import calendar
import codecs
import collections
import mmap
import os
import re
import time
import zlib
from ._util import py3

try:
    from UserDict import UserDict  # Python 2.x
except ImportError:
    UserDict = collections.UserDict  # Python 3.x


if py3:  # Python 3.x

    def make_bytes(s):
        return s.encode("us-ascii")


else:  # Python 2.x

    def make_bytes(s):  # pragma: no cover
        return s  # pragma: no cover


# see 7.9.2.2 Text String Type on page 86 and D.3 PDFDocEncoding Character Set
# on page 656
def encode_text(s):
    return codecs.BOM_UTF16_BE + s.encode("utf_16_be")


PDFDocEncoding = {
    0x16: u"\u0017",
    0x18: u"\u02D8",
    0x19: u"\u02C7",
    0x1A: u"\u02C6",
    0x1B: u"\u02D9",
    0x1C: u"\u02DD",
    0x1D: u"\u02DB",
    0x1E: u"\u02DA",
    0x1F: u"\u02DC",
    0x80: u"\u2022",
    0x81: u"\u2020",
    0x82: u"\u2021",
    0x83: u"\u2026",
    0x84: u"\u2014",
    0x85: u"\u2013",
    0x86: u"\u0192",
    0x87: u"\u2044",
    0x88: u"\u2039",
    0x89: u"\u203A",
    0x8A: u"\u2212",
    0x8B: u"\u2030",
    0x8C: u"\u201E",
    0x8D: u"\u201C",
    0x8E: u"\u201D",
    0x8F: u"\u2018",
    0x90: u"\u2019",
    0x91: u"\u201A",
    0x92: u"\u2122",
    0x93: u"\uFB01",
    0x94: u"\uFB02",
    0x95: u"\u0141",
    0x96: u"\u0152",
    0x97: u"\u0160",
    0x98: u"\u0178",
    0x99: u"\u017D",
    0x9A: u"\u0131",
    0x9B: u"\u0142",
    0x9C: u"\u0153",
    0x9D: u"\u0161",
    0x9E: u"\u017E",
    0xA0: u"\u20AC",
}


def decode_text(b):
    if b[: len(codecs.BOM_UTF16_BE)] == codecs.BOM_UTF16_BE:
        return b[len(codecs.BOM_UTF16_BE) :].decode("utf_16_be")
    elif py3:  # Python 3.x
        return "".join(PDFDocEncoding.get(byte, chr(byte)) for byte in b)
    else:  # Python 2.x
        return u"".join(PDFDocEncoding.get(ord(byte), byte) for byte in b)


class PdfFormatError(RuntimeError):
    """An error that probably indicates a syntactic or semantic error in the
    PDF file structure"""

    pass


def check_format_condition(condition, error_message):
    if not condition:
        raise PdfFormatError(error_message)


class IndirectReference(
    collections.namedtuple("IndirectReferenceTuple", ["object_id", "generation"])
):
    def __str__(self):
        return "%s %s R" % self

    def __bytes__(self):
        return self.__str__().encode("us-ascii")

    def __eq__(self, other):
        return (
            other.__class__ is self.__class__
            and other.object_id == self.object_id
            and other.generation == self.generation
        )

    def __ne__(self, other):
        return not (self == other)

    def __hash__(self):
        return hash((self.object_id, self.generation))


class IndirectObjectDef(IndirectReference):
    def __str__(self):
        return "%s %s obj" % self


class XrefTable:
    def __init__(self):
        self.existing_entries = {}  # object ID => (offset, generation)
        self.new_entries = {}  # object ID => (offset, generation)
        self.deleted_entries = {0: 65536}  # object ID => generation
        self.reading_finished = False

    def __setitem__(self, key, value):
        if self.reading_finished:
            self.new_entries[key] = value
        else:
            self.existing_entries[key] = value
        if key in self.deleted_entries:
            del self.deleted_entries[key]

    def __getitem__(self, key):
        try:
            return self.new_entries[key]
        except KeyError:
            return self.existing_entries[key]

    def __delitem__(self, key):
        if key in self.new_entries:
            generation = self.new_entries[key][1] + 1
            del self.new_entries[key]
            self.deleted_entries[key] = generation
        elif key in self.existing_entries:
            generation = self.existing_entries[key][1] + 1
            self.deleted_entries[key] = generation
        elif key in self.deleted_entries:
            generation = self.deleted_entries[key]
        else:
            raise IndexError(
                "object ID " + str(key) + " cannot be deleted because it doesn't exist"
            )

    def __contains__(self, key):
        return key in self.existing_entries or key in self.new_entries

    def __len__(self):
        return len(
            set(self.existing_entries.keys())
            | set(self.new_entries.keys())
            | set(self.deleted_entries.keys())
        )

