# Copyright 2019 The meson development team
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

"""Provides mixins for GNU compilers and GNU-like compilers."""

import abc
import functools
import os
import multiprocessing
import pathlib
import re
import subprocess
import typing as T

from ... import mesonlib
from ... import mlog
from ...mesonlib import OptionKey

if T.TYPE_CHECKING:
    from ...environment import Environment
    from ..compilers import Compiler
else:
    # This is a bit clever, for mypy we pretend that these mixins descend from
    # Compiler, so we get all of the methods and attributes defined for us, but
    # for runtime we make them descend from object (which all classes normally
    # do). This gives up DRYer type checking, with no runtime impact
    Compiler = object

# XXX: prevent circular references.
# FIXME: this really is a posix interface not a c-like interface
clike_debug_args = {
    False: [],
    True: ['-g'],
}  # type: T.Dict[bool, T.List[str]]

gnulike_buildtype_args = {
    'plain': [],
    'debug': [],
    'debugoptimized': [],
    'release': [],
    'minsize': [],
    'custom': [],
}  # type: T.Dict[str, T.List[str]]

gnu_optimization_args = {
    '0': [],
    'g': ['-Og'],
    '1': ['-O1'],
    '2': ['-O2'],
    '3': ['-O3'],
    's': ['-Os'],
}  # type: T.Dict[str, T.List[str]]

gnulike_instruction_set_args = {
    'mmx': ['-mmmx'],
    'sse': ['-msse'],
    'sse2': ['-msse2'],
    'sse3': ['-msse3'],
    'ssse3': ['-mssse3'],
    'sse41': ['-msse4.1'],
    'sse42': ['-msse4.2'],
    'avx': ['-mavx'],
    'avx2': ['-mavx2'],
    'neon': ['-mfpu=neon'],
}  # type: T.Dict[str, T.List[str]]

gnu_symbol_visibility_args = {
    '': [],
    'default': ['-fvisibility=default'],
    'internal': ['-fvisibility=internal'],
    'hidden': ['-fvisibility=hidden'],
    'protected': ['-fvisibility=protected'],
    'inlineshidden': ['-fvisibility=hidden', '-fvisibility-inlines-hidden'],
}  # type: T.Dict[str, T.List[str]]

gnu_color_args = {
    'auto': ['-fdiagnostics-color=auto'],
    'always': ['-fdiagnostics-color=always'],
    'never': ['-fdiagnostics-color=never'],
}  # type: T.Dict[str, T.List[str]]


@functools.lru_cache(maxsize=None)
def gnulike_default_include_dirs(compiler: T.Tuple[str], lang: str) -> T.List[str]:
    lang_map = {
        'c': 'c',
        'cpp': 'c++',
        'objc': 'objective-c',
        'objcpp': 'objective-c++'
    }
    if lang not in lang_map:
        return []
    lang = lang_map[lang]
    env = os.environ.copy()
    env["LC_ALL"] = 'C'
    cmd = list(compiler) + [f'-x{lang}', '-E', '-v', '-']
    p = subprocess.Popen(
        cmd,
        stdin=subprocess.DEVNULL,
        stderr=subprocess.STDOUT,
        stdout=subprocess.PIPE,
        env=env
    )
    stdout = p.stdout.read().decode('utf-8', errors='replace')
    parse_state = 0
    paths = []  # type: T.List[str]
    for line in stdout.split('\n'):
        line = line.strip(' \n\r\t')
        if parse_state == 0:
            if line == '#include "..." search starts here:':
                parse_state = 1
        elif parse_state == 1:
            if line == '#include <...> search starts here:':
                parse_state = 2
            else:
                paths.append(line)
        elif parse_state == 2:
            if line == 'End of search list.':
                break
            else:
                paths.append(line)
    if not paths:
        mlog.warning('No include directory found parsing "{cmd}" output'.format(cmd=" ".join(cmd)))
    # Append a normalized copy of paths to make path lookup easier
    paths += [os.path.normpath(x) for x in paths]
    return paths


class GnuLikeCompiler(Compiler, metaclass=abc.ABCMeta):
    """
    GnuLikeCompiler is a common interface to all compilers implementing
    the GNU-style commandline interface. This includes GCC, Clang
    and ICC. Certain functionality between them is different and requires
    that the actual concrete subclass define their own implementation.
    """

