<?php
/**
 * Storage for leads that could not be delivered to ConvoHub yet.
 *
 * Leads are only stored here when delivery fails, so personal data is not kept
 * for successful submissions.
 *
 * @package convohub
 */

// This class owns a custom table, so direct queries are intentional.
// phpcs:disable WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching, WordPress.DB.DirectDatabaseQuery.SchemaChange

defined( 'ABSPATH' ) || exit;

/**
 * Failed and queued lead deliveries.
 */
class ConvoHub_Lead_Queue {

	const DB_VERSION        = '1';
	const DB_VERSION_OPTION = 'convohub_db_version';

	const STATUS_QUEUED = 'queued';
	const STATUS_FAILED = 'failed';

	/**
	 * Table name.
	 *
	 * @return string
	 */
	public static function table() {
		global $wpdb;
		return $wpdb->prefix . 'convohub_leads';
	}

	/**
	 * Creates or upgrades the table when the stored schema version is behind.
	 */
	public static function maybe_install() {
		if ( get_option( self::DB_VERSION_OPTION ) === self::DB_VERSION ) {
			return;
		}

		global $wpdb;
		require_once ABSPATH . 'wp-admin/includes/upgrade.php';
		$table   = self::table();
		$charset = $wpdb->get_charset_collate();
		dbDelta(
			"CREATE TABLE {$table} (
				id bigint(20) unsigned NOT NULL AUTO_INCREMENT,
				payload longtext NOT NULL,
				status varchar(10) NOT NULL DEFAULT 'queued',
				attempts smallint(5) unsigned NOT NULL DEFAULT 0,
				last_error text NULL,
				created_at datetime NOT NULL,
				updated_at datetime NOT NULL,
				PRIMARY KEY  (id),
				KEY status (status)
			) {$charset};"
		);
		update_option( self::DB_VERSION_OPTION, self::DB_VERSION );
	}

	/**
	 * Drops the table.
	 */
	public static function uninstall() {
		global $wpdb;
		$table = self::table();
		$wpdb->query( $wpdb->prepare( 'DROP TABLE IF EXISTS %i', $table ) );
		delete_option( self::DB_VERSION_OPTION );
	}

	/**
	 * Stores a lead.
	 *
	 * @param array  $lead     Sanitized lead.
	 * @param string $status   Status.
	 * @param int    $attempts Delivery attempts so far.
	 * @param string $error    Last error message.
	 * @return int New row ID.
	 */
	public static function insert( array $lead, $status, $attempts, $error ) {
		global $wpdb;
		$now = current_time( 'mysql', true );
		$wpdb->insert(
			self::table(),
			array(
				'payload'    => wp_json_encode( $lead ),
				'status'     => $status,
				'attempts'   => $attempts,
				'last_error' => $error,
				'created_at' => $now,
				'updated_at' => $now,
			),
			array( '%s', '%s', '%d', '%s', '%s', '%s' )
		);
		return (int) $wpdb->insert_id;
	}

	/**
	 * Fetches one row, with the payload decoded.
	 *
	 * @param int $id Row ID.
	 * @return array|null
	 */
	public static function get( $id ) {
		global $wpdb;
		$table = self::table();
		$row   = $wpdb->get_row( $wpdb->prepare( 'SELECT * FROM %i WHERE id = %d', $table, $id ), ARRAY_A );
		return $row ? self::decode( $row ) : null;
	}

	/**
	 * Most recent rows, newest first.
	 *
	 * @param int $limit Maximum rows.
	 * @return array
	 */
	public static function recent( $limit = 100 ) {
		global $wpdb;
		$table = self::table();
		$rows  = $wpdb->get_results( $wpdb->prepare( 'SELECT * FROM %i ORDER BY id DESC LIMIT %d', $table, $limit ), ARRAY_A );
		return array_map( array( __CLASS__, 'decode' ), (array) $rows );
	}

	/**
	 * Updates status, attempts and the last error of a row.
	 *
	 * @param int    $id       Row ID.
	 * @param string $status   Status.
	 * @param int    $attempts Attempts.
	 * @param string $error    Last error message.
	 */
	public static function update( $id, $status, $attempts, $error ) {
		global $wpdb;
		$wpdb->update(
			self::table(),
			array(
				'status'     => $status,
				'attempts'   => $attempts,
				'last_error' => $error,
				'updated_at' => current_time( 'mysql', true ),
			),
			array( 'id' => $id ),
			array( '%s', '%d', '%s', '%s' ),
			array( '%d' )
		);
	}

	/**
	 * Deletes a row.
	 *
	 * @param int $id Row ID.
	 */
	public static function delete( $id ) {
		global $wpdb;
		$wpdb->delete( self::table(), array( 'id' => $id ), array( '%d' ) );
	}

	/**
	 * Deletes rows not updated for a number of days.
	 *
	 * @param int $days Age in days.
	 */
	public static function purge_older_than( $days ) {
		global $wpdb;
		$table = self::table();
		$wpdb->query( $wpdb->prepare( 'DELETE FROM %i WHERE updated_at < %s', $table, gmdate( 'Y-m-d H:i:s', time() - $days * DAY_IN_SECONDS ) ) );
	}

	/**
	 * Decodes the payload column.
	 *
	 * @param array $row Raw row.
	 * @return array
	 */
	private static function decode( array $row ) {
		$row['id']       = (int) $row['id'];
		$row['attempts'] = (int) $row['attempts'];
		$row['lead']     = (array) json_decode( $row['payload'], true );
		unset( $row['payload'] );
		return $row;
	}
}