<?php
/**
 * Admin utility endpoints.
 *
 * @package Shiftora\Api\Endpoints
 */

declare(strict_types=1);

namespace Shiftora\Api\Endpoints;

use Shiftora\Connection\TokenGenerator;
use Shiftora\Core\ServiceFactory;
use Shiftora\Core\Uninstaller;
use Shiftora\Migration\MigrationEngineFactory;
use Shiftora\Support\DataDirectory;
use Shiftora\Support\Db\TableDdl;
use Shiftora\Support\DiagnosticsService;
use Shiftora\Support\HttpClient;
use Shiftora\Support\PluginCacheFlush;
use WP_Error;
use WP_REST_Request;
use WP_REST_Response;

// Prevent direct file access.
if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

final class AdminEndpoint {

	/**
	 * Every table a reset must empty, including the lease and receipt ledgers: a
	 * surviving lease would leave the destination busy for a transfer nobody can
	 * finish, and a surviving finalize marker would claim the next migration's id 1
	 * was already committed. None of them hold user content.
	 *
	 * @return string[] Unprefixed table names.
	 */
	public function resettable_tables(): array {
		return Uninstaller::OWNED_TABLES;
	}

	/**
	 * The recurring stall check stays: it reschedules itself only on activation.
	 *
	 * @return int Hooks cleared.
	 */
	private function unschedule_plugin_actions(): int {
		if ( ! function_exists( 'as_unschedule_all_actions' ) ) {
			return 0;
		}

		// A queued recovery would restore a snapshot whose records the reset just deleted.
		$hooks = [
			'shiftora_process_migration_chunk',
			'shiftora_process_file_chunk',
			'shiftora_auto_recovery',
		];
		foreach ( $hooks as $hook ) {
			as_unschedule_all_actions( $hook, [], 'shiftora' );
		}

		return count( $hooks );
	}

	/**
	 * Selects the value row only, since delete_transient() drops the timeout row too.
	 * Selecting both and stripping the prefix would mangle the timeout names, delete
	 * nothing under them and count each transient twice.
	 *
	 * @return int Transients deleted.
	 */
	private function delete_plugin_transients(): int {
		global $wpdb;

		$prefix = '_transient_';
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery -- the live option rows, fresh read required
		$names  = $wpdb->get_col(
			$wpdb->prepare(
				'SELECT option_name FROM %i WHERE option_name LIKE %s',
				$wpdb->options,
				$wpdb->esc_like( $prefix . 'shiftora_' ) . '%'
			)
		);

		$deleted = 0;
		foreach ( (array) $names as $name ) {
			if ( delete_transient( substr( (string) $name, strlen( $prefix ) ) ) ) {
				$deleted++;
			}
		}

		return $deleted;
	}

	/**
	 * Marks every migration that still holds a slot as cancelled.
	 *
	 * @param string $note Stored as the migration's error message.
	 *
	 * @return int Migrations cancelled.
	 */
	private function cancel_live_migrations( string $note ): int {
		global $wpdb;

		$table    = $wpdb->prefix . 'shiftora_migrations';
		$statuses = [ 'running', 'pending', 'paused' ];
		$select   = array_merge( [ $table ], $statuses );

		// phpcs:ignore WordPress.DB.DirectDatabaseQuery -- custom table, fresh read required
		$ids = $wpdb->get_col(
			$wpdb->prepare(
				'SELECT id FROM %i WHERE status IN (' . implode( ', ', array_fill( 0, count( $statuses ), '%s' ) ) . ')',
				$select
			)
		);

		if ( empty( $ids ) ) {
			return 0;
		}

		$values = array_merge( [ $table, $note, current_time( 'mysql', true ) ], $ids );

		// phpcs:ignore WordPress.DB.DirectDatabaseQuery -- custom table, fresh read required
		$wpdb->query(
			$wpdb->prepare(
				"UPDATE %i
				    SET status        = 'cancelled',
				        error_message = %s,
				        updated_at    = %s
				  WHERE id IN (" . implode( ', ', array_fill( 0, count( $ids ), '%d' ) ) . ')',
				$values
			)
		);

		return count( $ids );
	}

	/**
	 * Skips tables this install never created.
	 *
	 * @param string[] $results Appended to as tables are truncated.
	 */
	private function truncate_owned_tables( array &$results ): void {
		global $wpdb;

		foreach ( $this->resettable_tables() as $table ) {
			$table_name = $wpdb->prefix . $table;
			if ( TableDdl::exists( $wpdb, $table_name ) ) {
				// phpcs:ignore WordPress.DB.DirectDatabaseQuery.SchemaChange, WordPress.DB.DirectDatabaseQuery -- custom table, emptied on a full reset
				$wpdb->query( $wpdb->prepare( 'TRUNCATE TABLE %i', $table_name ) );
				$results[] = $table;
			}
		}
	}

