# 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.

# This class contains the basic functionality needed to run any interpreter
# or an interpreter-based tool.

import subprocess as S
from pathlib import Path
from threading import Thread
import typing as T
import re
import os
import shutil
import ctypes
import textwrap

from .. import mlog, mesonlib
from ..mesonlib import PerMachine, Popen_safe, version_compare, MachineChoice
from ..environment import Environment
from ..envconfig import get_env_var
from ..compilers import (
    AppleClangCCompiler, AppleClangCPPCompiler, AppleClangObjCCompiler,
    AppleClangObjCPPCompiler
)

if T.TYPE_CHECKING:
    from ..dependencies.base import ExternalProgram
    from ..compilers import Compiler

TYPE_result    = T.Tuple[int, T.Optional[str], T.Optional[str]]
TYPE_cache_key = T.Tuple[str, T.Tuple[str, ...], str, T.FrozenSet[T.Tuple[str, str]]]

_MESON_TO_CMAKE_MAPPING = {
    'arm':          'ARMCC',
    'armclang':     'ARMClang',
    'clang':        'Clang',
    'clang-cl':     'MSVC',
    'flang':        'Flang',
    'g95':          'G95',
    'gcc':          'GNU',
    'intel':        'Intel',
    'intel-cl':     'MSVC',
    'msvc':         'MSVC',
    'pathscale':    'PathScale',
    'pgi':          'PGI',
    'sun':          'SunPro',
}

def meson_compiler_to_cmake_id(cobj: 'Compiler') -> str:
    """Translate meson compiler's into CMAKE compiler ID's.

    Most of these can be handled by a simple table lookup, with a few
    exceptions.

    Clang and Apple's Clang are both identified as "clang" by meson. To make
    things more complicated gcc and vanilla clang both use Apple's ld64 on
    macOS. The only way to know for sure is to do an isinstance() check.
    """
    if isinstance(cobj, (AppleClangCCompiler, AppleClangCPPCompiler,
                         AppleClangObjCCompiler, AppleClangObjCPPCompiler)):
        return 'AppleClang'
    # If no mapping, try GNU and hope that the build files don't care
    return _MESON_TO_CMAKE_MAPPING.get(cobj.get_id(), 'GNU')


class CMakeExecutor:
    # The class's copy of the CMake path. Avoids having to search for it
    # multiple times in the same Meson invocation.
    class_cmakebin = PerMachine(None, None)   # type: PerMachine[T.Optional[ExternalProgram]]
    class_cmakevers = PerMachine(None, None)  # type: PerMachine[T.Optional[str]]
    class_cmake_cache = {}  # type: T.Dict[T.Any, TYPE_result]

    def __init__(self, environment: Environment, version: str, for_machine: MachineChoice, silent: bool = False):
        self.min_version = version
        self.environment = environment
        self.for_machine = for_machine
        self.cmakebin, self.cmakevers = self.find_cmake_binary(self.environment, silent=silent)
        self.always_capture_stderr = True
        self.print_cmout = False
        self.prefix_paths = []      # type: T.List[str]
        self.extra_cmake_args = []  # type: T.List[str]

        if self.cmakebin is None:
            return

        if not version_compare(self.cmakevers, self.min_version):
            mlog.warning(
                'The version of CMake', mlog.bold(self.cmakebin.get_path()),
                'is', mlog.bold(self.cmakevers), 'but version', mlog.bold(self.min_version),
                'is required')
            self.cmakebin = None
            return

        self.prefix_paths = self.environment.coredata.builtins_per_machine[self.for_machine]['cmake_prefix_path'].value
        env_pref_path_raw = get_env_var(
            self.for_machine,
            self.environment.is_cross_build(),
            'CMAKE_PREFIX_PATH')
        if env_pref_path_raw is not None:
            env_pref_path = []  # type: T.List[str]
            if mesonlib.is_windows():
                # Cannot split on ':' on Windows because its in the drive letter
                env_pref_path = env_pref_path_raw.split(os.pathsep)
            else:
                # https://github.com/mesonbuild/meson/issues/7294
                env_pref_path = re.split(r':|;', env_pref_path_raw)
            env_pref_path = [x for x in env_pref_path if x]  # Filter out empty strings
            if not self.prefix_paths:
                self.prefix_paths = []
            self.prefix_paths += env_pref_path

