<?php
/** Read-only retained external busy cache; no provider credentials or network access. */
namespace Abientot\Repositories;
use Abientot\Support\Db;
if ( ! defined( 'ABSPATH' ) ) {
	exit;
}
final class CalendarBusyRepository {
	private ?bool $ready = null;
	public function present(): bool {
		if ( $this->ready !== null ) {
			return $this->ready;
		}
		$read = new ResourceCapacityRepository();$definitions = array(
			'calendar_connections'  => array(
				'id'               => 'bigint unsigned',
				'provider'         => 'varchar(20)',
				'owner_user_id'    => 'bigint unsigned',
				'staff_id'         => 'bigint unsigned',
				'authority'        => 'varchar(20)',
				'timezone'         => 'varchar(64)',
				'calendars'        => 'longtext',
				'credential'       => 'longtext',
				'enabled'          => 'tinyint unsigned',
				'consent_revision' => 'bigint unsigned',
				'revision'         => 'bigint unsigned',
				'sync_revision'    => 'bigint unsigned',
				'coverage_start'   => 'datetime',
				'coverage_end'     => 'datetime',
				'last_attempt'     => 'datetime',
				'last_success'     => 'datetime',
				'next_attempt'     => 'datetime',
				'error_code'       => 'varchar(32)',
				'created_at'       => 'datetime'
			),
			'calendar_busy'         => array(
				'id'              => 'bigint unsigned',
				'connection_id'   => 'bigint unsigned',
				'calendar_digest' => 'char(64)',
				'start_utc'       => 'datetime',
				'end_utc'         => 'datetime',
				'sync_revision'   => 'bigint unsigned'
			),
			'calendar_oauth_states' => array(
				'token_hash'    => 'char(64)',
				'user_id'       => 'bigint unsigned',
				'staff_id'      => 'bigint unsigned',
				'provider'      => 'varchar(20)',
				'purpose'       => 'varchar(20)',
				'state_payload' => 'longtext',
				'expires_at'    => 'datetime'
			)
		);
		if ( ! OptionalStoreSchema::present(
			$read,
			'abientot_calendar_inbound_schema_version',
			'1',
			$definitions,
			array(
				'calendar_connections'  => array( array( 'id' ) ),
				'calendar_busy'         => array( array( 'id' ) ),
				'calendar_oauth_states' => array( array( 'token_hash' ) )
			)
		) ) {
			$this->ready = false;
			return false;
		}
		global $wpdb;
		foreach ( $definitions as$table => $columns ) {
			$engine = Db::rows( $wpdb->suppress_errors( true ), $wpdb->get_results( $wpdb->prepare( 'SELECT ENGINE FROM information_schema.TABLES WHERE TABLE_SCHEMA=DATABASE() AND TABLE_NAME=%s', $read->table( $table ) ), ARRAY_A ), 'retained_capacity_storage_unavailable' );
			if ( strtoupper( (string) ( $engine[0]['ENGINE'] ?? '' ) ) !== 'INNODB' ) {
				throw new \RuntimeException( 'calendar_retained_engine' );
			}
			foreach ( Db::rows( $wpdb->suppress_errors( true ), $wpdb->get_results( $wpdb->prepare( 'SHOW COLUMNS FROM %i', $read->table( $table ) ), ARRAY_A ), 'retained_capacity_storage_unavailable' )as$column ) {
				$nullable = $table === 'calendar_connections' && in_array( $column['Field'], array( 'coverage_start', 'coverage_end', 'last_attempt', 'last_success', 'next_attempt' ), true );
				if ( isset( $columns[ $column['Field'] ] ) && ( $column['Null'] === 'YES' ) !== $nullable ) {
					throw new \RuntimeException( 'calendar_retained_nullability' );
				}
			}
		}
		$this->ready = true;
		return true;
	}
	public function available( int $staffId, string $startUtc, string $endUtc ): bool {
		if ( $staffId < 1 || ! self::valid( $startUtc ) || ! self::valid( $endUtc ) || $startUtc >= $endUtc ) {
			throw new \DomainException( 'calendar_interval' );
		}
		if ( ! $this->present() ) {
			return true;
		}
		global $wpdb;
		$read        = new ResourceCapacityRepository();
		$connections = Db::rows( $wpdb->suppress_errors( true ), $wpdb->get_results( $wpdb->prepare( 'SELECT id,provider,consent_revision,revision,sync_revision,coverage_start,coverage_end,last_success,error_code FROM %i WHERE staff_id=%d AND enabled=1', $read->table( 'calendar_connections' ), $staffId ), ARRAY_A ), 'retained_capacity_storage_unavailable' );
		foreach ( $connections as$row ) {
			$success = is_string( $row['last_success'] ) && self::valid( $row['last_success'] ) ? strtotime( $row['last_success'] . ' UTC' ) : false;
			if ( ! in_array( $row['provider'], array( 'google', 'outlook' ), true ) || (int) $row['consent_revision'] !== 1 || (int) $row['sync_revision'] < 1 || $row['error_code'] !== '' || $success === false || time() - $success > 900 || $success - time() > 60 || ! is_string( $row['coverage_start'] ) || ! self::valid( $row['coverage_start'] ) || ! is_string( $row['coverage_end'] ) || ! self::valid( $row['coverage_end'] ) || $row['coverage_start'] > $startUtc || $row['coverage_end'] < $endUtc ) {
				return false;
			}
			$busy = Db::rows( $wpdb->suppress_errors( true ), $wpdb->get_results( $wpdb->prepare( 'SELECT start_utc,end_utc,sync_revision FROM %i WHERE connection_id=%d AND start_utc<%s AND end_utc>%s', $read->table( 'calendar_busy' ), (int) $row['id'], $endUtc, $startUtc ), ARRAY_A ), 'retained_capacity_storage_unavailable' );
			foreach ( $busy as$interval ) {
				if ( ! self::valid( $interval['start_utc'] ) || ! self::valid( $interval['end_utc'] ) || $interval['start_utc'] >= $interval['end_utc'] || (int) $interval['sync_revision'] !== (int) $row['sync_revision'] ) {
							return false;
				}
				return false;
			}
		}
		return true;
	}
	private static function valid( string $stamp ): bool {
		$date = \DateTimeImmutable::createFromFormat( '!Y-m-d H:i:s', $stamp, new \DateTimeZone( 'UTC' ) );
		return $date !== false && $date->format( 'Y-m-d H:i:s' ) === $stamp;
	}
}