    LINKER_PREFIX = '-Wl,'

    def __init__(self) -> None:
        self.base_options = {
            OptionKey(o) for o in ['b_pch', 'b_lto', 'b_pgo', 'b_coverage',
                                   'b_ndebug', 'b_staticpic', 'b_pie']}
        if not (self.info.is_windows() or self.info.is_cygwin() or self.info.is_openbsd()):
            self.base_options.add(OptionKey('b_lundef'))
        if not self.info.is_windows() or self.info.is_cygwin():
            self.base_options.add(OptionKey('b_asneeded'))
        if not self.info.is_hurd():
            self.base_options.add(OptionKey('b_sanitize'))
        # All GCC-like backends can do assembly
        self.can_compile_suffixes.add('s')

    def get_pic_args(self) -> T.List[str]:
        if self.info.is_windows() or self.info.is_cygwin() or self.info.is_darwin():
            return [] # On Window and OS X, pic is always on.
        return ['-fPIC']

    def get_pie_args(self) -> T.List[str]:
        return ['-fPIE']

    def get_buildtype_args(self, buildtype: str) -> T.List[str]:
        return gnulike_buildtype_args[buildtype]

    @abc.abstractmethod
    def get_optimization_args(self, optimization_level: str) -> T.List[str]:
        pass

    def get_debug_args(self, is_debug: bool) -> T.List[str]:
        return clike_debug_args[is_debug]

    @abc.abstractmethod
    def get_pch_suffix(self) -> str:
        pass

    def split_shlib_to_parts(self, fname: str) -> T.Tuple[str, str]:
        return os.path.dirname(fname), fname

    def get_instruction_set_args(self, instruction_set: str) -> T.Optional[T.List[str]]:
        return gnulike_instruction_set_args.get(instruction_set, None)

    def get_default_include_dirs(self) -> T.List[str]:
        return gnulike_default_include_dirs(tuple(self.exelist), self.language)

    @abc.abstractmethod
    def openmp_flags(self) -> T.List[str]:
        pass

    def gnu_symbol_visibility_args(self, vistype: str) -> T.List[str]:
        return gnu_symbol_visibility_args[vistype]

    def gen_vs_module_defs_args(self, defsfile: str) -> T.List[str]:
        if not isinstance(defsfile, str):
            raise RuntimeError('Module definitions file should be str')
        # On Windows targets, .def files may be specified on the linker command
        # line like an object file.
        if self.info.is_windows() or self.info.is_cygwin():
            return [defsfile]
        # For other targets, discard the .def file.
        return []

    def get_argument_syntax(self) -> str:
        return 'gcc'

    def get_profile_generate_args(self) -> T.List[str]:
        return ['-fprofile-generate']

    def get_profile_use_args(self) -> T.List[str]:
        return ['-fprofile-use', '-fprofile-correction']

    def get_gui_app_args(self, value: bool) -> T.List[str]:
        return ['-mwindows' if value else '-mconsole']

    def compute_parameters_with_absolute_paths(self, parameter_list: T.List[str], build_dir: str) -> T.List[str]:
        for idx, i in enumerate(parameter_list):
            if i[:2] == '-I' or i[:2] == '-L':
                parameter_list[idx] = i[:2] + os.path.normpath(os.path.join(build_dir, i[2:]))

        return parameter_list

    @functools.lru_cache()
    def _get_search_dirs(self, env: 'Environment') -> str:
        extra_args = ['--print-search-dirs']
        with self._build_wrapper('', env, extra_args=extra_args,
                                 dependencies=None, mode='compile',
                                 want_output=True) as p:
            return p.stdout

    def _split_fetch_real_dirs(self, pathstr: str) -> T.List[str]:
        # We need to use the path separator used by the compiler for printing
        # lists of paths ("gcc --print-search-dirs"). By default
        # we assume it uses the platform native separator.
        pathsep = os.pathsep

        # clang uses ':' instead of ';' on Windows https://reviews.llvm.org/D61121
        # so we need to repair things like 'C:\foo:C:\bar'
        if pathsep == ';':
            pathstr = re.sub(r':([^/\\])', r';\1', pathstr)

        # pathlib treats empty paths as '.', so filter those out
        paths = [p for p in pathstr.split(pathsep) if p]

        result = []
        for p in paths:
            # GCC returns paths like this:
            # /usr/lib/gcc/x86_64-linux-gnu/8/../../../../x86_64-linux-gnu/lib
            # It would make sense to normalize them to get rid of the .. parts
            # Sadly when you are on a merged /usr fs it also kills these:
            # /lib/x86_64-linux-gnu
            # since /lib is a symlink to /usr/lib. This would mean
            # paths under /lib would be considered not a "system path",
            # which is wrong and breaks things. Store everything, just to be sure.
            pobj = pathlib.Path(p)
            unresolved = pobj.as_posix()
            if pobj.exists():
                if unresolved not in result:
                    result.append(unresolved)
                try:
                    resolved = pathlib.Path(p).resolve().as_posix()
                    if resolved not in result:
                        result.append(resolved)
                except FileNotFoundError:
                    pass
        return result

