// Copyright 2010 The Emscripten Authors. All rights reserved.
// Emscripten is available under two separate licenses, 
//  the MIT license and the University of Illinois/NCSA Open Source License. 
// Both these licenses can be found in the LICENSE file.

mergeInto(LibraryManager.library, {
  
  interop_SaveBlob: function(blob, name) {
    if (window.navigator.msSaveBlob) {
      window.navigator.msSaveBlob(blob, name); return;
    }
    var url  = window.URL.createObjectURL(blob);
    var elem = document.createElement('a');

    elem.href     = url;
    elem.download = name;
    elem.style.display = 'none';

    document.body.appendChild(elem);
    elem.click();
    document.body.removeChild(elem);
    window.URL.revokeObjectURL(url);
  },
  interop_InitModule: function() {
    // these are required for older versions of emscripten, but the compiler removes
    // this by default as no syscalls are used by the C platform code anymore
    window.ERRNO_CODES={ENOENT:2,EBADF:9,EAGAIN:11,ENOMEM:12,EEXIST:17,EINVAL:22};
  },
  interop_InitModule__deps: ['interop_SaveBlob', 'interop_callVoidFunc', 'interop_callStringFunc'],
  interop_TakeScreenshot: function(path) {
    var name   = UTF8ToString(path);
    var canvas = Module['canvas'];
    if (canvas.toBlob) {
      canvas.toBlob(function(blob) { _interop_SaveBlob(blob, name); });
    } else if (canvas.msToBlob) {
      _interop_SaveBlob(canvas.msToBlob(), name);
    }
  },
  interop_callVoidFunc: function(func) {
    Module['_' + func]();
  },
  interop_callStringFunc: function(func, str) {
    var arg = 0;
    var stackTop = stackSave();

    if (str !== null && str !== undefined) {
      var len = (str.length * 4) + 1; // worst case, 4 bytes to encode a char
      arg = stackAlloc(len);
      stringToUTF8(str, arg, len);
    }

    Module['_' + func](arg);
    stackRestore(stackTop);
  },
  
  
//########################################################################################################################
//-----------------------------------------------------------Http---------------------------------------------------------
//########################################################################################################################
  interop_DownloadAsync: function(urlStr, method, reqID) {
    // onFinished = FUNC(data, len, status)
    // onProgress = FUNC(read, total)
    var url        = UTF8ToString(urlStr);
    var reqMethod  = method == 1 ? 'HEAD' : 'GET';  
    var onFinished = Module["_Http_OnFinishedAsync"];
    var onProgress = Module["_Http_OnUpdateProgress"];

    var xhr = new XMLHttpRequest();
    try {
      xhr.open(reqMethod, url);
    } catch (e) {
      // DOMException gets thrown when invalid URL provided. Test cases:
      //   http://%7https://www.example.com/test.zip
      //   http://example:app/test.zip
      console.log(e);
      return 1;
    }  
    xhr.responseType = 'arraybuffer';

    var getContentLength = function(e) {
      if (e.total) return e.total;

      try {
        var len = xhr.getResponseHeader('Content-Length');
        return parseInt(len, 10);
      } catch (ex) { return 0; }
    };
    
    xhr.onload = function(e) {
      var src  = new Uint8Array(xhr.response);
      var len  = src.byteLength;
      var data = _malloc(len);
      HEAPU8.set(src, data);
      onFinished(reqID, data, len || getContentLength(e), xhr.status);
    };
    xhr.onerror    = function(e) { onFinished(reqID, 0, 0, xhr.status);  };
    xhr.ontimeout  = function(e) { onFinished(reqID, 0, 0, xhr.status);  };
    xhr.onprogress = function(e) { onProgress(reqID, e.loaded, e.total); };

    try { xhr.send(); } catch (e) { onFinished(reqID, 0, 0, 0); }
    return 0;
  },
  interop_IsHttpsOnly : function() {
    // If this webpage is https://, browsers deny any http:// downloading
    return location.protocol === 'https:'; 
  },


//########################################################################################################################
//---------------------------------------------------------Dialogs--------------------------------------------------------
//########################################################################################################################
  interop_DownloadFile: function(filename, filters, titles) {
    try {
      if (_interop_ShowSaveDialog(filename, filters, titles)) return 0;
      
      var name = UTF8ToString(filename);
      var path = 'Downloads/' + name;
      _interop_callStringFunc('Window_OnFileUploaded', path);
      
      var data = CCFS.readFile(path);
      var blob = new Blob([data], { type: 'application/octet-stream' });
      _interop_SaveBlob(blob, UTF8ToString(filename));
      CCFS.unlink(path);
      return 0;
    } catch (e) {
      if (!(e instanceof CCFS.ErrnoError)) abort(e);
      return e.errno;
    }
  },
  interop_DownloadFile__deps: ['interop_SaveBlob', 'interop_ShowSaveDialog'],  
  interop_ShowSaveDialog: function(filename, filters, titles) {
    // not supported by all browsers
    if (!window.showSaveFilePicker) return 0;
    
    var fileTypes = [];
    for (var i = 0; HEAP32[(filters>>2)+i|0]; i++)
    {
      var filter = HEAP32[(filters>>2)+i|0];
      var title  = HEAP32[(titles >>2)+i|0];
      
      var filetype = {
        description: UTF8ToString(title),
        accept: {'application/octet-stream': [UTF8ToString(filter)]}
      };
      fileTypes.push(filetype);
    }
    
    // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Using_promises
    // https://web.dev/file-system-access/
    var path = null;
    var opts = {
      suggestedName: UTF8ToString(filename),
      types: fileTypes
    };
    window.showSaveFilePicker(opts)
      .then(function(fileHandle) {
        path = 'Downloads/' + fileHandle.name;
        return fileHandle.createWritable();
      })
      .then(function(writable) {
        _interop_callStringFunc('Window_OnFileUploaded', path);
      
        var data = CCFS.readFile(path);
        writable.write(data);
        return writable.close();
      })
      .catch(function(error) {
        _interop_callStringFunc('Platform_LogError', '&cError downloading file');
        _interop_callStringFunc('Platform_LogError', '   &c' + error);
      })
      .finally(function(result) {
        if (path) CCFS.unlink(path);
      });
      return 1;
  },
  
