<?php
/**
 * Import/Export: migrate from other SEO plugins, back up and restore settings.
 *
 * @package AiRankSuite
 */

declare(strict_types=1);

namespace AiRankSuite\Modules\ImportExport;

use AiRankSuite\Container;
use AiRankSuite\Contracts\ModuleInterface;
use AiRankSuite\Rest\RestController;
use AiRankSuite\Support\Migrator;
use WP_Error;
use WP_REST_Request;
use WP_REST_Response;

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

final class ImportExportModule extends RestController implements ModuleInterface {

	/**
	 * Never leaves this site. Credentials for the obvious reasons; the IndexNow
	 * key because it is bound to a verification file at this domain's root —
	 * carried to another site it would silently fail every submission.
	 *
	 * @var array<int, string>
	 */
	private const SECRETS = array(
		'airanksuite_ai_key',
		'airanksuite_gsc_credentials',
		'airanksuite_gsc_tokens',
		'airanksuite_license',
		'airanksuite_google_service_account',
		'airanksuite_indexnow_key',
	);

	public function id(): string {
		return 'import_export';
	}

	public function register( Container $container ): void {
		$container->share( Services\PluginImporter::class, static fn() => new Services\PluginImporter() );
		$container->share( Services\ImportRun::class, static fn() => new Services\ImportRun() );
	}

	public function boot( Container $container ): void {
		add_action( 'rest_api_init', array( $this, 'routes' ) );

		// A closed browser tab must not leave an import half applied: the
		// resumer ticks it from cron like every other long job.
		$run = $container->get( Services\ImportRun::class );
		\AiRankSuite\Support\Job::register( 'import', array( $run, 'state' ), array( $run, 'tick' ) );
	}

	public function routes(): void {
		// Anything that writes an import into the site, or reads an uploaded
		// file, replaces configuration and content wholesale. The plugin's
		// delegable capability is not enough for that; WordPress has to agree
		// that this is an administrator.

		register_rest_route(
			self::NAMESPACE,
			'/import/sources',
			array(
				'methods'             => 'GET',
				'callback'            => array( $this, 'sources' ),
				'permission_callback' => static fn(): bool => current_user_can( 'manage_options' ),
			)
		);

		register_rest_route(
			self::NAMESPACE,
			'/import/run',
			array(
				'methods'             => 'POST',
				'callback'            => array( $this, 'run' ),
				'permission_callback' => static fn(): bool => current_user_can( 'manage_options' ),
				'args'                => array(
					'source'    => array(
						'type'     => 'string',
						'required' => true,
						'enum'     => array_keys( Services\PluginImporter::sources() ),
					),
					'after'     => array( 'type' => 'integer', 'default' => null, 'minimum' => 0 ),
					'offset'    => array(
						'type'    => 'integer',
						'default' => 0,
					),
					'overwrite' => array(
						'type'    => 'boolean',
						'default' => false,
					),
					'redirects' => array(
						'type'    => 'boolean',
						'default' => true,
					),
				),
			)
		);

		// The universal importer: adapters, dry run, undo, CSV/JSON.
		register_rest_route(
			self::NAMESPACE,
			'/import/detect',
			array(
				'methods'             => 'GET',
				'callback'            => static fn() => new WP_REST_Response(
					array(
						'sources'   => Services\ImportRegistry::detect(),
						'conflicts' => \AiRankSuite\Kernel::service( Services\ImportRun::class )->conflicts(),
						'runs'      => Services\ImportLog::runs(),
						'fields'    => Services\FileImport::fields(),
						'job'       => \AiRankSuite\Kernel::service( Services\ImportRun::class )->state(),
					)
				),
				'permission_callback' => static fn(): bool => current_user_can( 'manage_options' ),
			)
		);

		register_rest_route(
			self::NAMESPACE,
			'/import/start',
			array(
				'methods'             => 'POST',
				'callback'            => array( $this, 'import_start' ),
				'permission_callback' => static fn(): bool => current_user_can( 'manage_options' ),
				'args'                => array(
					'source'  => array( 'type' => 'string', 'default' => '' ),
					'mode'    => array( 'type' => 'string', 'default' => 'fill', 'enum' => array( 'fill', 'overwrite' ) ),
					'dry_run' => array( 'type' => 'boolean', 'default' => false ),
					'parts'   => array( 'type' => 'array', 'default' => array( 'settings', 'posts', 'terms', 'redirects' ), 'items' => array( 'type' => 'string' ) ),
					'undo'    => array( 'type' => 'string', 'default' => '' ),
					'file'    => array( 'type' => 'object', 'default' => array() ),
				),
			)
		);

