<?php
/**
 * (c) 2025 Sakuragasaki46
 * 
 * This is an interface to the IP2Location Lite country IP database, CC BY-SA licensed 
 * and accessible free of charge at <https://lite.ip2location.com> (registration required).
 * IP2Location Lite® is a registered trademark of Hexasoft Development Sdn Bhd.
 */

namespace Yusurko\UserAgent;


use Yusurko\UserAgent\IpAddress;


class IpLocator {
    protected $conn, $source_file;

    const SOURCE_FILE = '.err/data/IP2LOCATION-LITE-DB1.IPV6.CSV';

    const LOCAL_RANGES = [
        ["0", "1", '@'],
        ["281470681743360", "281470698520575", '+'],
        ["281470849515520", "281470866292735", "+"],
        ["281472812449792", "281472829227007", "@"],
        ["281473533739008", "281473533804543", "+"],
        ["281473568473088", "281473569521663", "+"],
        ["281473913978880", "281473914044415", "+"],
        ["338288524927261089654018896841347694592", "338288524927261089672465640915057246207", "+"]
    ];

    public function __construct($conn, $source_file = self::SOURCE_FILE) {
        $this->conn = $conn;
        $this->source_file = $source_file;
    }

    public function locate($addr){
        $addr = new IpAddress($addr);

        if (!$this->isDbLoaded()) {
            $up_to_range = $this->getDbLoadedUpto();
            $this->loadCsvIntoDb($up_to_range);
        }

        $country = $this->lookupDb($addr);

        return new Country($country);
    }

    private function isDbLoaded() {
        $ex = $this->conn->prepare("SELECT 1 FROM af_ip2location WHERE range_end = x'ffffffffffffffffffffffffffffffff'");
        $ex->execute();
        $res = $ex->get_result();

        return ($res->num_rows > 0);
    }

    private function getDbLoadedUpto(){
        $ex = $this->conn->prepare("SELECT hex(range_end) FROM af_ip2location ORDER BY id DESC LIMIT 1");
        $ex->execute();
        $ex->store_result();
        $ex->bind_result($range_end);
        $ex->fetch();

        return IpAddress::fromHex($range_end);
    }

    private function loadCsvIntoDb($start = false) {
        
        $f = fopen($this->source_file, 'r');

        while (($line = fgetcsv($f)) !== false) {
            $rs = new IpAddress($line[0]);
            $re = new IpAddress($line[1]);
            if ($rs->compare($start) <= 0) continue;
            try {
                $this->storeRangeIntoDb($rs, $re, $line[2]);
            } catch (\mysqli_sql_exception $ee) {
                return false;
            }
        }

        return true;
    }

    private function storeRangeIntoDb($range_start, $range_end, $country) {
        $range_start_x = $range_start->toFullHex();
        $range_end_x = $range_end->toFullHex();
        $ins = $this->conn->prepare('INSERT INTO af_ip2location (range_start, range_end, country) VALUES (unhex(?), unhex(?), ?)');
        $ins->bind_param('sss', $range_start_x, $range_end_x, $country);
        $ins->execute();
        $ins->store_result();
    }

    private function lookupDb($addr) {
        // look up forbidden ranges first
        foreach (self::LOCAL_RANGES as $rang) {
            [ $rs, $re, $co ] = $rang;
            if ($addr->compare(new IpAddress($rs)) >= 0 && $addr->compare(new IpAddress($re)) <= 0) {
                return $co;
            }
        }

        $addr_x = $addr->toFullHex();
        $st = $this->conn->prepare('SELECT country FROM af_ip2location WHERE range_end >= unhex(?) AND range_start <= unhex(?)');
        $st->bind_param('ss', $addr_x, $addr_x);
        $st->execute();
        $res = $st->get_result();
        if ($res->num_rows < 1) {
            return false;
        }

        return $res->fetch_assoc()['country'];
    }
}