  
//########################################################################################################################
//-------------------------------------------------------Main driver------------------------------------------------------
//########################################################################################################################
  fetchTexturePackAsync: function(url, onload, onerror) {
    var xhr = new XMLHttpRequest();
    xhr.open('GET', url);
    xhr.responseType = 'arraybuffer';
    xhr.onerror = onerror;
    
    xhr.onload = function() {
      if (xhr.status == 200) {
        onload(xhr.response);
      } else {
        onerror();
      }
    };
    xhr.send();
  },
  interop_AsyncDownloadTexturePack__deps: ['fetchTexturePackAsync'],
  interop_AsyncDownloadTexturePack: function (rawPath) {
    var path = UTF8ToString(rawPath);
    var url  = '/static/default.zip';
    Module.setStatus('Downloading textures.. (1/2)');
    
    _fetchTexturePackAsync(url, 
      function(buffer) {
        CCFS.writeFile(path, new Uint8Array(buffer));
        _interop_callVoidFunc('main_phase1');
      },
      function() {
        _interop_callVoidFunc('main_phase1');
      }
    );
  },
  interop_AsyncLoadIndexedDB__deps: ['IDBFS_loadFS'],
  interop_AsyncLoadIndexedDB: function() {
    Module.setStatus('Preloading filesystem.. (2/2)');
    
    _IDBFS_loadFS(function(err) { 
      if (err) window.cc_idbErr = err;
      Module.setStatus('');
      _interop_callVoidFunc('main_phase2');
    });
  },


//########################################################################################################################
//---------------------------------------------------------Platform-------------------------------------------------------
//########################################################################################################################
  interop_OpenTab: function(url) {
    try {
      window.open(UTF8ToString(url));
    } catch (e) {
      // DOMException gets thrown when invalid URL provided. Test cases:
      //   http://example:app/test.zip
      console.log(e);
      return 1;
    }
    return 0;
  },
  interop_Log: function(msg, len) {
    Module.print(UTF8ArrayToString(HEAPU8, msg, len));
  },
  interop_GetLocalTime: function(time) {
    var date = new Date();
    HEAP32[(time|0 +  0)>>2] = date.getFullYear();
    HEAP32[(time|0 +  4)>>2] = date.getMonth() + 1|0;
    HEAP32[(time|0 +  8)>>2] = date.getDate();
    HEAP32[(time|0 + 12)>>2] = date.getHours();
    HEAP32[(time|0 + 16)>>2] = date.getMinutes();
    HEAP32[(time|0 + 20)>>2] = date.getSeconds();
  },
  interop_DirectorySetWorking: function (raw) {
    var path = UTF8ToString(raw);
    CCFS.chdir(path);
  },
  interop_DirectoryIter: function(raw) {
    var path = UTF8ToString(raw);
    try {
      var entries = CCFS.readdir(path);
      for (var i = 0; i < entries.length; i++) 
      {
        var path = entries[i];
        // absolute path to root relative path
        if (path.indexOf(CCFS.currentPath) === 0) {
          path = path.substring(CCFS.currentPath.length + 1);
        }
        _interop_callStringFunc('Directory_IterCallback', path);
      }
      return 0;
    } catch (e) {
      if (!(e instanceof CCFS.ErrnoError)) abort(e);
      return -e.errno;
    }
  },
  interop_FileExists: function (raw) {
    var path = UTF8ToString(raw);

    path = CCFS.resolvePath(path);
    return path in CCFS.entries;
  },
  interop_FileCreate: function(raw, flags) {
    var path = UTF8ToString(raw);
    try {
      var stream = CCFS.open(path, flags);
      return stream.fd|0;
    } catch (e) {
      if (!(e instanceof CCFS.ErrnoError)) abort(e);
      return -e.errno;
    }
  },
  interop_FileRead: function(fd, dst, count) {
    try {
      var stream = CCFS.getStream(fd);
      return CCFS.read(stream, HEAP8, dst, count)|0;
    } catch (e) {
      if (!(e instanceof CCFS.ErrnoError)) abort(e);
      return -e.errno;
    }
  },
  interop_FileWrite: function(fd, src, count) {
    try {
      var stream = CCFS.getStream(fd);
      return CCFS.write(stream, HEAP8, src, count)|0;
    } catch (e) {
      if (!(e instanceof CCFS.ErrnoError)) abort(e);
      return -e.errno;
    }
  },
  interop_FileSeek: function(fd, offset, whence) {
    try {
      var stream = CCFS.getStream(fd);
      return CCFS.llseek(stream, offset, whence)|0;
    } catch (e) {
      if (!(e instanceof CCFS.ErrnoError)) abort(e);
      return -e.errno;
    }
  },
  interop_FileLength: function(fd) {
    try {
      var stream = CCFS.getStream(fd);
      return stream.node.usedBytes|0;
    } catch (e) {
      if (!(e instanceof CCFS.ErrnoError)) abort(e);
      return -e.errno;
    }
  },
  interop_FileClose: function(fd) {
    try {
      var stream = CCFS.getStream(fd);
      CCFS.close(stream);
      // save writable files to IndexedDB (check for O_RDWR)
      if ((stream.flags & 3) == 2) _interop_SaveNode(stream.path);
      return 0;
    } catch (e) {
      if (!(e instanceof CCFS.ErrnoError)) abort(e);
      return -e.errno;
    }
  },
  interop_FileClose__deps: ['interop_SaveNode'],
  
  
//########################################################################################################################
//--------------------------------------------------------Filesystem------------------------------------------------------
//########################################################################################################################
  interop_InitFilesystem__deps: ['interop_SaveNode'],
  interop_InitFilesystem: function(buffer) {
    if (!window.cc_idbErr) return;
    var msg = 'Error preloading IndexedDB:' + window.cc_idbErr + '\n\nPreviously saved settings/maps will be lost';
    _interop_callStringFunc('Platform_LogError', msg);
  },
  interop_LoadIndexedDB: function() {
    // previously you were required to add interop_LoadIndexedDB to Module.preRun array
    //  to load the indexedDB asynchronously *before* starting ClassiCube, because it
    //  could not load indexedDB asynchronously
    // however, as ClassiCube now loads IndexedDB asynchronously itself, this is
    //   no longer necessary, but is kept around for backwards compatibility
  },
  interop_SaveNode__deps: ['IDBFS_getDB', 'IDBFS_storeRemoteEntry'],
  interop_SaveNode: function(path) {
    var callback = function(err) { 
      if (!err) return;
      console.log(err);
      _interop_callStringFunc('Platform_LogError', '&cError saving ' + path);
      _interop_callStringFunc('Platform_LogError', '   &c' + err);
    }; 
    
    var stat, node, entry;
    try {
      var lookup = CCFS.lookupPath(path);
      node = lookup.node;
    
      // Performance consideration: storing a normal JavaScript array to a IndexedDB is much slower than storing a typed array.
      // Therefore always convert the file contents to a typed array first before writing the data to IndexedDB.
      node.contents = MEMFS.getFileDataAsTypedArray(node);
      entry = { timestamp: node.timestamp, mode: CCFS.MODE_TYPE_FILE, contents: node.contents };
    } catch (err) {
      return callback(err);
    }
    
