'use strict';

const binding = process.binding('http_parser');
const methods = binding.methods;
const HTTPParser = binding.HTTPParser;

const FreeList = require('internal/freelist').FreeList;
const incoming = require('_http_incoming');
const IncomingMessage = incoming.IncomingMessage;
const readStart = incoming.readStart;
const readStop = incoming.readStop;

const debug = require('util').debuglog('http');
exports.debug = debug;

exports.CRLF = '\r\n';
exports.chunkExpression = /(?:^|\W)chunked(?:$|\W)/i;
exports.continueExpression = /(?:^|\W)100-continue(?:$|\W)/i;
exports.methods = methods;

const kOnHeaders = HTTPParser.kOnHeaders | 0;
const kOnHeadersComplete = HTTPParser.kOnHeadersComplete | 0;
const kOnBody = HTTPParser.kOnBody | 0;
const kOnMessageComplete = HTTPParser.kOnMessageComplete | 0;
const kOnExecute = HTTPParser.kOnExecute | 0;

// Only called in the slow case where slow means
// that the request headers were either fragmented
// across multiple TCP packets or too large to be
// processed in a single run. This method is also
// called to process trailing HTTP headers.
function parserOnHeaders(headers, url) {
  // Once we exceeded headers limit - stop collecting them
  if (this.maxHeaderPairs <= 0 ||
      this._headers.length < this.maxHeaderPairs) {
    this._headers = this._headers.concat(headers);
  }
  this._url += url;
}

// `headers` and `url` are set only if .onHeaders() has not been called for
// this request.
// `url` is not set for response parsers but that's not applicable here since
// all our parsers are request parsers.
function parserOnHeadersComplete(versionMajor, versionMinor, headers, method,
                                 url, statusCode, statusMessage, upgrade,
                                 shouldKeepAlive) {
  var parser = this;

  if (!headers) {
    headers = parser._headers;
    parser._headers = [];
  }

  if (!url) {
    url = parser._url;
    parser._url = '';
  }

  parser.incoming = new IncomingMessage(parser.socket);
  parser.incoming.httpVersionMajor = versionMajor;
  parser.incoming.httpVersionMinor = versionMinor;
  parser.incoming.httpVersion = versionMajor + '.' + versionMinor;
  parser.incoming.url = url;

  var n = headers.length;

  // If parser.maxHeaderPairs <= 0 assume that there's no limit.
  if (parser.maxHeaderPairs > 0)
    n = Math.min(n, parser.maxHeaderPairs);

  parser.incoming._addHeaderLines(headers, n);

  if (typeof method === 'number') {
    // server only
    parser.incoming.method = methods[method];
  } else {
    // client only
    parser.incoming.statusCode = statusCode;
    parser.incoming.statusMessage = statusMessage;
  }

  if (upgrade && parser.outgoing !== null && !parser.outgoing.upgrading) {
    // The client made non-upgrade request, and server is just advertising
    // supported protocols.
    //
    // See RFC7230 Section 6.7
    upgrade = false;
  }

  parser.incoming.upgrade = upgrade;

  var skipBody = 0; // response to HEAD or CONNECT

  if (!upgrade) {
    // For upgraded connections and CONNECT method request, we'll emit this
    // after parser.execute so that we can capture the first part of the new
    // protocol.
    skipBody = parser.onIncoming(parser.incoming, shouldKeepAlive);
  }

  if (typeof skipBody !== 'number')
    return skipBody ? 1 : 0;
  else
    return skipBody;
}

// XXX This is a mess.
// TODO: http.Parser should be a Writable emits request/response events.
function parserOnBody(b, start, len) {
  var parser = this;
  var stream = parser.incoming;

  // if the stream has already been removed, then drop it.
  if (!stream)
    return;

  var socket = stream.socket;

  // pretend this was the result of a stream._read call.
  if (len > 0 && !stream._dumped) {
    var slice = b.slice(start, start + len);
    var ret = stream.push(slice);
    if (!ret)
      readStop(socket);
  }
}

function parserOnMessageComplete() {
  var parser = this;
  var stream = parser.incoming;

  if (stream) {
    stream.complete = true;
    // Emit any trailing headers.
    var headers = parser._headers;
    if (headers) {
      parser.incoming._addHeaderLines(headers, headers.length);
      parser._headers = [];
      parser._url = '';
    }

    // For emit end event
    stream.push(null);
  }

  // force to read the next incoming message
  readStart(parser.socket);
}


var parsers = new FreeList('parsers', 1000, function() {
  var parser = new HTTPParser(HTTPParser.REQUEST);

  parser._headers = [];
  parser._url = '';
  parser._consumed = false;

  parser.socket = null;
  parser.incoming = null;
  parser.outgoing = null;