	/**
	 * Options a full reset keeps. The schema markers describe tables that are truncated,
	 * not dropped; clearing them would replay the legacy column migrations against an
	 * emptied database.
	 */
	public const PRESERVED_OPTIONS = [
		'shiftora_schema_rev',
		'shiftora_db_version',
	];

	/**
	 * Prefix-driven rather than a name list, which would drift from the code that writes options.
	 *
	 * @param string[] $option_names Every option name on the site.
	 *
	 * @return string[]
	 */
	public function resettable_options( array $option_names ): array {
		return array_values(
			array_filter(
				$option_names,
				static fn( string $name ): bool => str_starts_with( $name, 'shiftora_' )
					&& ! in_array( $name, self::PRESERVED_OPTIONS, true )
			)
		);
	}

	/** @return string[] Names of the options removed. */
	private function sweep_plugin_options(): array {
		global $wpdb;

		// phpcs:ignore WordPress.DB.DirectDatabaseQuery -- the live option rows, fresh read required
		$found = (array) $wpdb->get_col(
			$wpdb->prepare(
				'SELECT option_name FROM %i WHERE option_name LIKE %s',
				$wpdb->options,
				$wpdb->esc_like( 'shiftora_' ) . '%'
			)
		);

		$deleted = [];
		foreach ( $this->resettable_options( $found ) as $option ) {
			if ( delete_option( $option ) ) {
				$deleted[] = $option;
			}
		}

		return $deleted;
	}

	public function register(): void {
		register_rest_route(
			'shiftora/v1',
			'/admin/reset-plugin',
			[
				'methods'             => 'POST',
				'callback'            => [ $this, 'reset_plugin' ],
				'permission_callback' => [ $this, 'can_manage' ],
				'args'                => [
					'confirm' => [
						'required'          => true,
						'type'              => 'string',
						'sanitize_callback' => 'sanitize_text_field',
					],
				],
			]
		);

		register_rest_route(
			'shiftora/v1',
			'/admin/full-reset',
			[
				'methods'             => 'POST',
				'callback'            => [ $this, 'full_reset' ],
				'permission_callback' => [ $this, 'can_manage' ],
				'args'                => [
					'confirm' => [
						'required'    => true,
						'type'        => 'string',
						'validate_callback' => static function ( $value ) {
							return $value === 'RESET' ? true : new WP_Error(
								'shiftora_invalid_confirmation',
								__( 'Please type RESET to confirm full plugin reset.', 'shiftora' )
							);
						},
					],
				],
			]
		);

		register_rest_route(
			'shiftora/v1',
			'/admin/diagnostics',
			[
				'methods'             => 'GET',
				'callback'            => [ $this, 'diagnostics' ],
				'permission_callback' => [ $this, 'can_manage' ],
			]
		);

		register_rest_route(
			'shiftora/v1',
			'/admin/flush-cache',
			[
				'methods'             => 'POST',
				'callback'            => [ $this, 'flush_cache' ],
				'permission_callback' => [ $this, 'can_manage' ],
			]
		);

		register_rest_route(
			'shiftora/v1',
			'/admin/report-issue',
			[
				'methods'             => 'POST',
				'callback'            => [ $this, 'report_issue' ],
				'permission_callback' => [ $this, 'can_manage' ],
			]
		);

		register_rest_route(
			'shiftora/v1',
			'/admin/reporting-settings',
			[
				'methods'             => 'POST',
				'callback'            => [ $this, 'reporting_settings' ],
				'permission_callback' => [ $this, 'can_manage' ],
			]
		);
	}

	public function can_manage(): bool {
		return current_user_can( 'manage_options' );
	}

