#
#    Helper module to build macOS version of various source ports
#    Copyright (C) 2020-2021 Alexey Lysiuk
#
#    This program is free software: you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation, either version 3 of the License, or
#    (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program.  If not, see <http://www.gnu.org/licenses/>.
#

import argparse
import copy
import os
from pathlib import Path
from platform import machine
import shutil
import subprocess
import typing

from .state import BuildState
from .target import Target, targets
from .utility import CaseInsensitiveDict, TargetPlatform, symlink_directory, OS_VERSION_X86_64, OS_VERSION_ARM64


class Builder(object):
    def __init__(self, args: list):
        self._targets = CaseInsensitiveDict({target.name: target for target in targets()})

        arguments = self._parse_arguments(args)

        state = self._state = BuildState()
        state.xcode = arguments.xcode
        state.verbose = arguments.verbose

        self._platforms = []
        self._populate_platforms(arguments)

        state.platform = self._platforms[0]

        if arguments.source_path:
            state.source_path = Path(arguments.source_path).absolute()

        if arguments.target:
            self._target = self._targets[arguments.target]
            state.source = state.source_path / self._target.name
            state.external_source = False
        else:
            assert arguments.source
            state.source = Path(arguments.source).absolute()
            state.external_source = True
            self._detect_target()

        del self._targets

        if arguments.build_path:
            state.build_path = Path(arguments.build_path).absolute()
        else:
            state.build_path = state.root_path / 'build' / self._target.name / ('xcode' if state.xcode else 'make')

        if arguments.output_path:
            state.output_path = Path(arguments.output_path).absolute()
        else:
            state.output_path = state.root_path / 'output'

        state.jobs = arguments.jobs and arguments.jobs or \
            subprocess.check_output(['sysctl', '-n', 'hw.ncpu']).decode('ascii').strip()

    def _populate_platforms(self, arguments):
        state = self._state

        def adjust_sdk_path(path: Path) -> Path:
            if path:
                return path.absolute()

            sdk_probe_path = state.root_path / 'sdk' / f'MacOSX{os_version}.sdk'
            return sdk_probe_path if sdk_probe_path.exists() else None

        if not arguments.disable_x64:
            os_version = arguments.os_version_x64 if arguments.os_version_x64 else OS_VERSION_X86_64
            sdk_path = adjust_sdk_path(arguments.sdk_path_x64)
            platform = TargetPlatform('x86_64', 'x86_64-apple-darwin', os_version, sdk_path, state.prefix_path)
            self._platforms.append(platform)

        if not arguments.disable_arm:
            os_version = arguments.os_version_arm if arguments.os_version_arm else OS_VERSION_ARM64
            sdk_path = adjust_sdk_path(arguments.sdk_path_arm)
            platform = TargetPlatform('arm64', 'aarch64-apple-darwin', os_version, sdk_path, state.prefix_path)
            self._platforms.append(platform)

        assert len(self._platforms) > 0

        # Put native platform first in the list of platforms
        if self._platforms[0].architecture == machine():
            return

        for platform in self._platforms:
            if platform.architecture == machine():
                native_platform = platform
                self._platforms.remove(platform)
                self._platforms.insert(0, native_platform)
                break

    def run(self):
        state = self._state
        target = self._target
        target.prepare_source(state)

        if target.destination == Target.DESTINATION_DEPS:
            state.install_path = state.deps_path / target.name
        elif target.destination == Target.DESTINATION_OUTPUT:
            state.install_path = state.output_path / target.name

        assert state.install_path

        if not state.xcode and state.install_path.exists():
            shutil.rmtree(state.install_path)

        self._create_prefix_directory()

        if target.multi_platform and not state.xcode:
            self._build_multiple_platforms(target)
        else:
            self._build(target)

    def _build(self, target: Target):
        state = self._state

        target.configure(state)
        target.build(state)
        target.post_build(state)

    def _build_multiple_platforms(self, base_target: Target):
        assert base_target.multi_platform

        state = self._state
        base_build_path = state.build_path
        base_install_path = state.install_path
        install_paths = []

        for platform in self._platforms:
            if platform.architecture in base_target.unsupported_architectures:
                continue

            state.platform = platform
            state.build_path = base_build_path / ('build_' + platform.architecture)

            if platform.architecture == machine():
                state.native_build_path = state.build_path

            target = copy.deepcopy(base_target)
            state.install_path = base_build_path / ('install_' + platform.architecture)

            self._build(target)

            install_paths.append(state.install_path)