    _IDBFS_getDB(function(err, db) {
      if (err) return callback(err);
      var transaction, store;
      
      // can still throw errors here
      try {
        transaction = db.transaction([IDBFS_DB_STORE_NAME], 'readwrite');
        store = transaction.objectStore(IDBFS_DB_STORE_NAME);
      } catch (err) {
        return callback(err);
      }
      
      transaction.onerror = function(e) {
        callback(this.error);
        e.preventDefault();
      };
      
      _IDBFS_storeRemoteEntry(store, path, entry, callback);
    });
  },
//########################################################################################################################
//--------------------------------------------------------IndexedDB-------------------------------------------------------
//########################################################################################################################
  IDBFS_loadFS__deps: ['IDBFS_getRemoteSet', 'IDBFS_reconcile'],
  IDBFS_loadFS: function(callback) {
    _IDBFS_getRemoteSet(function(err, remote) {
      if (err) return callback(err);
      _IDBFS_reconcile(remote, callback);
    });
  },
  IDBFS_getDB: function(callback) {
    var db = window.IDBFS_db;
    if (db) return callback(null, db);
    
    IDBFS_DB_VERSION    = 21;
    IDBFS_DB_STORE_NAME = "FILE_DATA";

    var idb = window.indexedDB || window.mozIndexedDB || window.webkitIndexedDB || window.msIndexedDB;
    if (!idb) return callback("IndexedDB unsupported");

    var req;
    try {
      req = idb.open('/classicube', IDBFS_DB_VERSION);
    } catch (e) {
      return callback(e);
    }
    if (!req) return callback("Unable to connect to IndexedDB");

    req.onupgradeneeded = function(e) {
      var db = e.target.result;
      var transaction = e.target.transaction;  
      var fileStore;

      if (db.objectStoreNames.contains(IDBFS_DB_STORE_NAME)) {
        fileStore = transaction.objectStore(IDBFS_DB_STORE_NAME);
      } else {
        fileStore = db.createObjectStore(IDBFS_DB_STORE_NAME);
      }

      if (!fileStore.indexNames.contains('timestamp')) {
        fileStore.createIndex('timestamp', 'timestamp', { unique: false });
      }
    };
    req.onsuccess = function() {
      db = req.result;
      window.IDBFS_db = db;
      // browser will sometimes close IndexedDB connection behind the scenes
      db.onclose = function(ev) { 
        console.log('IndexedDB connection closed unexpectedly!');
        window.IDBFS_db = null; 
      }
      callback(null, db);
    };
    req.onerror = function(e) {
      callback(this.error);
      e.preventDefault();
    };
  },
  IDBFS_getRemoteSet__deps: ['IDBFS_getDB'],
  IDBFS_getRemoteSet: function(callback) {
    var entries = {};

    _IDBFS_getDB(function(err, db) {
      if (err) return callback(err);

      try {
        var transaction = db.transaction([IDBFS_DB_STORE_NAME], 'readonly');
        transaction.onerror = function(e) {
          callback(this.error);
          e.preventDefault();
        };

        var store = transaction.objectStore(IDBFS_DB_STORE_NAME);
        var index = store.index('timestamp');

        index.openKeyCursor().onsuccess = function(event) {
          var cursor = event.target.result;

          if (!cursor) {
            return callback(null, { type: 'remote', db: db, entries: entries });
          }

          entries[cursor.primaryKey] = { timestamp: cursor.key };
          cursor.continue();
        };
      } catch (e) {
        return callback(e);
      }
    });
  },
  IDBFS_loadRemoteEntry: function(store, path, callback) {
    var req = store.get(path);
    req.onsuccess = function(event) { callback(null, event.target.result); };
    req.onerror = function(e) {
      callback(this.error);
      e.preventDefault();
    };
  },
  IDBFS_storeRemoteEntry: function(store, path, entry, callback) {
    var req = store.put(entry, path);
    req.onsuccess = function() { callback(null); };
    req.onerror = function(e) {
      callback(this.error);
      e.preventDefault();
    };
  },
  IDBFS_storeLocalEntry: function(path, entry, callback) {
    try {
      // ignore directories from IndexedDB created in older game versions
      if (CCFS.isFile(entry.mode)) {
        CCFS.writeFile(path, entry.contents);
        CCFS.utime(path, entry.timestamp);
      }
    } catch (e) {
      return callback(e);
    }
  
    callback(null);
  },
  IDBFS_reconcile__deps: ['IDBFS_loadRemoteEntry', 'IDBFS_storeLocalEntry'],
  IDBFS_reconcile: function(src, callback) {
    var total  = 0;
    var create = [];

    Object.keys(src.entries).forEach(function (key) {
      create.push(key);
      total++;
    });
    if (!total) return callback(null);

    var errored = false;
    var completed = 0;
    var transaction = src.db.transaction([IDBFS_DB_STORE_NAME], 'readwrite');
    var store = transaction.objectStore(IDBFS_DB_STORE_NAME);

    function done(err) {
      if (err) {
        if (!done.errored) {
          done.errored = true;
          return callback(err);
        }
        return;
      }
      if (++completed >= total) {
        return callback(null);
      }
    };

    transaction.onerror = function(e) {
      done(this.error);
      e.preventDefault();
    };

    // sort paths in ascending order so directory entries are created
    // before the files inside them
    create.sort().forEach(function (path) {
      _IDBFS_loadRemoteEntry(store, path, function (err, entry) {
        if (err) return done(err);
        _IDBFS_storeLocalEntry(path, entry, done);
      });
    });
  },

//########################################################################################################################
//---------------------------------------------------------Sockets--------------------------------------------------------
//########################################################################################################################
  interop_InitSockets: function() {
    window.SOCKETS = {
      EBADF:-8,EISCONN:-30,ENOTCONN:-53,EAGAIN:-6,EHOSTUNREACH:-23,EINPROGRESS:-26,EALREADY:-7,ECONNRESET:-15,EINVAL:-28,ECONNREFUSED:-14,
      sockets: [],
    };
  },
  interop_SocketCreate: function() {
    var sock = {
      error: null, // Used by interop_SocketWritable
      recv_queue: [],
      socket: null,
    };

    SOCKETS.sockets.push(sock);
    return (SOCKETS.sockets.length - 1) | 0;
  },
  interop_SocketConnect: function(sockFD, raw, port) {
    var addr = UTF8ToString(raw);
    var sock = SOCKETS.sockets[sockFD];
    if (!sock) return SOCKETS.EBADF;

