<?php
/**
 * Eventin Count Attendees Tool
 *
 * @package Aisentic\Integrations\Eventin
 */

declare(strict_types=1);

namespace Aisentic\Integrations\Eventin;

use Aisentic\Contracts\Read_Only_Tool_Contract;
use Aisentic\Util\Log;
use NeuronAI\Tools\PropertyType;
use NeuronAI\Tools\ToolProperty;

defined( 'ABSPATH' ) || exit;

/**
 * How many attendees there are, filtered and split.
 *
 * An attendee is one ticket holder (an `etn-attendee` post). A "success"
 * attendee holds a confirmed seat, so this is also the booked-seat count.
 */
class Eventin_Count_Attendees_Tool extends Eventin_Stats_Base_Tool implements Read_Only_Tool_Contract {

	/**
	 * Attendee statuses Eventin writes.
	 */
	public const STATUSES = [ 'success', 'pending', 'failed', 'waitlisted' ];

	/**
	 * Ways the count can be split.
	 */
	private const GROUPS = [ 'none', 'status', 'event', 'ticket' ];

	/**
	 * Constructor.
	 *
	 * @param Eventin_Stats_Query|null $query Count queries; tests pass a fake.
	 */
	public function __construct( ?Eventin_Stats_Query $query = null ) {
		parent::__construct(
			'eventin-count-attendees',
			'Count Eventin attendees (ticket holders). Filter by event, status and ticket type, and split the count by status, event or ticket type. Status "success" means a confirmed seat, so it also answers "how many seats are booked". Never count the rows of a list instead. Every result has a status: "ok" means say the numbers from it; "needs_clarification" means ask the question it gives and never pick for them; "not_found" or "not_available" means say plainly you cannot see it and open the page in the result. Never assume a missing event or date range; "this month" and "last week" are fine, worked out from today. To open a page, use the page url in the result.',
			$query
		);
	}

	/**
	 * Define tool properties.
	 *
	 * @return array
	 */
	protected function properties(): array {
		return [
			new ToolProperty(
				name: 'event_id',
				type: PropertyType::NUMBER,
				description: 'Only attendees of this event.',
				required: false
			),
			new ToolProperty(
				name: 'event_name',
				type: PropertyType::STRING,
				description: 'Only attendees of the event with this title, when you do not have its ID.',
				required: false
			),
			new ToolProperty(
				name: 'status',
				type: PropertyType::STRING,
				description: 'Only attendees with this status. "success" means confirmed.',
				required: false,
				enum: self::STATUSES
			),
			new ToolProperty(
				name: 'ticket',
				type: PropertyType::STRING,
				description: 'Only attendees holding this ticket type, by its exact name, e.g. "Early Bird".',
				required: false
			),
			new ToolProperty(
				name: 'group_by',
				type: PropertyType::STRING,
				description: 'Split the count. Default: none.',
				required: false,
				enum: self::GROUPS
			),
		];
	}

	/**
	 * Execute the tool.
	 *
	 * @param int|null    $event_id   Event ID.
	 * @param string|null $event_name Event title.
	 * @param string|null $status     Attendee status.
	 * @param string|null $ticket     Ticket type name.
	 * @param string|null $group_by   Split.
	 * @return array
	 */
	public function __invoke( ?int $event_id = null, ?string $event_name = null, ?string $status = null, ?string $ticket = null, ?string $group_by = null ): array {
		return $this->answer( $event_id, $event_name, $status, $ticket, $group_by );
	}

	/**
	 * Work out the answer.
	 *
	 * @param int|null    $event_id   Event ID.
	 * @param string|null $event_name Event title.
	 * @param string|null $status     Attendee status.
	 * @param string|null $ticket     Ticket type name.
	 * @param string|null $group_by   Split.
	 * @return array
	 */
	private function answer( ?int $event_id, ?string $event_name, ?string $status, ?string $ticket, ?string $group_by ): array {
		$check = $this->guard( 'etn_manage_attendee' );
		if ( $check ) {
			return $check;
		}

		$page     = $this->page( __( 'Attendees', 'aisentic' ), '/attendees' );
		$status   = trim( (string) $status );
		$ticket   = trim( (string) $ticket );
		$group_by = ( null === $group_by || '' === $group_by ) ? 'none' : $group_by;

		if ( '' !== $status && ! in_array( $status, self::STATUSES, true ) ) {
			return $this->unclear( "\"{$status}\" is not an attendee status.", $page, self::STATUSES );
		}

		if ( ! in_array( $group_by, self::GROUPS, true ) ) {
			return $this->unclear( "Cannot split attendees by \"{$group_by}\".", $page, self::GROUPS );
		}

		list( $event_id, $event_title, $stop ) = $this->resolve_event( $event_id, $event_name, $page );
		if ( null !== $stop ) {
			return $stop;
		}

		try {
			$filters = array_filter(
				[
					'event_id' => $event_id,
					'status'   => $status,
					'ticket'   => $ticket,
				]
			);

			$counts = $this->query->count_records( 'attendee', $filters, 'none' === $group_by ? '' : $group_by );

			// Zero for a ticket name that does not exist: return the real names instead.
			// Why: a misheard ticket name gives 0, and "zero" would be a wrong answer.
			if ( '' !== $ticket && 0 === $counts['total'] ) {
				$known = $this->ticket_names( $filters );

				if ( ! in_array( $ticket, $known, true ) ) {
					return $this->unclear( "No ticket type is called \"{$ticket}\".", $page, $known );
				}
			}

			$result = [
				'status'  => 'ok',
				'total'   => $counts['total'],
				'filters' => $filters + ( '' !== $event_title ? [ 'event_title' => $event_title ] : [] ),
				'page'    => $page,
			];

			if ( 'none' !== $group_by ) {
				$result += $this->split( $counts['groups'], $group_by );
			}

			return $result;
		} catch ( \Throwable $e ) {
			Log::error( 'Eventin_Count_Attendees_Tool error', [ 'error' => $e->getMessage() ] );

			return [ 'error' => 'Could not count attendees: ' . $e->getMessage() ];
		}
	}

	/**
	 * Ticket type names in the same scope, without the ticket filter.
	 *
	 * @param array $filters Filters used for the count.
	 * @return string[] Up to 20 names, most used first.
	 */
	private function ticket_names( array $filters ): array {
		unset( $filters['ticket'], $filters['status'] );

		$groups = $this->query->count_records( 'attendee', $filters, 'ticket' )['groups'];

		return array_slice( array_map( 'strval', array_keys( $groups ) ), 0, 20 );
	}

	/**
	 * Shape the split for the model.
	 *
	 * @param array<string,int> $groups   Raw groups.
	 * @param string            $group_by Split.
	 * @return array
	 */
	private function split( array $groups, string $group_by ): array {
		if ( 'status' === $group_by ) {
			return [ 'by_status' => $groups ];
		}

		list( $kept, $folded, $others ) = $this->top_groups( $groups );

		$result = [ 'by_' . $group_by => 'event' === $group_by ? $this->named_event_groups( $kept ) : $kept ];

		if ( $folded > 0 ) {
			$result[ 'other_' . $group_by . 's' ] = [
				'groups'    => $folded,
				'attendees' => $others,
				'note'      => 'Only the 10 largest are listed.',
			];
		}

		return $result;
	}
}