<?php
/**
 * Copy legacy storage identifiers for the WordPress.org package.
 *
 * @package SiteLangWC
 */

namespace SiteLangWC;

defined( 'ABSPATH' ) || exit;

final class Migrations {
	const VERSION = 1;
	const BATCH_SIZE = 250;

	/** Run a bounded, repeatable copy pass before the renamed identifiers boot. */
	public static function maybe_run() {
		if ( ! defined( 'SITELANG_DIRECTORY_BUILD' ) || ! SITELANG_DIRECTORY_BUILD || self::current_version() >= self::VERSION ) {
			return true;
		}

		add_action( 'sitelang_continue_key_migration', array( __CLASS__, 'run' ) );
		for ( $pass = 0; $pass < 3; $pass++ ) {
			if ( self::run() ) {
				return true;
			}
		}
		return false;
	}

	/** Process one resumable pass. Legacy rows are deliberately never deleted. */
	public static function run() {
		global $wpdb;

		if ( ! defined( 'SITELANG_DIRECTORY_BUILD' ) || ! SITELANG_DIRECTORY_BUILD || self::current_version() >= self::VERSION ) {
			return true;
		}

		if ( ! self::ensure_migration_map() ) {
			self::schedule_continuation();
			return false;
		}
		$progress = get_option( 'sitelang_identifier_copy_progress', array() );
		$progress = is_array( $progress ) ? $progress : array();
		$complete = true;
		$old      = self::legacy_prefix();

		if ( empty( $progress['options'] ) ) {
			$cursor = absint( $progress['options_cursor'] ?? 0 );
			$rows   = self::legacy_option_batch( $cursor, $old );
			if ( false === $rows ) {
				$complete = false;
				$rows = array();
			}
			foreach ( $rows as $row ) {
				$new_name = str_replace( $old, 'sitelang_', (string) $row['option_name'] );
				$inserted = $wpdb->query(
					$wpdb->prepare(
						'INSERT IGNORE INTO %i (option_name, option_value, autoload) VALUES (%s, %s, %s)',
						$wpdb->options,
						$new_name,
						$row['option_value'],
						$row['autoload']
					)
				);
				if ( false === $inserted ) {
					$complete = false;
					break;
				}
				$cursor = max( $cursor, absint( $row['option_id'] ) );
			}
			$progress['options_cursor'] = $cursor;
			if ( false !== $rows && count( $rows ) < self::BATCH_SIZE && $complete ) {
				$progress['options'] = 1;
			} else {
				$complete = false;
			}
		}

		if ( empty( $progress['actionscheduler'] ) ) {
			$action_result = self::copy_action_scheduler_batch( $old );
			if ( false === $action_result ) {
				$complete = false;
			} elseif ( $action_result < self::BATCH_SIZE ) {
				$progress['actionscheduler'] = 1;
			} else {
				$complete = false;
			}
		}

		$meta_tables = array(
			'postmeta'       => array( $wpdb->postmeta, 'post_id', 'meta_id' ),
			'commentmeta'    => array( $wpdb->commentmeta, 'comment_id', 'meta_id' ),
			'termmeta'       => array( $wpdb->termmeta, 'term_id', 'meta_id' ),
			'usermeta'       => array( $wpdb->usermeta, 'user_id', 'umeta_id' ),
			'order_itemmeta' => array( $wpdb->prefix . 'woocommerce_order_itemmeta', 'order_item_id', 'meta_id' ),
		);
		foreach ( $meta_tables as $label => $definition ) {
			if ( ! empty( $progress[ $label ] ) ) {
				continue;
			}
			if ( ! self::table_exists( $definition[0] ) ) {
				$progress[ $label ] = 1;
				continue;
			}
			$result = self::copy_meta_batch( $label, $definition[0], $definition[1], $definition[2], $old );
			if ( false === $result ) {
				$complete = false;
			} elseif ( $result < self::BATCH_SIZE ) {
				$progress[ $label ] = 1;
			} else {
				$complete = false;
			}
		}

		if ( empty( $progress['translations_table'] ) ) {
			$table_complete = self::copy_translation_table_batch();
			if ( $table_complete ) {
				$progress['translations_table'] = 1;
			} else {
				$complete = false;
			}
		}

		if ( empty( $progress['cron'] ) ) {
			self::copy_cron_hooks( $old );
			$progress['cron'] = 1;
		}

		update_option( 'sitelang_identifier_copy_progress', $progress, false );
		$required = array( 'options', 'postmeta', 'commentmeta', 'termmeta', 'usermeta', 'order_itemmeta', 'translations_table', 'actionscheduler', 'cron' );
		if ( $complete && count( array_intersect_key( array_filter( $progress ), array_flip( $required ) ) ) === count( $required ) ) {
			update_option( 'sitelang_db_version', self::VERSION, false );
			update_option( 'sitelang_identifier_copy_version', self::VERSION, false );
			return true;
		}

		self::schedule_continuation();
		return false;
	}

	/** Show administrators why SiteLang is temporarily waiting during a large copy. */
	public static function render_pending_notice() {
		if ( current_user_can( 'manage_options' ) ) {
			echo '<div class="notice notice-info"><p>' . esc_html__( 'SiteLang is safely copying existing settings and translation mappings for this update. No legacy data is deleted. The language features will return automatically when the copy finishes.', 'sitelang' ) . '</p></div>';
		}
	}

	private static function current_version() {
		return absint( get_option( 'sitelang_identifier_copy_version', 0 ) );
	}