  // Only called in the slow case where slow means
  // that the request headers were either fragmented
  // across multiple TCP packets or too large to be
  // processed in a single run. This method is also
  // called to process trailing HTTP headers.
  parser[kOnHeaders] = parserOnHeaders;
  parser[kOnHeadersComplete] = parserOnHeadersComplete;
  parser[kOnBody] = parserOnBody;
  parser[kOnMessageComplete] = parserOnMessageComplete;
  parser[kOnExecute] = null;

  return parser;
});
exports.parsers = parsers;


// Free the parser and also break any links that it
// might have to any other things.
// TODO: All parser data should be attached to a
// single object, so that it can be easily cleaned
// up by doing `parser.data = {}`, which should
// be done in FreeList.free.  `parsers.free(parser)`
// should be all that is needed.
function freeParser(parser, req, socket) {
  if (parser) {
    parser._headers = [];
    parser.onIncoming = null;
    if (parser._consumed)
      parser.unconsume();
    parser._consumed = false;
    if (parser.socket)
      parser.socket.parser = null;
    parser.socket = null;
    parser.incoming = null;
    parser.outgoing = null;
    parser[kOnExecute] = null;
    if (parsers.free(parser) === false)
      parser.close();
  }
  if (req) {
    req.parser = null;
  }
  if (socket) {
    socket.parser = null;
  }
}
exports.freeParser = freeParser;


function ondrain() {
  if (this._httpMessage) this._httpMessage.emit('drain');
}


function httpSocketSetup(socket) {
  socket.removeListener('drain', ondrain);
  socket.on('drain', ondrain);
}
exports.httpSocketSetup = httpSocketSetup;

/**
 * Verifies that the given val is a valid HTTP token
 * per the rules defined in RFC 7230
 * See https://tools.ietf.org/html/rfc7230#section-3.2.6
 *
 * Allowed characters in an HTTP token:
 * ^_`a-z  94-122
 * A-Z     65-90
 * -       45
 * 0-9     48-57
 * !       33
 * #$%&'   35-39
 * *+      42-43
 * .       46
 * |       124
 * ~       126
 *
 * This implementation of checkIsHttpToken() loops over the string instead of
 * using a regular expression since the former is up to 180% faster with v8 4.9
 * depending on the string length (the shorter the string, the larger the
 * performance difference)
 *
 * Additionally, checkIsHttpToken() is currently designed to be inlinable by v8,
 * so take care when making changes to the implementation so that the source
 * code size does not exceed v8's default max_inlined_source_size setting.
 **/
var validTokens = [
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 0 - 15
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 16 - 31
  0, 1, 0, 1, 1, 1, 1, 1, 0, 0, 1, 1, 0, 1, 1, 0, // 32 - 47
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, // 48 - 63
  0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 64 - 79
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, // 80 - 95
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 96 - 111
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 0, 1, 0, // 112 - 127
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 128 ...
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0  // ... 255
];
function checkIsHttpToken(val) {
  if (!validTokens[val.charCodeAt(0)])
    return false;
  if (val.length < 2)
    return true;
  if (!validTokens[val.charCodeAt(1)])
    return false;
  if (val.length < 3)
    return true;
  if (!validTokens[val.charCodeAt(2)])
    return false;
  if (val.length < 4)
    return true;
  if (!validTokens[val.charCodeAt(3)])
    return false;
  for (var i = 4; i < val.length; ++i) {
    if (!validTokens[val.charCodeAt(i)])
      return false;
  }
  return true;
}
exports._checkIsHttpToken = checkIsHttpToken;

/**
 * True if val contains an invalid field-vchar
 *  field-value    = *( field-content / obs-fold )
 *  field-content  = field-vchar [ 1*( SP / HTAB ) field-vchar ]
 *  field-vchar    = VCHAR / obs-text
 *
 * checkInvalidHeaderChar() is currently designed to be inlinable by v8,
 * so take care when making changes to the implementation so that the source
 * code size does not exceed v8's default max_inlined_source_size setting.
 **/
var validHdrChars = [
  0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, // 0 - 15
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 16 - 31
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 32 - 47
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 48 - 63
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 64 - 79
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 80 - 95
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 96 - 111
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, // 112 - 127
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 128 ...
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1  // ... 255
];
function checkInvalidHeaderChar(val) {
  val += '';
  if (val.length < 1)
    return false;
  if (!validHdrChars[val.charCodeAt(0)])
    return true;
  if (val.length < 2)
    return false;
  if (!validHdrChars[val.charCodeAt(1)])
    return true;
  if (val.length < 3)
    return false;
  if (!validHdrChars[val.charCodeAt(2)])
    return true;
  if (val.length < 4)
    return false;
  if (!validHdrChars[val.charCodeAt(3)])
    return true;
  for (var i = 4; i < val.length; ++i) {
    if (!validHdrChars[val.charCodeAt(i)])
      return true;
  }
  return false;
}
exports._checkInvalidHeaderChar = checkInvalidHeaderChar;