<?php

namespace GuzzleHttp\Psr7;

final class Query
{
/**
* Parse a query string into an associative array.
*
* If multiple values are found for the same key, the value of that key
* value pair will become an array. This function does not parse nested
* PHP style arrays into an associative array (e.g., `foo[a]=1&foo[b]=2`
* will be parsed into `['foo[a]' => '1', 'foo[b]' => '2'])`.
*
* @param string $str Query string to parse
* @param int|bool $urlEncoding How the query string is encoded
*
* @return array
*/
public static function parse($str, $urlEncoding = true)
{
$result = [];

if ($str === '') {
return $result;
}

if ($urlEncoding === true) {
$decoder = function ($value) {
return rawurldecode(str_replace('+', ' ', $value));
};
} elseif ($urlEncoding === PHP_QUERY_RFC3986) {
$decoder = 'rawurldecode';
} elseif ($urlEncoding === PHP_QUERY_RFC1738) {
$decoder = 'urldecode';
} else {
$decoder = function ($str) {
return $str;
};
}

foreach (explode('&', $str) as $kvp) {
$parts = explode('=', $kvp, 2);
$key = $decoder($parts[0]);
$value = isset($parts[1]) ? $decoder($parts[1]) : null;
if (!isset($result[$key])) {
$result[$key] = $value;
} else {
if (!is_array($result[$key])) {
$result[$key] = [$result[$key]];
}
$result[$key][] = $value;
}
}

return $result;
}

/**
* Build a query string from an array of key value pairs.
*
* This function can use the return value of `parse()` to build a query
* string. This function does not modify the provided keys when an array is
* encountered (like `http_build_query()` would).
*
* @param array $params Query string parameters.
* @param int|false $encoding Set to false to not encode, PHP_QUERY_RFC3986
* to encode using RFC3986, or PHP_QUERY_RFC1738
* to encode using RFC1738.
*
* @return string
*/
public static function build(array $params, $encoding = PHP_QUERY_RFC3986)
{
if (!$params) {
return '';
}

if ($encoding === false) {
$encoder = function ($str) {
return $str;
};
} elseif ($encoding === PHP_QUERY_RFC3986) {
$encoder = 'rawurlencode';
} elseif ($encoding === PHP_QUERY_RFC1738) {
$encoder = 'urlencode';
} else {
throw new \InvalidArgumentException('Invalid type');
}

$qs = '';
foreach ($params as $k => $v) {
$k = $encoder($k);
if (!is_array($v)) {
$qs .= $k;
if ($v !== null) {
$qs .= '=' . $encoder($v);
}
$qs .= '&';
} else {
foreach ($v as $vv) {
$qs .= $k;
if ($vv !== null) {
$qs .= '=' . $encoder($vv);
}
$qs .= '&';
}
}
}

return $qs ? (string) substr($qs, 0, -1) : '';
}
}