# Copyright 2015 Facebook, Inc.

# All rights reserved.

#

# Redistribution and use in source and binary forms, with or without

# modification, are permitted provided that the following conditions are met:

#

#  * Redistributions of source code must retain the above copyright notice,

#    this list of conditions and the following disclaimer.

#

#  * Redistributions in binary form must reproduce the above copyright notice,

#    this list of conditions and the following disclaimer in the documentation

#    and/or other materials provided with the distribution.

#

#  * Neither the name Facebook nor the names of its contributors may be used to

#    endorse or promote products derived from this software without specific

#    prior written permission.

#

# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE

# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE

# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR

# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER

# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,

# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

from __future__ import absolute_import

from __future__ import division

from __future__ import print_function

# no unicode literals

import binascii

import collections

import ctypes

import struct

import sys

from . import (

    compat,

)

BSER_ARRAY = b'\x00'

BSER_OBJECT = b'\x01'

BSER_BYTESTRING = b'\x02'

BSER_INT8 = b'\x03'

BSER_INT16 = b'\x04'

BSER_INT32 = b'\x05'

BSER_INT64 = b'\x06'

BSER_REAL = b'\x07'

BSER_TRUE = b'\x08'

BSER_FALSE = b'\x09'

BSER_NULL = b'\x0a'

BSER_TEMPLATE = b'\x0b'

BSER_SKIP = b'\x0c'

BSER_UTF8STRING = b'\x0d'

if compat.PYTHON3:

    STRING_TYPES = (str, bytes)

    unicode = str

    def tobytes(i):

        return str(i).encode('ascii')

    long = int

else:

    STRING_TYPES = (unicode, str)

    tobytes = bytes

# Leave room for the serialization header, which includes

# our overall length.  To make things simpler, we'll use an

# int32 for the header

EMPTY_HEADER = b"\x00\x01\x05\x00\x00\x00\x00"

EMPTY_HEADER_V2 = b"\x00\x02\x00\x00\x00\x00\x05\x00\x00\x00\x00"

def _int_size(x):

    """Return the smallest size int that can store the value"""

    if -0x80 <= x <= 0x7F:

        return 1

    elif -0x8000 <= x <= 0x7FFF:

        return 2

    elif -0x80000000 <= x <= 0x7FFFFFFF:

        return 4

    elif long(-0x8000000000000000) <= x <= long(0x7FFFFFFFFFFFFFFF):

        return 8

    else:

        raise RuntimeError('Cannot represent value: ' + str(x))

def _buf_pos(buf, pos):

    ret = buf[pos]

    # In Python 2, buf is a str array so buf[pos] is a string. In Python 3, buf

    # is a bytes array and buf[pos] is an integer.

    if compat.PYTHON3:

        ret = bytes((ret,))

    return ret

class _bser_buffer(object):

    def __init__(self, version):

        self.bser_version = version

        self.buf = ctypes.create_string_buffer(8192)

        if self.bser_version == 1:

            struct.pack_into(tobytes(len(EMPTY_HEADER)) + b's', self.buf, 0,

                             EMPTY_HEADER)

            self.wpos = len(EMPTY_HEADER)

        else:

            assert self.bser_version == 2

            struct.pack_into(tobytes(len(EMPTY_HEADER_V2)) + b's', self.buf, 0,

                             EMPTY_HEADER_V2)

            self.wpos = len(EMPTY_HEADER_V2)

    def ensure_size(self, size):

        while ctypes.sizeof(self.buf) - self.wpos < size:

            ctypes.resize(self.buf, ctypes.sizeof(self.buf) * 2)

    def append_long(self, val):

        size = _int_size(val)

        to_write = size + 1

        self.ensure_size(to_write)

        if size == 1:

            struct.pack_into(b'=cb', self.buf, self.wpos, BSER_INT8, val)

        elif size == 2:

            struct.pack_into(b'=ch', self.buf, self.wpos, BSER_INT16, val)

        elif size == 4:

            struct.pack_into(b'=ci', self.buf, self.wpos, BSER_INT32, val)

        elif size == 8:

            struct.pack_into(b'=cq', self.buf, self.wpos, BSER_INT64, val)

        else:

            raise RuntimeError('Cannot represent this long value')

        self.wpos += to_write

    def append_string(self, s):

        if isinstance(s, unicode):