        if self.prefix_paths:
            self.extra_cmake_args += ['-DCMAKE_PREFIX_PATH={}'.format(';'.join(self.prefix_paths))]

    def find_cmake_binary(self, environment: Environment, silent: bool = False) -> T.Tuple[T.Optional['ExternalProgram'], T.Optional[str]]:
        from ..dependencies.base import find_external_program, NonExistingExternalProgram

        # Only search for CMake the first time and store the result in the class
        # definition
        if isinstance(CMakeExecutor.class_cmakebin[self.for_machine], NonExistingExternalProgram):
            mlog.debug('CMake binary for %s is cached as not found' % self.for_machine)
            return None, None
        elif CMakeExecutor.class_cmakebin[self.for_machine] is not None:
            mlog.debug('CMake binary for %s is cached.' % self.for_machine)
        else:
            assert CMakeExecutor.class_cmakebin[self.for_machine] is None

            mlog.debug('CMake binary for %s is not cached' % self.for_machine)
            for potential_cmakebin in find_external_program(
                    environment, self.for_machine, 'cmake', 'CMake',
                    environment.default_cmake, allow_default_for_cross=False):
                version_if_ok = self.check_cmake(potential_cmakebin)
                if not version_if_ok:
                    continue
                if not silent:
                    mlog.log('Found CMake:', mlog.bold(potential_cmakebin.get_path()),
                             '({})'.format(version_if_ok))
                CMakeExecutor.class_cmakebin[self.for_machine] = potential_cmakebin
                CMakeExecutor.class_cmakevers[self.for_machine] = version_if_ok
                break
            else:
                if not silent:
                    mlog.log('Found CMake:', mlog.red('NO'))
                # Set to False instead of None to signify that we've already
                # searched for it and not found it
                CMakeExecutor.class_cmakebin[self.for_machine] = NonExistingExternalProgram()
                CMakeExecutor.class_cmakevers[self.for_machine] = None
                return None, None

        return CMakeExecutor.class_cmakebin[self.for_machine], CMakeExecutor.class_cmakevers[self.for_machine]

    def check_cmake(self, cmakebin: 'ExternalProgram') -> T.Optional[str]:
        if not cmakebin.found():
            mlog.log('Did not find CMake {!r}'.format(cmakebin.name))
            return None
        try:
            p, out = Popen_safe(cmakebin.get_command() + ['--version'])[0:2]
            if p.returncode != 0:
                mlog.warning('Found CMake {!r} but couldn\'t run it'
                             ''.format(' '.join(cmakebin.get_command())))
                return None
        except FileNotFoundError:
            mlog.warning('We thought we found CMake {!r} but now it\'s not there. How odd!'
                         ''.format(' '.join(cmakebin.get_command())))
            return None
        except PermissionError:
            msg = 'Found CMake {!r} but didn\'t have permissions to run it.'.format(' '.join(cmakebin.get_command()))
            if not mesonlib.is_windows():
                msg += '\n\nOn Unix-like systems this is often caused by scripts that are not executable.'
            mlog.warning(msg)
            return None
        cmvers = re.search(r'(cmake|cmake3)\s*version\s*([\d.]+)', out).group(2)
        return cmvers

    def set_exec_mode(self, print_cmout: T.Optional[bool] = None, always_capture_stderr: T.Optional[bool] = None) -> None:
        if print_cmout is not None:
            self.print_cmout = print_cmout
        if always_capture_stderr is not None:
            self.always_capture_stderr = always_capture_stderr

