<?php
/**
 * Enterprise REST API (v2): dashboard, operations, audit.
 *
 * @package SpinxQuickMigrate
 */

namespace SpinxQM;

use WP_Error;
use WP_REST_Request;
use WP_REST_Server;

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

/**
 * REST API v2 routes for the dashboard overview, operations and audit log.
 */
class Rest_API_V2 {

	/**
	 * Hook route registration onto rest_api_init.
	 */
	public static function register(): void {
		add_action( 'rest_api_init', array( __CLASS__, 'register_routes' ) );
	}

	/**
	 * Register the v2 dashboard, operations and audit log routes.
	 */
	public static function register_routes(): void {
		$ns         = 'spinxqm/v2';
		$permission = array( 'permission_callback' => array( Security::class, 'rest_permission' ) );

		register_rest_route(
			$ns,
			'/dashboard/overview',
			array_merge(
				$permission,
				array(
					'methods'  => WP_REST_Server::READABLE,
					'callback' => array( __CLASS__, 'dashboard_overview' ),
				)
			)
		);

		register_rest_route(
			$ns,
			'/operations',
			array_merge(
				$permission,
				array(
					'methods'  => WP_REST_Server::READABLE,
					'callback' => array( __CLASS__, 'get_operations' ),
					'args'     => array(
						'type'     => array(
							'type'              => 'string',
							'sanitize_callback' => 'sanitize_key',
						),
						'status'   => array(
							'type'              => 'string',
							'sanitize_callback' => 'sanitize_key',
						),
						'page'     => array(
							'type'    => 'integer',
							'default' => 1,
							'minimum' => 1,
						),
						'per_page' => array(
							'type'    => 'integer',
							'default' => 50,
							'minimum' => 1,
							'maximum' => 100,
						),
					),
				)
			)
		);

		register_rest_route(
			$ns,
			'/operations/(?P<id>[a-zA-Z0-9\-]+)',
			array_merge(
				$permission,
				array(
					'methods'  => WP_REST_Server::READABLE,
					'callback' => array( __CLASS__, 'get_operation' ),
				)
			)
		);

		register_rest_route(
			$ns,
			'/audit-log',
			array_merge(
				$permission,
				array(
					'methods'  => WP_REST_Server::READABLE,
					'callback' => array( __CLASS__, 'get_audit_log' ),
					'args'     => array(
						'user_id'        => array(
							'type'    => 'integer',
							'minimum' => 1,
						),
						'operation_type' => array(
							'type'              => 'string',
							'sanitize_callback' => 'sanitize_key',
						),
						'status'         => array(
							'type'              => 'string',
							'sanitize_callback' => 'sanitize_key',
						),
						'date_from'      => array(
							'type'              => 'string',
							'sanitize_callback' => 'sanitize_text_field',
						),
						'page'           => array(
							'type'    => 'integer',
							'default' => 1,
							'minimum' => 1,
						),
					),
				)
			)
		);
	}

	/**
	 * Build the dashboard overview: queue counts, storage usage, health and recent operations.
	 *
	 * @return array<string,mixed>
	 */
	public static function dashboard_overview(): array {
		$queue  = new Job_Queue();
		$audit  = new Audit_Logger();
		$counts = $queue->count_by_status();

		$storage_dir = Helpers::storage_dir();
		$size        = Helpers::directory_size( $storage_dir );
		$limit       = (int) apply_filters( 'spinxqm_storage_limit', 100 * 1024 * 1024 * 1024 );

		$last = self::get_last_operation_summary( $audit );

		$recent_raw = $audit->get_logs( array(), 1, 40 );
		$recent     = array_values(
			array_filter(
				$recent_raw['logs'],
				static function ( $row ) {
					return is_array( $row ) && ! empty( $row['action'] ) && in_array( $row['action'], array( 'completed', 'failed' ), true );
				}
			)
		);
		$recent     = array_slice( $recent, 0, 10 );

