<?php
/*
 * 微信网关代理
 * https://wechat.1zh888.com/transfer.php
 * 把程序中的
 * https://open.weixin.qq.com/connect/oauth2/authorize (mobile)
 * 或
 * https://open.weixin.qq.com/connect/qrconnect (pc)
 * 换成 https://wechat.1zh888.com/transfer.php
 * 并在后面拼上 &device=mobile 或 &device=pc
 * **/
function is_HTTPS()
{
  if (!isset($_SERVER['HTTPS'])) return FALSE;
  if ($_SERVER['HTTPS'] === 1) {  //Apache
    return TRUE;
  } elseif ($_SERVER['HTTPS'] === 'on') { //IIS
    return TRUE;
  } elseif ($_SERVER['SERVER_PORT'] == 443) { //其他
    return TRUE;
  }
  return FALSE;
}

function getDomain()
{
  $server_name = $_SERVER['SERVER_NAME'];
  if (strpos($server_name, 'www.') !== false) {
    return substr($server_name, 4);
  }
  return $server_name;
}

$appid = '';
$scope = 'snsapi_login';
$state = '';
$code = '';
$redirect_uri = '';
$device = '';
$protocol = '';
if (is_HTTPS()) {
  $protocol = 'https';
} else {
  $protocol = 'http';
}
if (isset($_GET['device'])) {
  $device = $_GET['device'];
}
if (isset($_GET['appid'])) {
  $appid = $_GET['appid'];
}
if (isset($_GET['state'])) {
  $state = $_GET['state'];
}
if (isset($_GET['redirect_uri'])) {
  $redirect_uri = $_GET['redirect_uri'];
}
if (isset($_GET['code'])) {
  $code = $_GET['code'];
}
if (isset($_GET['scope'])) {
  $scope = $_GET['scope'];
}
if ($code == 'test') {
  exit;
}
if (empty($code)) {
  $authUrl = '';
  if ($device == 'pc') {
    $authUrl = 'https://open.weixin.qq.com/connect/qrconnect';
  } else {
    $authUrl = 'https://open.weixin.qq.com/connect/oauth2/authorize';
  }
  $options = [
    $authUrl,
    '?appid=' . $appid,
    '&redirect_uri=' . urlencode($protocol . '://' . $_SERVER['HTTP_HOST'] . '/transfer.php'),
    '&response_type=code',
    '&scope=' . $scope,
    '&state=' . $state,
    '#wechat_redirect'
  ];
  //把redirect_uri先写到cookie
  header(implode('', [
    "Set-Cookie: redirect_uri=",
    urlencode($redirect_uri),
    "; path=/; domain=",
    getDomain(),
    "; expires=" . gmstrftime("%A, %d-%b-%Y %H:%M:%S GMT", time() + 60),
    "; Max-Age=" + 60,
    "; httponly"
  ]));
  header('Location: ' . implode('', $options));
} else {
  if (isset($_COOKIE['redirect_uri'])) {
    $back_url = urldecode($_COOKIE['redirect_uri']);
    header('Location: ' . implode('', [
        $back_url,
        strpos($back_url, '?') ? '&' : '?',
        'code=' . $code,
        '&state=' . $state
      ]));
  }
}
?>