    // already connecting or connected
    var ws = sock.socket;
    if (ws) {
      if (ws.readyState === ws.CONNECTING) return SOCKETS.EALREADY;
      return SOCKETS.EISCONN;
    }

    // create the actual websocket object and connect
    try {
      var parts = addr.split('/');
      var proto = _interop_IsHttpsOnly() ? 'wss://' : 'ws://';
      var url   = proto + parts[0] + ":" + port + "/" + parts.slice(1).join('/');
      
      ws = new WebSocket(url, 'ClassiCube');
      ws.binaryType = 'arraybuffer';
    } catch (e) {
      return SOCKETS.EHOSTUNREACH;
    }
    sock.socket = ws;

    ws.onopen  = function() {};
    ws.onclose = function() {};
    ws.onmessage = function(event) {
      var data = event.data;
      if (typeof data === 'string') {
        var encoder = new TextEncoder(); // should be utf-8
        data = encoder.encode(data); // make a typed array from the string
      } else {
        assert(data.byteLength !== undefined); // must receive an ArrayBuffer
        if (data.byteLength == 0) {
          // An empty ArrayBuffer will emit a pseudo disconnect event
          // as recv/recvmsg will return zero which indicates that a socket
          // has performed a shutdown although the connection has not been disconnected yet.
          return;
        } else {
          data = new Uint8Array(data); // make a typed array view on the array buffer
        }
      }
      sock.recv_queue.push(data);
    };
    ws.onerror = function(error) {
      // The WebSocket spec only allows a 'simple event' to be thrown on error,
      // so we only really know as much as ECONNREFUSED.
      sock.error = SOCKETS.ECONNREFUSED; // Used by interop_SocketWritable
    };
    // always "fail" in non-blocking mode
    return SOCKETS.EINPROGRESS;
  },
  interop_SocketClose: function(sockFD) {
    var sock = SOCKETS.sockets[sockFD];
    if (!sock) return SOCKETS.EBADF;

    try {
      sock.socket.close();
    } catch (e) {
    }
    delete sock.socket;
    return 0;
  },
  interop_SocketSend: function(sockFD, src, length) {
    var sock = SOCKETS.sockets[sockFD];
    if (!sock) return SOCKETS.EBADF;

    var ws = sock.socket;
    if (!ws || ws.readyState === ws.CLOSING || ws.readyState === ws.CLOSED) {
      return SOCKETS.ENOTCONN;
    } else if (ws.readyState === ws.CONNECTING) {
      return SOCKETS.EAGAIN;
    }

    // var data = HEAP8.slice(src, src + length); unsupported in IE11
    var data = new Uint8Array(length);
    for (var i = 0; i < length; i++) {  
      data[i] = HEAP8[src + i];
    }

    try {
      ws.send(data);
      return length;
    } catch (e) {
      return SOCKETS.EINVAL;
    }
  },
  interop_SocketRecv: function(sockFD, dst, length) {
    var sock = SOCKETS.sockets[sockFD];
    if (!sock) return SOCKETS.EBADF;

    var packet = sock.recv_queue.shift();
    if (!packet) {
      var ws = sock.socket;

      if (!ws || ws.readyState == ws.CLOSING || ws.readyState == ws.CLOSED) {
        return SOCKETS.ENOTCONN;
      } else {
        // socket is in a valid state but truly has nothing available
        return SOCKETS.EAGAIN;
      }
    }

    // packet will be an ArrayBuffer if it's unadulterated, but if it's
    // requeued TCP data it'll be an ArrayBufferView
    var packetLength = packet.byteLength || packet.length;
    var packetOffset = packet.byteOffset || 0;
    var packetBuffer = packet.buffer || packet;
    var bytesRead = Math.min(length, packetLength);
    var msg = new Uint8Array(packetBuffer, packetOffset, bytesRead);

    // push back any unread data for TCP connections
    if (bytesRead < packetLength) {
      var bytesRemaining = packetLength - bytesRead;
      packet = new Uint8Array(packetBuffer, packetOffset + bytesRead, bytesRemaining);
      sock.recv_queue.unshift(packet);
    }

    HEAPU8.set(msg, dst);
    return msg.byteLength;
  },
  interop_SocketWritable: function(sockFD, writable) {
    HEAPU8[writable|0] = 0;
    var sock = SOCKETS.sockets[sockFD];
    if (!sock) return SOCKETS.EBADF;

    var ws = sock.socket;
    if (!ws) return SOCKETS.ENOTCONN;
    if (ws.readyState === ws.OPEN || ws.readyState == ws.CLOSED) HEAPU8[writable|0] = 1;

    return 0;
  },
  interop_SocketLastError: function(sockFD) {
    var sock = SOCKETS.sockets[sockFD];
    if (!sock) return SOCKETS.EBADF;

    var ws = sock.socket;
    if (!ws) return SOCKETS.ENOTCONN;

    return sock.error || 0;
  },


//########################################################################################################################
//----------------------------------------------------------Window--------------------------------------------------------
//########################################################################################################################
  interop_CanvasWidth: function()  { return Module['canvas'].width;  },
  interop_CanvasHeight: function() { return Module['canvas'].height; },
  interop_ScreenWidth: function()  { return screen.width;  },
  interop_ScreenHeight: function() { return screen.height; },

  interop_IsAndroid: function() {
    return /Android/i.test(navigator.userAgent);
  },
  interop_IsIOS: function() {
    // iOS 13 on iPad doesn't identify itself as iPad by default anymore
    //  https://stackoverflow.com/questions/57765958/how-to-detect-ipad-and-ipad-os-version-in-ios-13-and-up
    return /iPhone|iPad|iPod/i.test(navigator.userAgent) || 
      (navigator.platform === 'MacIntel' && navigator.maxTouchPoints && navigator.maxTouchPoints > 2);
  },
  interop_InitContainer: function() {
    // Create wrapper div if necessary (so input textbox shows in fullscreen on android)
    var agent  = navigator.userAgent;  
    var canvas = Module['canvas'];
    window.cc_container = document.body;

    if (/Android/i.test(agent)) {
      var wrapper = document.createElement("div");
      wrapper.id  = 'canvas_wrapper';

      canvas.parentNode.insertBefore(wrapper, canvas);
      wrapper.appendChild(canvas);
      window.cc_container = wrapper;
    }
  },
  interop_GetContainerID: function() {
    // For chrome on android, need to make container div fullscreen instead
    return document.getElementById('canvas_wrapper') ? 1 : 0;
  },
  interop_ForceTouchPageLayout: function() {
    if (typeof(forceTouchLayout) === 'function') forceTouchLayout();
  },
  interop_SetPageTitle : function(title) {
    document.title = UTF8ToString(title);
  },
  interop_AddClipboardListeners: function() {
    // Copy text, but only if user isn't selecting something else on the webpage
    // (don't check window.clipboardData here, that's handled in interop_TrySetClipboardText instead)
    window.addEventListener('copy', 
    function(e) {
      if (window.getSelection && window.getSelection().toString()) return;
      _interop_callVoidFunc('Window_RequestClipboardText');
      if (!window.cc_copyText) return;

      if (e.clipboardData) {
        e.clipboardData.setData('text/plain', window.cc_copyText);
        e.preventDefault();
      }
      window.cc_copyText = null;
    });

