<?php
declare(strict_types=1);

function parse_env_file(string $path): array
{
    if (!is_file($path)) {
        return [];
    }

    $result = [];
    $lines = file($path, FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES);
    if ($lines === false) {
        return [];
    }

    foreach ($lines as $line) {
        $trimmed = trim($line);
        if ($trimmed === '' || str_starts_with($trimmed, '#')) {
            continue;
        }

        $pos = strpos($trimmed, '=');
        if ($pos === false) {
            continue;
        }

        $key = trim(substr($trimmed, 0, $pos));
        $value = trim(substr($trimmed, $pos + 1));
        if ($key === '') {
            continue;
        }

        if (strlen($value) >= 2) {
            $first = $value[0];
            $last = $value[strlen($value) - 1];
            if (($first === '"' && $last === '"') || ($first === "'" && $last === "'")) {
                $value = substr($value, 1, -1);
            }
        }

        $result[$key] = $value;
    }

    return $result;
}

function expand_env_values(array $env): array
{
    $expanded = $env;
    $pattern = '/\$\{([A-Za-z_][A-Za-z0-9_]*)\}/';

    foreach ($expanded as $key => $value) {
        $expanded[$key] = preg_replace_callback(
            $pattern,
            static function (array $matches) use (&$expanded): string {
                $lookup = $matches[1];
                return (string) ($expanded[$lookup] ?? getenv($lookup) ?: '');
            },
            (string) $value
        ) ?? (string) $value;
    }

    return $expanded;
}

function env_value(string $key, array $localEnv, string $default = ''): string
{
    $runtime = getenv($key);
    if ($runtime !== false && $runtime !== '') {
        return $runtime;
    }

    if (isset($localEnv[$key]) && $localEnv[$key] !== '') {
        return (string) $localEnv[$key];
    }

    return $default;
}

function connect_database(): PDO
{
    $env = parse_env_file(__DIR__ . '/../.env');
    $env = expand_env_values($env);

    $databaseUrl = env_value('DATABASE_URL', $env);
    if ($databaseUrl !== '') {
        $parts = parse_url($databaseUrl);
        if ($parts !== false && ($parts['scheme'] ?? '') === 'postgresql') {
            $host = (string) ($parts['host'] ?? '');
            $port = (string) ($parts['port'] ?? '5432');
            $dbName = ltrim((string) ($parts['path'] ?? ''), '/');
            $user = (string) ($parts['user'] ?? '');
            $pass = (string) ($parts['pass'] ?? '');
            if ($host !== '' && $dbName !== '' && $user !== '') {
                $dsn = "pgsql:host={$host};port={$port};dbname={$dbName}";
                return new PDO($dsn, $user, $pass, [
                    PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
                    PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
                ]);
            }
        }
    }

    $host = env_value('DB_HOST', $env);
    $port = env_value('DB_PORT', $env, '5432');
    $dbName = env_value('DB_NAME', $env);
    $user = env_value('DB_USER', $env);
    $pass = env_value('DB_PASSWORD', $env);

    if ($host === '' || $dbName === '' || $user === '') {
        throw new RuntimeException('Missing DB configuration');
    }

    $dsn = "pgsql:host={$host};port={$port};dbname={$dbName}";
    return new PDO($dsn, $user, $pass, [
        PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
        PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
    ]);
}

function parse_number(mixed $value): ?float
{
    if ($value === null || $value === '') {
        return null;
    }

    if (is_int($value) || is_float($value)) {
        return (float) $value;
    }

    if (!is_string($value)) {
        return null;
    }

    $normalized = str_replace(["\u{00A0}", ' '], '', trim($value));
    $normalized = str_replace(',', '.', $normalized);

    if (!is_numeric($normalized)) {
        return null;
    }

    return (float) $normalized;
}

function json_response(int $status, array $payload): void
{
    http_response_code($status);
    header('Content-Type: application/json; charset=utf-8');
    echo json_encode($payload, JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES);
    exit;
}