            s = s.encode('utf-8')

        s_len = len(s)

        size = _int_size(s_len)

        to_write = 2 + size + s_len

        self.ensure_size(to_write)

        if size == 1:

            struct.pack_into(b'=ccb' + tobytes(s_len) + b's', self.buf,

                self.wpos, BSER_BYTESTRING, BSER_INT8, s_len, s)

        elif size == 2:

            struct.pack_into(b'=cch' + tobytes(s_len) + b's', self.buf,

                self.wpos, BSER_BYTESTRING, BSER_INT16, s_len, s)

        elif size == 4:

            struct.pack_into(b'=cci' + tobytes(s_len) + b's', self.buf,

                self.wpos, BSER_BYTESTRING, BSER_INT32, s_len, s)

        elif size == 8:

            struct.pack_into(b'=ccq' + tobytes(s_len) + b's', self.buf,

                self.wpos, BSER_BYTESTRING, BSER_INT64, s_len, s)

        else:

            raise RuntimeError('Cannot represent this string value')

        self.wpos += to_write

    def append_recursive(self, val):

        if isinstance(val, bool):

            needed = 1

            self.ensure_size(needed)

            if val:

                to_encode = BSER_TRUE

            else:

                to_encode = BSER_FALSE

            struct.pack_into(b'=c', self.buf, self.wpos, to_encode)

            self.wpos += needed

        elif val is None:

            needed = 1

            self.ensure_size(needed)

            struct.pack_into(b'=c', self.buf, self.wpos, BSER_NULL)

            self.wpos += needed

        elif isinstance(val, (int, long)):

            self.append_long(val)

        elif isinstance(val, STRING_TYPES):

            self.append_string(val)

        elif isinstance(val, float):

            needed = 9

            self.ensure_size(needed)

            struct.pack_into(b'=cd', self.buf, self.wpos, BSER_REAL, val)

            self.wpos += needed

        elif isinstance(val, collections.Mapping) and \

            isinstance(val, collections.Sized):

            val_len = len(val)

            size = _int_size(val_len)

            needed = 2 + size

            self.ensure_size(needed)

            if size == 1:

                struct.pack_into(b'=ccb', self.buf, self.wpos, BSER_OBJECT,

                    BSER_INT8, val_len)

            elif size == 2:

                struct.pack_into(b'=cch', self.buf, self.wpos, BSER_OBJECT,

                    BSER_INT16, val_len)

            elif size == 4:

                struct.pack_into(b'=cci', self.buf, self.wpos, BSER_OBJECT,

                    BSER_INT32, val_len)

            elif size == 8:

                struct.pack_into(b'=ccq', self.buf, self.wpos, BSER_OBJECT,

                    BSER_INT64, val_len)

            else:

                raise RuntimeError('Cannot represent this mapping value')

            self.wpos += needed

            if compat.PYTHON3:

                iteritems = val.items()

            else:

                iteritems = val.iteritems()

            for k, v in iteritems:

                self.append_string(k)

                self.append_recursive(v)

        elif isinstance(val, collections.Iterable) and \

            isinstance(val, collections.Sized):

            val_len = len(val)

            size = _int_size(val_len)

            needed = 2 + size

            self.ensure_size(needed)

            if size == 1:

                struct.pack_into(b'=ccb', self.buf, self.wpos, BSER_ARRAY,

                    BSER_INT8, val_len)

            elif size == 2:

                struct.pack_into(b'=cch', self.buf, self.wpos, BSER_ARRAY,

                    BSER_INT16, val_len)

            elif size == 4:

                struct.pack_into(b'=cci', self.buf, self.wpos, BSER_ARRAY,

                    BSER_INT32, val_len)

            elif size == 8:

                struct.pack_into(b'=ccq', self.buf, self.wpos, BSER_ARRAY,

                    BSER_INT64, val_len)

            else:

                raise RuntimeError('Cannot represent this sequence value')

            self.wpos += needed

            for v in val:

                self.append_recursive(v)

        else:

            raise RuntimeError('Cannot represent unknown value type')

def dumps(obj, version=1, capabilities=0):

    bser_buf = _bser_buffer(version=version)

    bser_buf.append_recursive(obj)

