# -*- coding: utf-8 -*-
#
# Copyright (C) 2013-2015 Vinay Sajip.
# Licensed to the Python Software Foundation under a contributor agreement.
# See LICENSE.txt and CONTRIBUTORS.txt.
#
from io import BytesIO
import logging
import os
import re
import struct
import sys

from .compat import sysconfig, detect_encoding, ZipFile
from .resources import finder
from .util import (FileOperator, get_export_entry, convert_path,
                   get_executable, in_venv)

logger = logging.getLogger(__name__)

_DEFAULT_MANIFEST = '''
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<assembly xmlns="urn:schemas-microsoft-com:asm.v1" manifestVersion="1.0">
 <assemblyIdentity version="1.0.0.0"
 processorArchitecture="X86"
 name="%s"
 type="win32"/>

 <!-- Identify the application security requirements. -->
 <trustInfo xmlns="urn:schemas-microsoft-com:asm.v3">
 <security>
 <requestedPrivileges>
 <requestedExecutionLevel level="asInvoker" uiAccess="false"/>
 </requestedPrivileges>
 </security>
 </trustInfo>
</assembly>'''.strip()

# check if Python is called on the first line with this expression
FIRST_LINE_RE = re.compile(b'^#!.*pythonw?[0-9.]*([ \t].*)?$')
SCRIPT_TEMPLATE = r'''# -*- coding: utf-8 -*-
import re
import sys
from %(module)s import %(import_name)s
if __name__ == '__main__':
    sys.argv[0] = re.sub(r'(-script\.pyw|\.exe)?$', '', sys.argv[0])
    sys.exit(%(func)s())
'''


def _enquote_executable(executable):
    if ' ' in executable:
        # make sure we quote only the executable in case of env
        # for example /usr/bin/env "/dir with spaces/bin/jython"
        # instead of "/usr/bin/env /dir with spaces/bin/jython"
        # otherwise whole
        if executable.startswith('/usr/bin/env '):
            env, _executable = executable.split(' ', 1)
            if ' ' in _executable and not _executable.startswith('"'):
                executable = '%s "%s"' % (env, _executable)
        else:
            if not executable.startswith('"'):
                executable = '"%s"' % executable
    return executable


class ScriptMaker(object):
    """
    A class to copy or create scripts from source scripts or callable
    specifications.
    """
    script_template = SCRIPT_TEMPLATE

    executable = None  # for shebangs

    def __init__(self, source_dir, target_dir, add_launchers=True,
                 dry_run=False, fileop=None):
        self.source_dir = source_dir
        self.target_dir = target_dir
        self.add_launchers = add_launchers
        self.force = False
        self.clobber = False
        # It only makes sense to set mode bits on POSIX.
        self.set_mode = (os.name == 'posix') or (os.name == 'java' and
                                                 os._name == 'posix')
        self.variants = set(('', 'X.Y'))
        self._fileop = fileop or FileOperator(dry_run)

        self._is_nt = os.name == 'nt' or (
            os.name == 'java' and os._name == 'nt')

    def _get_alternate_executable(self, executable, options):
        if options.get('gui', False) and self._is_nt:  # pragma: no cover
            dn, fn = os.path.split(executable)
            fn = fn.replace('python', 'pythonw')
            executable = os.path.join(dn, fn)
        return executable

    if sys.platform.startswith('java'):  # pragma: no cover
        def _is_shell(self, executable):
            """
            Determine if the specified executable is a script
            (contains a #! line)
            """
            try:
                with open(executable) as fp:
                    return fp.read(2) == '#!'
            except (OSError, IOError):
                logger.warning('Failed to open %s', executable)
                return False

        def _fix_jython_executable(self, executable):
            if self._is_shell(executable):
                # Workaround for Jython is not needed on Linux systems.
                import java

                if java.lang.System.getProperty('os.name') == 'Linux':
                    return executable
            elif executable.lower().endswith('jython.exe'):
                # Use wrapper exe for Jython on Windows
                return executable
            return '/usr/bin/env %s' % executable

    def _build_shebang(self, executable, post_interp):
        """
        Build a shebang line. In the simple case (on Windows, or a shebang line
        which is not too long or contains spaces) use a simple formulation for
        the shebang. Otherwise, use /bin/sh as the executable, with a contrived
        shebang which allows the script to run either under Python or sh, using
        suitable quoting. Thanks to Harald Nordgren for his input.

        See also: http://www.in-ulm.de/~mascheck/various/shebang/#length
                  https://hg.mozilla.org/mozilla-central/file/tip/mach
        """
        if os.name != 'posix':
            simple_shebang = True
        else:
            # Add 3 for '#!' prefix and newline suffix.
            shebang_length = len(executable) + len(post_interp) + 3
            if sys.platform == 'darwin':
                max_shebang_length = 512
            else:
                max_shebang_length = 127
            simple_shebang = ((b' ' not in executable) and
                              (shebang_length <= max_shebang_length))

        if simple_shebang:
            result = b'#!' + executable + post_interp + b'\n'
        else:
            result = b'#!/bin/sh\n'
            result += b"'''exec' " + executable + post_interp + b' "$0" "$@"\n'
            result += b"' '''"
        return result

    def _get_shebang(self, encoding, post_interp=b'', options=None):
        enquote = True
        if self.executable:
            executable = self.executable
            enquote = False     # assume this will be taken care of
        elif not sysconfig.is_python_build():
            executable = get_executable()
        elif in_venv():  # pragma: no cover
            executable = os.path.join(sysconfig.get_path('scripts'),
  
                          'python%s' % sysconfig.get_config_var('EXE'))
        else:  # pragma: no cover
            executable = os.path.join(
                sysconfig.get_config_var('BINDIR'),
               'python%s%s' % (sysconfig.get_config_var
('VERSION'),
                               sysconfig.get_config_var('EXE')))
        if options:
            executable = self._get_alternate_executable(executable, options)

        if sys.platform.startswith('java'):  # pragma: no cover
            executable = self._fix_jython_executable(executable)

        # Normalise case for Windows - COMMENTED OUT
        # executable = os.path.normcase(executable)
        # N.B. The normalising operation above has been commented out: See
        # issue #124. Although paths in Windows are generally case-insensitive,
        # they aren't always. For example, a path containing a ẞ (which is a
        # LATIN CAPITAL LETTER SHARP S - U+1E9E) is normcased to ß (which is a
        # LATIN SMALL LETTER SHARP S' - U+00DF). The two are not considered by
        # Windows as equivalent in path names.

        # If the user didn't specify an executable, it may be necessary to
        # cater for executable paths with spaces (not uncommon on Windows)
        if enquote:
            executable = _enquote_executable(executable)
        # Issue #51: don't use fsencode, since we later try to
        # check that the shebang is decodable using utf-8.
        executable = executable.encode('utf-8')
        # in case of IronPython, play safe and enable frames support
        if (sys.platform == 'cli' and '-X:Frames' not in post_interp
            and '-X:FullFrames' not in post_interp):  # pragma: no cover
            post_interp += b' -X:Frames'
        shebang = self._build_shebang(executable, post_interp)
        # Python parser starts to read a script using UTF-8 until
        # it gets a #coding:xxx cookie. The shebang has to be the
        # first line of a file, the #coding:xxx cookie cannot be
        # written before. So the shebang has to be decodable from
        # UTF-8.
        try:
            shebang.decode('utf-8')
        except UnicodeDecode