    def keys(self):
        return (
            set(self.existing_entries.keys()) - set(self.deleted_entries.keys())
        ) | set(self.new_entries.keys())

    def write(self, f):
        keys = sorted(set(self.new_entries.keys()) | set(self.deleted_entries.keys()))
        deleted_keys = sorted(set(self.deleted_entries.keys()))
        startxref = f.tell()
        f.write(b"xref\n")
        while keys:
            # find a contiguous sequence of object IDs
            prev = None
            for index, key in enumerate(keys):
                if prev is None or prev + 1 == key:
                    prev = key
                else:
                    contiguous_keys = keys[:index]
                    keys = keys[index:]
                    break
            else:
                contiguous_keys = keys
                keys = None
            f.write(make_bytes("%d %d\n" % (contiguous_keys[0], len(contiguous_keys))))
            for object_id in contiguous_keys:
                if object_id in self.new_entries:
                    f.write(make_bytes("%010d %05d n \n" % self.new_entries[object_id]))
                else:
                    this_deleted_object_id = deleted_keys.pop(0)
                    check_format_condition(
                        object_id == this_deleted_object_id,
                        "expected the next deleted object ID to be %s, instead found %s"
                        % (object_id, this_deleted_object_id),
                    )
                    try:
                        next_in_linked_list = deleted_keys[0]
                    except IndexError:
                        next_in_linked_list = 0
                    f.write(
                        make_bytes(
                            "%010d %05d f \n"
                            % (next_in_linked_list, self.deleted_entries[object_id])
                        )
                    )
        return startxref


class PdfName:
    def __init__(self, name):
        if isinstance(name, PdfName):
            self.name = name.name
        elif isinstance(name, bytes):
            self.name = name
        else:
            self.name = name.encode("us-ascii")

    def name_as_str(self):
        return self.name.decode("us-ascii")

    def __eq__(self, other):
        return (
            isinstance(other, PdfName) and other.name == self.name
        ) or other == self.name

    def __hash__(self):
        return hash(self.name)

    def __repr__(self):
        return "PdfName(%s)" % repr(self.name)

    @classmethod
    def from_pdf_stream(cls, data):
        return cls(PdfParser.interpret_name(data))

    allowed_chars = set(range(33, 127)) - set(ord(c) for c in "#%/()<>[]{}")

    def __bytes__(self):
        result = bytearray(b"/")
        for b in self.name:
            if py3:  # Python 3.x
                if b in self.allowed_chars:
                    result.append(b)
                else:
                    result.extend(make_bytes("#%02X" % b))
            else:  # Python 2.x
                if ord(b) in self.allowed_chars:
                    result.append(b)
                else:
                    result.extend(b"#%02X" % ord(b))
        return bytes(result)

    __str__ = __bytes__


class PdfArray(list):
    def __bytes__(self):
        return b"[ " + b" ".join(pdf_repr(x) for x in self) + b" ]"

    __str__ = __bytes__


class PdfDict(UserDict):
    def __setattr__(self, key, value):
        if key == "data":
            if hasattr(UserDict, "__setattr__"):
                UserDict.__setattr__(self, key, value)
            else:
                self.__dict__[key] = value
        else:
            self[key.encode("us-ascii")] = value

    def __getattr__(self, key):
        try:
            value = self[key.encode("us-ascii")]
        except KeyError:
            raise AttributeError(key)
        if isinstance(value, bytes):
            value = decode_text(value)
        if key.endswith("Date"):
            if value.startswith("D:"):
                value = value[2:]

            relationship = "Z"
            if len(value) > 17:
                relationship = value[14]
                offset = int(value[15:17]) * 60
                if len(value) > 20:
                    offset += int(value[18:20])

            format = "%Y%m%d%H%M%S"[: len(value) - 2]
            value = time.strptime(value[: len(format) + 2], format)
            if relationship in ["+", "-"]:
                offset *= 60
                if relationship == "+":
                    offset *= -1
                value = time.gmtime(calendar.timegm(value) + offset)
        return value

    def __bytes__(self):
        out = bytearray(b"<<")
        for key, value in self.items():
            if value is None:
                continue
            value = pdf_repr(value)
            out.extend(b"\n")
            out.extend(bytes(PdfName(key)))
            out.extend(b" ")
            out.extend(value)
        out.extend(b"\n>>")
        return bytes(out)

    if not py3:
        __str__ = __bytes__


class PdfBinary:
    def __init__(self, data):
        self.data = data

    if py3:  # Python 3.x

        def __bytes__(self):
            return make_bytes("<%s>" % "".join("%02X" % b for b in self.data))

    else:  # Python 2.x

        def __str__(self):
            return "<%s>" % "".join("%02X" % ord(b) for b in self.data)


class PdfStream: