<?php
declare(strict_types=1);

namespace FDMTech;

final class Config
{
    public function __construct(private array $values, public readonly string $root) {}

    public static function load(string $root): self
    {
        $values = [];
        if (is_file($root . '/.env')) {
            foreach (file($root . '/.env', FILE_IGNORE_NEW_LINES) as $line) {
                $line = trim($line);
                if ($line === '' || str_starts_with($line, '#')) {
                    continue;
                }
                if (!preg_match('/^([A-Z][A-Z0-9_]*)=(.*)$/D', $line, $match)) {
                    throw new \RuntimeException('Invalid environment configuration');
                }
                $value = trim($match[2]);
                if (strlen($value) >= 2 && in_array($value[0], ['"', "'"], true) && $value[-1] === $value[0]) {
                    $value = substr($value, 1, -1);
                }
                $values[$match[1]] = $value;
            }
        }
        return new self(array_replace($values, getenv()), $root);
    }

    public function get(string $key, string $default = ''): string
    {
        return (string) ($this->values[$key] ?? $default);
    }

    public function bool(string $key, bool $default = false): bool
    {
        $raw = $this->get($key, $default ? 'true' : 'false');
        $value = filter_var($raw, FILTER_VALIDATE_BOOLEAN, FILTER_NULL_ON_FAILURE);
        if ($value === null) {
            throw new \RuntimeException('Invalid boolean configuration');
        }
        return $value;
    }

    public function number(string $key, int $default): int
    {
        $value = filter_var($this->get($key, (string) $default), FILTER_VALIDATE_INT);
        if ($value === false || $value < 1 || $value > 86400) {
            throw new \RuntimeException('Invalid rate limit configuration');
        }
        return $value;
    }

    public function canonical(string $path): string
    {
        $url = rtrim($this->get('APP_URL'), '/');
        if ($url === '') {
            return '';
        }
        if (!filter_var($url, FILTER_VALIDATE_URL) || !in_array(parse_url($url, PHP_URL_SCHEME), ['https', 'http'], true)
            || parse_url($url, PHP_URL_USER) || parse_url($url, PHP_URL_QUERY) || parse_url($url, PHP_URL_FRAGMENT)
            || !in_array(parse_url($url, PHP_URL_PATH), [null, '', '/'], true)) {
            throw new \RuntimeException('Invalid APP_URL');
        }
        return $url . $path;
    }
}