from __future__ import division, absolute_import, print_function

import re
import os
import sys
import warnings
import platform
import tempfile
import hashlib
import base64
from subprocess import Popen, PIPE, STDOUT
from copy import copy
from numpy.distutils.fcompiler import FCompiler
from numpy.distutils.exec_command import exec_command
from numpy.distutils.compat import get_exception
from numpy.distutils.system_info import system_info

compilers = ['GnuFCompiler', 'Gnu95FCompiler']

TARGET_R = re.compile(r"Target: ([a-zA-Z0-9_\-]*)")

# XXX: handle cross compilation


def is_win64():
    return sys.platform == "win32" and platform.architecture()[0] == "64bit"


if is_win64():
    #_EXTRAFLAGS = ["-fno-leading-underscore"]
    _EXTRAFLAGS = []
else:
    _EXTRAFLAGS = []


class GnuFCompiler(FCompiler):
    compiler_type = 'gnu'
    compiler_aliases = ('g77', )
    description = 'GNU Fortran 77 compiler'

    def gnu_version_match(self, version_string):
        """Handle the different versions of GNU fortran compilers"""
        # Strip warning(s) that may be emitted by gfortran
        while version_string.startswith('gfortran: warning'):
            version_string = version_string[version_string.find('\n') + 1:]

        # Gfortran versions from after 2010 will output a simple string
        # (usually "x.y", "x.y.z" or "x.y.z-q") for ``-dumpversion``; older
        # gfortrans may still return long version strings (``-dumpversion`` was
        # an alias for ``--version``)
        if len(version_string) <= 20:
            # Try to find a valid version string
            m = re.search(r'([0-9.]+)', version_string)
            if m:
                # g77 provides a longer version string that starts with GNU
                # Fortran
                if version_string.startswith('GNU Fortran'):
                    return ('g77', m.group(1))

                # gfortran only outputs a version string such as #.#.#, so check
                # if the match is at the start of the string
                elif m.start() == 0:
                    return ('gfortran', m.group(1))
        else:
            # Output probably from --version, try harder:
            m = re.search(r'GNU Fortran\s+95.*?([0-9-.]+)', version_string)
            if m:
                return ('gfortran', m.group(1))
            m = re.search(
                r'GNU Fortran.*?\-?([0-9-.]+\.[0-9-.]+)', version_string)
            if m:
                v = m.group(1)
                if v.startswith('0') or v.startswith('2') or v.startswith('3'):
                    # the '0' is for early g77's
                    return ('g77', v)
                else:
                    # at some point in the 4.x series, the ' 95' was dropped
                    # from the version string
                    return ('gfortran', v)

        # If still nothing, raise an error to make the problem easy to find.
        err = 'A valid Fortran version was not found in this string:\n'
        raise ValueError(err + version_string)

    def version_match(self, version_string):
        v = self.gnu_version_match(version_string)
        if not v or v[0] != 'g77':
            return None
        return v[1]

    possible_executables = ['g77', 'f77']
    executables = {
        'version_cmd'  : [None, "-dumpversion"],
        'compiler_f77' : [None, "-g", "-Wall", "-fno-second-underscore"],
        'compiler_f90' : None,  # Use --fcompiler=gnu95 for f90 codes
        'compiler_fix' : None,
        'linker_so'    : [None, "-g", "-Wall"],
        'archiver'     : ["ar", "-cr"],
        'ranlib'       : ["ranlib"],
        'linker_exe'   : [None, "-g", "-Wall"]
    }
    module_dir_switch = None
    module_include_switch = None

    # Cygwin: f771: warning: -fPIC ignored for target (all code is
    # position independent)
    if os.name != 'nt' and sys.platform != 'cygwin':
        pic_flags = ['-fPIC']

    # use -mno-cygwin for g77 when Python is not Cygwin-Python
    if sys.platform == 'win32':
        for key in ['version_cmd', 'compiler_f77', 'linker_so', 'linker_exe']:
            executables[key].append('-mno-cygwin')

    g2c = 'g2c'
    suggested_f90_compiler = 'gnu95'