    // Paste text (window.clipboardData is handled in interop_TryGetClipboardText instead)
    window.addEventListener('paste',
    function(e) {
      if (e.clipboardData) {
        var contents = e.clipboardData.getData('text/plain');
        _interop_callStringFunc('Window_GotClipboardText', contents);
      }
    });
  },
  interop_TryGetClipboardText: function() {
    // For IE11, use window.clipboardData to get the clipboard
    if (window.clipboardData) {
      var contents = window.clipboardData.getData('Text');
      _interop_callStringFunc('Window_StoreClipboardText', contents);
    } 
  },
  interop_TrySetClipboardText: function(text) {
    // For IE11, use window.clipboardData to set the clipboard */
    // For other browsers, instead use the window.copy events */
    if (window.clipboardData) {
      if (window.getSelection && window.getSelection().toString()) return;
      window.clipboardData.setData('Text', UTF8ToString(text));
    } else {
      window.cc_copyText = UTF8ToString(text);
    }
  },
  interop_isInFullscreen: function() {
    return document.fullscreenElement || document.mozFullScreenElement || document.webkitFullscreenElement || document.msFullscreenElement;
  },
  interop_EnterFullscreen: function() {
    // emscripten sets css size to screen's base width/height,
    //  except that becomes wrong when device rotates.
    // Better to just set CSS width/height to always be 100%
    var canvas = Module['canvas'];
    canvas.style.width  = '100%';
    canvas.style.height = '100%';
    
    // By default, pressing Escape will immediately exit fullscreen - which is
    //   quite annoying given that it is also the Menu key. Some browsers allow
    //   'locking' the Escape key, so that you have to hold down Escape to exit.
    // NOTE: This ONLY works when the webpage is a https:// one
    try { navigator.keyboard.lock(["Escape"]); } catch (ex) { }
  },

  // Adjust from document coordinates to element coordinates
  interop_AdjustXY: function(x, y) {
    var canvasRect = Module['canvas'].getBoundingClientRect();
    HEAP32[x >> 2] = HEAP32[x >> 2] - canvasRect.left;
    HEAP32[y >> 2] = HEAP32[y >> 2] - canvasRect.top;
  },
  interop_RequestCanvasResize: function() {
    if (typeof(resizeGameCanvas) === 'function') resizeGameCanvas();
  },
  interop_SetCursorVisible: function(visible) {
    Module['canvas'].style['cursor'] = visible ? 'default' : 'none';
  },
  interop_ShowDialog: function(title, msg) {
    alert(UTF8ToString(title) + "\n\n" + UTF8ToString(msg));
  },
  interop_OpenKeyboard: function(text, flags, placeholder) {
    var elem  = window.cc_inputElem;
    var shown = true;
    var type  = flags & 0xFF;
    
    if (!elem) {
      if (type == 1) { // KEYBOARD_TYPE_NUMBER
        elem = document.createElement('input');
        elem.setAttribute('type', 'text')
        elem.setAttribute('inputmode', 'decimal');
      } else if (type == 3) { // KEYBOARD_TYPE_INTEGER
        elem = document.createElement('input');
        elem.setAttribute('type', 'text')
        elem.setAttribute('inputmode', 'numeric');
        // Fix for older iOS safari where inputmode is unsupported
        //  https://news.ycombinator.com/item?id=22433654
        //  https://technology.blog.gov.uk/2020/02/24/why-the-gov-uk-design-system-team-changed-the-input-type-for-numbers/
        elem.setAttribute('pattern', '[0-9]*');
      } else {
        elem = document.createElement('textarea');
      }
      shown = false;
    }
    
    if (flags & 0x100) { elem.setAttribute('enterkeyhint', 'send'); }
    //elem.setAttribute('style', 'position:absolute; left:0.5%; bottom:1%; margin: 0px; width: 99%; background-color: #080808; border: none; color: white; opacity: 0.7');
    elem.setAttribute('style', 'position:absolute; left:0; bottom:0; margin: 0px; width: 100%; background-color: #222222; border: none; color: white;');
    elem.setAttribute('placeholder', UTF8ToString(placeholder));
    elem.value = UTF8ToString(text);
  
    if (!shown) {
      // stop event propagation, because we don't want the game trying to handle these events
      elem.addEventListener('touchstart', function(ev) { ev.stopPropagation(); }, false);
      elem.addEventListener('touchmove',  function(ev) { ev.stopPropagation(); }, false);
      elem.addEventListener('mousedown',  function(ev) { ev.stopPropagation(); }, false);
      elem.addEventListener('mousemove',  function(ev) { ev.stopPropagation(); }, false);

      elem.addEventListener('input', 
        function(ev) {
          _interop_callStringFunc('Window_OnTextChanged', ev.target.value);
        }, false);
      window.cc_inputElem = elem;

      window.cc_divElem = document.createElement('div');
      window.cc_divElem.setAttribute('style', 'position:absolute; left:0; top:0; width:100%; height:100%; background-color: black; opacity:0.4; resize:none; pointer-events:none;');

      window.cc_container.appendChild(window.cc_divElem);
      window.cc_container.appendChild(elem);
    }

    // force on-screen keyboard to be shown
    elem.focus();
    elem.click();
  },
  interop_SetKeyboardText: function(text) {
    if (!window.cc_inputElem) return;
    var str = UTF8ToString(text);
    var cur = window.cc_inputElem.value;
    