	/**
	 * POST /admin/reset-plugin: returns the plugin to a fresh-install state. Deletes
	 * connections, migrations, backups, logs, scheduled actions, transients and
	 * options, and regenerates the secret key.
	 */
	public function reset_plugin( WP_REST_Request $request ): WP_REST_Response {
		$permission = $this->assert_destructive_request( $request, 'RESET' );
		if ( is_wp_error( $permission ) ) {
			return new WP_REST_Response(
				[
					'code'    => $permission->get_error_code(),
					'message' => $permission->get_error_message(),
				],
				(int) ( $permission->get_error_data()['status'] ?? 403 )
			);
		}

		global $wpdb;

		$results = [
			'migrations_cancelled'     => 0,
			'tables_truncated'         => [],
			'backup_files_removed'     => 0,
			'actions_unscheduled'      => 0,
			'transients_deleted'       => 0,
			'options_deleted'          => 0,
			'secret_key_regenerated'   => false,
		];

		// Cancel all running and pending migrations.
		$results['migrations_cancelled'] = $this->cancel_live_migrations( 'Cancelled by plugin reset.' );

		// Unschedule all Action Scheduler actions.
		$results['actions_unscheduled'] += $this->unschedule_plugin_actions();

		// Delete all backup and export files from disk; the folder guards stay.
		$results['backup_files_removed'] = DataDirectory::clear( DataDirectory::BACKUPS );
		DataDirectory::clear( DataDirectory::EXPORTS );

		// After unscheduling: a worker mid-chunk would write its receipt straight back
		// and the reset would report a clean site it hasn't produced.
		$this->truncate_owned_tables( $results['tables_truncated'] );

		// Delete all Shiftora transients.
		$results['transients_deleted'] += $this->delete_plugin_transients();

		// Schema markers are kept, see PRESERVED_OPTIONS.
		$deleted_options = $this->sweep_plugin_options();

		// Regenerate the secret key for a fresh start.
		$new_secret = TokenGenerator::generate_secret();
		add_option( 'shiftora_secret_key', $new_secret, '', false );
		$results['secret_key_regenerated'] = true;
		$results['options_deleted']        = count( $deleted_options );

		// Reset default options to fresh-install state.
		add_option( 'shiftora_chunk_size', 500 );
		add_option( 'shiftora_request_timeout', HttpClient::INSTALLED_DEFAULT_TIMEOUT );
		add_option( 'shiftora_ssl_verify', HttpClient::TLS_AUTO );
		add_option( 'shiftora_allow_pull', true );

		// Flush caches.
		wp_cache_flush();

		return new WP_REST_Response(
			[
				'success' => true,
				'message' => __( 'Plugin fully reset. All connections, migrations, backups, logs, and settings have been cleared. The plugin is now in a fresh state.', 'shiftora' ),
				'results' => $results,
			],
			200
		);
	}

	/** POST /admin/full-reset: same wipe as reset-plugin; the body must carry `confirm: "RESET"`. */
	public function full_reset( WP_REST_Request $request ): WP_REST_Response {
		$permission = $this->assert_destructive_request( $request, 'RESET' );
		if ( is_wp_error( $permission ) ) {
			return new WP_REST_Response(
				[
					'code'    => $permission->get_error_code(),
					'message' => $permission->get_error_message(),
				],
				(int) ( $permission->get_error_data()['status'] ?? 403 )
			);
		}

		global $wpdb;

		$results = [
			'connections_deleted'      => 0,
			'migrations_cancelled'     => 0,
			'tables_truncated'         => [],
			'backups_deleted'          => 0,
			'backup_files_removed'     => 0,
			'logs_cleared'             => 0,
			'actions_unscheduled'      => 0,
			'transients_deleted'       => 0,
			'options_deleted'          => 0,
			'secret_key_regenerated'   => false,
		];

		// Cancel all running and pending migrations.
		$results['migrations_cancelled'] = $this->cancel_live_migrations( 'Cancelled by full plugin reset.' );

		// Unschedule all Action Scheduler actions.
		$results['actions_unscheduled'] += $this->unschedule_plugin_actions();

		// Delete all backup files first, before truncating the table.
		$results['backup_files_removed'] = DataDirectory::clear( DataDirectory::BACKUPS );

		// Truncate all Shiftora tables.
		$this->truncate_owned_tables( $results['tables_truncated'] );

		// Clear all Shiftora transients.
		$results['transients_deleted'] += $this->delete_plugin_transients();

		$deleted_options = $this->sweep_plugin_options();

