<?php
/** Read-only compatibility for retained physical-resource occupancy, in either edition. */
namespace Abientot\Repositories;
use Abientot\Support\Db;
if ( ! defined( 'ABSPATH' ) ) {
	exit;
}
final class ResourceCapacityRepository {
	private ?bool $schema_ready                         = null;
	private ?ResourceBookingRepository $retained_reader = null;
	public function present(): bool {
		if ( $this->schema_ready !== null ) {
			return $this->schema_ready;
		}
		return $this->schema_ready = OptionalStoreSchema::present(
			$this,
			'abientot_resources_schema_version',
			'1',
			array(
				'resources'            => array(
					'id'          => 'bigint unsigned',
					'label'       => 'varchar(190)',
					'location_id' => 'bigint unsigned',
					'capacity'    => 'int unsigned',
					'status'      => 'varchar(20)'
				),
				'service_resources'    => array(
					'service_id'  => 'bigint unsigned',
					'resource_id' => 'bigint unsigned',
					'units'       => 'int unsigned'
				),
				'resource_allocations' => array(
					'owner_type'  => 'varchar(20)',
					'owner_id'    => 'bigint unsigned',
					'resource_id' => 'bigint unsigned',
					'units'       => 'int unsigned',
					'start_utc'   => 'datetime',
					'end_utc'     => 'datetime'
				)
			),
			array(
				'resources'            => array( array( 'id' ) ),
				'service_resources'    => array( array( 'service_id', 'resource_id' ) ),
				'resource_allocations' => array( array( 'owner_type', 'owner_id', 'resource_id' ) )
			)
		);
	}
	public function table( string $suffix ): string {
		global $wpdb;
		return $wpdb->prefix . 'abientot_' . $suffix;
	}
	public function exists( string $suffix ): bool {
		global $wpdb;
		$table = $this->table( $suffix );
		$rows  = Db::rows( $wpdb->suppress_errors( true ), $wpdb->get_results( $wpdb->prepare( 'SHOW TABLES LIKE %s', $wpdb->esc_like( $table ) ), ARRAY_A ), 'retained_capacity_storage_unavailable' );
		return ! empty( $rows );
	}
	public function requirements( int $service, int $location ): array {
		global $wpdb;
		if ( ! $this->present() ) {
			return array();
		}
		$rows = Db::rows( $wpdb->suppress_errors( true ), $wpdb->get_results( $wpdb->prepare( "SELECT q.resource_id,q.units,r.capacity,r.status,r.location_id FROM {$wpdb->prefix}abientot_service_resources q LEFT JOIN {$wpdb->prefix}abientot_resources r ON r.id=q.resource_id WHERE q.service_id=%d ORDER BY q.resource_id LIMIT 201", $service ), ARRAY_A ), 'retained_capacity_storage_unavailable' );
		if ( count( $rows ) > 200 ) {
			throw new \RuntimeException( 'retained_capacity_limit' );
		}
		foreach ( $rows as$r ) {
			if ( (int) $r['units'] < 1 || (int) $r['capacity'] < 1 || $r['status'] !== 'active' || (int) $r['location_id'] !== $location || (int) $r['units'] > (int) $r['capacity'] ) {
				throw new \RuntimeException( 'retained_resource_unavailable' );
			}
		}
		return $rows;
	}
	public function for_owner( string $type, int $id ): array {
		global $wpdb;
		if ( ! in_array( $type, array( 'appointment', 'session' ), true ) || $id < 1 ) {
			throw new \RuntimeException( 'retained_capacity_owner' );
		}
		if ( ! $this->present() ) {
			return array();
		}
		$rows = Db::rows( $wpdb->suppress_errors( true ), $wpdb->get_results( $wpdb->prepare( "SELECT resource_id,units,start_utc,end_utc FROM {$wpdb->prefix}abientot_resource_allocations WHERE owner_type=%s AND owner_id=%d ORDER BY resource_id LIMIT 201", $type, $id ), ARRAY_A ), 'retained_capacity_storage_unavailable' );
		if ( count( $rows ) > 200 ) {
			throw new \RuntimeException( 'retained_capacity_limit' );
		}
		return $rows;
	}
	/** Only canonical blocking owners contribute; missing appointment status stays blocking. */
	public function occupancy( int $resource, string $after ): array {
		global $wpdb;
		if ( ! $this->present() ) {
			return array();
		}
