// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

final int _STDIO_HANDLE_TYPE_TERMINAL = 0;
final int _STDIO_HANDLE_TYPE_PIPE = 1;
final int _STDIO_HANDLE_TYPE_FILE = 2;
final int _STDIO_HANDLE_TYPE_SOCKET = 3;
final int _STDIO_HANDLE_TYPE_OTHER = -1;


InputStream _stdin;
OutputStream _stdout;
OutputStream _stderr;


InputStream _getStdioInputStream() {
  switch (_getStdioHandleType(0)) {
    case _STDIO_HANDLE_TYPE_TERMINAL:
    case _STDIO_HANDLE_TYPE_PIPE:
    case _STDIO_HANDLE_TYPE_SOCKET:
      Socket s = new _Socket._internalReadOnly();
      _getStdioHandle(s, 0);
      return s.inputStream;
    case _STDIO_HANDLE_TYPE_FILE:
      return new _FileInputStream.fromStdio(0);
    default:
      throw new FileIOException("Unsupported stdin type");
  }
}


OutputStream _getStdioOutputStream(int fd) {
  assert(fd == 1 || fd == 2);
  switch (_getStdioHandleType(fd)) {
    case _STDIO_HANDLE_TYPE_TERMINAL:
    case _STDIO_HANDLE_TYPE_PIPE:
    case _STDIO_HANDLE_TYPE_SOCKET:
      Socket s = new _Socket._internalWriteOnly();
      _getStdioHandle(s, fd);
      return s.outputStream;
    case _STDIO_HANDLE_TYPE_FILE:
      return new _FileOutputStream.fromStdio(fd);
    default:
      throw new FileIOException("Unsupported stdin type");
  }
}


InputStream get stdin() {
  if (_stdin == null) {
    _stdin = _getStdioInputStream();
  }
  return _stdin;
}


OutputStream get stdout() {
  if (_stdout == null) {
    _stdout = _getStdioOutputStream(1);
  }
  return _stdout;
}


OutputStream get stderr() {
  if (_stderr == null) {
    _stderr = _getStdioOutputStream(2);
  }
  return _stderr;
}

_getStdioHandle(Socket socket, int num) native "Socket_GetStdioHandle";
_getStdioHandleType(int num) native "File_GetStdioHandleType";