		register_rest_route(
			self::NAMESPACE,
			'/import/tick',
			array(
				'methods'             => 'POST',
				'callback'            => static fn() => new WP_REST_Response( \AiRankSuite\Support\Job::guard( 'import', array( \AiRankSuite\Kernel::service( Services\ImportRun::class ), 'tick' ) ) ),
				'permission_callback' => static fn(): bool => current_user_can( 'manage_options' ),
			)
		);

		register_rest_route(
			self::NAMESPACE,
			'/import/cancel',
			array(
				'methods'             => 'POST',
				'callback'            => static fn() => new WP_REST_Response( \AiRankSuite\Kernel::service( Services\ImportRun::class )->cancel() ),
				'permission_callback' => static fn(): bool => current_user_can( 'manage_options' ),
			)
		);

		register_rest_route(
			self::NAMESPACE,
			'/import/preview-file',
			array(
				'methods'             => 'POST',
				'callback'            => static function ( WP_REST_Request $request ) {
					$parsed = Services\FileImport::parse( (string) $request['content'], (string) $request['format'] );
					return new WP_REST_Response( array_merge( $parsed, array( 'fields' => Services\FileImport::fields() ) ) );
				},
				'permission_callback' => static fn(): bool => current_user_can( 'manage_options' ),
				'args'                => array(
					'content' => array( 'type' => 'string', 'required' => true ),
					'format'  => array( 'type' => 'string', 'default' => 'csv', 'enum' => array( 'csv', 'json' ) ),
				),
			)
		);

		register_rest_route(
			self::NAMESPACE,
			'/settings/export',
			array(
				'methods'             => 'GET',
				'callback'            => array( $this, 'export' ),
				'permission_callback' => static fn(): bool => current_user_can( 'manage_options' ),
			)
		);

		register_rest_route(
			self::NAMESPACE,
			'/settings/import',
			array(
				'methods'             => 'POST',
				'callback'            => array( $this, 'import_settings' ),
				'permission_callback' => static fn(): bool => current_user_can( 'manage_options' ),
				'args'                => array(
					'payload' => array(
						'type'     => 'object',
						'required' => true,
					),
				),
			)
		);

		register_rest_route(
			self::NAMESPACE,
			'/settings/backup',
			array(
				array(
					'methods'             => 'GET',
					'callback'            => array( $this, 'backup_info' ),
					'permission_callback' => static fn(): bool => current_user_can( 'manage_options' ),
				),
				array(
					'methods'             => 'POST',
					'callback'            => array( $this, 'restore' ),
					'permission_callback' => static fn(): bool => current_user_can( 'manage_options' ),
				),
			)
		);
	}

	/**
	 * Start an import, an undo or a preview.
	 */
	public function import_start( WP_REST_Request $request ): WP_REST_Response|WP_Error {
		$run    = \AiRankSuite\Kernel::service( Services\ImportRun::class );
		$result = $run->start(
			array(
				'source'  => (string) $request['source'],
				'mode'    => (string) $request['mode'],
				'dry_run' => (bool) $request['dry_run'],
				'parts'   => (array) $request['parts'],
				'undo'    => (string) $request['undo'],
				'file'    => (array) $request['file'],
			)
		);
		return $result instanceof WP_Error ? $result : new WP_REST_Response( $result );
	}

	/**
	 * The sources the setup wizard offers.
	 *
	 * This used to answer from PluginImporter, which knows nine plugins,
	 * while the import screen answered from the adapter registry, which knows
	 * fourteen. A site running Squirrly, Genesis, Jetpack, WooCommerce or
	 * Redirection was told during setup that there was nothing to bring
	 * across, and then found its data on the import screen ten minutes later.
	 * One registry answers both, and it is the one that also performs the
	 * import the wizard starts.
	 */
	public function sources(): WP_REST_Response {
		$importer = \AiRankSuite\Kernel::service( Services\PluginImporter::class );
		return new WP_REST_Response(
			array(
				'sources' => Services\ImportRegistry::detect(),
				'total'   => $importer->total_posts(),
			)
		);
	}

	/**
	 * Import one batch; the client loops until done = true.
	 */
	public function run( WP_REST_Request $request ): WP_REST_Response {
		$importer = \AiRankSuite\Kernel::service( Services\PluginImporter::class );
		$source   = (string) $request['source'];
		$offset   = max( 0, (int) $request['offset'] );

