"""Implementation of JSONEncoder
"""
import re

try:
	from _json import encode_basestring_ascii as c_encode_basestring_ascii
except ImportError:
	c_encode_basestring_ascii = None
try:
	from _json import encode_basestring as c_encode_basestring
except ImportError:
	c_encode_basestring = None

# do not use C encoder
c_make_encoder = None

ESCAPE = re.compile(r'[\x00-\x1f\\"\b\f\n\r\t]')
ESCAPE_ASCII = re.compile(r'([\\"]|[^\ -~])')
HAS_UTF8 = re.compile(b'[\x80-\xff]')
ESCAPE_DCT = {
	'\\': '\\\\',
	'"': '\\"',
	'\b': '\\b',
	'\f': '\\f',
	'\n': '\\n',
	'\r': '\\r',
	'\t': '\\t',
}
for i in range(0x20):
	ESCAPE_DCT.setdefault(chr(i), '\\u{0:04x}'.format(i))
	#ESCAPE_DCT.setdefault(chr(i), '\\u%04x' % (i,))

INFINITY = float('inf')

def py_encode_basestring(s):
	"""Return a JSON representation of a Python string

	"""
	def replace(match):
		return ESCAPE_DCT[match.group(0)]
	return '"' + ESCAPE.sub(replace, s) + '"'


encode_basestring = (c_encode_basestring or py_encode_basestring)


def py_encode_basestring_ascii(s):
	"""Return an ASCII-only JSON representation of a Python string

	"""
	def replace(match):
		s = match.group(0)
		try:
			return ESCAPE_DCT[s]
		except KeyError:
			n = ord(s)
			if n < 0x10000:
				return '\\u{0:04x}'.format(n)
				#return '\\u%04x' % (n,)
			else:
				# surrogate pair
				n -= 0x10000
				s1 = 0xd800 | ((n >> 10) & 0x3ff)
				s2 = 0xdc00 | (n & 0x3ff)
				return '\\u{0:04x}\\u{1:04x}'.format(s1, s2)
	return '"' + ESCAPE_ASCII.sub(replace, s) + '"'


encode_basestring_ascii = (
	c_encode_basestring_ascii or py_encode_basestring_ascii)

class StructInfoValueEncoder(object):
	"""Extensible JSON <http://json.org> encoder for Python data structures.

	Supports the following objects and types by default:

	+-------------------+---------------+
	| Python            | JSON          |
	+===================+===============+
	| dict              | object        |
	+-------------------+---------------+
	| list, tuple       | array         |
	+-------------------+---------------+
	| str               | string        |
	+-------------------+---------------+
	| int, float        | number        |
	+-------------------+---------------+
	| True              | true          |
	+-------------------+---------------+
	| False             | false         |
	+-------------------+---------------+
	| None              | null          |
	+-------------------+---------------+

	To extend this to recognize other objects, subclass and implement a
	``.default()`` method with another method that returns a serializable
	object for ``o`` if possible, otherwise it should call the superclass
	implementation (to raise ``TypeError``).

	"""
	item_separator = ', '
	key_separator = ': '
	def __init__(self, *, skipkeys=False, ensure_ascii=True,
			check_circular=True, allow_nan=True, sort_keys=False,
			indent=None, separators=None, default=None):
		"""Constructor for JSONEncoder, with sensible defaults.

		If skipkeys is false, then it is a TypeError to attempt
		encoding of keys that are not str, int, float or None.  If
		skipkeys is True, such items are simply skipped.

		If ensure_ascii is true, the output is guaranteed to be str
		objects with all incoming non-ASCII characters escaped.  If
		ensure_ascii is false, the output can contain non-ASCII characters.

		If check_circular is true, then lists, dicts, and custom encoded
		objects will be checked for circular references during encoding to
		prevent an infinite recursion (which would cause an OverflowError).
		Otherwise, no such check takes place.

		If allow_nan is true, then NaN, Infinity, and -Infinity will be
		encoded as such.  This behavior is not JSON specification compliant,
		but is consistent with most JavaScript based encoders and decoders.
		Otherwise, it will be a ValueError to encode such floats.

		If sort_keys is true, then the output of dictionaries will be
		sorted by key; this is useful for regression tests to ensure
		that JSON serializations can be compared on a day-to-day basis.

		If indent is a non-negative integer, then JSON array
		elements and object members will be pretty-printed with that
		indent level.  An indent level of 0 will only insert newlines.
		None is the most compact representation.