		$rows = Db::rows( $wpdb->suppress_errors( true ), $wpdb->get_results( $wpdb->prepare( "SELECT r.owner_type,r.owner_id,r.resource_id,r.units,r.start_utc,r.end_utc FROM {$wpdb->prefix}abientot_resource_allocations r LEFT JOIN {$wpdb->prefix}abientot_appointments a ON a.id=r.owner_id LEFT JOIN {$wpdb->prefix}abientot_booking_statuses s ON s.id=a.status_id WHERE r.owner_type='appointment' AND r.resource_id=%d AND r.end_utc>%s AND COALESCE(s.blocks_availability,1)=1 ORDER BY r.start_utc,r.end_utc LIMIT 10001", $resource, $after ), ARRAY_A ), 'retained_capacity_storage_unavailable' );
		if ( $this->exists( 'group_sessions' ) ) {
			$rows = array_merge( $rows, Db::rows( $wpdb->suppress_errors( true ), $wpdb->get_results( $wpdb->prepare( "SELECT r.owner_type,r.owner_id,r.resource_id,r.units,r.start_utc,r.end_utc FROM {$wpdb->prefix}abientot_resource_allocations r LEFT JOIN {$wpdb->prefix}abientot_group_sessions g ON g.id=r.owner_id WHERE r.owner_type='session' AND r.resource_id=%d AND r.end_utc>%s AND COALESCE(g.status,'scheduled')<>'cancelled' ORDER BY r.start_utc,r.end_utc LIMIT 10001", $resource, $after ), ARRAY_A ), 'retained_capacity_storage_unavailable' ) );
		}
		if ( count( $rows ) > 10000 ) {
			throw new \RuntimeException( 'retained_capacity_limit' );
		}
		foreach ( $rows as$r ) {
			if ( (int) $r['units'] < 1 || $r['start_utc'] >= $r['end_utc'] ) {
				throw new \RuntimeException( 'retained_capacity_invalid' );
			}
		}
		$this->retained_reader = $this->retained_reader ?? new ResourceBookingRepository();
		return $this->retained_reader->released_intervals( $rows );
	}
	/** Peak concurrency, never the sum of all overlaps. Endpoints use half-open intervals. */
	public static function peak( array $intervals ): int {
		$points = array();
		foreach ( $intervals as$r ) {
			if ( $r['start_utc'] >= $r['end_utc'] || (int) $r['units'] < 1 ) {
				throw new \RuntimeException( 'retained_capacity_invalid' );
			}
			$points[] = array( $r['start_utc'], (int) $r['units'] );
			$points[] = array( $r['end_utc'], - (int) $r['units'] );
		}
		usort( $points, static fn( $a, $b )=>strcmp( $a[0], $b[0] ) ?: ( $a[1] <=> $b[1] ) );
		$used = 0;
		$peak = 0;
		foreach ( $points as$point ) {
			$used += $point[1];
			$peak  = max( $peak, $used );
		}
		return $peak;
	}
	public function available( array $allocations, ?array $excludeOwner = null ): bool {
		global $wpdb;
		$seen = array();
		foreach ( $allocations as$candidate ) {
			$resource = (int) $candidate['resource_id'];
			if ( $resource < 1 || isset( $seen[ $resource ] ) || $candidate['start_utc'] >= $candidate['end_utc'] || (int) $candidate['units'] < 1 ) {
				throw new \RuntimeException( 'retained_capacity_invalid' );
			}
			$seen[ $resource ] = true;
			$r                 = Db::rows( $wpdb->suppress_errors( true ), $wpdb->get_results( $wpdb->prepare( "SELECT capacity,status FROM {$wpdb->prefix}abientot_resources WHERE id=%d", $resource ), ARRAY_A ), 'retained_capacity_storage_unavailable' );
			if ( empty( $r ) || $r[0]['status'] !== 'active' ) {
				return false;
			}
			$overlap = array( $candidate );
			foreach ( $this->occupancy( $resource, $candidate['start_utc'] ) as$existing ) {
				if ( \Abientot\Support\BookingConstraints::exclude_resource_owner( $existing ) ) {
					continue;
				}
				if ( $excludeOwner && $existing['owner_type'] === ( $excludeOwner['owner_type'] ?? '' ) && (int) $existing['owner_id'] === (int) ( $excludeOwner['owner_id'] ?? 0 ) ) {
					continue;
				}
				if ( $existing['start_utc'] >= $candidate['end_utc'] || $existing['end_utc'] <= $candidate['start_utc'] ) {
					continue;
				}
				$existing['start_utc'] = max( $existing['start_utc'], $candidate['start_utc'] );
				$existing['end_utc']   = min( $existing['end_utc'], $candidate['end_utc'] );
				$overlap[]             = $existing;
			}
			if ( self::peak( $overlap ) > (int) $r[0]['capacity'] ) {
				return false;
			}
		}
		return true;
	}
}