"""
Support code for building Python extensions on Windows.

    # NT stuff
    # 1. Make sure libpython<version>.a exists for gcc.  If not, build it.
    # 2. Force windows to use gcc (we're struggling with MSVC and g77 support)
    # 3. Force windows to use g77

"""
import os
import platform
import sys
import subprocess
import re
import textwrap

# Overwrite certain distutils.ccompiler functions:
import numpy.distutils.ccompiler  # noqa: F401
from numpy.distutils import log
# NT stuff
# 1. Make sure libpython<version>.a exists for gcc.  If not, build it.
# 2. Force windows to use gcc (we're struggling with MSVC and g77 support)
#    --> this is done in numpy/distutils/ccompiler.py
# 3. Force windows to use g77

import distutils.cygwinccompiler
from distutils.unixccompiler import UnixCCompiler
from distutils.msvccompiler import get_build_version as get_build_msvc_version
from distutils.errors import UnknownFileError
from numpy.distutils.misc_util import (msvc_runtime_library,
                                       msvc_runtime_version,
                                       msvc_runtime_major,
                                       get_build_architecture)

def get_msvcr_replacement():
    """Replacement for outdated version of get_msvcr from cygwinccompiler"""
    msvcr = msvc_runtime_library()
    return [] if msvcr is None else [msvcr]

# monkey-patch cygwinccompiler with our updated version from misc_util
# to avoid getting an exception raised on Python 3.5
distutils.cygwinccompiler.get_msvcr = get_msvcr_replacement

# Useful to generate table of symbols from a dll
_START = re.compile(r'\[Ordinal/Name Pointer\] Table')
_TABLE = re.compile(r'^\s+\[([\s*[0-9]*)\] ([a-zA-Z0-9_]*)')

# the same as cygwin plus some additional parameters
class Mingw32CCompiler(distutils.cygwinccompiler.CygwinCCompiler):
    """ A modified MingW32 compiler compatible with an MSVC built Python.

    """

    compiler_type = 'mingw32'

    def __init__ (self,
                  verbose=0,
                  dry_run=0,
                  force=0):

        distutils.cygwinccompiler.CygwinCCompiler.__init__ (self, verbose,
                                                            dry_run, force)

        # **changes: eric jones 4/11/01
        # 1. Check for import library on Windows.  Build if it doesn't exist.

        build_import_library()

        # Check for custom msvc runtime library on Windows. Build if it doesn't exist.
        msvcr_success = build_msvcr_library()
        msvcr_dbg_success = build_msvcr_library(debug=True)
        if msvcr_success or msvcr_dbg_success:
            # add preprocessor statement for using customized msvcr lib
            self.define_macro('NPY_MINGW_USE_CUSTOM_MSVCR')

        # Define the MSVC version as hint for MinGW
        msvcr_version = msvc_runtime_version()
        if msvcr_version:
            self.define_macro('__MSVCRT_VERSION__', '0x%04i' % msvcr_version)

        # MS_WIN64 should be defined when building for amd64 on windows,
        # but python headers define it only for MS compilers, which has all
        # kind of bad consequences, like using Py_ModuleInit4 instead of
        # Py_ModuleInit4_64, etc... So we add it here
        if get_build_architecture() == 'AMD64':
            self.set_executables(
                compiler='gcc -g -DDEBUG -DMS_WIN64 -O0 -Wall',
                compiler_so='gcc -g -DDEBUG -DMS_WIN64 -O0 -Wall '
                            '-Wstrict-prototypes',
                linker_exe='gcc -g',
                linker_so='gcc -g -shared')
        else:
            self.set_executables(
                compiler='gcc -O2 -Wall',
                compiler_so='gcc -O2 -Wall -Wstrict-prototypes',
                linker_exe='g++ ',
                linker_so='g++ -shared')
        # added for python2.3 support
        # we can't pass it through set_executables because pre 2.2 would fail
        self.compiler_cxx = ['g++']

        # Maybe we should also append -mthreads, but then the finished dlls
        # need another dll (mingwm10.dll see Mingw32 docs) (-mthreads: Support
        # thread-safe exception handling on `Mingw32')