    def _cache_key(self, args: T.List[str], build_dir: str, env: T.Optional[T.Dict[str, str]]) -> TYPE_cache_key:
        fenv = frozenset(env.items()) if env is not None else frozenset()
        targs = tuple(args)
        return (self.cmakebin.get_path(), targs, build_dir, fenv)

    def _call_cmout_stderr(self, args: T.List[str], build_dir: str, env: T.Optional[T.Dict[str, str]]) -> TYPE_result:
        cmd = self.cmakebin.get_command() + args
        proc = S.Popen(cmd, stdout=S.PIPE, stderr=S.PIPE, cwd=build_dir, env=env)

        # stdout and stderr MUST be read at the same time to avoid pipe
        # blocking issues. The easiest way to do this is with a separate
        # thread for one of the pipes.
        def print_stdout() -> None:
            while True:
                line = proc.stdout.readline()
                if not line:
                    break
                mlog.log(line.decode(errors='ignore').strip('\n'))
            proc.stdout.close()

        t = Thread(target=print_stdout)
        t.start()

        try:
            # Read stderr line by line and log non trace lines
            raw_trace = ''
            tline_start_reg = re.compile(r'^\s*(.*\.(cmake|txt))\(([0-9]+)\):\s*(\w+)\(.*$')
            inside_multiline_trace = False
            while True:
                line_raw = proc.stderr.readline()
                if not line_raw:
                    break
                line = line_raw.decode(errors='ignore')
                if tline_start_reg.match(line):
                    raw_trace += line
                    inside_multiline_trace = not line.endswith(' )\n')
                elif inside_multiline_trace:
                    raw_trace += line
                else:
                    mlog.warning(line.strip('\n'))

        finally:
            proc.stderr.close()
            t.join()
            proc.wait()

        return proc.returncode, None, raw_trace

    def _call_cmout(self, args: T.List[str], build_dir: str, env: T.Optional[T.Dict[str, str]]) -> TYPE_result:
        cmd = self.cmakebin.get_command() + args
        proc = S.Popen(cmd, stdout=S.PIPE, stderr=S.STDOUT, cwd=build_dir, env=env)
        while True:
            line = proc.stdout.readline()
            if not line:
                break
            mlog.log(line.decode(errors='ignore').strip('\n'))
        proc.stdout.close()
        proc.wait()
        return proc.returncode, None, None

    def _call_quiet(self, args: T.List[str], build_dir: str, env: T.Optional[T.Dict[str, str]]) -> TYPE_result:
        os.makedirs(build_dir, exist_ok=True)
        cmd = self.cmakebin.get_command() + args
        ret = S.run(cmd, env=env, cwd=build_dir, close_fds=False,
                    stdout=S.PIPE, stderr=S.PIPE, universal_newlines=False)
        rc = ret.returncode
        out = ret.stdout.decode(errors='ignore')
        err = ret.stderr.decode(errors='ignore')
        call = ' '.join(cmd)
        mlog.debug("Called `{}` in {} -> {}".format(call, build_dir, rc))
        return rc, out, err

    def _call_impl(self, args: T.List[str], build_dir: str, env: T.Optional[T.Dict[str, str]]) -> TYPE_result:
        if not self.print_cmout:
            return self._call_quiet(args, build_dir, env)
        else:
            if self.always_capture_stderr:
                return self._call_cmout_stderr(args, build_dir, env)
            else:
                return self._call_cmout(args, build_dir, env)

    def call(self, args: T.List[str], build_dir: str, env: T.Optional[T.Dict[str, str]] = None, disable_cache: bool = False) -> TYPE_result:
        if env is None:
            env = os.environ.copy()

        args = args + self.extra_cmake_args
        if disable_cache:
            return self._call_impl(args, build_dir, env)

