<?php

$rest_last_api_request_nexturl = "";

function fetchAccessToken($oauth_url, $client_id, $client_secret, $scopes = ["oaid:codes:read"]) {
  //echo "called fetchAccessToken $oauth_url\n";
  global $token_file;
  global $access_token;
  
  $headers = [
    "Accept: application/json",
    "Content-Type: application/x-www-form-urlencoded",
  ];
  
  $post_content = [
    "grant_type" => "client_credentials",
    "client_id" => $client_id,
    "client_secret" => $client_secret,
    "scope" => implode(" ", $scopes),
  ];
  
  $output = postRestUrl($oauth_url, $headers, $post_content);
  $output_values = json_decode($output);
  if(!is_object($output_values) || !property_exists($output_values, "access_token")) {
    return false;
  }
  
  $access_token = $output_values->access_token;
  file_put_contents($token_file, $access_token);
  
  return $access_token;
}

function getRestUrl($url, $headers, $params = [], $debug = false) {
  global $rest_last_api_request_nexturl;

  //echo "called getRestUrl $url\n";
  $ctx_options = ["http" => [
    "ignore_errors" => true,
    "method" => "GET",
    "header" => $headers,
  ]];
  
  $_url = $url;
  if(count($params)) {
    $_url .= "?".http_build_query($params);
  }
  
  if($debug) {
    var_dump($_url, $ctx_options);
    //exit;
  }
  
  $ctx = stream_context_create($ctx_options);
  $output = file_get_contents($_url, false, $ctx);

  if($debug) {
    echo $output;
  }

  $_return = "";
  $http_status_line = "";

  foreach($http_response_header as $h_line) {
    if($debug) {
      echo "HEADER: " . trim($h_line) . "\n";
    }
    if(preg_match('/HTTP\/\d+(?:\.\d+) ([245]\d+)/', $h_line, $m)) {
      $http_status_line = $h_line;
      $response_code = $m[1];
      if(substr($response_code, 0, 1) == "2") {
        $_return = $output;
      } elseif($response_code == "401") {
        $_return = "__err__401";
      }
    }

    if(preg_match('/^Link: .*<([^>]+)>; rel=next/', $h_line, $m)) {
        $rest_last_api_request_nexturl = $m[1];
    }
  }

  if(!$_return) die("getRestUrl():\n$http_status_line\n$output");
  return $_return;
}

function putRestUrl($url, $headers, $content, $content_type = "application/x-www-form-urlencoded", $follow_location = true, $debug = false) {
  return postRestUrl($url, $headers, $content, $content_type, $follow_location, $debug, 'PUT');
}

function patchRestUrl($url, $headers, $content, $content_type = "application/x-www-form-urlencoded", $follow_location = true, $debug = false) {
    return postRestUrl($url, $headers, $content, $content_type, $follow_location, $debug, 'PATCH');
}

function postRestUrl($url, $headers, $content, $content_type = "application/x-www-form-urlencoded", $follow_location = true, $debug = false, $method = "POST") {
  //echo "called postResturl $url\n";
  $ctx_options = ["http" => [
    "ignore_errors" => true,
    "method" => "POST",
    "header" => $headers,
  ]];
  
  if(!$follow_location) {
    $ctx_options["http"]["follow_location"] = false;
  }
  
  if($method == "PUT") {
    $ctx_options["http"]["method"] = "PUT";
  }
  if($method == "PATCH") {
    $ctx_options["http"]["method"] = "PATCH";
  }
  
  if($content_type == "application/x-www-form-urlencoded") {
    $ctx_options["http"]["content"] = http_build_query($content);
  }
  if($content_type == "application/json") {
    $ctx_options["http"]["content"] = json_encode($content);
  }
  
  if($debug) {
    var_dump($url, $ctx_options);
    exit;
  }
  
  $ctx = stream_context_create($ctx_options);
  $output = file_get_contents($url, false, $ctx);
  //var_dump($http_response_header);
  
  if(!$follow_location) {
    return $output;
  }
  
  foreach($http_response_header as $h_line) {
    $m = [];
    $status_code_types = "245";
    if(!$follow_location) {
      $status_code_types = "2345";
    }
    if(preg_match('/HTTP\/\d+(?:\.\d+) ([245]\d+)/', $h_line, $m)) {
      $response_code = $m[1];
      if(substr($response_code, 0, 1) == "2") {
        return $output;
      } elseif(substr($response_code, 0, 1) == "3") {
        return $output;
      } elseif($response_code == "401") {
        return "__err__401";
      } else {
        die("postRestUrl(): $h_line\n");
      }
    }
  }
  
}

function guidv4($data = null) {
    // Generate 16 bytes (128 bits) of random data or use the data passed into the function.
    $data = $data ?? random_bytes(16);
    assert(strlen($data) == 16);

    // Set version to 0100
    $data[6] = chr(ord($data[6]) & 0x0f | 0x40);
    // Set bits 6-7 to 10
    $data[8] = chr(ord($data[8]) & 0x3f | 0x80);

    // Output the 36 character UUID.
    return vsprintf('%s%s-%s-%s-%s-%s%s%s', str_split(bin2hex($data), 4));
}