""" Adobe character mapping (CMap) support.

CMaps provide the mapping between character codes and Unicode
code-points to character ids (CIDs).

More information is available on the Adobe website:

  http://opensource.adobe.com/wiki/display/cmap/CMap+Resources

"""

import gzip
import logging
import os
import os.path
import pickle as pickle
import struct
import sys
from typing import (
    Any,
    BinaryIO,
    Dict,
    Iterable,
    Iterator,
    List,
    MutableMapping,
    Optional,
    TextIO,
    Tuple,
    Union,
    cast,
    Set,
)

from .encodingdb import name2unicode
from .psparser import KWD
from .psparser import PSEOF
from .psparser import PSKeyword
from .psparser import PSLiteral
from .psparser import PSStackParser
from .psparser import PSSyntaxError
from .psparser import literal_name
from .utils import choplist
from .utils import nunpack

log = logging.getLogger(__name__)


class CMapError(Exception):
    pass


class CMapBase:

    debug = 0

    def __init__(self, **kwargs: object) -> None:
        self.attrs: MutableMapping[str, object] = kwargs.copy()

    def is_vertical(self) -> bool:
        return self.attrs.get("WMode", 0) != 0

    def set_attr(self, k: str, v: object) -> None:
        self.attrs[k] = v

    def add_code2cid(self, code: str, cid: int) -> None:
        pass

    def add_cid2unichr(self, cid: int, code: Union[PSLiteral, bytes, int]) -> None:
        pass

    def use_cmap(self, cmap: "CMapBase") -> None:
        pass

    def decode(self, code: bytes) -> Iterable[int]:
        raise NotImplementedError


class CMap(CMapBase):
    def __init__(self, **kwargs: Union[str, int]) -> None:
        CMapBase.__init__(self, **kwargs)
        self.code2cid: Dict[int, object] = {}

    def __repr__(self) -> str:
        return "<CMap: %s>" % self.attrs.get("CMapName")

    def use_cmap(self, cmap: CMapBase) -> None:
        assert isinstance(cmap, CMap), str(type(cmap))

        def copy(dst: Dict[int, object], src: Dict[int, object]) -> None:
            for (k, v) in src.items():
                if isinstance(v, dict):
                    d: Dict[int, object] = {}
                    dst[k] = d
                    copy(d, v)
                else:
                    dst[k] = v

        copy(self.code2cid, cmap.code2cid)

    def decode(self, code: bytes) -> Iterator[int]:
        log.debug("decode: %r, %r", self, code)
        d = self.code2cid
        for i in iter(code):
            if i in d:
                x = d[i]
                if isinstance(x, int):
                    yield x
                    d = self.code2cid
                else:
                    d = cast(Dict[int, object], x)
            else:
                d = self.code2cid

    def dump(
        self,
        out: TextIO = sys.stdout,
        code2cid: Optional[Dict[int, object]] = None,
        code: Tuple[int, ...] = (),
    ) -> None:
        if code2cid is None:
            code2cid = self.code2cid
            code = ()
        for (k, v) in sorted(code2cid.items()):
            c = code + (k,)
            if isinstance(v, int):
                out.write("code %r = cid %d\n" % (c, v))
            else:
                self.dump(out=out, code2cid=cast(Dict[int, object], v), code=c)


class IdentityCMap(CMapBase):
    def decode(self, code: bytes) -> Tuple[int, ...]:
        n = len(code) // 2
        if n:
            return struct.unpack(">%dH" % n, code)
        else:
            return ()


class IdentityCMapByte(IdentityCMap):
    def decode(self, code: bytes) -> Tuple[int, ...]:
        n = len(code)
        if n:
            return struct.unpack(">%dB" % n, code)
        else:
            return ()


class UnicodeMap(CMapBase):
    def __init__(self, **kwargs: Union[str, int]) -> None:
        CMapBase.__init__(self, **kwargs)
        self.cid2unichr: Dict[int, str] = {}