		// Normalize timestamps to UTC ISO 8601 so the browser computes "x ago"
		// correctly regardless of the site's timezone — the raw DB values from
		// current_time('mysql') are timezone-naive site-local strings, which
		// Date.parse() would otherwise read in the browser's own timezone.
		$recent = array_map(
			static function ( $row ) {
				if ( is_array( $row ) ) {
					$row['created_at']   = self::to_utc_iso( $row['created_at'] ?? '' );
					$row['completed_at'] = self::to_utc_iso( $row['completed_at'] ?? '' );
				}
				return $row;
			},
			$recent
		);

		return array(
			'stats'             => array(
				'active_jobs'    => $counts['running'],
				'queued_jobs'    => $counts['queued'],
				'storage_used'   => $size,
				'storage_total'  => $limit,
				'last_operation' => $last,
			),
			'health'            => self::get_system_health( $size, $limit ),
			'recent_operations' => $recent,
		);
	}

	/**
	 * List queue operations with optional type/status filters and pagination.
	 *
	 * @param WP_REST_Request $request REST request.
	 * @return array<string,mixed>|WP_Error
	 */
	public static function get_operations( WP_REST_Request $request ) {
		$queue = new Job_Queue();
		if ( ! $queue->table_ready() ) {
			return new WP_Error( 'spinxqm_no_queue', __( 'Database tables are not ready yet. Reload after activation.', 'spinx-quick-migrate' ), array( 'status' => 503 ) );
		}

		// get_param() returns the values validated/sanitized by the route's args.
		$filters  = array(
			'type'   => sanitize_key( (string) $request->get_param( 'type' ) ),
			'status' => sanitize_key( (string) $request->get_param( 'status' ) ),
		);
		$page     = max( 1, absint( $request->get_param( 'page' ) ) );
		$per_page = min( 100, max( 1, absint( $request->get_param( 'per_page' ) ) ) );

		return $queue->list_jobs( $filters, $page, $per_page );
	}

	/**
	 * Fetch a single queue operation by job ID, with server paths and raw state removed.
	 *
	 * @param WP_REST_Request $request REST request.
	 * @return array<string,mixed>|WP_Error
	 */
	public static function get_operation( WP_REST_Request $request ) {
		global $wpdb;
		$id    = sanitize_text_field( (string) $request['id'] );
		$table = $wpdb->prefix . 'spinxqm_queue';
		$row   = $wpdb->get_row( $wpdb->prepare( 'SELECT * FROM %i WHERE job_id = %s', $table, $id ), ARRAY_A ); // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching -- Fetch live job row from the custom queue table; prepared (%i/%s).
		if ( empty( $row ) ) {
			return new WP_Error( 'spinxqm_not_found', __( 'Operation not found.', 'spinx-quick-migrate' ), array( 'status' => 404 ) );
		}
		// Never expose the raw job state (checkpoint) or absolute server paths.
		unset( $row['payload'] );
		$result = is_string( $row['result'] ?? null ) ? json_decode( $row['result'], true ) : null;
		if ( is_array( $result ) ) {
			unset( $result['file'] );
			if ( is_array( $result['backup'] ?? null ) ) {
				unset( $result['backup']['file'] );
			}
			$row['result'] = wp_json_encode( $result );
		}
		return $row;
	}

	/**
	 * Fetch a filtered page of audit log entries.
	 *
	 * @param WP_REST_Request $request REST request.
	 * @return array<string,mixed>|WP_Error
	 */
	public static function get_audit_log( WP_REST_Request $request ) {
		$logger = new Audit_Logger();
		if ( ! $logger->table_ready() ) {
			return new WP_Error( 'spinxqm_no_audit', __( 'Audit log is not available yet.', 'spinx-quick-migrate' ), array( 'status' => 503 ) );
		}

