<?php
/**
 * One-time upgrade from 2.x, run in small batches on admin requests and the
 * hourly cron until done (per site on multisite):
 *
 *  1. Settings: keep 2.6's form-encoded webhooks for sites that have
 *     webhooks set up; new installs get signed JSON.
 *  2. Documents: 2.6 left borrower uploads as plaintext zips at public,
 *     timestamp-named URLs. Each zip is imported into the private encrypted
 *     store (attached to its 2.6 upload record, matched by time) and the
 *     public copy is deleted; the old folders get deny-all rules.
 *  3. SSNs: values in the 2.x formats are re-encrypted with AES-256-GCM.
 *
 * Progress lives in the mapp_upgrade_30 option.
 *
 * @package mortgage_application
 */

namespace Mapp\Legacy;

use Mapp\Files\Store;
use Mapp\Security\Crypto;

defined( 'ABSPATH' ) || exit;

class Upgrade {

	const OPTION = 'mapp_upgrade_30';
	const BATCH  = 25;

	/** Wire hooks. */
	public static function register() {
		add_action( 'admin_init', array( __CLASS__, 'maybe_run' ) );
		add_action( 'mortgate_hourly_event', array( __CLASS__, 'maybe_run' ), 5 );
		add_action( 'admin_init', array( __CLASS__, 'email_defaults' ) );
		add_action( 'admin_init', array( __CLASS__, 'email_tokens' ), 11 );
	}

	/** Email texts that may hold 2.x layout placeholders. */
	const EMAIL_TEXTS = array( 'mortgage_application_user_mail_message', 'mortgage_application_reminder_mail_message', 'mortgage_application_submision_message', 'mortgage_application_submision_client_message' );

	/**
	 * Once: take {all_fields}, {edit_url}, export and file-list placeholders
	 * out of saved email text (the emails place those parts themselves), so
	 * the editors show only what a site can change. Text left empty gets the
	 * default.
	 */
	public static function email_tokens() {
		if ( get_option( 'mapp_email_tokens_30' ) || ! class_exists( '\Mapp\Notifications\Mailer' ) ) {
			return;
		}
		$clean = function ( $value, $option ) {
			$after = \Mapp\Notifications\Mailer::clean_template( (string) $value );
			return '' === trim( wp_strip_all_tags( $after ) ) && function_exists( 'mapp_default_option' ) ? mapp_default_option( $option ) : $after;
		};
		foreach ( self::EMAIL_TEXTS as $option ) {
			$current = get_option( $option, false );
			if ( false !== $current && '' !== (string) $current ) {
				$new = $clean( $current, $option );
				if ( $new !== $current ) {
					update_option( $option, $new );
				}
			}
			if ( is_multisite() && is_main_site() ) {
				$network = get_site_option( $option, false );
				if ( false !== $network && '' !== (string) $network ) {
					$new = $clean( $network, $option );
					if ( $new !== $network ) {
						update_site_option( $option, $new );
					}
				}
			}
		}
		update_option( 'mapp_email_tokens_30', time(), false );
	}

	/** The 2.6 default email texts, as 2.6 stored them. */
	const OLD_EMAIL_DEFAULTS = array(
		'mortgage_application_mail_subject'             => 'New Application ({first_name} {last_name})',
		'mortgage_application_user_mail_subject'        => 'Your Application Receipt',
		'mortgage_application_user_mail_message'        => 'Thank you very much for submitting your application. We look forward to guiding you through your home loan process and will follow up with you shortly! {all_fields}',
		'mortgage_application_reminder_mail_subject'    => 'Incomplete Application',
		'mortgage_application_reminder_mail_message'    => 'To complete your mortgage application please click the following link: {edit_url}',
		'mortgage_ma_submissions_subject'               => '{name} Uploaded Files',
		'mortgage_ma_submissions_client_subject'        => 'File Upload Receipt',
		'mortgage_application_submision_client_message' => 'Your files have been uploaded successfully!',
	);

