<?php
/**
 * Records every change Orbitstem SEO makes, with the state needed to undo it.
 *
 * @package OrbitstemSEO
 */

namespace Orbitstem\SEO\Repair;

use Orbitstem\SEO\Diagnostics\Tables;

defined( 'ABSPATH' ) || exit;

/**
 * One row per change: who, when, what, the state before and after (JSON),
 * whether it was verified, and whether it was rolled back.
 */
class ChangeLog {

	/**
	 * Records a change.
	 *
	 * @param string $fixer       Fixer or feature id.
	 * @param string $object_type Object type (post, redirect).
	 * @param int    $object_id   Object ID.
	 * @param string $summary     Plain-text summary.
	 * @param mixed  $before      State before (JSON-serializable), null when created.
	 * @param mixed  $after       State after (JSON-serializable), null when deleted.
	 * @return int Change ID.
	 */
	public function record( $fixer, $object_type, $object_id, $summary, $before, $after ) {
		global $wpdb;
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery
		$wpdb->insert(
			Tables::changes(),
			array(
				'created_at'   => current_time( 'mysql', true ),
				'user_id'      => get_current_user_id(),
				'fixer'        => substr( (string) $fixer, 0, 50 ),
				'object_type'  => substr( (string) $object_type, 0, 20 ),
				'object_id'    => (int) $object_id,
				'summary'      => mb_substr( (string) $summary, 0, 500 ),
				'state_before' => null === $before ? null : wp_json_encode( $before ),
				'state_after'  => null === $after ? null : wp_json_encode( $after ),
				'status'       => 'applied',
			),
			array( '%s', '%d', '%s', '%s', '%d', '%s', '%s', '%s', '%s' )
		);
		return (int) $wpdb->insert_id;
	}

	/**
	 * Stores the verification result of a change.
	 *
	 * @param int    $id   Change ID.
	 * @param bool   $ok   Whether verification passed.
	 * @param string $note Explanation.
	 */
	public function set_verified( $id, $ok, $note ) {
		global $wpdb;
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery
		$wpdb->update(
			Tables::changes(),
			array(
				'verified'    => $ok ? 1 : -1,
				'verify_note' => mb_substr( (string) $note, 0, 500 ),
			),
			array( 'id' => (int) $id ),
			array( '%d', '%s' ),
			array( '%d' )
		);
	}

	/**
	 * Puts a label in front of a change's summary, e.g. to mark automatic repairs.
	 *
	 * @param int    $id     Change ID.
	 * @param string $prefix Label including trailing space.
	 */
	public function prefix_summary( $id, $prefix ) {
		global $wpdb;
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery
		$wpdb->query( $wpdb->prepare( 'UPDATE %i SET summary = LEFT( CONCAT( %s, summary ), 500 ) WHERE id = %d', Tables::changes(), (string) $prefix, (int) $id ) );
	}

	/**
	 * Marks a change as rolled back.
	 *
	 * @param int $id Change ID.
	 */
	public function set_rolled_back( $id ) {
		global $wpdb;
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery
		$wpdb->update( Tables::changes(), array( 'status' => 'rolled_back' ), array( 'id' => (int) $id ), array( '%s' ), array( '%d' ) );
	}

	/**
	 * One change with decoded states.
	 *
	 * @param int $id Change ID.
	 * @return array|null
	 */
	public function get( $id ) {
		global $wpdb;
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery
		$row = $wpdb->get_row( $wpdb->prepare( 'SELECT * FROM %i WHERE id = %d', Tables::changes(), (int) $id ), ARRAY_A );
		return $row ? $this->decode( $row ) : null;
	}

	/**
	 * Most recent changes, newest first.
	 *
	 * @param int $limit  Rows.
	 * @param int $offset Offset.
	 * @return array<int,array>
	 */
	public function recent( $limit = 50, $offset = 0 ) {
		global $wpdb;
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery
		$rows = $wpdb->get_results( $wpdb->prepare( 'SELECT * FROM %i ORDER BY id DESC LIMIT %d OFFSET %d', Tables::changes(), (int) $limit, (int) $offset ), ARRAY_A );
		return array_map( array( $this, 'decode' ), $rows );
	}

	/**
	 * Most recent changes made by some fixers, newest first.
	 *
	 * @param string[] $fixers Fixer ids.
	 * @param int      $limit  Rows.
	 * @param int      $offset Offset.
	 * @return array<int,array>
	 */
	public function recent_for( array $fixers, $limit = 50, $offset = 0 ) {
		global $wpdb;
		if ( ! $fixers ) {
			return array();
		}
		$in = implode( ',', array_fill( 0, count( $fixers ), '%s' ) );
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery, WordPress.DB.PreparedSQL.InterpolatedNotPrepared, WordPress.DB.PreparedSQLPlaceholders.ReplacementsWrongNumber -- one %s per fixer, built above.
		$rows = $wpdb->get_results( $wpdb->prepare( "SELECT * FROM %i WHERE fixer IN ({$in}) ORDER BY id DESC LIMIT %d OFFSET %d", ...array_merge( array( Tables::changes() ), array_values( $fixers ), array( (int) $limit, (int) $offset ) ) ), ARRAY_A );
		return array_map( array( $this, 'decode' ), $rows );
	}

	/**
	 * Number of changes made by some fixers.
	 *
	 * @param string[] $fixers Fixer ids.
	 * @return int
	 */
	public function count_for( array $fixers ) {
		global $wpdb;
		if ( ! $fixers ) {
			return 0;
		}
		$in = implode( ',', array_fill( 0, count( $fixers ), '%s' ) );
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery, WordPress.DB.PreparedSQL.InterpolatedNotPrepared, WordPress.DB.PreparedSQLPlaceholders.ReplacementsWrongNumber -- one %s per fixer, built above.
		return (int) $wpdb->get_var( $wpdb->prepare( "SELECT COUNT(*) FROM %i WHERE fixer IN ({$in})", ...array_merge( array( Tables::changes() ), array_values( $fixers ) ) ) );
	}

	/**
	 * Total number of changes.
	 *
	 * @return int
	 */
	public function count() {
		global $wpdb;
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery
		return (int) $wpdb->get_var( $wpdb->prepare( 'SELECT COUNT(*) FROM %i', Tables::changes() ) );
	}

	/**
	 * Deletes changes older than the retention period.
	 *
	 * @param int $days Days to keep.
	 * @return int Rows deleted.
	 */
	public function prune( $days ) {
		global $wpdb;
		$cutoff = gmdate( 'Y-m-d H:i:s', time() - max( 1, (int) $days ) * DAY_IN_SECONDS );
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery
		return (int) $wpdb->query( $wpdb->prepare( 'DELETE FROM %i WHERE created_at < %s', Tables::changes(), $cutoff ) );
	}

	/**
	 * Decodes JSON states.
	 *
	 * @param array $row Raw row.
	 * @return array
	 */
	private function decode( array $row ) {
		$row['state_before'] = null === $row['state_before'] ? null : json_decode( $row['state_before'], true );
		$row['state_after']  = null === $row['state_after'] ? null : json_decode( $row['state_after'], true );
		$row['id']           = (int) $row['id'];
		$row['object_id']    = (int) $row['object_id'];
		$row['verified']     = (int) $row['verified'];
		return $row;
	}
}