    def get_flags_linker_so(self):
        opt = self.linker_so[1:]
        if sys.platform == 'darwin':
            target = os.environ.get('MACOSX_DEPLOYMENT_TARGET', None)
            # If MACOSX_DEPLOYMENT_TARGET is set, we simply trust the value
            # and leave it alone.  But, distutils will complain if the
            # environment's value is different from the one in the Python
            # Makefile used to build Python.  We let disutils handle this
            # error checking.
            if not target:
                # If MACOSX_DEPLOYMENT_TARGET is not set in the environment,
                # we try to get it first from the Python Makefile and then we
                # fall back to setting it to 10.3 to maximize the set of
                # versions we can work with.  This is a reasonable default
                # even when using the official Python dist and those derived
                # from it.
                import distutils.sysconfig as sc
                g = {}
                try:
                    get_makefile_filename = sc.get_makefile_filename
                except AttributeError:
                    pass  # i.e. PyPy
                else:
                    filename = get_makefile_filename()
                    sc.parse_makefile(filename, g)
                target = g.get('MACOSX_DEPLOYMENT_TARGET', '10.3')
                os.environ['MACOSX_DEPLOYMENT_TARGET'] = target
                if target == '10.3':
                    s = 'Env. variable MACOSX_DEPLOYMENT_TARGET set to 10.3'
                    warnings.warn(s, stacklevel=2)

            opt.extend(['-undefined', 'dynamic_lookup', '-bundle'])
        else:
            opt.append("-shared")
        if sys.platform.startswith('sunos'):
            # SunOS often has dynamically loaded symbols defined in the
            # static library libg2c.a  The linker doesn't like this.  To
            # ignore the problem, use the -mimpure-text flag.  It isn't
            # the safest thing, but seems to work. 'man gcc' says:
            # ".. Instead of using -mimpure-text, you should compile all
            #  source code with -fpic or -fPIC."
            opt.append('-mimpure-text')
        return opt

    def get_libgcc_dir(self):
        status, output = exec_command(
            self.compiler_f77 + ['-print-libgcc-file-name'], use_tee=0)
        if not status:
            return os.path.dirname(output)
        return None

    def get_libgfortran_dir(self):
        if sys.platform[:5] == 'linux':
            libgfortran_name = 'libgfortran.so'
        elif sys.platform == 'darwin':
            libgfortran_name = 'libgfortran.dylib'
        else:
            libgfortran_name = None

        libgfortran_dir = None
        if libgfortran_name:
            find_lib_arg = ['-print-file-name={0}'.format(libgfortran_name)]
            status, output = exec_command(
                self.compiler_f77 + find_lib_arg, use_tee=0)
            if not status:
                libgfortran_dir = os.path.dirname(output)
        return libgfortran_dir

    def get_library_dirs(self):
        opt = []
        if sys.platform[:5] != 'linux':
            d = self.get_libgcc_dir()
            if d:
                # if windows and not cygwin, libg2c lies in a different folder
                if sys.platform == 'win32' and not d.startswith('/usr/lib'):
                    d = os.path.normpath(d)
                    path = os.path.join(d, "lib%s.a" % self.g2c)
                    if not os.path.exists(path):
                        root = os.path.join(d, *((os.pardir, ) * 4))
                        d2 = os.path.abspath(os.path.join(root, 'lib'))
                        path = os.path.join(d2, "lib%s.a" % self.g2c)
                        if os.path.exists(path):
                            opt.append(d2)
                opt.append(d)
        # For Macports / Linux, libgfortran and libgcc are not co-located
        lib_gfortran_dir = self.get_libgfortran_dir()
        if lib_gfortran_dir:
            opt.append(lib_gfortran_dir)
        return opt

    def get_libraries(self):
        opt = []
        d = self.get_libgcc_dir()
        if d is not None:
            g2c = self.g2c + '-pic'
            f = self.static_lib_format % (g2c, self.static_lib_extension)
            if not os.path.isfile(os.path.join(d, f)):
                g2c = self.g2c
        else:
            g2c = self.g2c

        if g2c is not None:
            opt.append(g2c)
        c_compiler = self.c_compiler
        if sys.platform == 'win32' and c_compiler and \
                c_compiler.compiler_type == 'msvc':
            opt.append('gcc')
        if sys.platform == 'darwin':
            opt.append('cc_dynamic')
        return opt

    def get_flags_debug(self):
        return ['-g']

    def get_flags_opt(self):
        v = self.get_version()
        if v and v <= '3.3.3':
            # With this compiler version building Fortran BLAS/LAPACK
            # with -O3 caused failures in lib.lapack heevr,syevr tests.
            opt = ['-O2']
        else:
            opt = ['-O3']
        opt.append('-funroll-loops')
        return opt

    def _c_arch_flags(self):
        """ Return detected arch flags from CFLAGS """
        from distutils import sysconfig
        try:
            cflags = sysconfig.get_config_vars()['CFLAGS']
        except KeyError:
            return []
        arch_re = re.compile(r"-arch\s+(\w+)")
        arch_flags = []
        for arch in arch_re.findall(cflags):
            arch_flags += ['-arch', arch]
        return arch_flags

    def get_flags_arch(self):
        return []