        # no additional libraries needed
        #self.dll_libraries=[]
        return

    # __init__ ()

    def link(self,
             target_desc,
             objects,
             output_filename,
             output_dir,
             libraries,
             library_dirs,
             runtime_library_dirs,
             export_symbols = None,
             debug=0,
             extra_preargs=None,
             extra_postargs=None,
             build_temp=None,
             target_lang=None):
        # Include the appropriate MSVC runtime library if Python was built
        # with MSVC >= 7.0 (MinGW standard is msvcrt)
        runtime_library = msvc_runtime_library()
        if runtime_library:
            if not libraries:
                libraries = []
            libraries.append(runtime_library)
        args = (self,
                target_desc,
                objects,
                output_filename,
                output_dir,
                libraries,
                library_dirs,
                runtime_library_dirs,
                None, #export_symbols, we do this in our def-file
                debug,
                extra_preargs,
                extra_postargs,
                build_temp,
                target_lang)
        func = UnixCCompiler.link
        func(*args[:func.__code__.co_argcount])
        return

    def object_filenames (self,
                          source_filenames,
                          strip_dir=0,
                          output_dir=''):
        if output_dir is None: output_dir = ''
        obj_names = []
        for src_name in source_filenames:
            # use normcase to make sure '.rc' is really '.rc' and not '.RC'
            (base, ext) = os.path.splitext (os.path.normcase(src_name))

            # added these lines to strip off windows drive letters
            # without it, .o files are placed next to .c files
            # instead of the build directory
            drv, base = os.path.splitdrive(base)
            if drv:
                base = base[1:]

            if ext not in (self.src_extensions + ['.rc', '.res']):
                raise UnknownFileError(
                      "unknown file type '%s' (from '%s')" % \
                      (ext, src_name))
            if strip_dir:
                base = os.path.basename (base)
            if ext == '.res' or ext == '.rc':
                # these need to be compiled to object files
                obj_names.append (os.path.join (output_dir,
                                                base + ext + self.obj_extension))
            else:
                obj_names.append (os.path.join (output_dir,
                                                base + self.obj_extension))
        return obj_names

    # object_filenames ()


def find_python_dll():
    # We can't do much here:
    # - find it in the virtualenv (sys.prefix)
    # - find it in python main dir (sys.base_prefix, if in a virtualenv)
    # - sys.real_prefix is main dir for virtualenvs in Python 2.7
    # - in system32,
    # - ortherwise (Sxs), I don't know how to get it.
    stems = [sys.prefix]
    if hasattr(sys, 'base_prefix') and sys.base_prefix != sys.prefix:
        stems.append(sys.base_prefix)
    elif hasattr(sys, 'real_prefix') and sys.real_prefix != sys.prefix:
        stems.append(sys.real_prefix)

    sub_dirs = ['', 'lib', 'bin']
    # generate possible combinations of directory trees and sub-directories
    lib_dirs = []
    for stem in stems:
        for folder in sub_dirs:
            lib_dirs.append(os.path.join(stem, folder))

    # add system directory as well
    if 'SYSTEMROOT' in os.environ:
        lib_dirs.append(os.path.join(os.environ['SYSTEMROOT'], 'System32'))

    # search in the file system for possible candidates
    major_version, minor_version = tuple(sys.version_info[:2])
    implementation = platform.python_implementation()
    if implementation == 'CPython':
        dllname = f'python{major_version}{minor_version}.dll'
    elif implementation == 'PyPy':
        dllname = f'libpypy{major_version}-c.dll'
    else:
        dllname = 'Unknown platform {implementation}' 
    print("Looking for %s" % dllname)
    for folder in lib_dirs:
        dll = os.path.join(folder, dllname)
        if os.path.exists(dll):
            return dll
 
    raise ValueError("%s not found in %s" % (dllname, lib_dirs))

def dump_table(dll):
    st = subprocess.check_output(["objdump.exe", "-p", dll])
    return st.split(b'\n')

def generate_def(dll, dfile):
    """Given a dll file location,  get all its exported symbols and dump them
    into the given def file.