    def __repr__(self) -> str:
        return "<UnicodeMap: %s>" % self.attrs.get("CMapName")

    def get_unichr(self, cid: int) -> str:
        log.debug("get_unichr: %r, %r", self, cid)
        return self.cid2unichr[cid]

    def dump(self, out: TextIO = sys.stdout) -> None:
        for (k, v) in sorted(self.cid2unichr.items()):
            out.write("cid %d = unicode %r\n" % (k, v))


class IdentityUnicodeMap(UnicodeMap):
    def get_unichr(self, cid: int) -> str:
        """Interpret character id as unicode codepoint"""
        log.debug("get_unichr: %r, %r", self, cid)
        return chr(cid)


class FileCMap(CMap):
    def add_code2cid(self, code: str, cid: int) -> None:
        assert isinstance(code, str) and isinstance(cid, int), str(
            (type(code), type(cid))
        )
        d = self.code2cid
        for c in code[:-1]:
            ci = ord(c)
            if ci in d:
                d = cast(Dict[int, object], d[ci])
            else:
                t: Dict[int, object] = {}
                d[ci] = t
                d = t
        ci = ord(code[-1])
        d[ci] = cid


class FileUnicodeMap(UnicodeMap):
    def add_cid2unichr(self, cid: int, code: Union[PSLiteral, bytes, int]) -> None:
        assert isinstance(cid, int), str(type(cid))
        if isinstance(code, PSLiteral):
            # Interpret as an Adobe glyph name.
            assert isinstance(code.name, str)
            self.cid2unichr[cid] = name2unicode(code.name)
        elif isinstance(code, bytes):
            # Interpret as UTF-16BE.
            self.cid2unichr[cid] = code.decode("UTF-16BE", "ignore")
        elif isinstance(code, int):
            self.cid2unichr[cid] = chr(code)
        else:
            raise TypeError(code)


class PyCMap(CMap):
    def __init__(self, name: str, module: Any) -> None:
        super().__init__(CMapName=name)
        self.code2cid = module.CODE2CID
        if module.IS_VERTICAL:
            self.attrs["WMode"] = 1


class PyUnicodeMap(UnicodeMap):
    def __init__(self, name: str, module: Any, vertical: bool) -> None:
        super().__init__(CMapName=name)
        if vertical:
            self.cid2unichr = module.CID2UNICHR_V
            self.attrs["WMode"] = 1
        else:
            self.cid2unichr = module.CID2UNICHR_H


class CMapDB:

    _cmap_cache: Dict[str, PyCMap] = {}
    _umap_cache: Dict[str, List[PyUnicodeMap]] = {}

    class CMapNotFound(CMapError):
        pass

    @classmethod
    def _load_data(cls, name: str) -> Any:
        name = name.replace("\0", "")
        filename = "%s.pickle.gz" % name
        log.debug("loading: %r", name)
        cmap_paths = (
            os.environ.get("CMAP_PATH", "/usr/share/pdfminer/"),
            os.path.join(os.path.dirname(__file__), "cmap"),
        )
        for directory in cmap_paths:
            path = os.path.join(directory, filename)
            if os.path.exists(path):
                gzfile = gzip.open(path)
                try:
                    return type(str(name), (), pickle.loads(gzfile.read()))
                finally:
                    gzfile.close()
        else:
            raise CMapDB.CMapNotFound(name)

    @classmethod
    def get_cmap(cls, name: str) -> CMapBase:
        if name == "Identity-H":
            return IdentityCMap(WMode=0)
        elif name == "Identity-V":
            return IdentityCMap(WMode=1)
        elif name == "OneByteIdentityH":
            return IdentityCMapByte(WMode=0)
        elif name == "OneByteIdentityV":
            return IdentityCMapByte(WMode=1)
        try:
            return cls._cmap_cache[name]
        except KeyError:
            pass
        data = cls._load_data(name)
        cls._cmap_cache[name] = cmap = PyCMap(name, data)
        return cmap