        # First check if cached, if not call the real cmake function
        cache = CMakeExecutor.class_cmake_cache
        key = self._cache_key(args, build_dir, env)
        if key not in cache:
            cache[key] = self._call_impl(args, build_dir, env)
        return cache[key]

    def call_with_fake_build(self, args: T.List[str], build_dir: str, env: T.Optional[T.Dict[str, str]] = None) -> TYPE_result:
        # First check the cache
        cache = CMakeExecutor.class_cmake_cache
        key = self._cache_key(args, build_dir, env)
        if key in cache:
            return cache[key]

        os.makedirs(build_dir, exist_ok=True)

        # Try to set the correct compiler for C and C++
        # This step is required to make try_compile work inside CMake
        fallback = os.path.realpath(__file__)  # A file used as a fallback wehen everything else fails
        compilers = self.environment.coredata.compilers[MachineChoice.BUILD]

        def make_abs(exe: str, lang: str) -> str:
            if os.path.isabs(exe):
                return exe

            p = shutil.which(exe)
            if p is None:
                mlog.debug('Failed to find a {} compiler for CMake. This might cause CMake to fail.'.format(lang))
                p = fallback
            return p

        def choose_compiler(lang: str) -> T.Tuple[str, str, str, str]:
            comp_obj = None
            exe_list = []
            if lang in compilers:
                comp_obj = compilers[lang]
            else:
                try:
                    comp_obj = self.environment.compiler_from_language(lang, MachineChoice.BUILD)
                except Exception:
                    pass

            if comp_obj is not None:
                exe_list = comp_obj.get_exelist()
                comp_id = meson_compiler_to_cmake_id(comp_obj)
                comp_version = comp_obj.version.upper()

            if len(exe_list) == 1:
                return make_abs(exe_list[0], lang), '', comp_id, comp_version
            elif len(exe_list) == 2:
                return make_abs(exe_list[1], lang), make_abs(exe_list[0], lang), comp_id, comp_version
            else:
                mlog.debug('Failed to find a {} compiler for CMake. This might cause CMake to fail.'.format(lang))
                return fallback, '', 'GNU', ''

        c_comp, c_launcher, c_id, c_version = choose_compiler('c')
        cxx_comp, cxx_launcher, cxx_id, cxx_version = choose_compiler('cpp')
        fortran_comp, fortran_launcher, _, _ = choose_compiler('fortran')

        # on Windows, choose_compiler returns path with \ as separator - replace by / before writing to CMAKE file
        c_comp = c_comp.replace('\\', '/')
        c_launcher = c_launcher.replace('\\', '/')
        cxx_comp = cxx_comp.replace('\\', '/')
        cxx_launcher = cxx_launcher.replace('\\', '/')
        fortran_comp = fortran_comp.replace('\\', '/')
        fortran_launcher = fortran_launcher.replace('\\', '/')

        # Reset the CMake cache
        (Path(build_dir) / 'CMakeCache.txt').write_text('CMAKE_PLATFORM_INFO_INITIALIZED:INTERNAL=1\n')

        # Fake the compiler files
        comp_dir = Path(build_dir) / 'CMakeFiles' / self.cmakevers
        comp_dir.mkdir(parents=True, exist_ok=True)

        c_comp_file = comp_dir / 'CMakeCCompiler.cmake'
        cxx_comp_file = comp_dir / 'CMakeCXXCompiler.cmake'
        fortran_comp_file = comp_dir / 'CMakeFortranCompiler.cmake'