    The .def file will be overwritten"""
    dump = dump_table(dll)
    for i in range(len(dump)):
        if _START.match(dump[i].decode()):
            break
    else:
        raise ValueError("Symbol table not found")

    syms = []
    for j in range(i+1, len(dump)):
        m = _TABLE.match(dump[j].decode())
        if m:
            syms.append((int(m.group(1).strip()), m.group(2)))
        else:
            break

    if len(syms) == 0:
        log.warn('No symbols found in %s' % dll)

    with open(dfile, 'w') as d:
        d.write('LIBRARY        %s\n' % os.path.basename(dll))
        d.write(';CODE          PRELOAD MOVEABLE DISCARDABLE\n')
        d.write(';DATA          PRELOAD SINGLE\n')
        d.write('\nEXPORTS\n')
        for s in syms:
            #d.write('@%d    %s\n' % (s[0], s[1]))
            d.write('%s\n' % s[1])

def find_dll(dll_name):

    arch = {'AMD64' : 'amd64',
            'Intel' : 'x86'}[get_build_architecture()]

    def _find_dll_in_winsxs(dll_name):
        # Walk through the WinSxS directory to find the dll.
        winsxs_path = os.path.join(os.environ.get('WINDIR', r'C:\WINDOWS'),
                                   'winsxs')
        if not os.path.exists(winsxs_path):
            return None
        for root, dirs, files in os.walk(winsxs_path):
            if dll_name in files and arch in root:
                return os.path.join(root, dll_name)
        return None

    def _find_dll_in_path(dll_name):
        # First, look in the Python directory, then scan PATH for
        # the given dll name.
        for path in [sys.prefix] + os.environ['PATH'].split(';'):
            filepath = os.path.join(path, dll_name)
            if os.path.exists(filepath):
                return os.path.abspath(filepath)

    return _find_dll_in_winsxs(dll_name) or _find_dll_in_path(dll_name)

def build_msvcr_library(debug=False):
    if os.name != 'nt':
        return False

    # If the version number is None, then we couldn't find the MSVC runtime at
    # all, because we are running on a Python distribution which is customed
    # compiled; trust that the compiler is the same as the one available to us
    # now, and that it is capable of linking with the correct runtime without
    # any extra options.
    msvcr_ver = msvc_runtime_major()
    if msvcr_ver is None:
        log.debug('Skip building import library: '
                  'Runtime is not compiled with MSVC')
        return False

    # Skip using a custom library for versions < MSVC 8.0
    if msvcr_ver < 80:
        log.debug('Skip building msvcr library:'
                  ' custom functionality not present')
        return False

    msvcr_name = msvc_runtime_library()
    if debug:
        msvcr_name += 'd'

    # Skip if custom library already exists
    out_name = "lib%s.a" % msvcr_name
    out_file = os.path.join(sys.prefix, 'libs', out_name)
    if os.path.isfile(out_file):
        log.debug('Skip building msvcr library: "%s" exists' %
                  (out_file,))
        return True

    # Find the msvcr dll
    msvcr_dll_name = msvcr_name + '.dll'
    dll_file = find_dll(msvcr_dll_name)
    if not dll_file:
        log.warn('Cannot build msvcr library: "%s" not found' %
                 msvcr_dll_name)
        return False

    def_name = "lib%s.def" % msvcr_name
    def_file = os.path.join(sys.prefix, 'libs', def_name)

    log.info('Building msvcr library: "%s" (from %s)' \
             % (out_file, dll_file))

    # Generate a symbol definition file from the msvcr dll
    generate_def(dll_file, def_file)

    # Create a custom mingw library for the given symbol definitions
    cmd = ['dlltool', '-d', def_file, '-l', out_file]
    retcode = subprocess.call(cmd)

    # Clean up symbol definitions
    os.remove(def_file)

    return (not retcode)

def build_import_library():
    if os.name != 'nt':
        return

    arch = get_build_architecture()
    if arch == 'AMD64':
        return _build_import_library_amd64()
    elif arch == 'Intel':
        return _build_import_library_x86()
    else:
        raise ValueError("Unhandled arch %s" % arch)

def _check_for_import_lib():
    """Check if an import library for the Python runtime already exists."""
    major_version, minor_version = tuple(sys.version_info[:2])

    # patterns for the file name of the library itself
    patterns = ['libpython%d%d.a',
                'libpython%d%d.dll.a',
                'libpython%d.%d.dll.a']

    # directory trees that may contain the library
    stems = [sys.prefix]
    if hasattr(sys, 'base_prefix') and sys.base_prefix != sys.prefix:
        stems.append(sys.base_prefix)
    elif hasattr(sys, 'real_prefix') and sys.real_prefix != sys.prefix:
        stems.append(sys.real_prefix)

