"""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
try:
    from _json import make_encoder as c_make_encoder
except ImportError:
    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,))
del 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 JSONEncoder(object):
    """Extensible JSON <https://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, bool 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 and non-printable characters escaped.
        If ensure_ascii is false, the output can contain non-ASCII and
        non-printable 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 a RecursionError).
        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 super().default(o)

        """
        raise TypeError(f'Object of type {o.__class__.__name__} '
                        f'is not JSON serializable')

    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 self.indent is None or isinstance(self.indent, str):
            indent = self.indent
        else:
            indent = ' ' * self.indent
        if _one_shot and c_make_encoder is not None:
            _iterencode = c_make_encoder(
                markers, self.default, _encoder, indent,
                self.key_separator, self.item_separator, self.sort_keys,
                self.skipkeys, self.allow_nan)
        else:
            _iterencode = _make_iterencode(
                markers, self.default, _encoder, 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.__repr__,
    ):

    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
        for i, value in enumerate(lst):
            if i:
                buf = separator
            try:
                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 __repr__, 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)
                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
            except GeneratorExit:
                raise
            except BaseException as exc:
                exc.add_note(f'when serializing {type(lst).__name__} item {i}')
                raise
        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
        else:
            newline_indent = None
            item_separator = _item_separator
        first = True
        if _sort_keys:
            items = sorted(dct.items())
        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(f'keys must be str, int, float, bool or None, '
                                f'not {key.__class__.__name__}')
            if first:
                first = False
                if newline_indent is not None:
                    yield newline_indent
            else:
                yield item_separator
            yield _encoder(key)
            yield _key_separator
            try:
                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)
                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
            except GeneratorExit:
                raise
            except BaseException as exc:
                exc.add_note(f'when serializing {type(dct).__name__} item {key!r}')
                raise
        if not first and 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)
        else:
            if markers is not None:
                markerid = id(o)
                if markerid in markers:
                    raise ValueError("Circular reference detected")
                markers[markerid] = o
            newobj = _default(o)
            try:
                yield from _iterencode(newobj, _current_indent_level)
            except GeneratorExit:
                raise
            except BaseException as exc:
                exc.add_note(f'when serializing {type(o).__name__} object')
                raise
            if markers is not None:
                del markers[markerid]
    return _iterencode