    // when pressing 'Go' on the on-screen keyboard, some web browsers add \n to value
    if (cur.length && cur[cur.length - 1] == '\n') { cur = cur.substring(0, cur.length - 1); }
    if (str != cur) window.cc_inputElem.value = str;
  },
  interop_CloseKeyboard: function() {
    if (!window.cc_inputElem) return;
    window.cc_container.removeChild(window.cc_divElem);
    window.cc_container.removeChild(window.cc_inputElem);
    window.cc_divElem   = null;
    window.cc_inputElem = null;
  },
  interop_OpenFileDialog: function(filter, action, folder) {
    var elem = window.cc_uploadElem;
    var root = UTF8ToString(folder);

    if (!elem) {
      elem = document.createElement('input');
      elem.setAttribute('type', 'file');
      elem.setAttribute('style', 'display: none');
      elem.accept = UTF8ToString(filter);

      elem.addEventListener('change', 
        function(ev) {
          var files = ev.target.files;
          for (var i = 0; i < files.length; i++) {
            var reader = new FileReader();
            var name   = files[i].name;

            reader.onload = function(e) { 
              var data = new Uint8Array(e.target.result);
              var path = root + '/' + name;
              CCFS.writeFile(path, data);
              _interop_callStringFunc('Window_OnFileUploaded', path);
              
              if (action == 0) CCFS.unlink(path); // OFD_UPLOAD_DELETE
              if (action == 1) _interop_SaveNode(path); // OFD_UPLOAD_PERSIST
            };
            reader.readAsArrayBuffer(files[i]);
          }
          window.cc_container.removeChild(window.cc_uploadElem);
          window.cc_uploadElem = null;
        }, false);
      window.cc_uploadElem = elem;
      window.cc_container.appendChild(elem);
    }
    elem.click();
  },


//########################################################################################################################
//--------------------------------------------------------GLContext-------------------------------------------------------
//#########################################################################################################################
  CC_gpu_getRenderer: function(buffer, len) { 
    var dbg = GLctx.getExtension('WEBGL_debug_renderer_info');
    var str = dbg ? GLctx.getParameter(dbg.UNMASKED_RENDERER_WEBGL) : "";
    stringToUTF8(str, buffer, len);
  },
  

//########################################################################################################################
//---------------------------------------------------------Sockets--------------------------------------------------------
//########################################################################################################################
  interop_AudioLog: function(err) {
    console.log(err);
    window.AUDIO.errors.push(''+err);
    return window.AUDIO.errors.length|0;
  },
  interop_InitAudio: function() {
    window.AUDIO = window.AUDIO || {
      context: null,
      sources: [],
      buffers: {},
      errors: [],
      seen: {},
    };
    if (window.AUDIO.context) return 0;

    try {
      if (window.AudioContext) {
        AUDIO.context = new window.AudioContext();
      } else {
        AUDIO.context = new window.webkitAudioContext();
      }
      return 0;
    } catch (err) {
      return _interop_AudioLog(err)
    }
  },
  interop_InitAudio__deps: ['interop_AudioLog'],
  interop_AudioCreate: function() {
    var src = {
      source: null,
      gain: AUDIO.context.createGain(),
      playing: false,
    };
    AUDIO.sources.push(src);
    return AUDIO.sources.length|0; 
    // NOTE: 0 is used by Audio.c for "no source"
  },
  interop_AudioClose: function(ctxID) {
    var src = AUDIO.sources[ctxID - 1|0];
    if (src.source) src.source.stop();
    AUDIO.sources[ctxID - 1|0] = null;
  },
  interop_AudioPoll: function(ctxID, inUse) {
    var src = AUDIO.sources[ctxID - 1|0];
    HEAP32[inUse >> 2] = src.playing; // only 1 buffer
    return 0;
  },
  interop_AudioVolume: function(ctxID, volume) {
    var src = AUDIO.sources[ctxID - 1|0];
    src.gain.gain.value = volume / 100;
  },
  interop_AudioPlay: function(ctxID, sndID, rate) {
    var src  = AUDIO.sources[ctxID - 1|0];
    var name = UTF8ToString(sndID);
    
    // do we need to download this file?
    if (!AUDIO.seen.hasOwnProperty(name)) {
      AUDIO.seen[name] = true;
      _interop_AudioDownload(name);
      return 0;
    }

    // still downloading or failed to download this file
    var buffer = AUDIO.buffers[name];
    if (!buffer) return 0;
    
    try {
      // AudioBufferSourceNode only allows the buffer property
      //  to be assigned *ONCE* (throws InvalidStateError next time)
      // MDN says that these nodes are very inexpensive to create though
      //  https://developer.mozilla.org/en-US/docs/Web/API/AudioBufferSourceNode
      src.source = AUDIO.context.createBufferSource();
      src.source.buffer   = buffer;
      src.source.playbackRate.value = rate / 100;
      
      // source -> gain -> output
      src.source.connect(src.gain);
      src.gain.connect(AUDIO.context.destination);
      src.source.start();
      return 0;
    } catch (err) {
      return _interop_AudioLog(err)
    }
  },
  interop_AudioPlay__deps: ['interop_AudioDownload'],
  interop_AudioDownload: function(name) {
    var xhr = new XMLHttpRequest();
    xhr.open('GET', '/static/sounds/' + name + '.wav', true);   
    xhr.responseType = 'arraybuffer';
    
    xhr.onload = function() {
      var data = xhr.response;
      AUDIO.context.decodeAudioData(data, function(buffer) {
          AUDIO.buffers[name] = buffer;
        });
    };
    xhr.send();
  },
  interop_AudioDescribe: function(errCode, buffer, bufferLen) {
    if (errCode > AUDIO.errors.length) return 0;
    
    var str = AUDIO.errors[errCode - 1];
    return stringToUTF8(str, buffer, bufferLen);
  },
  
  
//########################################################################################################################
//-----------------------------------------------------------Font---------------------------------------------------------
//########################################################################################################################
  interop_SetFont: function(fontStr, size, flags) {
    if (!window.FONT_CANVAS) {
      window.FONT_CANVAS  = document.createElement('canvas');
      window.FONT_CONTEXT = window.FONT_CANVAS.getContext('2d');
    }
    
    var prefix = '';
    if (flags & 1) prefix += 'Bold ';
    size += 4; // adjust font size so text appears more like FreeType
    
    var font = UTF8ToString(fontStr);
    var ctx  = window.FONT_CONTEXT;
    ctx.font = prefix + size + 'px ' + font;
    ctx.textAlign    = 'left';
    ctx.textBaseline = 'top';
    return ctx;
  },
  interop_TextWidth: function(textStr, textLen) {
    var text = UTF8ArrayToString(HEAPU8, textStr, textLen);
    var ctx  = window.FONT_CONTEXT;
    var data = ctx.measureText(text);
    return data.width;
  },
  interop_TextDraw: function(textStr, textLen, bmp, dstX, dstY, shadow, hexStr) {
    var text = UTF8ArrayToString(HEAPU8, textStr, textLen);
    var hex  = UTF8ArrayToString(HEAPU8, hexStr, 7);
    var ctx  = window.FONT_CONTEXT;