    # possible subdirectories within those trees where it is placed
    sub_dirs = ['libs', 'lib']

    # generate a list of candidate locations
    candidates = []
    for pat in patterns:
        filename = pat % (major_version, minor_version)
        for stem_dir in stems:
            for folder in sub_dirs:
                candidates.append(os.path.join(stem_dir, folder, filename))

    # test the filesystem to see if we can find any of these
    for fullname in candidates:
        if os.path.isfile(fullname):
            # already exists, in location given
            return (True, fullname)

    # needs to be built, preferred location given first
    return (False, candidates[0])

def _build_import_library_amd64():
    out_exists, out_file = _check_for_import_lib()
    if out_exists:
        log.debug('Skip building import library: "%s" exists', out_file)
        return

    # get the runtime dll for which we are building import library
    dll_file = find_python_dll()
    log.info('Building import library (arch=AMD64): "%s" (from %s)' %
             (out_file, dll_file))

    # generate symbol list from this library
    def_name = "python%d%d.def" % tuple(sys.version_info[:2])
    def_file = os.path.join(sys.prefix, 'libs', def_name)
    generate_def(dll_file, def_file)

    # generate import library from this symbol list
    cmd = ['dlltool', '-d', def_file, '-l', out_file]
    subprocess.check_call(cmd)

def _build_import_library_x86():
    """ Build the import libraries for Mingw32-gcc on Windows
    """
    out_exists, out_file = _check_for_import_lib()
    if out_exists:
        log.debug('Skip building import library: "%s" exists', out_file)
        return

    lib_name = "python%d%d.lib" % tuple(sys.version_info[:2])
    lib_file = os.path.join(sys.prefix, 'libs', lib_name)
    if not os.path.isfile(lib_file):
        # didn't find library file in virtualenv, try base distribution, too,
        # and use that instead if found there. for Python 2.7 venvs, the base
        # directory is in attribute real_prefix instead of base_prefix.
        if hasattr(sys, 'base_prefix'):
            base_lib = os.path.join(sys.base_prefix, 'libs', lib_name)
        elif hasattr(sys, 'real_prefix'):
            base_lib = os.path.join(sys.real_prefix, 'libs', lib_name)
        else:
            base_lib = ''  # os.path.isfile('') == False

        if os.path.isfile(base_lib):
            lib_file = base_lib
        else:
            log.warn('Cannot build import library: "%s" not found', lib_file)
            return
    log.info('Building import library (ARCH=x86): "%s"', out_file)

    from numpy.distutils import lib2def

    def_name = "python%d%d.def" % tuple(sys.version_info[:2])
    def_file = os.path.join(sys.prefix, 'libs', def_name)
    nm_output = lib2def.getnm(
            lib2def.DEFAULT_NM + [lib_file], shell=False)
    dlist, flist = lib2def.parse_nm(nm_output)
    with open(def_file, 'w') as fid:
        lib2def.output_def(dlist, flist, lib2def.DEF_HEADER, fid)

    dll_name = find_python_dll ()

    cmd = ["dlltool",
           "--dllname", dll_name,
           "--def", def_file,
           "--output-lib", out_file]
    status = subprocess.check_output(cmd)
    if status:
        log.warn('Failed to build import library for gcc. Linking will fail.')
    return

#=====================================
# Dealing with Visual Studio MANIFESTS
#=====================================

# Functions to deal with visual studio manifests. Manifest are a mechanism to
# enforce strong DLL versioning on windows, and has nothing to do with
# distutils MANIFEST. manifests are XML files with version info, and used by
# the OS loader; they are necessary when linking against a DLL not in the
# system path; in particular, official python 2.6 binary is built against the
# MS runtime 9 (the one from VS 2008), which is not available on most windows
# systems; python 2.6 installer does install it in the Win SxS (Side by side)
# directory, but this requires the manifest for this to work. This is a big
# mess, thanks MS for a wonderful system.