    # Now fill in the overall length

    if version == 1:

        obj_len = bser_buf.wpos - len(EMPTY_HEADER)

        struct.pack_into(b'=i', bser_buf.buf, 3, obj_len)

    else:

        obj_len = bser_buf.wpos - len(EMPTY_HEADER_V2)

        struct.pack_into(b'=i', bser_buf.buf, 2, capabilities)

        struct.pack_into(b'=i', bser_buf.buf, 7, obj_len)

    return bser_buf.buf.raw[:bser_buf.wpos]

# This is a quack-alike with the bserObjectType in bser.c

# It provides by getattr accessors and getitem for both index

# and name.

class _BunserDict(object):

    __slots__ = ('_keys', '_values')

    def __init__(self, keys, values):

        self._keys = keys

        self._values = values

    def __getattr__(self, name):

        return self.__getitem__(name)

    def __getitem__(self, key):

        if isinstance(key, (int, long)):

            return self._values[key]

        elif key.startswith('st_'):

            # hack^Wfeature to allow mercurial to use "st_size" to

            # reference "size"

            key = key[3:]

        try:

            return self._values[self._keys.index(key)]

            raise KeyError('_BunserDict has no key %s' % key)

    def __len__(self):

        return len(self._keys)

class Bunser(object):

    def __init__(self, mutable=True, value_encoding=None, value_errors=None):

        self.mutable = mutable

        self.value_encoding = value_encoding

        if value_encoding is None:

            self.value_errors = None

        elif value_errors is None:

            self.value_errors = 'strict'

        else:

            self.value_errors = value_errors

    @staticmethod

    def unser_int(buf, pos):

        try:

            int_type = _buf_pos(buf, pos)

        except IndexError:

            raise ValueError('Invalid bser int encoding, pos out of range')

        if int_type == BSER_INT8:

            needed = 2

            fmt = b'=b'

        elif int_type == BSER_INT16:

            needed = 3

            fmt = b'=h'

        elif int_type == BSER_INT32:

            needed = 5

            fmt = b'=i'

        elif int_type == BSER_INT64:

            needed = 9

            fmt = b'=q'

        else:

            raise ValueError('Invalid bser int encoding 0x%s' %

                             binascii.hexlify(int_type).decode('ascii'))

        int_val = struct.unpack_from(fmt, buf, pos + 1)[0]

        return (int_val, pos + needed)

    def unser_utf8_string(self, buf, pos):

        str_len, pos = self.unser_int(buf, pos + 1)

        str_val = struct.unpack_from(tobytes(str_len) + b's', buf, pos)[0]

        return (str_val.decode('utf-8'), pos + str_len)

    def unser_bytestring(self, buf, pos):

        str_len, pos = self.unser_int(buf, pos + 1)

        str_val = struct.unpack_from(tobytes(str_len) + b's', buf, pos)[0]

        if self.value_encoding is not None:

            str_val = str_val.decode(self.value_encoding, self.value_errors)

            # str_len stays the same because that's the length in bytes

        return (str_val, pos + str_len)

    def unser_array(self, buf, pos):

        arr_len, pos = self.unser_int(buf, pos + 1)

        arr = []

        for i in range(arr_len):

            arr_item, pos = self.loads_recursive(buf, pos)

            arr.append(arr_item)

        if not self.mutable:

          arr = tuple(arr)

        return arr, pos

    def unser_object(self, buf, pos):

        obj_len, pos = self.unser_int(buf, pos + 1)

        if self.mutable:

            obj = {}

        else:

            keys = []

            vals = []

        for i in range(obj_len):

            key, pos = self.unser_utf8_string(buf, pos)

            val, pos = self.loads_recursive(buf, pos)

            if self.mutable:

                obj[key] = val

            else:

                keys.append(key)

                vals.append(val)

        if not self.mutable:

            obj = _BunserDict(keys, vals)

        return obj, pos

    def unser_template(self, buf, pos):

        val_type = _buf_pos(buf, pos + 1)

        if val_type != BSER_ARRAY:

            raise RuntimeError('Expect ARRAY to follow TEMPLATE')

        # force UTF-8 on keys

        keys_bunser = Bunser(mutable=self.mutable, value_encoding='utf-8')

        keys, pos = keys_bunser.unser_array(buf, pos + 1)

        nitems, pos = self.unser_int(buf, pos)

        arr = []

        for i in range(nitems):

            if self.mutable:

                obj = {}