		// get_param() returns the values validated/sanitized by the route's args.
		$page    = max( 1, absint( $request->get_param( 'page' ) ) );
		$filters = array_filter(
			array(
				'user_id'        => null !== $request->get_param( 'user_id' ) ? absint( $request->get_param( 'user_id' ) ) : null,
				'operation_type' => null !== $request->get_param( 'operation_type' ) ? sanitize_key( (string) $request->get_param( 'operation_type' ) ) : null,
				'status'         => null !== $request->get_param( 'status' ) ? sanitize_key( (string) $request->get_param( 'status' ) ) : null,
				'date_from'      => null !== $request->get_param( 'date_from' ) ? sanitize_text_field( (string) $request->get_param( 'date_from' ) ) : null,
			),
			static function ( $v ) {
				return null !== $v && '' !== $v;
			}
		);

		return $logger->get_logs( $filters, $page, 50 );
	}

	/**
	 * Convert a site-local "Y-m-d H:i:s" timestamp (as written by
	 * current_time('mysql')) to an unambiguous UTC ISO 8601 string, so the browser
	 * computes relative time ("2m ago") correctly no matter its own timezone.
	 * Empty / zero input returns ''.
	 *
	 * @param mixed $local Site-local "Y-m-d H:i:s" timestamp.
	 * @return string
	 */
	private static function to_utc_iso( $local ): string {
		$local = trim( (string) $local );
		if ( '' === $local || '0000-00-00 00:00:00' === $local ) {
			return '';
		}
		return get_gmt_from_date( $local, 'c' );
	}

	/**
	 * Summarize the most recent completed or failed operation for the dashboard.
	 *
	 * @param Audit_Logger $logger Audit logger to read from.
	 * @return array<string,mixed>
	 */
	private static function get_last_operation_summary( Audit_Logger $logger ): array {
		$data = $logger->get_logs( array(), 1, 30 );
		$log  = null;
		foreach ( $data['logs'] as $row ) {
			if ( is_array( $row ) && ! empty( $row['action'] ) && in_array( $row['action'], array( 'completed', 'failed' ), true ) ) {
				$log = $row;
				break;
			}
		}

		if ( is_array( $log ) ) {
			$name = (string) ( $log['operation_type'] ?? '' );
			if ( '' === $name ) {
				$name = 'operation';
			}
			$st = 'failed' === ( $log['action'] ?? '' ) ? 'failed' : self::map_log_status( (string) ( $log['status'] ?? '' ) );
			return array(
				'name'      => $name,
				'timestamp' => self::to_utc_iso( (string) ( $log['completed_at'] ?? $log['created_at'] ?? '' ) ),
				'status'    => $st,
			);
		}

		$fallback = get_option( 'spinxqm_last_operation', array() );
		if ( is_array( $fallback ) && ! empty( $fallback['type'] ) ) {
			return array(
				'name'      => (string) $fallback['type'],
				'timestamp' => ! empty( $fallback['timestamp'] ) ? gmdate( 'c', (int) $fallback['timestamp'] ) : '',
				'status'    => 'success',
			);
		}

		return array(
			'name'      => '',
			'timestamp' => '',
			'status'    => 'success',
		);
	}

	/**
	 * Map an audit log status to a dashboard status (success, failed or running).
	 *
	 * @param string $status Audit log status.
	 * @return string
	 */
	private static function map_log_status( string $status ): string {
		if ( 'success' === $status ) {
			return 'success';
		}
		if ( 'error' === $status || 'failed' === $status ) {
			return 'failed';
		}
		if ( 'running' === $status ) {
			return 'running';
		}
		return 'success';
	}

	/**
	 * Report system health warnings for storage usage and the database connection.
	 *
	 * @param int $storage_used  Bytes used in plugin storage.
	 * @param int $storage_limit Storage limit in bytes (0 = unlimited).
	 * @return array<string,mixed>
	 */
	private static function get_system_health( int $storage_used, int $storage_limit ): array {
		$warnings = array();
		if ( $storage_limit > 0 && $storage_used > ( $storage_limit * 0.9 ) ) {
			$warnings[] = __( 'Storage usage is above 90% of the configured limit.', 'spinx-quick-migrate' );
		}

		global $wpdb;
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching
		if ( method_exists( $wpdb, 'check_connection' ) && ! $wpdb->check_connection( false ) ) {
			$warnings[] = __( 'Database connection could not be verified.', 'spinx-quick-migrate' );
		}

		$status = empty( $warnings ) ? 'healthy' : ( count( $warnings ) > 2 ? 'critical' : 'warning' );

		return array(
			'status'   => $status,
			'warnings' => $warnings,
		);
	}
}