// Typemaps to allow Python director class methods to write to C++ std::ostream
// objects as if they were Python file-like objects; should only be included
// directly by the kernel so that the class is only defined there
%import "IMP_streams_kernel.i"

// Typemaps to allow Python file-like objects to be used for C++ code that
// expects a std::ostream

%typemap(in) IMP::TextProxy<std::ostream> (IMP::internal::OwnerPointer<PyOutFileAdapter> tmp){
  tmp=new PyOutFileAdapter();
    try {
      $1 = IMP::TextProxy<std::ostream>(tmp->set_python_file($input), tmp);
    } catch (...) {
      // If Python error indicator is set (e.g. from a failed director method),
      // it will be reraised at the end of the method
      if (!PyErr_Occurred()) {
        handle_imp_exception();
      }
      SWIG_fail;
    }
  if (!$1.str_) {
    SWIG_fail;
  }
}

%typemap(in) std::ostream& (IMP::internal::OwnerPointer<PyOutFileAdapter> tmp){
  tmp=new PyOutFileAdapter();
  try {
       $1 = tmp->set_python_file($input);
    } catch (...) {
      // If Python error indicator is set (e.g. from a failed director method),
      // it will be reraised at the end of the method
      if (!PyErr_Occurred()) {
        handle_imp_exception();
      }
      SWIG_fail;
    }
   
  if (!$1) {
    SWIG_fail;
  }
}

// Something of an abuse of argout: force anything in our streambuf adapter to
// be flushed out to the file, and catch any exceptions raised. (Ideally the
// call to pubsync would come immediately after the method call, but the only
// way to handle that would be to use %exception or %feature("action") for
// each method using ostreams.)
// Potential memory leak here if there are other argout arguments that come
// after the ostream.
%typemap(argout) std::ostream& {
  try {
    tmp$argnum->pubsync();
  } catch (...) {
    Py_DECREF($result);
    if (!PyErr_Occurred()) {
      handle_imp_exception();
    }
    SWIG_fail;
  }
}

%typemap(argout) TextOutput {
  try {
    tmp$argnum->pubsync();
  } catch (...) {
    Py_DECREF($result);
    if (!PyErr_Occurred()) {
      handle_imp_exception();
    }
    SWIG_fail;
  }
}

  %typemap(typecheck) IMP::TextOutputProxy = PyObject *;

%typemap(typecheck) std::ostream& = PyObject *;

// Typemaps to allow Python file objects to be used for C++ code that
// expects a std::istream
%typemap(in) IMP::TextProxy<std::istream> (IMP::internal::OwnerPointer<PyInFileAdapter> tmp) {
    tmp=new PyInFileAdapter();
    $1 = IMP::TextProxy<std::istream>(tmp->set_python_file($input), tmp);
  if (!$1.str_) {
    SWIG_fail;
  }
}

%typemap(in) std::istream& (IMP::internal::OwnerPointer<PyInFileAdapter> tmp){
    tmp= new PyInFileAdapter();
    $1 = tmp->set_python_file($input);
  if (!$1) {
    SWIG_fail;
  }
}

%typemap(typecheck) IMP::TextProxy<std::istream> = PyObject *;
%typemap(typecheck) IMP::TextProxy<std::ostream> = PyObject *;
%typemap(typecheck) std::istream& = PyObject *;


%{
// Adapter class that acts like an output std::streambuf but delegates to
// a Python file-like object, p
class PyOutFileAdapter : public IMP::Object
{
 
  std::auto_ptr<std::ostream> ostr_;

  struct StreamBuf:public std::streambuf {
    PyObject *write_method_;
    std::vector<char> buffer_;
    StreamBuf(PyObject *wm): write_method_(wm),
                             buffer_(1024){
      setp(&buffer_.front(), &buffer_.front() + buffer_.size());
      // to make errors occur earlier
      static char fmt[] = "(s#)";
      PyObject *result = PyObject_CallFunction(write_method_, fmt, fmt, 0);
      if (!result) {
        // Python exception will be reraised when SWIG method finishes
        throw std::ostream::failure("Python error on write");
      } else {
        Py_DECREF(result);
      }
    }
  protected:
    virtual int_type overflow(int_type c) {
      if (c != EOF) {
        sync();
        *pptr() = c;
        pbump(1);
      }
      return c;
    }
    
    virtual int_type sync() {
      // Python API uses char* arguments rather than const char*, so create
      // here to quell the compiler warning
      static char fmt[] = "(s#)";
      int num = pptr() - pbase();
      if (num <= 0) {
        return 0;
      }
      PyObject *result = PyObject_CallFunction(write_method_, fmt, pbase(), num);
      if (!result) {
        // Python exception will be reraised when SWIG method finishes
        throw std::ostream::failure("Python error on write");
      } else {
        pbump(-num);
        Py_DECREF(result);
        return 0;
      }
    }
    
