<?php
namespace Relay\Remote;

use Relay\Support\RelayError;
use Relay\Support\SiteInfo;

/**
 * Connecting to another site: save a connection string (kept only if the other site answers) and describe
 * the other site — handshake, tables and file inventory. Used by the Pull/Push screen and the CLI.
 */
final class ConnectionService
{
    private ConnectionRepository $connections;
    private Client $client;

    public function __construct(ConnectionRepository $connections, Client $client)
    {
        $this->connections = $connections;
        $this->client = $client;
    }

    /** @return array{connection: array, peer: array, tables: array, files: ?array} */
    public function connect(string $connection_string, string $label, bool $allow_insecure, ?array $basic_auth = null): array
    {
        $before = array_column($this->connections->all(), 'id');
        $row = $this->connections->save($connection_string, $label, $allow_insecure, $basic_auth);
        try {
            $described = $this->describe($row);
        } catch (RelayError $e) {
            if (!in_array($row['id'], $before, true)) {
                $this->connections->delete($row['id']); // a connection that never worked is not kept
            }
            throw $e;
        }
        return ['connection' => $this->connections->get($row['id'])] + $described;
    }

    /**
     * Handshake, tables and file inventory: what Pull/Push show about the other site. A network shows its subsites
     * first; with $subsite (one of them) the tables and files are that subsite's, and "subsite" says which it is.
     *
     * @return array{peer: array, tables: array, files: ?array, subsites?: array[], subsite?: array}
     */
    public function describe(array $connection, int $subsite = 0): array
    {
        $hello = $this->client->call($connection, 'hello')['meta'];
        SiteInfo::refuse_this_site((array) ($hello['site'] ?? []));
        $features = array_values(array_filter((array) ($hello['features'] ?? []), 'is_string'));
        $network = in_array('subsites', $features, true);
        if ($subsite > 0 && !$network) {
            throw self::no_subsites(esc_html((string) ($hello['site']['home_url'] ?? '')));
        }
        $described = in_array('pull', (array) ($hello['permissions'] ?? []), true) || in_array('push', (array) ($hello['permissions'] ?? []), true)
            ? $this->client->call($connection, 'db.describe', '', $subsite > 0 ? ['subsite' => $subsite] : [])['meta']
            : [];
        $out = [
            'peer' => [
                'site' => $hello['site'] ?? [],
                'mode' => (string) ($hello['mode'] ?? ''),
                'permissions' => array_values(array_intersect(['pull', 'push'], (array) ($hello['permissions'] ?? []))),
                'key' => $hello['key'] ?? [],
                'protocol' => (int) ($hello['protocol'] ?? 0),
                'features' => $features,
            ],
            'tables' => (array) ($described['tables'] ?? []),
            'files' => is_array($described['files'] ?? null) ? $described['files'] : null,
        ];
        if ($network) {
            $out['subsites'] = array_values(array_filter((array) ($described['subsites'] ?? []), 'is_array'));
        }
        if ($subsite > 0) {
            $site = SiteInfo::from_peer($described['site'] ?? null);
            $out['subsite'] = ['id' => $subsite, 'name' => $site['name'], 'home_url' => $site['home_url']];
        }
        return $out;
    }

    /** The other site's Relay can't choose subsites: it is older, or not a network. */
    public static function no_subsites(string $site): RelayError
    {
        return new RelayError(
            'remote.no_subsites',
            /* translators: %s: other site's address */
            esc_html(sprintf(__('%s can\'t send or receive one subsite: it isn\'t a network, or its SiteRelay is older.', 'siterelay'), $site)),
            esc_html__('Update SiteRelay on the other site, or don\'t choose a subsite there.', 'siterelay')
        );
    }
}