    // resize canvas if necessary so text fits
    var data = ctx.measureText(text);
    var text_width = Math.ceil(data.width)|0;
    if (text_width > ctx.canvas.width) {
      var font = ctx.font;
      ctx.canvas.width = text_width;
      // resizing canvas also resets the properties of CanvasRenderingContext2D
      ctx.font = font;
      ctx.textAlign    = 'left';
      ctx.textBaseline = 'top';
    }
    
    var text_offset = 0.0;
    ctx.fillStyle   = hex;
    if (shadow) { text_offset = 1.3; }

    ctx.clearRect(0, 0, ctx.canvas.width, ctx.canvas.height);
    ctx.fillText(text, text_offset, text_offset);
    
    bmp  = bmp|0;
    dstX = dstX|0;
    dstY = dstY|0;
    
    var dst_pixels = HEAP32[(bmp + 0|0)>>2] + (dstX << 2);
    var dst_width  = HEAP32[(bmp + 4|0)>>2];
    var dst_height = HEAP32[(bmp + 8|0)>>2];
    
    // TODO not all of it
    var src = ctx.getImageData(0, 0, ctx.canvas.width, ctx.canvas.height);
    var src_pixels = src.data;
    var src_width  = src.width|0;
    var src_height = src.height|0;

    var img_width  = Math.min(src_width,  dst_width);
    var img_height = Math.min(src_height, dst_height);

    for (var y = 0; y < img_height; y++)
    {
      var yy = y + dstY;
      if (yy < 0 || yy >= dst_height) continue;
      
      var src_row =              (y *(src_width << 2))|0;
      var dst_row = dst_pixels + (yy*(dst_width << 2))|0;
      
      for (var x = 0; x < img_width; x++)
      {
        var xx = x + dstX;
        if (xx < 0 || xx >= dst_width) continue;
        var I = src_pixels[src_row + (x<<2)+3], invI = 255 - I|0;

        HEAPU8[dst_row + (x<<2)+0] = ((src_pixels[src_row + (x<<2)+0] * I) >> 8) + ((HEAPU8[dst_row + (x<<2)+0] * invI) >> 8);
        HEAPU8[dst_row + (x<<2)+1] = ((src_pixels[src_row + (x<<2)+1] * I) >> 8) + ((HEAPU8[dst_row + (x<<2)+1] * invI) >> 8);
        HEAPU8[dst_row + (x<<2)+2] = ((src_pixels[src_row + (x<<2)+2] * I) >> 8) + ((HEAPU8[dst_row + (x<<2)+2] * invI) >> 8);
        HEAPU8[dst_row + (x<<2)+3] =                                          I  + ((HEAPU8[dst_row + (x<<2)+3] * invI) >> 8);
      }
    }
    return data.width;
  },
  
  
//########################################################################################################################
//------------------------------------------------------------FS----------------------------------------------------------
//########################################################################################################################
  interop_FS_Init: function() {
    if (window.CCFS) return;

    window.MEMFS={
      createNode:function(path) {
        var node = CCFS.createNode(path);
        node.usedBytes = 0; // The actual number of bytes used in the typed array, as opposed to contents.length which gives the whole capacity.
        // When the byte data of the file is populated, this will point to either a typed array, or a normal JS array. Typed arrays are preferred
        // for performance, and used by default. However, typed arrays are not resizable like normal JS arrays are, so there is a small disk size
        // penalty involved for appending file writes that continuously grow a file similar to std::vector capacity vs used -scheme.
        node.contents = null; 
        node.timestamp = Date.now();
        return node;
      },
      getFileDataAsTypedArray:function(node) {
        if (!node.contents) return new Uint8Array;
        if (node.contents.subarray) return node.contents.subarray(0, node.usedBytes); // Make sure to not return excess unused bytes.
        return new Uint8Array(node.contents);
      },
      expandFileStorage:function(node, newCapacity) {
        var prevCapacity = node.contents ? node.contents.length : 0;
        if (prevCapacity >= newCapacity) return; // No need to expand, the storage was already large enough.
        // Don't expand strictly to the given requested limit if it's only a very small increase, but instead geometrically grow capacity.
        // For small filesizes (<1MB), perform size*2 geometric increase, but for large sizes, do a much more conservative size*1.125 increase to
        // avoid overshooting the allocation cap by a very large margin.
        var CAPACITY_DOUBLING_MAX = 1024 * 1024;
        newCapacity = Math.max(newCapacity, (prevCapacity * (prevCapacity < CAPACITY_DOUBLING_MAX ? 2.0 : 1.125)) | 0);
        if (prevCapacity != 0) newCapacity = Math.max(newCapacity, 256); // At minimum allocate 256b for each file when expanding.
        var oldContents = node.contents;
        node.contents = new Uint8Array(newCapacity); // Allocate new storage.
        if (node.usedBytes > 0) node.contents.set(oldContents.subarray(0, node.usedBytes), 0); // Copy old data over to the new storage.
        return;
      },
      clearFileStorage:function(node) {
        node.contents = null; // Fully decommit when requesting a resize to zero.
        node.usedBytes = 0;
      },
      stream_read:function(stream, buffer, offset, length, position) {
        var contents = stream.node.contents;
        if (position >= stream.node.usedBytes) return 0;
        var size = Math.min(stream.node.usedBytes - position, length);
        assert(size >= 0);
        if (size > 8 && contents.subarray) { // non-trivial, and typed array
          buffer.set(contents.subarray(position, position + size), offset);
        } else {
          for (var i = 0; i < size; i++) buffer[offset + i] = contents[position + i];
        }
        return size;
      },
      stream_write:function(stream, buffer, offset, length, position, canOwn) {
        if (!length) return 0;
        var node  = stream.node;
        var chunk = buffer.subarray(offset, offset + length);
        node.timestamp = Date.now();
  
        if (canOwn) {
          // NOTE: buffer cannot be a part of the memory buffer (i.e. HEAP8)
          //  - don't want to hold on to references of the memory Buffer, 
          //  as they may get invalidated.
          assert(position === 0, 'canOwn must imply no weird position inside the file');
          node.contents  = chunk;
          node.usedBytes = length;
        } else if (node.usedBytes === 0 && position === 0) { 
          // First write to an empty file, do a fast set since don't need to care about old data
          node.contents  = new Uint8Array(chunk);
          node.usedBytes = length;
        } else if (position + length <= node.usedBytes) { 
          // Writing to an already allocated and used subrange of the file
          node.contents.set(chunk, position);
        } else {
          // Appending to an existing file and we need to reallocate
          MEMFS.expandFileStorage(node, position+length);
          node.contents.set(chunk, position); 
          node.usedBytes = Math.max(node.usedBytes, position+length);
        }
        return length;
      }
    };
  