		If specified, separators should be an (item_separator, key_separator)
		tuple.  The default is (', ', ': ') if *indent* is ``None`` and
		(',', ': ') otherwise.  To get the most compact JSON representation,
		you should specify (',', ':') to eliminate whitespace.

		If specified, default is a function that gets called for objects
		that can't otherwise be serialized.  It should return a JSON encodable
		version of the object or raise a ``TypeError``.

		"""

		self.skipkeys = skipkeys
		self.ensure_ascii = ensure_ascii
		self.check_circular = check_circular
		self.allow_nan = allow_nan
		self.sort_keys = sort_keys
		self.indent = indent
		if separators is not None:
			self.item_separator, self.key_separator = separators
		elif indent is not None:
			self.item_separator = ','
		if default is not None:
			self.default = default

	def default(self, o):
		"""Implement this method in a subclass such that it returns
		a serializable object for ``o``, or calls the base implementation
		(to raise a ``TypeError``).

		For example, to support arbitrary iterators, you could
		implement default like this::

			def default(self, o):
				try:
					iterable = iter(o)
				except TypeError:
					pass
				else:
					return list(iterable)
				# Let the base class default method raise the TypeError
				return JSONEncoder.default(self, o)

		"""
		raise TypeError("Object of type '%s' is not JSON serializable" %
						o.__class__.__name__)

	def encode(self, o):
		"""Return a JSON string representation of a Python data structure.

		>>> from json.encoder import JSONEncoder
		>>> JSONEncoder().encode({"foo": ["bar", "baz"]})
		'{"foo": ["bar", "baz"]}'

		"""
		# This is for extremely simple cases and benchmarks.
		if isinstance(o, str):
			if self.ensure_ascii:
				return encode_basestring_ascii(o)
			else:
				return encode_basestring(o)
		# This doesn't pass the iterator directly to ''.join() because the
		# exceptions aren't as detailed.  The list call should be roughly
		# equivalent to the PySequence_Fast that ''.join() would do.
		chunks = self.iterencode(o, _one_shot=True)
		if not isinstance(chunks, (list, tuple)):
			chunks = list(chunks)
		return ''.join(chunks)

	def iterencode(self, o, _one_shot=False):
		"""Encode the given object and yield each string
		representation as available.

		For example::

			for chunk in JSONEncoder().iterencode(bigobject):
				mysocket.write(chunk)

		"""
		if self.check_circular:
			markers = {}
		else:
			markers = None
		if self.ensure_ascii:
			_encoder = encode_basestring_ascii
		else:
			_encoder = encode_basestring

		def floatstr(o, allow_nan=self.allow_nan,
				_repr=float.__repr__, _inf=INFINITY, _neginf=-INFINITY):
			# Check for specials.  Note that this type of test is processor
			# and/or platform-specific, so do tests which don't depend on the
			# internals.

			if o != o:
				text = 'NaN'
			elif o == _inf:
				text = 'Infinity'
			elif o == _neginf:
				text = '-Infinity'
			else:
				return _repr(o)

			if not allow_nan:
				raise ValueError(
					"Out of range float values are not JSON compliant: " +
					repr(o))

			return text


		if (_one_shot and c_make_encoder is not None
				and self.indent is None):
			_iterencode = c_make_encoder(
				markers, self.default, _encoder, self.indent,
				self.key_separator, self.item_separator, self.sort_keys,
				self.skipkeys, self.allow_nan)
		else:
			_iterencode = _make_iterencode(
				markers, self.default, _encoder, self.indent, floatstr,
				self.key_separator, self.item_separator, self.sort_keys,
				self.skipkeys, _one_shot)
		return _iterencode(o, 0)

def _make_iterencode(markers, _default, _encoder, _indent, _floatstr,
		_key_separator, _item_separator, _sort_keys, _skipkeys, _one_shot,
		## HACK: hand-optimized bytecode; turn globals into locals
		ValueError=ValueError,
		dict=dict,
		float=float,
		id=id,
		int=int,
		isinstance=isinstance,
		list=list,
		str=str,
		tuple=tuple,
		_intstr=int.__str__,
	):

	if _indent is not None and not isinstance(_indent, str):
		_indent = ' ' * _indent