    virtual std::streamsize xsputn(const char *s, std::streamsize n) {
      if (static_cast<std::size_t>(n) > buffer_.size() * 2) {
        // Only take this route for large buffers, since two Python calls will
        // result per call (one here, potentially one in sync) rather than one per
        // buffer_.size() characters via the regular buffering
        sync();
        static char fmt[] = "(s#)";
        PyObject *result = PyObject_CallFunction(write_method_, fmt, s, n);
        if (!result) {
          throw std::ostream::failure("Python error on write");
        } else {
          Py_DECREF(result);
        }
        return n;
      } else {
        // Use the regular buffering mechanism
        for (std::streamsize i = 0; i < n; ++i) {
          if (sputc(s[i]) == EOF) {
            return i;
          }
        }
      return n;
      }
    }
  public:
    virtual ~StreamBuf() {
      Py_XDECREF(write_method_);
    }
  };
  std::auto_ptr<StreamBuf> stream_buf_;
public:
  PyOutFileAdapter():IMP::Object("PyOutFileAdapter") {
  }
  void do_show(std::ostream &out) const {
  }
  std::string get_type_name() const {return "Pyton output file";}
  IMP::VersionInfo get_version_info() const {return IMP::get_module_version_info();}
  void pubsync() {
    stream_buf_->pubsync();
  }
  // Given a Python file object, return an ostream that will write to this
  // object, or NULL if the object is not suitable.
  std::ostream* set_python_file(PyObject *p) {
    PyObject *wm=PyObject_GetAttrString(p, "write");
    if (!wm) {
      return NULL;
    }
    stream_buf_= std::auto_ptr<StreamBuf>(new StreamBuf(wm));
    
    IMP_INTERNAL_CHECK(!ostr_.get(), "Already set the stream.");
    ostr_ = std::auto_ptr<std::ostream>(new std::ostream(stream_buf_.get()));
    ostr_->exceptions(std::ostream::badbit);
    return ostr_.get();
    fail:
    return NULL;
  }


 private:
  template <class T, class E> friend class IMP::internal::RefStuff;
  virtual ~PyOutFileAdapter() {
    try {
      if (stream_buf_.get()) pubsync();
    } catch (...) {
      // at this point we have no choice but to eat it
    }
  }
};%}

%{
// Base for input adapters
class InAdapter : public std::streambuf
{
};

// Adapter class that acts like an input std::streambuf but delegates to
// C-style stdio via a FILE pointer
class PyInCFileAdapter : public InAdapter
{
  FILE *fh_;
public:
  PyInCFileAdapter(FILE *fh) : fh_(fh) {}
  virtual ~PyInCFileAdapter(){
  }
protected:
  virtual int_type uflow() {
    return getc(fh_);
  }

  virtual int_type underflow() {
    int c = getc(fh_);
    if (c != EOF) {
      ungetc(c, fh_);
    }
    return c;
  }

  virtual std::streamsize xsgetn(char *s, std::streamsize n) {
    return fread(s, 1, n, fh_);
  }

  virtual int_type pbackfail(int c) {
    return c == EOF ? EOF : ungetc(c, fh_);
  }

  virtual int_type sync() {
    return fflush(fh_);
  }
};

// Adapter class that acts like an input std::streambuf but delegates to
// a Python file-like object
class PyInFilelikeAdapter : public InAdapter
{
  PyObject *read_method_;
  // Last character peeked from the stream by underflow(), or -1
  int peeked_;
public:
  PyInFilelikeAdapter(PyObject *read_method)
    :  read_method_(read_method), peeked_(-1) {}
  virtual ~PyInFilelikeAdapter() {
    Py_DECREF(read_method_);
    if (peeked_ != -1) {
      IMP_WARN("One excess character read from Python stream - "
               "cannot be put back." << std::endl)
    }
  }
protected:
  virtual int_type uflow() {
    int c;
    c = (peeked_ == -1 ? underflow() : peeked_);
    peeked_ = -1;
    return c;
  }

  virtual int_type underflow() {
    static char fmt[] = "(i)";
    if (peeked_!= -1) return peeked_;
    PyObject *result = PyObject_CallFunction(read_method_, fmt, 1);
    if (!result) {
      // Python exception will be reraised when SWIG method finishes
      throw std::ostream::failure("Python error on read");
    } else {
      if (PyString_Check(result)) {
        if (PyString_Size(result) == 1) {
          int c = peeked_ = PyString_AsString(result)[0];
          Py_DECREF(result);
          return c;
        } else {
          Py_DECREF(result);
          return EOF;
        }
      } else {
        Py_DECREF(result);
        PyErr_SetString(PyExc_TypeError, "Python file-like object read method "
                        "should return a string");
        throw std::ostream::failure("Python error on read");
      }
    }
  }