    def runtime_library_dir_option(self, dir):
        sep = ',' if sys.platform == 'darwin' else '='
        return '-Wl,-rpath%s"%s"' % (sep, dir)


class Gnu95FCompiler(GnuFCompiler):
    compiler_type = 'gnu95'
    compiler_aliases = ('gfortran', )
    description = 'GNU Fortran 95 compiler'

    def version_match(self, version_string):
        v = self.gnu_version_match(version_string)
        if not v or v[0] != 'gfortran':
            return None
        v = v[1]
        if v >= '4.':
            # gcc-4 series releases do not support -mno-cygwin option
            pass
        else:
            # use -mno-cygwin flag for gfortran when Python is not
            # Cygwin-Python
            if sys.platform == 'win32':
                for key in [
                        'version_cmd', 'compiler_f77', 'compiler_f90',
                        'compiler_fix', 'linker_so', 'linker_exe'
                ]:
                    self.executables[key].append('-mno-cygwin')
        return v

    possible_executables = ['gfortran', 'f95']
    executables = {
        'version_cmd'  : ["<F90>", "-dumpversion"],
        'compiler_f77' : [None, "-Wall", "-g", "-ffixed-form",
                          "-fno-second-underscore"] + _EXTRAFLAGS,
        'compiler_f90' : [None, "-Wall", "-g",
                          "-fno-second-underscore"] + _EXTRAFLAGS,
        'compiler_fix' : [None, "-Wall",  "-g","-ffixed-form",
                          "-fno-second-underscore"] + _EXTRAFLAGS,
        'linker_so'    : ["<F90>", "-Wall", "-g"],
        'archiver'     : ["ar", "-cr"],
        'ranlib'       : ["ranlib"],
        'linker_exe'   : [None, "-Wall"]
    }

    module_dir_switch = '-J'
    module_include_switch = '-I'

    g2c = 'gfortran'

    def _universal_flags(self, cmd):
        """Return a list of -arch flags for every supported architecture."""
        if not sys.platform == 'darwin':
            return []
        arch_flags = []
        # get arches the C compiler gets.
        c_archs = self._c_arch_flags()
        if "i386" in c_archs:
            c_archs[c_archs.index("i386")] = "i686"
        # check the arches the Fortran compiler supports, and compare with
        # arch flags from C compiler
        for arch in ["ppc", "i686", "x86_64", "ppc64"]:
            if _can_target(cmd, arch) and arch in c_archs:
                arch_flags.extend(["-arch", arch])
        return arch_flags

    def get_flags(self):
        flags = GnuFCompiler.get_flags(self)
        arch_flags = self._universal_flags(self.compiler_f90)
        if arch_flags:
            flags[:0] = arch_flags
        return flags

    def get_flags_linker_so(self):
        flags = GnuFCompiler.get_flags_linker_so(self)
        arch_flags = self._universal_flags(self.linker_so)
        if arch_flags:
            flags[:0] = arch_flags
        return flags

    def get_library_dirs(self):
        opt = GnuFCompiler.get_library_dirs(self)
        if sys.platform == 'win32':
            c_compiler = self.c_compiler
            if c_compiler and c_compiler.compiler_type == "msvc":
                target = self.get_target()
                if target:
                    d = os.path.normpath(self.get_libgcc_dir())
                    root = os.path.join(d, *((os.pardir, ) * 4))
                    path = os.path.join(root, "lib")
                    mingwdir = os.path.normpath(path)
                    if os.path.exists(os.path.join(mingwdir, "libmingwex.a")):
                        opt.append(mingwdir)
        # For Macports / Linux, libgfortran and libgcc are not co-located
        lib_gfortran_dir = self.get_libgfortran_dir()
        if lib_gfortran_dir:
            opt.append(lib_gfortran_dir)
        return opt

    def get_libraries(self):
        opt = GnuFCompiler.get_libraries(self)
        if sys.platform == 'darwin':
            opt.remove('cc_dynamic')
        if sys.platform == 'win32':
            c_compiler = self.c_compiler
            if c_compiler and c_compiler.compiler_type == "msvc":
                if "gcc" in opt:
                    i = opt.index("gcc")
                    opt.insert(i + 1, "mingwex")
                    opt.insert(i + 1, "mingw32")
            c_compiler = self.c_compiler
            if c_compiler and c_compiler.compiler_type == "msvc":
                return []
            else:
                pass
        return opt

    def get_target(self):
        status, output = exec_command(self.compiler_f77 + ['-v'], use_tee=0)
        if not status:
            m = TARGET_R.search(output)
            if m:
                return m.group(1)
        return ""

    def _hash_files(self, filenames):
        h = hashlib.sha1()
        for fn in filenames:
            with open(fn, 'rb') as f:
                while True:
                    block = f.read(131072)
                    if not block:
                        break
                    h.update(block)
        text = base64.b32encode(h.digest())
        if sys.version_info[0] >= 3:
            text = text.decode('ascii')
        return text.rstrip('=')

    def _link_wrapper_lib(self, objects, output_dir, extra_dll_dir,
                          chained_dlls, is_archive):
        """Create a wrapper shared library for the given objects

