import os

import winreg  # pytype: disable=import-error

from typing import (

    List,

    TYPE_CHECKING,

    Tuple,

)

from . import (

    encoding,

    pycompat,

    util,

    win32,

)

if TYPE_CHECKING:

    from . import ui as uimod

# MS-DOS 'more' is the only pager available by default on Windows.

fallbackpager = b'more'

def systemrcpath() -> List[bytes]:

    '''return default os-specific hgrc search path'''

    rcpath = []

    filename = win32.executablepath()

    # Use mercurial.ini found in directory with hg.exe

    progrc = os.path.join(os.path.dirname(filename), b'mercurial.ini')

    rcpath.append(progrc)

    def _processdir(progrcd: bytes) -> None:

        if os.path.isdir(progrcd):

            for f, kind in sorted(util.listdir(progrcd)):

                if f.endswith(b'.rc'):

                    rcpath.append(os.path.join(progrcd, f))

    # Use hgrc.d found in directory with hg.exe

    _processdir(os.path.join(os.path.dirname(filename), b'hgrc.d'))

    # treat a PROGRAMDATA directory as equivalent to /etc/mercurial

    programdata = encoding.environ.get(b'PROGRAMDATA')

    if programdata:

        programdata = os.path.join(programdata, b'Mercurial')

        _processdir(os.path.join(programdata, b'hgrc.d'))

        ini = os.path.join(programdata, b'mercurial.ini')

        if os.path.isfile(ini):

            rcpath.append(ini)

        ini = os.path.join(programdata, b'hgrc')

        if os.path.isfile(ini):

            rcpath.append(ini)

    # next look for a system rcpath in the registry

    value = util.lookupreg(

        # pytype: disable=module-attr

        b'SOFTWARE\\Mercurial',

        None,

        winreg.HKEY_LOCAL_MACHINE

        # pytype: enable=module-attr

    )

    if value and isinstance(value, bytes):

        value = util.localpath(value)

        for p in value.split(pycompat.ospathsep):

            if p.lower().endswith(b'mercurial.ini'):

                rcpath.append(p)

            else:

                _processdir(p)

    return rcpath

def userrcpath() -> List[bytes]:

    '''return os-specific hgrc search path to the user dir'''

    home = _legacy_expanduser(b'~')

    path = [os.path.join(home, b'mercurial.ini'), os.path.join(home, b'.hgrc')]

    userprofile = encoding.environ.get(b'USERPROFILE')

    if userprofile and userprofile != home:

        path.append(os.path.join(userprofile, b'mercurial.ini'))

        path.append(os.path.join(userprofile, b'.hgrc'))

    return path

def _legacy_expanduser(path: bytes) -> bytes:

    """Expand ~ and ~user constructs in the pre 3.8 style"""

    # Python 3.8+ changed the expansion of '~' from HOME to USERPROFILE.  See

    # https://bugs.python.org/issue36264.  It also seems to capitalize the drive

    # letter, as though it was processed through os.path.realpath().

    if not path.startswith(b'~'):

        return path

    i, n = 1, len(path)

    while i < n and path[i] not in b'\\/':

        i += 1

    if b'HOME' in encoding.environ:

        userhome = encoding.environ[b'HOME']

    elif b'USERPROFILE' in encoding.environ:

        userhome = encoding.environ[b'USERPROFILE']

    elif b'HOMEPATH' not in encoding.environ:

        return path

    else:

        try:

            drive = encoding.environ[b'HOMEDRIVE']

        except KeyError:

            drive = b''

        userhome = os.path.join(drive, encoding.environ[b'HOMEPATH'])

    if i != 1:  # ~user

        userhome = os.path.join(os.path.dirname(userhome), path[1:i])

    return userhome + path[i:]

def termsize(ui: "uimod.ui") -> Tuple[int, int]:

    return win32.termsize()