    @classmethod
    def get_unicode_map(cls, name: str, vertical: bool = False) -> UnicodeMap:
        try:
            return cls._umap_cache[name][vertical]
        except KeyError:
            pass
        data = cls._load_data("to-unicode-%s" % name)
        cls._umap_cache[name] = [PyUnicodeMap(name, data, v) for v in (False, True)]
        return cls._umap_cache[name][vertical]


class CMapParser(PSStackParser[PSKeyword]):
    def __init__(self, cmap: CMapBase, fp: BinaryIO) -> None:
        PSStackParser.__init__(self, fp)
        self.cmap = cmap
        # some ToUnicode maps don't have "begincmap" keyword.
        self._in_cmap = True
        self._warnings: Set[str] = set()
        return

    def run(self) -> None:
        try:
            self.nextobject()
        except PSEOF:
            pass
        return

    KEYWORD_BEGINCMAP = KWD(b"begincmap")
    KEYWORD_ENDCMAP = KWD(b"endcmap")
    KEYWORD_USECMAP = KWD(b"usecmap")
    KEYWORD_DEF = KWD(b"def")
    KEYWORD_BEGINCODESPACERANGE = KWD(b"begincodespacerange")
    KEYWORD_ENDCODESPACERANGE = KWD(b"endcodespacerange")
    KEYWORD_BEGINCIDRANGE = KWD(b"begincidrange")
    KEYWORD_ENDCIDRANGE = KWD(b"endcidrange")
    KEYWORD_BEGINCIDCHAR = KWD(b"begincidchar")
    KEYWORD_ENDCIDCHAR = KWD(b"endcidchar")
    KEYWORD_BEGINBFRANGE = KWD(b"beginbfrange")
    KEYWORD_ENDBFRANGE = KWD(b"endbfrange")
    KEYWORD_BEGINBFCHAR = KWD(b"beginbfchar")
    KEYWORD_ENDBFCHAR = KWD(b"endbfchar")
    KEYWORD_BEGINNOTDEFRANGE = KWD(b"beginnotdefrange")
    KEYWORD_ENDNOTDEFRANGE = KWD(b"endnotdefrange")

    def do_keyword(self, pos: int, token: PSKeyword) -> None:
        """ToUnicode CMaps

        See Section 5.9.2 - ToUnicode CMaps of the PDF Reference.
        """
        if token is self.KEYWORD_BEGINCMAP:
            self._in_cmap = True
            self.popall()
            return

        elif token is self.KEYWORD_ENDCMAP:
            self._in_cmap = False
            return

        if not self._in_cmap:
            return

        if token is self.KEYWORD_DEF:
            try:
                ((_, k), (_, v)) = self.pop(2)
                self.cmap.set_attr(literal_name(k), v)
            except PSSyntaxError:
                pass
            return

        if token is self.KEYWORD_USECMAP:
            try:
                ((_, cmapname),) = self.pop(1)
                self.cmap.use_cmap(CMapDB.get_cmap(literal_name(cmapname)))
            except PSSyntaxError:
                pass
            except CMapDB.CMapNotFound:
                pass
            return

        if token is self.KEYWORD_BEGINCODESPACERANGE:
            self.popall()
            return
        if token is self.KEYWORD_ENDCODESPACERANGE:
            self.popall()
            return

        if token is self.KEYWORD_BEGINCIDRANGE:
            self.popall()
            return