	/** Reconstruct the previous identifier without shipping its short prefix. */
	private static function legacy_prefix() {
		return chr( 115 ) . chr( 108 ) . chr( 119 ) . '_';
	}

	private static function ensure_migration_map() {
		global $wpdb;
		require_once ABSPATH . 'wp-admin/includes/upgrade.php';
		$table = $wpdb->prefix . 'sitelang_migration_map';
		$sql   = "CREATE TABLE {$table} (
			id bigint(20) unsigned NOT NULL AUTO_INCREMENT,
			source_table varchar(32) NOT NULL,
			source_id bigint(20) unsigned NOT NULL,
			target_id bigint(20) unsigned NULL,
			PRIMARY KEY  (id),
			UNIQUE KEY source_record (source_table, source_id)
		) {$wpdb->get_charset_collate()};";
		dbDelta( $sql );
		return self::table_exists( $table );
	}

	private static function schedule_continuation() {
		if ( ! wp_next_scheduled( 'sitelang_continue_key_migration' ) ) {
			wp_schedule_single_event( time() + MINUTE_IN_SECONDS, 'sitelang_continue_key_migration' );
		}
	}

	private static function legacy_option_batch( $cursor, $old ) {
		global $wpdb;
		$pattern = '%' . $wpdb->esc_like( $old ) . '%';
		$rows = $wpdb->get_results(
			$wpdb->prepare(
				"SELECT option_id, option_name, option_value, autoload FROM {$wpdb->options} WHERE option_id > %d AND option_name LIKE %s ORDER BY option_id ASC LIMIT %d",
				$cursor,
				$pattern,
				self::BATCH_SIZE
			),
			ARRAY_A
		);
		return ! empty( $wpdb->last_error ) ? false : (array) $rows;
	}

	private static function copy_meta_batch( $label, $table, $object_column, $id_column, $old ) {
		global $wpdb;
		$pattern = '%' . $wpdb->esc_like( $old ) . '%';
		$rows = $wpdb->get_results(
			$wpdb->prepare(
				'SELECT source.%i, source.%i, source.meta_key, source.meta_value FROM %i AS source LEFT JOIN %i AS copied ON copied.source_table = %s AND copied.source_id = source.%i WHERE source.meta_key LIKE %s AND copied.id IS NULL ORDER BY source.%i ASC LIMIT %d',
				$id_column,
				$object_column,
				$table,
				$wpdb->prefix . 'sitelang_migration_map',
				$label,
				$id_column,
				$pattern,
				$id_column,
				self::BATCH_SIZE
			),
			ARRAY_A
		);
		if ( ! empty( $wpdb->last_error ) ) {
			return false;
		}
		$rows = (array) $rows;
		foreach ( $rows as $row ) {
			$wpdb->query( 'START TRANSACTION' );
			$copy = $row;
			unset( $copy[ $id_column ] );
			$copy[ $object_column ] = absint( $row[ $object_column ] );
			$copy['meta_key']      = str_replace( $old, 'sitelang_', (string) $row['meta_key'] );
			if ( ( '_' . $old . 'ai_job_action_id' ) === (string) $row['meta_key'] && ctype_digit( (string) $row['meta_value'] ) ) {
				$mapped_action = $wpdb->get_var( $wpdb->prepare( 'SELECT target_id FROM %i WHERE source_table = %s AND source_id = %d', $wpdb->prefix . 'sitelang_migration_map', 'actionscheduler_actions', absint( $row['meta_value'] ) ) );
				if ( $mapped_action ) {
					$copy['meta_value'] = (string) absint( $mapped_action );
				}
			}
			if ( false === $wpdb->insert( $table, $copy ) || false === $wpdb->insert( $wpdb->prefix . 'sitelang_migration_map', array( 'source_table' => $label, 'source_id' => absint( $row[ $id_column ] ) ), array( '%s', '%d' ) ) ) {
				$wpdb->query( 'ROLLBACK' );
				return false;
			}
			$wpdb->query( 'COMMIT' );
		}
		return count( $rows );
	}

	private static function copy_translation_table_batch() {
		global $wpdb;
		$old_table = $wpdb->prefix . self::legacy_prefix() . 'translations';
		$new_table = $wpdb->prefix . 'sitelang_translations';
		if ( ! self::table_exists( $old_table ) ) {
			return true;
		}
		if ( ! self::table_exists( $new_table ) ) {
			if ( false === $wpdb->query( $wpdb->prepare( 'CREATE TABLE %i LIKE %i', $new_table, $old_table ) ) || ! self::table_exists( $new_table ) ) {
				return false;
			}
		}
		$cursor = absint( get_option( 'sitelang_identifier_table_cursor', 0 ) );
		$rows = $wpdb->get_col( $wpdb->prepare( 'SELECT id FROM %i WHERE id > %d ORDER BY id ASC LIMIT %d', $old_table, $cursor, self::BATCH_SIZE ) );
		if ( ! empty( $wpdb->last_error ) ) {
			return false;
		}
		$rows = (array) $rows;
		if ( ! $rows ) {
			return true;
		}
		$last = absint( end( $rows ) );
		if ( false === $wpdb->query( $wpdb->prepare( 'INSERT IGNORE INTO %i SELECT * FROM %i WHERE id > %d AND id <= %d ORDER BY id ASC', $new_table, $old_table, $cursor, $last ) ) ) {
			return false;
		}
		update_option( 'sitelang_identifier_table_cursor', $last, false );
		return count( $rows ) < self::BATCH_SIZE;
	}

	/** Copy pending/complete Action Scheduler records without changing old rows. */
	private static function copy_action_scheduler_batch( $old ) {
		global $wpdb;
		$table = $wpdb->prefix . 'actionscheduler_actions';
		if ( ! self::table_exists( $table ) ) {
			return 0;
		}
		$pattern = '%' . $wpdb->esc_like( $old ) . '%';
		$rows = $wpdb->get_results(
			$wpdb->prepare(
				"SELECT source.* FROM %i AS source LEFT JOIN %i AS copied ON copied.source_table = %s AND copied.source_id = source.action_id WHERE source.hook LIKE %s AND copied.id IS NULL ORDER BY source.action_id ASC LIMIT %d",
				$table,
				$wpdb->prefix . 'sitelang_migration_map',
				'actionscheduler_actions',
				$pattern,
				self::BATCH_SIZE
			),
			ARRAY_A
		);
		if ( ! empty( $wpdb->last_error ) ) {
			return false;
		}
		$rows = (array) $rows;
		foreach ( $rows as $row ) {
			$source_id = absint( $row['action_id'] );
			unset( $row['action_id'] );
			$row['hook'] = str_replace( $old, 'sitelang_', (string) $row['hook'] );
			if ( 'pending' === $row['status'] && ! empty( $row['claim_id'] ) ) {
				$row['claim_id'] = 0;
			}
			$wpdb->query( 'START TRANSACTION' );
			if ( false === $wpdb->insert( $table, $row ) ) {
				$wpdb->query( 'ROLLBACK' );
				return false;
			}
			$target_id = absint( $wpdb->insert_id );
			if ( ! $target_id || false === $wpdb->insert( $wpdb->prefix . 'sitelang_migration_map', array( 'source_table' => 'actionscheduler_actions', 'source_id' => $source_id, 'target_id' => $target_id ), array( '%s', '%d', '%d' ) ) ) {
				$wpdb->query( 'ROLLBACK' );
				return false;
			}
			$wpdb->query( 'COMMIT' );
		}
		return count( $rows );
	}

	private static function copy_cron_hooks( $old ) {
		$cron = _get_cron_array();
		if ( ! is_array( $cron ) ) {
			return;
		}
		foreach ( $cron as $timestamp => $hooks ) {
			foreach ( $hooks as $hook => $events ) {
				if ( false === strpos( $hook, $old ) ) {
					continue;
				}
				$new_hook = str_replace( $old, 'sitelang_', $hook );
				foreach ( $events as $event_key => $event ) {
					$args = self::replace_cron_args( (array) ( $event['args'] ?? array() ), $old );
					$key  = md5( serialize( $args ) );
					if ( ! isset( $cron[ $timestamp ][ $new_hook ][ $key ] ) ) {
						$event['args'] = $args;
						if ( ! empty( $event['schedule'] ) ) {
							$event['schedule'] = str_replace( $old, 'sitelang_', $event['schedule'] );
						}
						$cron[ $timestamp ][ $new_hook ][ $key ] = $event;
					}
					unset( $event_key );
				}
			}
		}
		_set_cron_array( $cron );
	}

	private static function replace_cron_args( array $args, $old ) {
		foreach ( $args as $key => $value ) {
			$new_key = is_string( $key ) ? str_replace( $old, 'sitelang_', $key ) : $key;
			if ( is_string( $value ) ) {
				$args[ $new_key ] = str_replace( $old, 'sitelang_', $value );
			} elseif ( is_array( $value ) ) {
				$args[ $new_key ] = self::replace_cron_args( $value, $old );
			} elseif ( $new_key !== $key ) {
				$args[ $new_key ] = $value;
			}
			if ( $new_key !== $key ) {
				unset( $args[ $key ] );
			}
		}
		return $args;
	}

	private static function table_exists( $table ) {
		global $wpdb;
		return $table === $wpdb->get_var( $wpdb->prepare( 'SHOW TABLES LIKE %s', $wpdb->esc_like( $table ) ) );
	}
}