  virtual std::streamsize xsgetn(char *s, std::streamsize n) {
    static char fmt[] = "(i)";
    PyObject *result = PyObject_CallFunction(read_method_, fmt, n);
    if (!result) {
      throw std::ostream::failure("Python error on read");
    } else {
      if (PyString_Check(result)) {
        int len = PyString_Size(result);
        char *str = PyString_AsString(result);
        if (len > n) {
          Py_DECREF(result);
          PyErr_SetString(PyExc_IOError, "Python file-like object read method "
                          "returned data longer than the input buffer");
          throw std::ostream::failure("Python error on read");
        } else {
          memcpy(s, str, len);
          Py_DECREF(result);
          return len;
        }
      } else {
        Py_DECREF(result);
        PyErr_SetString(PyExc_TypeError, "Python file-like object read method "
                        "should return a string");
        throw std::ostream::failure("Python error on read");
      }
    }
  }
};

// Adapter class that delegates C++ stream input to a Python object.

// It is rather expensive to call the Python 'read' method for every character
// (and we cannot read multiple bytes from the Python file, since there is no
// way to put them back if we read too many; even if the stream is seekable
// there is no guarantee we can restore the file position unless it is opened
// in binary mode). Thus, we try to use the underlying FILE pointer (only
// available for real files, not for file-like objects) if possible. This may
// fail on Windows where different C runtimes can make FILE pointers unusable:
// http://www.python.org/doc/faq/windows/#pyrun-simplefile-crashes-on-windows-but-not-on-unix-why

// Note that this is still not optimal, since the streambuf is not buffered;
// uflow() or underflow() virtual methods will be called for each character
// (unless xsgetn can be used). This could be alleviated (at the expense of
// making the classes rather more complex) by buffering if the underlying file
// is seekable:
//   populate_buffer() {
//     pos_ = (fgetpos() or Python tell());
//     fill buffer with fread(buffer_size) or Python read(buffer_size);
//   }
//   sync() {
//     fsetpos(pos_) or Python seek(pos_);
//     chars_consumed = gptr() - eback();
//     read and discard char array with
//                      fread(chars_consumed) or Python read(chars_consumed);
//     empty buffer;
//   }
//   uflow() and underflow() call populate_buffer(); sync ensures that future
//   reads from the underlying file will reread characters currently between
//   gptr() and egptr(). Note that we cannot simply do
//   fseek(fh, gptr() - egptr(), SEEK_CUR) in sync since this doesn't work with
//   text files on Windows, or with Python file-like objects, where the only
//   inputs to seek() that have defined behavior are offsets previously
//   returned by tell().

class PyInFileAdapter: public IMP::Object
{ 
  template <class T, class E> friend class IMP::internal::RefStuff;
  virtual ~PyInFileAdapter(){
  }
  std::auto_ptr<InAdapter> streambuf_;
  std::auto_ptr<std::istream> istr_;
public:
  PyInFileAdapter(): IMP::Object("PyInFileAdapter") {}
  void do_show(std::ostream &out) const {
  }
  std::string get_type_name() const {return "Pyton input file";}
  IMP::VersionInfo get_version_info() const {return IMP::get_module_version_info();}
  // Given a Python file object, return an istream that will read from this
  // object, or NULL if the object is not suitable.
  std::istream* set_python_file(PyObject *p) {
    // Is the object a 'real' C-style FILE ?
    bool real_file;
    /* Cannot reliably detect a "real" file pointer on Windows
       (differing C runtimes) so always use a file-like approach here */
#ifdef _MSC_VER
    real_file = false;
#else
    try {
      real_file = (PyFile_Check(p) && ftell(PyFile_AsFile(p)) != -1);
    } catch(...) {
      real_file = false;
    }
#endif

    if (real_file) {
      streambuf_ = std::auto_ptr<InAdapter>(new PyInCFileAdapter(PyFile_AsFile(p)));
    } else {
      PyObject *read_method;
      if (!(read_method = PyObject_GetAttrString(p, "read"))) {
        return NULL;
      }
      streambuf_ = std::auto_ptr<InAdapter>(new PyInFilelikeAdapter(read_method));
    }
    IMP_INTERNAL_CHECK(!istr_.get(), "Already set the stream.");
    istr_ = std::auto_ptr<std::istream>(new std::istream(streambuf_.get()));
    istr_->exceptions(std::istream::badbit);
    return istr_.get();
  }
};
%}