	/**
	 * Once: email texts still at their 2.6 default get the 3.0 default.
	 * Anything a site edited is left alone.
	 */
	public static function email_defaults() {
		if ( get_option( 'mapp_email_defaults_30' ) || ! function_exists( 'mapp_default_option' ) ) {
			return;
		}
		$norm = function ( $text ) {
			return preg_replace( '/\s+/', ' ', trim( wp_strip_all_tags( (string) $text ) ) );
		};
		foreach ( self::OLD_EMAIL_DEFAULTS as $option => $old ) {
			$current = get_option( $option, false );
			if ( false !== $current && $norm( $current ) === $norm( $old ) ) {
				update_option( $option, mapp_default_option( $option ) );
			}
			if ( is_multisite() && is_main_site() ) {
				$network = get_site_option( $option, false );
				if ( false !== $network && $norm( $network ) === $norm( $old ) ) {
					update_site_option( $option, mapp_default_option( $option ) );
				}
			}
		}
		update_option( 'mapp_email_defaults_30', time(), false );
	}

	/** @return array */
	public static function state() {
		$state = get_option( self::OPTION, array() );
		return wp_parse_args(
			is_array( $state ) ? $state : array(),
			array(
				'settings' => false,
				'files'    => false,
				'ssn'      => false,
				'exports'  => false,
				'imported' => 0,
				'ssn_done' => 0,
				'errors'   => array(),
			)
		);
	}

	/** @return bool */
	public static function done() {
		$s = self::state();
		return $s['settings'] && $s['files'] && ! empty( $s['exports'] ) && $s['ssn'];
	}

	/** Run the next batch if there is work left. */
	public static function maybe_run() {
		if ( self::done() ) {
			return;
		}
		// A real mutex: two admin requests (a page load plus a heartbeat) must
		// never run the SSN re-encryption at the same time.
		if ( ! \Mapp\Security\Lock::acquire( 'upgrade_' . get_current_blog_id(), 5 * MINUTE_IN_SECONDS ) ) {
			return;
		}
		wp_cache_delete( self::OPTION, 'options' );
		$state = self::state();
		if ( $state['settings'] && $state['files'] && ! empty( $state['exports'] ) && $state['ssn'] ) {
			\Mapp\Security\Lock::release( 'upgrade_' . get_current_blog_id() );
			return;
		}
		try {
			if ( ! $state['settings'] ) {
				self::settings();
				$state['settings'] = true;
				flush_rewrite_rules( false );
			}
			if ( ! $state['files'] ) {
				$state['files'] = self::import_files( $state );
			}
			if ( empty( $state['exports'] ) ) {
				$state['exports'] = self::remove_public_exports( $state );
			}
			if ( ! $state['ssn'] ) {
				$state['ssn'] = self::reencrypt_ssns( $state );
			}
		} catch ( \Throwable $e ) {
			$state['errors'][] = gmdate( 'c' ) . ' ' . $e->getMessage();
			$state['errors']   = array_slice( $state['errors'], -10 );
		}
		update_option( self::OPTION, $state, false );
		\Mapp\Security\Lock::release( 'upgrade_' . get_current_blog_id() );
	}

	/** Step 1: settings defaults that keep 2.6 integrations working. */
	public static function settings() {
		if ( false === get_option( 'mapp_webhook_format', false ) ) {
			$hooks = function_exists( 'get_front_mortgage_application_option' ) ? trim( (string) get_front_mortgage_application_option( 'mortgage_application_webhooks', 'mortgage_application_use_network_settings' ) ) : '';
			update_option( 'mapp_webhook_format', '' !== $hooks ? 'form' : 'json', false );
		}
	}

	/**
	 * Legacy upload folders that may hold public files.
	 *
	 * @return string[]
	 */
	public static function legacy_dirs() {
		$uploads = wp_upload_dir( null, false );
		$blog    = get_current_blog_id();
		return array_filter(
			array(
				trailingslashit( $uploads['basedir'] ) . '1003-mortgage-application/' . $blog . '/',
				MAPP_MORTGAGE_APP_BASE_PATH . 'uploads/' . $blog . '/',
			),
			'is_dir'
		);
	}