		// Keyset paging: the client hands back the cursor it received. A client
		// from before this (offset only) is translated once per batch to the
		// ID at that position, so it still imports everything, batch by batch.
		if ( null !== $request['after'] ) {
			$after = max( 0, (int) $request['after'] );
		} elseif ( 0 === $offset ) {
			$after = 0;
		} else {
			global $wpdb;
			// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery
			$after = (int) $wpdb->get_var( $wpdb->prepare( "SELECT ID FROM {$wpdb->posts} WHERE post_type NOT IN ('attachment','revision','nav_menu_item') AND post_status NOT IN ('auto-draft','trash') ORDER BY ID ASC LIMIT 1 OFFSET %d", max( 0, $offset - 1 ) ) );
		}
		$batch = $importer->import_posts( $source, (bool) $request['overwrite'], $offset, 50, $after );
		$redirects = array(
			'imported' => 0,
			'skipped'  => 0,
		);

		// Redirects and the site-wide templates are imported once, on the
		// first batch — the templates are what a Rank Math or Yoast site
		// actually runs on; per-post values exist only where somebody typed one.
		$site = array( 'applied' => 0, 'templates' => array() );
		if ( 0 === $offset ) {
			if ( $request['redirects'] ) {
				$redirects = $importer->import_redirects( $source );
			}
			$site = $importer->import_site_settings( $source, (bool) $request['overwrite'] );
		}

		$next = $offset + $batch['processed'];
		$done = $batch['processed'] < 50;

		if ( $done ) {
			// Scores depend on the imported descriptions — mark analyses stale.
			delete_transient( \AiRankSuite\Modules\LlmsTxt\LlmsTxtModule::CACHE_KEY );
			delete_transient( \AiRankSuite\Modules\LlmsTxt\LlmsTxtModule::CACHE_KEY_FULL );
		}

		return new WP_REST_Response(
			array(
				'done'      => $done,
				'offset'    => $next,
				'after'     => (int) ( $batch['last_id'] ?? 0 ),
				'total'     => $importer->total_posts(),
				'imported'  => $batch['imported'],
				'skipped'   => $batch['skipped'],
				'fields'    => $batch['fields'] ?? array(),
				'site'      => $site,
				'redirects' => $redirects,
			)
		);
	}

	/**
	 * Export all settings as JSON — secrets are excluded by design.
	 */
	public function export(): WP_REST_Response {
		$options = array();
		foreach ( Migrator::settings_keys() as $key ) {
			if ( in_array( $key, self::SECRETS, true ) ) {
				continue;
			}
			$value = get_option( $key, null );
			if ( null !== $value ) {
				$options[ $key ] = $value;
			}
		}
		return new WP_REST_Response(
			array(
				'format'  => 'ai-rank-suite/1',
				'plugin'  => AIRANKSUITE_VERSION,
				'site'    => home_url( '/' ),
				'created' => gmdate( 'c' ),
				'options' => $options,
			)
		);
	}

	public function import_settings( WP_REST_Request $request ): WP_REST_Response|WP_Error {
		$payload = (array) $request->get_param( 'payload' );
		if ( ( $payload['format'] ?? '' ) !== 'ai-rank-suite/1' || ! is_array( $payload['options'] ?? null ) ) {
			return new WP_Error(
				'airanksuite_import_invalid',
				__( 'This file is not an AI Rank Suite settings export.', 'ai-rank-suite' ),
				array( 'status' => 400 )
			);
		}

		$allowed = array_diff( Migrator::settings_keys(), self::SECRETS );
		$applied = 0;
		foreach ( $payload['options'] as $key => $value ) {
			// An export made before 0.2.36 names its options under the old prefix.
			$key = Migrator::current_key( (string) $key );
			if ( ! in_array( $key, $allowed, true ) || ! is_array( $value ) ) {
				continue;
			}
			update_option( $key, $value, false );
			++$applied;
		}

		return new WP_REST_Response(
			array(
				'applied' => $applied,
				'skipped' => count( $payload['options'] ) - $applied,
			)
		);
	}

	public function backup_info(): WP_REST_Response {
		$backup = get_option( 'airanksuite_settings_backup' );
		return new WP_REST_Response(
			array(
				'exists' => is_array( $backup ) && ! empty( $backup['options'] ),
				'from'   => is_array( $backup ) ? (string) ( $backup['plugin'] ?? '' ) : '',
				'time'   => is_array( $backup ) ? (int) ( $backup['time'] ?? 0 ) : 0,
			)
		);
	}

	public function restore(): WP_REST_Response|WP_Error {
		if ( ! Migrator::restore_backup() ) {
			return new WP_Error( 'airanksuite_no_backup', __( 'No settings backup available.', 'ai-rank-suite' ), array( 'status' => 404 ) );
		}
		return new WP_REST_Response( array( 'restored' => true ) );
	}
}