<?php
declare(strict_types=1);

namespace App;

final class Search
{
    public function __construct(private ?\PDO $pdo) {}

    public function searchEvents(string $query, int $limit = 100, ?array $geo = null): array
    {
        if (!$this->pdo) return [];

        $q = trim($query);
        $hasGeo = isset($geo['lat'], $geo['lng']) && is_numeric($geo['lat']) && is_numeric($geo['lng']);
        if ($q === '' && !$hasGeo) return [];

        $tokens = array_filter(preg_split('/\s+/', $q) ?: [], fn($t) => $t !== '');
        if (!$tokens) {
            $tokens = [$q];
        }

        $conditions = [];
        $params = [];
        $i = 0;
        foreach ($tokens as $tok) {
            $tok = trim($tok);
            if ($tok === '') continue;
            $ph = [
                't' . $i . 'a',
                't' . $i . 'b',
                't' . $i . 'c',
                't' . $i . 'd',
                't' . $i . 'e',
                't' . $i . 'f',
            ];
            $conditions[] = "(title LIKE :{$ph[0]} OR teaser_public LIKE :{$ph[1]} OR description LIKE :{$ph[2]} OR city LIKE :{$ph[3]} OR region LIKE :{$ph[4]} OR zip LIKE :{$ph[5]})";
            foreach ($ph as $p) {
                $params[$p] = '%' . $tok . '%';
            }
            $i++;
        }
        $whereParts = [
            "starts_at >= NOW()",
            "status != 'cancelled'",
        ];
        if ($conditions) {
            $whereParts[] = implode(' AND ', $conditions);
        }

        $sql = "SELECT id, title, teaser_public, description, city, region, zip, starts_at, visibility, allow_kids, location_label, lat, lng";
        $distanceFiltering = false;

        if ($hasGeo) {
            $lat = (float)$geo['lat'];
            $lng = (float)$geo['lng'];
            $radius = isset($geo['radius']) && is_numeric($geo['radius']) ? max(0.1, (float)$geo['radius']) : 5.0;
            $sql .= ",
            (6371 * ACOS(LEAST(1,
              COS(RADIANS(:glat)) * COS(RADIANS(lat)) * COS(RADIANS(lng) - RADIANS(:glng)) +
              SIN(RADIANS(:glat)) * SIN(RADIANS(lat))
            ))) AS distance_km";
            $distanceFiltering = true;

            $latRange = $radius / 111.0;
            $lngRange = $radius / (111.0 * max(0.1, cos($lat * M_PI / 180)));
            $whereParts[] = "(lat IS NOT NULL AND lng IS NOT NULL)";
            $whereParts[] = "(lat BETWEEN :latMin AND :latMax)";
            $whereParts[] = "(lng BETWEEN :lngMin AND :lngMax)";
            $params['glat'] = $lat;
            $params['glng'] = $lng;
            $params['latMin'] = $lat - $latRange;
            $params['latMax'] = $lat + $latRange;
            $params['lngMin'] = $lng - $lngRange;
            $params['lngMax'] = $lng + $lngRange;
            $params['radius'] = $radius;
        }

        $where = $whereParts ? ('WHERE ' . implode(' AND ', $whereParts)) : '';
        $sql .= " FROM events $where";
        if ($distanceFiltering) {
            $sql .= " HAVING distance_km <= :radius";
            $sql .= " ORDER BY distance_km ASC, starts_at ASC";
        } else {
            $sql .= " ORDER BY starts_at ASC";
        }
        $sql .= " LIMIT :lim";

        $stmt = $this->pdo->prepare($sql);
        $execParams = $params;
        $execParams['lim'] = $limit;
        $stmt->execute($execParams);
        return $stmt->fetchAll(\PDO::FETCH_ASSOC) ?: [];
    }
}