  
  window.CCFS={
      streams:[],entries:{},currentPath:"/",ErrnoError:null,
      resolvePath:function(path) {
        if (path.charAt(0) !== '/') {
          path = CCFS.currentPath + '/' + path;
        }
        return path;
      },
      lookupPath:function(path) {
        path = CCFS.resolvePath(path);
        var node = CCFS.entries[path];
        
        if (!node) throw new CCFS.ErrnoError(2);
        return { path: path, node: node };
      },
      createNode:function(path) {
        var node = { path: path };
        CCFS.entries[path] = node; 
        return node;
      },
      MODE_TYPE_FILE:32768,
      isFile:function(mode) {
        return (mode & 61440) === CCFS.MODE_TYPE_FILE;
      },
      nextfd:function() {
        // max 4096 open files
        for (var fd = 0; fd <= 4096; fd++) 
        {
          if (!CCFS.streams[fd]) return fd;
        }
        throw new CCFS.ErrnoError(24);
      },
      getStream:function(fd) {
        return CCFS.streams[fd];
      },
      createStream:function(stream) {
        var fd = CCFS.nextfd();
        stream.fd = fd;
        CCFS.streams[fd] = stream;
        return stream;
      },
      readdir:function(path) {
        path = CCFS.resolvePath(path) + '/';

        // all entries starting with given directory
        var entries = [];
        for (var entry in CCFS.entries) 
        {
          if (entry.indexOf(path) !== 0) continue;
          entries.push(entry);
        }
        return entries;
      },
      unlink:function(path) {
        var lookup = CCFS.lookupPath(path);
        delete CCFS.entries[lookup.path];
      },
      utime:function(path, mtime) {
        var lookup = CCFS.lookupPath(path);
        var node = lookup.node;
        
        node.timestamp = mtime;
      },
      open:function(path, flags) {
        path  = CCFS.resolvePath(path);

        var node = CCFS.entries[path];
        // perhaps we need to create the node
        var created = false;
        if ((flags & 64)) {
          if (node) {
            // if O_CREAT and O_EXCL are set, error out if the node already exists
            if ((flags & 128)) {
              throw new CCFS.ErrnoError(17);
            }
          } else {
            // node doesn't exist, try to create it
            node = MEMFS.createNode(path);
            created = true;
          }
        }
        if (!node) {
          throw new CCFS.ErrnoError(2);
        }
        
        // do truncation if necessary
        if ((flags & 512)) {
          MEMFS.clearFileStorage(node);
          node.timestamp = Date.now();
        }
        
        // we've already handled these, don't pass down to the underlying vfs
        flags &= ~(128 | 512);
  
        // register the stream with the filesystem
        var stream = CCFS.createStream({
          node: node,
          path: path,
          flags: flags,
          position: 0
        });
        return stream;
      },
      close:function(stream) {
        if (CCFS.isClosed(stream)) {
          throw new CCFS.ErrnoError(9);
        }
        
        CCFS.streams[stream.fd] = null;
        stream.fd = null;
      },
      isClosed:function(stream) {
        return stream.fd === null;
      },
      llseek:function(stream, offset, whence) {
        if (CCFS.isClosed(stream)) {
          throw new CCFS.ErrnoError(9);
        }
        
        var position = offset;
        if (whence === 0) { // SEEK_SET
          // beginning of file, no need to add anything
        } else if (whence === 1) { // SEEK_CUR
          position += stream.position;
        } else if (whence === 2) { // SEEK_END
          position += stream.node.usedBytes;
        }

        if (position < 0) {
          throw new CCFS.ErrnoError(22);
        }
        stream.position = position;
        return stream.position;
      },
      read:function(stream, buffer, offset, length) {
        if (length < 0) {
          throw new CCFS.ErrnoError(22);
        }
        if (CCFS.isClosed(stream)) {
          throw new CCFS.ErrnoError(9);
        }
        if ((stream.flags & 2097155) === 1) {
          throw new CCFS.ErrnoError(9);
        }
        
        var position  = stream.position;
        var bytesRead = MEMFS.stream_read(stream, buffer, offset, length, position);
        stream.position += bytesRead;
        return bytesRead;
      },
      write:function(stream, buffer, offset, length, canOwn) {
        if (length < 0) {
          throw new CCFS.ErrnoError(22);
        }
        if (CCFS.isClosed(stream)) {
          throw new CCFS.ErrnoError(9);
        }
        if ((stream.flags & 2097155) === 0) {
          throw new CCFS.ErrnoError(9);
        }
        if (stream.flags & 1024) {
          // seek to the end before writing in append mode
          CCFS.llseek(stream, 0, 2);
        }
        
        var position = stream.position;
        var bytesWritten = MEMFS.stream_write(stream, buffer, offset, length, position, canOwn);
        stream.position += bytesWritten;
        return bytesWritten;
      },
      readFile:function(path, encoding) {
        encoding = encoding || 'binary';
        
        var ret;
        var stream = CCFS.open(path, 0); // O_RDONLY
        var length = stream.node.usedBytes;
        var buf    = new Uint8Array(length);
        CCFS.read(stream, buf, 0, length);
        
        if (encoding === 'utf8') {
          ret = UTF8ArrayToString(buf, 0);
        } else if (encoding === 'binary') {
          ret = buf;
        } else {
          throw new Error("Invalid encoding: " + encoding);
        }
        
        CCFS.close(stream);
        return ret;
      },
      writeFile:function(path, data) {
        var stream = CCFS.open(path, 577); // O_WRONLY | O_CREAT | O_TRUNC

        if (typeof data === 'string') {
          var buf = new Uint8Array(lengthBytesUTF8(data)+1);
          var actualNumBytes = stringToUTF8Array(data, buf, 0, buf.length);
          CCFS.write(stream, buf, 0, actualNumBytes, true);
        } else if (ArrayBuffer.isView(data)) {
          CCFS.write(stream, data, 0, data.byteLength, true);
        } else {
          throw new Error('Unsupported data type');
        }
        CCFS.close(stream);
      },
      chdir:function(path) {
        CCFS.currentPath = CCFS.resolvePath(path);
      },
      ensureErrnoError:function() {
        CCFS.ErrnoError = function ErrnoError(errno, node) {
          this.node  = node;
          this.errno = errno;
        };
        CCFS.ErrnoError.prototype = new Error();
        CCFS.ErrnoError.prototype.constructor = CCFS.ErrnoError;
      }};
  
    CCFS.ensureErrnoError();
  },
});