	/**
	 * Step 2: import public 2.6 zips into the private store.
	 *
	 * @param array $state State (imported count updated).
	 * @return bool Whether every legacy file is handled.
	 */
	public static function import_files( &$state ) {
		$remaining = 0;
		$handled   = 0;
		foreach ( self::legacy_dirs() as $dir ) {
			Store::protect( $dir );
			foreach ( (array) glob( $dir . '*' ) as $path ) {
				if ( ! is_file( $path ) || in_array( basename( $path ), array( '.htaccess', 'web.config', 'index.php' ), true ) ) {
					continue;
				}
				if ( $handled >= self::BATCH ) {
					++$remaining;
					continue;
				}
				++$handled;
				if ( preg_match( '/^(\d{9,11})uploadedfiles\.zip$/', basename( $path ), $m ) ) {
					$moved = self::import_zip( $path, (int) $m[1] );
				} elseif ( filesize( $path ) <= 16 ) {
					// 2.6's encryptFile() truncated each upload to its 16-byte IV:
					// nothing recoverable is left in these.
					$moved = true;
				} else {
					// Anything else that still has content is kept, privately.
					$moved = self::keep_whole( $path, (int) filemtime( $path ) );
				}
				// Only delete the public copy once the private one exists.
				if ( $moved ) {
					wp_delete_file( $path );
					++$state['imported'];
				} else {
					$state['errors'][] = gmdate( 'c' ) . ' could not move ' . basename( $path ) . '; left in place behind deny-all rules';
				}
			}
		}
		return 0 === $remaining;
	}

	/**
	 * @param string $path Zip path.
	 * @param int    $time Upload time from the file name.
	 */
	/**
	 * Move a 2.6 zip's files into the private store. Falls back to storing
	 * the zip itself when it cannot be opened or an entry cannot be stored.
	 *
	 * @param string $path Zip path.
	 * @param int    $time Upload time from the file name.
	 * @return bool Whether everything in the zip is now in private storage.
	 */
	private static function import_zip( $path, $time ) {
		$record = self::record_for( $time );
		if ( ! class_exists( 'ZipArchive' ) ) {
			return self::keep_whole( $path, $time, $record );
		}
		$zip = new \ZipArchive();
		if ( true !== $zip->open( $path ) ) {
			return self::keep_whole( $path, $time, $record );
		}
		$stored = array();
		$ok     = true;
		for ( $i = 0; $i < $zip->numFiles; $i++ ) {
			$name = (string) $zip->getNameIndex( $i );
			if ( '/' === substr( $name, -1 ) ) {
				continue;
			}
			$bytes = $zip->getFromIndex( $i );
			if ( false === $bytes ) {
				$ok = false;
				break;
			}
			if ( '' === $bytes ) {
				continue;
			}
			$check   = wp_check_filetype( $name );
			$file_id = Store::put_bytes( $record, $bytes, wp_basename( $name ), $check['type'] ? $check['type'] : 'application/octet-stream', 'imported' );
			if ( is_wp_error( $file_id ) ) {
				$ok = false;
				break;
			}
			$stored[] = $file_id;
		}
		$zip->close();
		if ( ! $ok ) {
			// Undo the partial import and keep the original zip, encrypted, as one file.
			foreach ( $stored as $file_id ) {
				Store::delete( $record, $file_id );
			}
			return self::keep_whole( $path, $time, $record );
		}
		update_post_meta( $record, 'mapp_imported_from_26', time() );
		return true;
	}

	/**
	 * Store a legacy file unchanged (encrypted) on an upload record.
	 *
	 * @param string   $path   File.
	 * @param int      $time   Its time.
	 * @param int|null $record Record, or null to find one by time.
	 * @return bool
	 */
	private static function keep_whole( $path, $time, $record = null ) {
		// phpcs:ignore WordPress.WP.AlternativeFunctions.file_get_contents_file_get_contents
		$bytes = file_get_contents( $path );
		if ( false === $bytes ) {
			return false;
		}
		$record  = $record ? $record : self::record_for( $time );
		$check   = wp_check_filetype( basename( $path ) );
		$file_id = Store::put_bytes( $record, $bytes, basename( $path ), $check['type'] ? $check['type'] : 'application/octet-stream', 'imported' );
		if ( is_wp_error( $file_id ) ) {
			return false;
		}
		update_post_meta( $record, 'mapp_imported_from_26', time() );
		return true;
	}

	/**
	 * The 2.6 upload record created at (about) this time, or a new one.
	 *
	 * @param int $time Unix time.
	 * @return int
	 */
	private static function record_for( $time ) {
		$found = get_posts(
			array(
				'post_type'      => Store::UPLOAD_POST_TYPE,
				'post_status'    => 'any',
				'posts_per_page' => 1,
				'fields'         => 'ids',
				// phpcs:ignore WordPress.DB.SlowDBQuery.slow_db_query_meta_query
				'meta_query'     => array(
					array(
						'key'     => 'file_uploads_date',
						'value'   => array( $time - 30, $time + 30 ),
						'compare' => 'BETWEEN',
						'type'    => 'NUMERIC',
					),
				),
			)
		);
		if ( $found ) {
			return (int) $found[0];
		}
		$id = wp_insert_post(
			array(
				'post_type'   => Store::UPLOAD_POST_TYPE,
				'post_status' => 'publish',
				'post_title'  => sprintf( 'Imported 2.6 upload (%s)', gmdate( 'm-d-Y H:i', $time ) ),
			)
		);
		update_post_meta( $id, 'file_uploads_date', $time );
		return (int) $id;
	}