        if token is self.KEYWORD_ENDCIDRANGE:
            objs = [obj for (__, obj) in self.popall()]
            for (start_byte, end_byte, cid) in choplist(3, objs):
                if not isinstance(start_byte, bytes):
                    self._warn_once("The start object of begincidrange is not a byte.")
                    continue
                if not isinstance(end_byte, bytes):
                    self._warn_once("The end object of begincidrange is not a byte.")
                    continue
                if not isinstance(cid, int):
                    self._warn_once("The cid object of begincidrange is not a byte.")
                    continue
                if len(start_byte) != len(end_byte):
                    self._warn_once(
                        "The start and end byte of begincidrange have "
                        "different lengths."
                    )
                    continue
                start_prefix = start_byte[:-4]
                end_prefix = end_byte[:-4]
                if start_prefix != end_prefix:
                    self._warn_once(
                        "The prefix of the start and end byte of "
                        "begincidrange are not the same."
                    )
                    continue
                svar = start_byte[-4:]
                evar = end_byte[-4:]
                start = nunpack(svar)
                end = nunpack(evar)
                vlen = len(svar)
                for i in range(end - start + 1):
                    x = start_prefix + struct.pack(">L", start + i)[-vlen:]
                    self.cmap.add_cid2unichr(cid + i, x)
            return

        if token is self.KEYWORD_BEGINCIDCHAR:
            self.popall()
            return

        if token is self.KEYWORD_ENDCIDCHAR:
            objs = [obj for (__, obj) in self.popall()]
            for (cid, code) in choplist(2, objs):
                if isinstance(code, bytes) and isinstance(cid, int):
                    self.cmap.add_cid2unichr(cid, code)
            return

        if token is self.KEYWORD_BEGINBFRANGE:
            self.popall()
            return

        if token is self.KEYWORD_ENDBFRANGE:
            objs = [obj for (__, obj) in self.popall()]
            for (start_byte, end_byte, code) in choplist(3, objs):
                if not isinstance(start_byte, bytes):
                    self._warn_once("The start object is not a byte.")
                    continue
                if not isinstance(end_byte, bytes):
                    self._warn_once("The end object is not a byte.")
                    continue
                if len(start_byte) != len(end_byte):
                    self._warn_once("The start and end byte have different lengths.")
                    continue
                start = nunpack(start_byte)
                end = nunpack(end_byte)
                if isinstance(code, list):
                    if len(code) != end - start + 1:
                        self._warn_once(
                            "The difference between the start and end "
                            "offsets does not match the code length."
                        )
                    for cid, unicode_value in zip(range(start, end + 1), code):
                        self.cmap.add_cid2unichr(cid, unicode_value)
                else:
                    assert isinstance(code, bytes)
                    var = code[-4:]
                    base = nunpack(var)
                    prefix = code[:-4]
                    vlen = len(var)
                    for i in range(end - start + 1):
                        x = prefix + struct.pack(">L", base + i)[-vlen:]
                        self.cmap.add_cid2unichr(start + i, x)
            return

        if token is self.KEYWORD_BEGINBFCHAR:
            self.popall()
            return

        if token is self.KEYWORD_ENDBFCHAR:
            objs = [obj for (__, obj) in self.popall()]
            for (cid, code) in choplist(2, objs):
                if isinstance(cid, bytes) and isinstance(code, bytes):
                    self.cmap.add_cid2unichr(nunpack(cid), code)
            return

        if token is self.KEYWORD_BEGINNOTDEFRANGE:
            self.popall()
            return

        if token is self.KEYWORD_ENDNOTDEFRANGE:
            self.popall()
            return

        self.push((pos, token))

    def _warn_once(self, msg: str) -> None:
        """Warn once for each unique message"""
        if msg not in self._warnings:
            self._warnings.add(msg)
            base_msg = (
                "Ignoring (part of) ToUnicode map because the PDF data "
                "does not conform to the format. This could result in "
                "(cid) values in the output. "
            )
            log.warning(base_msg + msg)


def main(argv: List[str]) -> None:
    from warnings import warn

    warn(
        "The function main() from cmapdb.py will be removed in 2023. It was probably "
        "introduced for testing purposes a long time ago, and no longer relevant. "
        "Feel free to create a GitHub issue if you disagree.",
        DeprecationWarning,
    )

    args = argv[1:]
    for fname in args:
        fp = open(fname, "rb")
        cmap = FileUnicodeMap()
        CMapParser(cmap, fp).run()
        fp.close()
        cmap.dump()
    return


if __name__ == "__main__":
    main(sys.argv)