	def _iterencode_list(lst, _current_indent_level):
		if not lst:
			yield '[]'
			return
		if markers is not None:
			markerid = id(lst)
			if markerid in markers:
				raise ValueError("Circular reference detected")
			markers[markerid] = lst
		buf = '['
		if _indent is not None:
			_current_indent_level += 1
			newline_indent = '\n' + _indent * _current_indent_level
			separator = _item_separator + newline_indent
			buf += newline_indent
		else:
			newline_indent = None
			separator = _item_separator
		first = True
		for value in lst:
			if first:
				first = False
			else:
				buf = separator
			if isinstance(value, str):
				yield buf + _encoder(value)
			elif value is None:
				yield buf + 'null'
			elif value is True:
				yield buf + 'true'
			elif value is False:
				yield buf + 'false'
			elif isinstance(value, int):
				# Subclasses of int/float may override __str__, but we still
				# want to encode them as integers/floats in JSON. One example
				# within the standard library is IntEnum.
				yield buf + _intstr(value)
			elif isinstance(value, float):
				# see comment above for int
				yield buf + _floatstr(value)
			elif hasattr(value, 'to_text'):
				yield buf + value.to_text()
			else:
				yield buf
				if isinstance(value, (list, tuple)):
					chunks = _iterencode_list(value, _current_indent_level)
				elif isinstance(value, dict):
					chunks = _iterencode_dict(value, _current_indent_level)
				else:
					chunks = _iterencode(value, _current_indent_level)
				yield from chunks
		if newline_indent is not None:
			_current_indent_level -= 1
			yield '\n' + _indent * _current_indent_level
		yield ']'
		if markers is not None:
			del markers[markerid]

	def _iterencode_dict(dct, _current_indent_level):
		if not dct:
			yield '{}'
			return
		if markers is not None:
			markerid = id(dct)
			if markerid in markers:
				raise ValueError("Circular reference detected")
			markers[markerid] = dct
		yield '{'
		if _indent is not None:
			_current_indent_level += 1
			newline_indent = '\n' + _indent * _current_indent_level
			item_separator = _item_separator + newline_indent
			yield newline_indent
		else:
			newline_indent = None
			item_separator = _item_separator
		first = True
		if _sort_keys:
			items = sorted(dct.items(), key=lambda kv: kv[0])
		else:
			items = dct.items()
		for key, value in items:
			if isinstance(key, str):
				pass
			# JavaScript is weakly typed for these, so it makes sense to
			# also allow them.  Many encoders seem to do something like this.
			elif isinstance(key, float):
				# see comment for int/float in _make_iterencode
				key = _floatstr(key)
			elif key is True:
				key = 'true'
			elif key is False:
				key = 'false'
			elif key is None:
				key = 'null'
			elif isinstance(key, int):
				# see comment for int/float in _make_iterencode
				key = _intstr(key)
			elif _skipkeys:
				continue
			else:
				raise TypeError("key " + repr(key) + " is not a string")
			if first:
				first = False
			else:
				yield item_separator
			yield _encoder(key)
			yield _key_separator
			if isinstance(value, str):
				yield _encoder(value)
			elif value is None:
				yield 'null'
			elif value is True:
				yield 'true'
			elif value is False:
				yield 'false'
			elif isinstance(value, int):
				# see comment for int/float in _make_iterencode
				yield _intstr(value)
			elif isinstance(value, float):
				# see comment for int/float in _make_iterencode
				yield _floatstr(value)
			elif hasattr(value, 'to_text'):
				yield value.to_text()
			else:
				if isinstance(value, (list, tuple)):
					chunks = _iterencode_list(value, _current_indent_level)
				elif isinstance(value, dict):
					chunks = _iterencode_dict(value, _current_indent_level)
				else:
					chunks = _iterencode(value, _current_indent_level)
				yield from chunks
		if newline_indent is not None:
			_current_indent_level -= 1
			yield '\n' + _indent * _current_indent_level
		yield '}'
		if markers is not None:
			del markers[markerid]

	def _iterencode(o, _current_indent_level):
		if isinstance(o, str):
			yield _encoder(o)
		elif o is None:
			yield 'null'
		elif o is True:
			yield 'true'
		elif o is False:
			yield 'false'
		elif isinstance(o, int):
			# see comment for int/float in _make_iterencode
			yield _intstr(o)
		elif isinstance(o, float):
			# see comment for int/float in _make_iterencode
			yield _floatstr(o)
		elif isinstance(o, (list, tuple)):
			yield from _iterencode_list(o, _current_indent_level)
		elif isinstance(o, dict):
			yield from _iterencode_dict(o, _current_indent_level)
		elif hasattr(o, 'to_text'):
			yield o.to_text()
		else:
			if markers is not None:
				markerid = id(o)
				if markerid in markers:
					raise ValueError("Circular reference detected")
				markers[markerid] = o
			o = _default(o)
			yield from _iterencode(o, _current_indent_level)
			if markers is not None:
				del markers[markerid]
	return _iterencode
