import subprocess

try: from shutils import which
except ImportError: from distutils.spawn import find_executable as which

PANDOC_PATH = which('pandoc')


class Document(object):
	"""A formatted document."""

	INPUT_FORMATS = (
		'native', 'markdown', 'markdown+lhs', 'rst',
		'rst+lhs', 'html', 'latex', 'latex+lhs'
	)

	OUTPUT_FORMATS = (
		'native', 'html', 'html+lhs', 's5', 'slidy',
		'docbook', 'opendocument', 'odt', 'epub',
		'latex', 'latex+lhs', 'context', 'texinfo',
		'man', 'markdown', 'markdown+lhs', 'plain',
		'rst', 'rst+lhs', 'mediawiki', 'rtf', 'html5'
	)

	SPECIAL_FORMATS = (
		('html+mathjax', 'html', 'mathjax'),
		('html5+mathjax', 'html5', 'mathjax'),
	)

	# TODO: Add odt, epub formats (requires file access, not stdout)

	def __init__(self):
		self._content = None
		self._format = None
		self._register_formats()

	@classmethod
	def _register_formats(cls):
		"""Adds format properties."""
		for fmt in cls.OUTPUT_FORMATS:
			clean_fmt = fmt.replace('+', '_')
			setattr(cls, clean_fmt, property(
				(lambda x, fmt=fmt: cls._output(x, fmt)), # fget
				(lambda x, y, fmt=fmt: cls._input(x, y, fmt)))) # fset
		for fmt in cls.SPECIAL_FORMATS:
			clean_fmt = fmt[0].replace('+', '_')
			setattr(cls, clean_fmt, property(
				(lambda x, fmt=fmt: cls._output(x, fmt[1], fmt[2])), # fget
				(lambda x, y, fmt=fmt: cls._input(x, y, fmt[1], fmt[2])))) # fset



	def _input(self, value, format=None, modifiers=None):
		# format = format.replace('_', '+')
		self._content = value
		self._format = format
		self._modifiers = None

	def _output(self, format, modifiers=None):
		# print format
		if modifiers is None:
			cmdline = [PANDOC_PATH, '--from=%s' % self._format, '--to=%s' % format]
		else:
			cmdline = [PANDOC_PATH, '--from=%s' % self._format, '--to=%s' % format, '--%s' % modifiers]

		p = subprocess.Popen(
			cmdline,
			stdin=subprocess.PIPE,
			stdout=subprocess.PIPE
		)

		return p.communicate(self._content)[0]