
				}
				$snap_table = $wpdb->prefix . TMDO_Snapshot_Manager::TABLE_SLUG;
				$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',
						$snap_table
					)
				);
				if ( 0 === $exists ) {
					return self::fail(
						__( 'Snapshot table missing', '2meet-data-optimizer' ),
						__( 'Snapshot system table not present. Run wp wpdo install.', '2meet-data-optimizer' ),
						'critical'
					);
				}
				$days   = (int) apply_filters( 'wpdo/site_health/snapshot_max_age_days', 7 );
				$recent = (int) $wpdb->get_var(
					$wpdb->prepare(
						"SELECT COUNT(*) FROM `{$snap_table}` WHERE created_at >= DATE_SUB(UTC_TIMESTAMP(), INTERVAL %d DAY)", // phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared -- {$snap_table} is $wpdb->prefix + TABLE_SLUG constant (no user input)
						$days
					)
				);
				if ( $recent > 0 ) {
					return self::pass(
						sprintf(
						/* translators: 1: count, 2: days */
							__( 'Found %1$d snapshot(s) within the last %2$d days.', '2meet-data-optimizer' ),
							$recent,
							$days
						)
					);
				}
				return self::fail(
					__( 'No recent WPDO snapshot', '2meet-data-optimizer' ),
					sprintf(
						/* translators: 1: comma-separated module names, 2: days */
						__( 'Modules in risk state (%1$s) but no snapshot in last %2$d days. Run: wp wpdo snapshot create --trigger=manual --notes="catch-up safety net"', '2meet-data-optimizer' ),
						implode( ', ', $risk_modules ),
						$days
					),
					'critical'
				);
			}
		);
		return self::wrap( 'wpdo_missing_snapshot', $result );
	}

	// ─── helpers ──────────────────────────────────────────────────────────

	/**
	 * Wrap a raw check result with required Site Health envelope fields.
	 *
	 * @param string $key    Test slug.
	 * @param array  $result Raw result with keys label, status, description, severity.
	 * @return array
	 */
	private static function wrap( string $key, array $result ): array {
		$result['test']  = $key;
		$result['badge'] = array(
			'label' => 'WPDO',
			'color' => 'blue',
		);
		return $result;
	}

	/**
	 * Cache a callable's return value via transient.
	 *
	 * @param string   $key      Transient key.
	 * @param callable $producer Callable returning result array.
	 * @return array
	 */
	private static function cached( string $key, callable $producer ): array {
		$cached = get_transient( $key );
		if ( is_array( $cached ) ) {
			return $cached;
		}
		$result = $producer();
		set_transient( $key, $result, self::CACHE_TTL );
		return $result;
	}

	/**
	 * Build a "pass" result envelope.
	 *
	 * @param string $description Body text.
	 * @return array
	 */
	private static function pass( string $description ): array {
		return array(
			'label'       => __( 'WPDO check passed', '2meet-data-optimizer' ),
			'status'      => 'good',
			'description' => '<p>' . esc_html( $description ) . '</p>',
			'severity'    => 'good',
			'actions'     => '',
		);
	}

	/**
	 * Build a fail / warning result envelope.
	 *
	 * @param string $label       Test heading.
	 * @param string $description Body.
	 * @param string $severity    'critical' | 'recommended'.
	 * @return array
	 */
	private static function fail( string $label, string $description, string $severity ): array {
		return array(
			'label'       => $label,
			'status'      => 'critical' === $severity ? 'critical' : 'recommended',
			'description' => '<p>' . esc_html( $description ) . '</p>',
			'severity'    => $severity,
			'actions'     => '<p><a href="' . esc_url( admin_url( 'tools.php?page=wp-data-optimizer' ) ) . '">' . esc_html__( 'Open WPDO admin', '2meet-data-optimizer' ) . '</a></p>',
		);
	}
}