	/**
	 * Step 2b: 2.6 built exports (CSV / FNM / MISMO, SSNs included) inside the
	 * public uploads month folders and never removed them. Delete those
	 * leftovers: applications.zip files that hold only export files, and the
	 * csv / fannie / mismo work folders.
	 *
	 * @param array $state State.
	 * @return bool Done.
	 */
	public static function remove_public_exports( &$state ) {
		$uploads = wp_upload_dir( null, false );
		$base    = trailingslashit( $uploads['basedir'] );
		$removed = 0;
		foreach ( (array) glob( $base . '[0-9][0-9][0-9][0-9]/[0-9][0-9]/', GLOB_ONLYDIR ) as $month ) {
			$zip_path = $month . 'applications.zip';
			if ( is_file( $zip_path ) && self::is_export_zip( $zip_path ) ) {
				wp_delete_file( $zip_path );
				++$removed;
			}
			foreach ( array( 'csv', 'fannie', 'mismo' ) as $folder ) {
				$dir = $month . $folder . '/';
				if ( ! is_dir( $dir ) ) {
					continue;
				}
				$files = (array) glob( $dir . '*' );
				$ours  = array_filter(
					$files,
					function ( $f ) {
						return is_file( $f ) && preg_match( '/\.(csv|fnm|xml)$/i', $f );
					}
				);
				if ( count( $ours ) === count( $files ) ) {
					foreach ( $ours as $f ) {
						wp_delete_file( $f );
						++$removed;
					}
					@rmdir( $dir ); // phpcs:ignore
				}
			}
		}
		$state['exports_removed'] = $removed;
		return true;
	}

	/**
	 * @param string $path Zip.
	 * @return bool Whether every entry is a CSV / FNM / XML export file.
	 */
	private static function is_export_zip( $path ) {
		if ( ! class_exists( 'ZipArchive' ) ) {
			return false;
		}
		$zip = new \ZipArchive();
		if ( true !== $zip->open( $path ) ) {
			return false;
		}
		$ok = $zip->numFiles > 0;
		for ( $i = 0; $i < $zip->numFiles; $i++ ) {
			if ( ! preg_match( '/\.(csv|fnm|xml)$/i', (string) $zip->getNameIndex( $i ) ) ) {
				$ok = false;
				break;
			}
		}
		$zip->close();
		return $ok;
	}

	/**
	 * Step 3: re-encrypt 2.x SSNs.
	 *
	 * @param array $state State (count updated).
	 * @return bool Whether every SSN is in the 3.0 format.
	 */
	public static function reencrypt_ssns( &$state ) {
		global $wpdb;
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery
		$rows = $wpdb->get_results(
			$wpdb->prepare(
				"SELECT pm.meta_id, pm.post_id, pm.meta_key, pm.meta_value FROM {$wpdb->postmeta} pm
				 INNER JOIN {$wpdb->posts} p ON p.ID = pm.post_id AND p.post_type = 'mortgage_application'
				 WHERE pm.meta_key IN ('ss_number','co_ss_number') AND pm.meta_value <> '' AND pm.meta_value NOT LIKE %s
				 LIMIT %d",
				$wpdb->esc_like( Crypto::PREFIX ) . '%',
				self::BATCH
			)
		);
		foreach ( (array) $rows as $row ) {
			$plain = Crypto::read_ssn( $row->meta_value );
			if ( '' === $plain ) {
				// Unreadable (e.g. 1.x key tied to an old server, or a double-encrypted
				// value from the 2.6 edit-link bug): keep it, but out of this loop.
				update_post_meta( $row->post_id, 'mapp_' . $row->meta_key . '_unreadable', $row->meta_value );
				delete_post_meta( $row->post_id, $row->meta_key );
				continue;
			}
			update_post_meta( $row->post_id, $row->meta_key, Crypto::encrypt( $plain ) );
			++$state['ssn_done'];
		}
		return count( (array) $rows ) < self::BATCH;
	}
}