        Return an MSVC-compatible lib
        """

        c_compiler = self.c_compiler
        if c_compiler.compiler_type != "msvc":
            raise ValueError("This method only supports MSVC")

        object_hash = self._hash_files(list(objects) + list(chained_dlls))

        if is_win64():
            tag = 'win_amd64'
        else:
            tag = 'win32'

        basename = 'lib' + os.path.splitext(
            os.path.basename(objects[0]))[0][:8]
        root_name = basename + '.' + object_hash + '.gfortran-' + tag
        dll_name = root_name + '.dll'
        def_name = root_name + '.def'
        lib_name = root_name + '.lib'
        dll_path = os.path.join(extra_dll_dir, dll_name)
        def_path = os.path.join(output_dir, def_name)
        lib_path = os.path.join(output_dir, lib_name)

        if os.path.isfile(lib_path):
            # Nothing to do
            return lib_path, dll_path

        if is_archive:
            objects = (["-Wl,--whole-archive"] + list(objects) +
                       ["-Wl,--no-whole-archive"])
        self.link_shared_object(
            objects,
            dll_name,
            output_dir=extra_dll_dir,
            extra_postargs=list(chained_dlls) + [
                '-Wl,--allow-multiple-definition',
                '-Wl,--output-def,' + def_path,
                '-Wl,--export-all-symbols',
                '-Wl,--enable-auto-import',
                '-static',
                '-mlong-double-64',
            ])

        # No PowerPC!
        if is_win64():
            specifier = '/MACHINE:X64'
        else:
            specifier = '/MACHINE:X86'

        # MSVC specific code
        lib_args = ['/def:' + def_path, '/OUT:' + lib_path, specifier]
        if not c_compiler.initialized:
            c_compiler.initialize()
        c_compiler.spawn([c_compiler.lib] + lib_args)

        return lib_path, dll_path

    def can_ccompiler_link(self, compiler):
        # MSVC cannot link objects compiled by GNU fortran
        return compiler.compiler_type not in ("msvc", )

    def wrap_unlinkable_objects(self, objects, output_dir, extra_dll_dir):
        """
        Convert a set of object files that are not compatible with the default
        linker, to a file that is compatible.
        """
        if self.c_compiler.compiler_type == "msvc":
            # Compile a DLL and return the lib for the DLL as
            # the object. Also keep track of previous DLLs that
            # we have compiled so that we can link against them.

            # If there are .a archives, assume they are self-contained
            # static libraries, and build separate DLLs for each
            archives = []
            plain_objects = []
            for obj in objects:
                if obj.lower().endswith('.a'):
                    archives.append(obj)
                else:
                    plain_objects.append(obj)

            chained_libs = []
            chained_dlls = []
            for archive in archives[::-1]:
                lib, dll = self._link_wrapper_lib(
                    [archive],
                    output_dir,
                    extra_dll_dir,
                    chained_dlls=chained_dlls,
                    is_archive=True)
                chained_libs.insert(0, lib)
                chained_dlls.insert(0, dll)

            if not plain_objects:
                return chained_libs

            lib, dll = self._link_wrapper_lib(
                plain_objects,
                output_dir,
                extra_dll_dir,
                chained_dlls=chained_dlls,
                is_archive=False)
            return [lib] + chained_libs
        else:
            raise ValueError("Unsupported C compiler")


def _can_target(cmd, arch):
    """Return true if the architecture supports the -arch flag"""
    newcmd = cmd[:]
    fid, filename = tempfile.mkstemp(suffix=".f")
    os.close(fid)
    try:
        d = os.path.dirname(filename)
        output = os.path.splitext(filename)[0] + ".o"
        try:
            newcmd.extend(["-arch", arch, "-c", filename])
            p = Popen(newcmd, stderr=STDOUT, stdout=PIPE, cwd=d)
            p.communicate()
            return p.returncode == 0
        finally:
            if os.path.exists(output):
                os.remove(output)
    finally:
        os.remove(filename)
    return False


if __name__ == '__main__':
    from distutils import log
    from numpy.distutils import customized_fcompiler
    log.set_verbosity(2)

    print(customized_fcompiler('gnu').get_version())
    try:
        print(customized_fcompiler('g95').get_version())
    except Exception:
        print(get_exception())