    def get_compiler_dirs(self, env: 'Environment', name: str) -> T.List[str]:
        '''
        Get dirs from the compiler, either `libraries:` or `programs:`
        '''
        stdo = self._get_search_dirs(env)
        for line in stdo.split('\n'):
            if line.startswith(name + ':'):
                return self._split_fetch_real_dirs(line.split('=', 1)[1])
        return []

    def get_lto_compile_args(self, *, threads: int = 0, mode: str = 'default') -> T.List[str]:
        # This provides a base for many compilers, GCC and Clang override this
        # for their specific arguments
        return ['-flto']

    def sanitizer_compile_args(self, value: str) -> T.List[str]:
        if value == 'none':
            return []
        args = ['-fsanitize=' + value]
        if 'address' in value:  # for -fsanitize=address,undefined
            args.append('-fno-omit-frame-pointer')
        return args

    def get_output_args(self, target: str) -> T.List[str]:
        return ['-o', target]

    def get_dependency_gen_args(self, outtarget: str, outfile: str) -> T.List[str]:
        return ['-MD', '-MQ', outtarget, '-MF', outfile]

    def get_compile_only_args(self) -> T.List[str]:
        return ['-c']

    def get_include_args(self, path: str, is_system: bool) -> T.List[str]:
        if not path:
            path = '.'
        if is_system:
            return ['-isystem' + path]
        return ['-I' + path]

    @classmethod
    def use_linker_args(cls, linker: str) -> T.List[str]:
        if linker not in {'gold', 'bfd', 'lld'}:
            raise mesonlib.MesonException(
                'Unsupported linker, only bfd, gold, and lld are supported, '
                'not {}.'.format(linker))
        return [f'-fuse-ld={linker}']

    def get_coverage_args(self) -> T.List[str]:
        return ['--coverage']


class GnuCompiler(GnuLikeCompiler):
    """
    GnuCompiler represents an actual GCC in its many incarnations.
    Compilers imitating GCC (Clang/Intel) should use the GnuLikeCompiler ABC.
    """

    def __init__(self, defines: T.Optional[T.Dict[str, str]]):
        super().__init__()
        self.id = 'gcc'
        self.defines = defines or {}
        self.base_options.update({OptionKey('b_colorout'), OptionKey('b_lto_threads')})

    def get_colorout_args(self, colortype: str) -> T.List[str]:
        if mesonlib.version_compare(self.version, '>=4.9.0'):
            return gnu_color_args[colortype][:]
        return []

    def get_warn_args(self, level: str) -> T.List[str]:
        # Mypy doesn't understand cooperative inheritance
        args = super().get_warn_args(level)
        if mesonlib.version_compare(self.version, '<4.8.0') and '-Wpedantic' in args:
            # -Wpedantic was added in 4.8.0
            # https://gcc.gnu.org/gcc-4.8/changes.html
            args[args.index('-Wpedantic')] = '-pedantic'
        return args

    def has_builtin_define(self, define: str) -> bool:
        return define in self.defines

    def get_builtin_define(self, define: str) -> T.Optional[str]:
        if define in self.defines:
            return self.defines[define]
        return None

    def get_optimization_args(self, optimization_level: str) -> T.List[str]:
        return gnu_optimization_args[optimization_level]

    def get_pch_suffix(self) -> str:
        return 'gch'

    def openmp_flags(self) -> T.List[str]:
        return ['-fopenmp']

    def has_arguments(self, args: T.List[str], env: 'Environment', code: str,
                      mode: str) -> T.Tuple[bool, bool]:
        # For some compiler command line arguments, the GNU compilers will
        # emit a warning on stderr indicating that an option is valid for a
        # another language, but still complete with exit_success
        with self._build_wrapper(code, env, args, None, mode) as p:
            result = p.returncode == 0
            if self.language in {'cpp', 'objcpp'} and 'is valid for C/ObjC' in p.stderr:
                result = False
            if self.language in {'c', 'objc'} and 'is valid for C++/ObjC++' in p.stderr:
                result = False
        return result, p.cached

    def get_has_func_attribute_extra_args(self, name: str) -> T.List[str]:
        # GCC only warns about unknown or ignored attributes, so force an
        # error.
        return ['-Werror=attributes']

    def get_prelink_args(self, prelink_name: str, obj_list: T.List[str]) -> T.List[str]:
        return ['-r', '-o', prelink_name] + obj_list

    def get_lto_compile_args(self, *, threads: int = 0, mode: str = 'default') -> T.List[str]:
        if threads == 0:
            if mesonlib.version_compare(self.version, '>= 10.0'):
                return ['-flto=auto']
            # This matches clang's behavior of using the number of cpus
            return [f'-flto={multiprocessing.cpu_count()}']
        elif threads > 0:
            return [f'-flto={threads}']
        return super().get_lto_compile_args(threads=threads)