# XXX: ideally, we should use exactly the same version as used by python. I
# submitted a patch to get this version, but it was only included for python
# 2.6.1 and above. So for versions below, we use a "best guess".
_MSVCRVER_TO_FULLVER = {}
if sys.platform == 'win32':
    try:
        import msvcrt
        # I took one version in my SxS directory: no idea if it is the good
        # one, and we can't retrieve it from python
        _MSVCRVER_TO_FULLVER['80'] = "8.0.50727.42"
        _MSVCRVER_TO_FULLVER['90'] = "9.0.21022.8"
        # Value from msvcrt.CRT_ASSEMBLY_VERSION under Python 3.3.0
        # on Windows XP:
        _MSVCRVER_TO_FULLVER['100'] = "10.0.30319.460"
        crt_ver = getattr(msvcrt, 'CRT_ASSEMBLY_VERSION', None)
        if crt_ver is not None:  # Available at least back to Python 3.3
            maj, min = re.match(r'(\d+)\.(\d)', crt_ver).groups()
            _MSVCRVER_TO_FULLVER[maj + min] = crt_ver
            del maj, min
        del crt_ver
    except ImportError:
        # If we are here, means python was not built with MSVC. Not sure what
        # to do in that case: manifest building will fail, but it should not be
        # used in that case anyway
        log.warn('Cannot import msvcrt: using manifest will not be possible')

def msvc_manifest_xml(maj, min):
    """Given a major and minor version of the MSVCR, returns the
    corresponding XML file."""
    try:
        fullver = _MSVCRVER_TO_FULLVER[str(maj * 10 + min)]
    except KeyError:
        raise ValueError("Version %d,%d of MSVCRT not supported yet" %
                         (maj, min)) from None
    # Don't be fooled, it looks like an XML, but it is not. In particular, it
    # should not have any space before starting, and its size should be
    # divisible by 4, most likely for alignment constraints when the xml is
    # embedded in the binary...
    # This template was copied directly from the python 2.6 binary (using
    # strings.exe from mingw on python.exe).
    template = textwrap.dedent("""\
        <assembly xmlns="urn:schemas-microsoft-com:asm.v1" manifestVersion="1.0">
          <trustInfo xmlns="urn:schemas-microsoft-com:asm.v3">
            <security>
              <requestedPrivileges>
                <requestedExecutionLevel level="asInvoker" uiAccess="false"></requestedExecutionLevel>
              </requestedPrivileges>
            </security>
          </trustInfo>
          <dependency>
            <dependentAssembly>
              <assemblyIdentity type="win32" name="Microsoft.VC%(maj)d%(min)d.CRT" version="%(fullver)s" processorArchitecture="*" publicKeyToken="1fc8b3b9a1e18e3b"></assemblyIdentity>
            </dependentAssembly>
          </dependency>
        </assembly>""")

    return template % {'fullver': fullver, 'maj': maj, 'min': min}

def manifest_rc(name, type='dll'):
    """Return the rc file used to generate the res file which will be embedded
    as manifest for given manifest file name, of given type ('dll' or
    'exe').

    Parameters
    ----------
    name : str
            name of the manifest file to embed
    type : str {'dll', 'exe'}
            type of the binary which will embed the manifest

    """
    if type == 'dll':
        rctype = 2
    elif type == 'exe':
        rctype = 1
    else:
        raise ValueError("Type %s not supported" % type)

    return """\
#include "winuser.h"
%d RT_MANIFEST %s""" % (rctype, name)

def check_embedded_msvcr_match_linked(msver):
    """msver is the ms runtime version used for the MANIFEST."""
    # check msvcr major version are the same for linking and
    # embedding
    maj = msvc_runtime_major()
    if maj:
        if not maj == int(msver):
            raise ValueError(
                  "Discrepancy between linked msvcr " \
                  "(%d) and the one about to be embedded " \
                  "(%d)" % (int(msver), maj))

def configtest_name(config):
    base = os.path.basename(config._gen_temp_sourcefile("yo", [], "c"))
    return os.path.splitext(base)[0]

def manifest_name(config):
    # Get configest name (including suffix)
    root = configtest_name(config)
    exext = config.compiler.exe_extension
    return root + exext + ".manifest"

def rc_name(config):
    # Get configtest name (including suffix)
    root = configtest_name(config)
    return root + ".rc"

def generate_manifest(config):
    msver = get_build_msvc_version()
    if msver is not None:
        if msver >= 8:
            check_embedded_msvcr_match_linked(msver)
            ma_str, mi_str = str(msver).split('.')
            # Write the manifest file
            manxml = msvc_manifest_xml(int(ma_str), int(mi_str))
            with open(manifest_name(config), "w") as man:
                config.temp_files.append(manifest_name(config))
                man.write(manxml)