		// Regenerate the secret key for a fresh start.
		$new_secret = TokenGenerator::generate_secret();
		add_option( 'shiftora_secret_key', $new_secret, '', false );
		$results['secret_key_regenerated'] = true;
		$results['options_deleted']        = count( $deleted_options );

		// Reset default options.
		add_option( 'shiftora_chunk_size', 500 );
		add_option( 'shiftora_request_timeout', HttpClient::INSTALLED_DEFAULT_TIMEOUT );
		add_option( 'shiftora_ssl_verify', HttpClient::TLS_AUTO );
		add_option( 'shiftora_allow_pull', true );

		// Flush caches.
		wp_cache_flush();

		return new WP_REST_Response(
			[
				'success'       => true,
				'message'       => __( 'Plugin fully reset. All connections, migrations, backups, and logs have been cleared. A new secret key has been generated.', 'shiftora' ),
				'results'       => $results,
				'new_secret'    => substr( $new_secret, 0, 8 ) . '... (copy from Connection Info)',
			],
			200
		);
	}

	public function diagnostics( WP_REST_Request $request ): WP_REST_Response {
		$service = $this->diagnostics_service();

		return new WP_REST_Response(
			[
				'success'             => true,
				'snapshot'            => $service->build_snapshot(),
				'recent_errors'       => $service->get_recent_errors( 10 ),
				'auto_report_enabled' => $service->auto_report_enabled(),
			],
			200
		);
	}

	/**
	 * Hard flush of interrupted transfers, staging tables and cached values.
	 * Connections, settings, logs and history are left to the full reset.
	 *
	 * Discarding an unfinished lease discards its recovery state too, so a migration
	 * interrupted mid-finalize restarts rather than resumes. The UI warns first.
	 */
	public function flush_cache( WP_REST_Request $request ): WP_REST_Response {
		$flushed = ( new PluginCacheFlush(
			ServiceFactory::wpdb(),
			ServiceFactory::transfer_registry(),
			MigrationEngineFactory::make()
		) )->flush();

		return new WP_REST_Response(
			array_merge( [ 'success' => true ], $flushed ),
			200
		);
	}

	public function report_issue( WP_REST_Request $request ): WP_REST_Response|WP_Error {
		$payload = $request->get_json_params();
		$payload = is_array( $payload ) ? $payload : [];
		$result  = $this->diagnostics_service()->report_issue( $payload );

		return new WP_REST_Response(
			[
				'success'       => true,
				'sent'          => (bool) ( $result['sent'] ?? false ),
				'saved_locally' => (bool) ( $result['saved_locally'] ?? false ),
				'delivery'      => (string) ( $result['delivery'] ?? 'support_mail' ),
				'message'       => (string) ( $result['message'] ?? __( 'Your support report has been sent.', 'shiftora' ) ),
			],
			200
		);
	}

	public function reporting_settings( WP_REST_Request $request ): WP_REST_Response {
		$enabled = (bool) $request->get_param( 'enabled' );
		$this->diagnostics_service()->update_auto_report( $enabled );

		return new WP_REST_Response(
			[
				'success'             => true,
				'auto_report_enabled' => $enabled,
			],
			200
		);
	}

	private function diagnostics_service(): DiagnosticsService {
		return new DiagnosticsService();
	}

	private function assert_destructive_request( WP_REST_Request $request, string $confirmation ): bool|WP_Error {
		if ( ! $this->has_valid_rest_nonce( $request ) ) {
			return new WP_Error(
				'shiftora_invalid_nonce',
				__( 'Security check failed. Please refresh the page and try again.', 'shiftora' ),
				[ 'status' => 403 ]
			);
		}

		if ( (string) $request->get_param( 'confirm' ) !== $confirmation ) {
			return new WP_Error(
				'shiftora_invalid_confirmation',
				__( 'Please type RESET to confirm full plugin reset.', 'shiftora' ),
				[ 'status' => 400 ]
			);
		}

		return true;
	}

	private function has_valid_rest_nonce( WP_REST_Request $request ): bool {
		$nonce = (string) ( $request->get_header( 'X-WP-Nonce' ) ?: $request->get_param( '_wpnonce' ) );

		return '' !== $nonce && (bool) wp_verify_nonce( sanitize_text_field( wp_unslash( $nonce ) ), 'wp_rest' );
	}
}