        if c_comp and not c_comp_file.is_file():
            is_gnu = '1' if c_id == 'GNU' else ''
            c_comp_file.write_text(textwrap.dedent('''\
                # Fake CMake file to skip the boring and slow stuff
                set(CMAKE_C_COMPILER "{}") # Should be a valid compiler for try_compile, etc.
                set(CMAKE_C_COMPILER_LAUNCHER "{}") # The compiler launcher (if presentt)
                set(CMAKE_COMPILER_IS_GNUCC {})
                set(CMAKE_C_COMPILER_ID "{}")
                set(CMAKE_C_COMPILER_VERSION "{}")
                set(CMAKE_C_COMPILER_LOADED 1)
                set(CMAKE_C_COMPILER_FORCED 1)
                set(CMAKE_C_COMPILER_WORKS TRUE)
                set(CMAKE_C_ABI_COMPILED TRUE)
                set(CMAKE_C_SOURCE_FILE_EXTENSIONS c;m)
                set(CMAKE_C_IGNORE_EXTENSIONS h;H;o;O;obj;OBJ;def;DEF;rc;RC)
                set(CMAKE_SIZEOF_VOID_P "{}")
            '''.format(c_comp, c_launcher, is_gnu, c_id, c_version,
                       ctypes.sizeof(ctypes.c_void_p))))

        if cxx_comp and not cxx_comp_file.is_file():
            is_gnu = '1' if cxx_id == 'GNU' else ''
            cxx_comp_file.write_text(textwrap.dedent('''\
                # Fake CMake file to skip the boring and slow stuff
                set(CMAKE_CXX_COMPILER "{}") # Should be a valid compiler for try_compile, etc.
                set(CMAKE_CXX_COMPILER_LAUNCHER "{}") # The compiler launcher (if presentt)
                set(CMAKE_COMPILER_IS_GNUCXX {})
                set(CMAKE_CXX_COMPILER_ID "{}")
                set(CMAKE_CXX_COMPILER_VERSION "{}")
                set(CMAKE_CXX_COMPILER_LOADED 1)
                set(CMAKE_CXX_COMPILER_FORCED 1)
                set(CMAKE_CXX_COMPILER_WORKS TRUE)
                set(CMAKE_CXX_ABI_COMPILED TRUE)
                set(CMAKE_CXX_IGNORE_EXTENSIONS inl;h;hpp;HPP;H;o;O;obj;OBJ;def;DEF;rc;RC)
                set(CMAKE_CXX_SOURCE_FILE_EXTENSIONS C;M;c++;cc;cpp;cxx;mm;CPP)
                set(CMAKE_SIZEOF_VOID_P "{}")
            '''.format(cxx_comp, cxx_launcher, is_gnu, cxx_id, cxx_version,
                       ctypes.sizeof(ctypes.c_void_p))))

        if fortran_comp and not fortran_comp_file.is_file():
            fortran_comp_file.write_text(textwrap.dedent('''\
                # Fake CMake file to skip the boring and slow stuff
                set(CMAKE_Fortran_COMPILER "{}") # Should be a valid compiler for try_compile, etc.
                set(CMAKE_Fortran_COMPILER_LAUNCHER "{}") # The compiler launcher (if presentt)
                set(CMAKE_Fortran_COMPILER_ID "GNU") # Pretend we have found GCC
                set(CMAKE_COMPILER_IS_GNUG77 1)
                set(CMAKE_Fortran_COMPILER_LOADED 1)
                set(CMAKE_Fortran_COMPILER_WORKS TRUE)
                set(CMAKE_Fortran_ABI_COMPILED TRUE)
                set(CMAKE_Fortran_IGNORE_EXTENSIONS h;H;o;O;obj;OBJ;def;DEF;rc;RC)
                set(CMAKE_Fortran_SOURCE_FILE_EXTENSIONS f;F;fpp;FPP;f77;F77;f90;F90;for;For;FOR;f95;F95)
                set(CMAKE_SIZEOF_VOID_P "{}")
            '''.format(fortran_comp, fortran_launcher, ctypes.sizeof(ctypes.c_void_p))))

        return self.call(args, build_dir, env)

    def found(self) -> bool:
        return self.cmakebin is not None

    def version(self) -> str:
        return self.cmakevers

    def executable_path(self) -> str:
        return self.cmakebin.get_path()

    def get_command(self) -> T.List[str]:
        return self.cmakebin.get_command()

    def get_cmake_prefix_paths(self) -> T.List[str]:
        return self.prefix_paths

    def machine_choice(self) -> MachineChoice:
        return self.for_machine