        Builder._merge_install_paths(install_paths, base_install_path)

    @staticmethod
    def _compare_files(paths: typing.Sequence[Path]) -> bool:
        content = None

        for path in paths:
            if not path.exists():
                return False

            with path.open('rb') as f:
                if content:
                    if content != f.read():
                        return False
                else:
                    content = f.read()

        return True

    @staticmethod
    def _merge_file(src: Path, src_sub_paths: typing.Sequence[Path], dst_path: Path):
        with open(src, 'rb') as f:
            header = f.read(8)

        is_executable = header[:4] == b'\xcf\xfa\xed\xfe'
        is_library = header == b'!<arch>\n'

        if is_executable or is_library:
            # Merge executable and library files
            dst_file = dst_path / src.name

            args = ['lipo']
            args += src_sub_paths
            args += ['-create', '-output', dst_file]
            subprocess.check_call(args)

            # Apply ad-hoc code signing on executable files outside of application bundles
            if is_executable and '.app/Contents/' not in str(src):
                args = ('codesign', '--sign', '-', dst_file)
                subprocess.check_call(args)
        else:
            if not Builder._compare_files(src_sub_paths):
                print(f'WARNING: Source files for {dst_path / src.name} don\'t match')
            shutil.copy(src_sub_paths[0], dst_path)

    @staticmethod
    def _merge_missing_files(src_paths: typing.Sequence[Path], dst_path: Path):
        shifted_src_paths = [path for path in src_paths]
        last_path_index = len(src_paths) - 1

        for _ in range(last_path_index):
            shifted_src_paths.append(shifted_src_paths[0])
            del shifted_src_paths[0]

            if not shifted_src_paths[0].exists():
                continue

            Builder._merge_install_paths(shifted_src_paths, dst_path, missing_files_only=True)

    @staticmethod
    def _merge_install_paths(src_paths: typing.Sequence[Path], dst_path: Path, missing_files_only=False):
        if len(src_paths) == 0:
            return

        if not missing_files_only:
            if dst_path.exists():
                shutil.rmtree(dst_path)

        os.makedirs(dst_path, exist_ok=True)

        for src in src_paths[0].iterdir():
            src_sub_paths = [path / src.name for path in src_paths]

            if src.is_dir():
                Builder._merge_install_paths(src_sub_paths, dst_path / src.name, missing_files_only)
            elif src.name.endswith('.la'):
                # Skip libtool files
                continue
            elif missing_files_only:
                for src_sub_path in src_sub_paths[1:]:
                    if not src_sub_path.exists():
                        shutil.copy(src_sub_paths[0], dst_path)
            else:
                Builder._merge_file(src, src_sub_paths, dst_path)

        if not missing_files_only:
            Builder._merge_missing_files(src_paths, dst_path)

    def _create_prefix_directory(self):
        state = self._state
        os.makedirs(state.prefix_path, exist_ok=True)

        cleanup = True

        for dep in state.deps_path.iterdir():
            if dep.is_dir():
                symlink_directory(dep, state.prefix_path, cleanup)

                # Do symlink cleanup only once
                cleanup = False

    def _detect_target(self):
        for name, target in self._targets.items():
            if target.detect(self._state):
                self._target = self._targets[name]
                break

        assert self._target

    def _parse_arguments(self, args: list):
        assert self._targets

        parser = argparse.ArgumentParser(description='*ZDoom binary dependencies for macOS')

        group = parser.add_mutually_exclusive_group(required=True)
        group.add_argument('--target', choices=self._targets.keys(), help='target to build')
        group.add_argument('--source', metavar='path', help='path to target\'s source code')

        group = parser.add_argument_group()
        group.add_argument('--xcode', action='store_true', help='generate Xcode project instead of build')
        group.add_argument('--source-path', metavar='path',
                           help='path to store downloaded and checked out source code')
        group.add_argument('--build-path', metavar='path', help='target build path')
        group.add_argument('--output-path', metavar='path', help='output path for main targets')
        group.add_argument('--sdk-path-x64', metavar='path', help='path to macOS SDK for x86_64')
        group.add_argument('--sdk-path-arm', metavar='path', help='path to macOS SDK for ARM64')
        group.add_argument('--os-version-x64', metavar='version', help='macOS deployment version for x86_64')
        group.add_argument('--os-version-arm', metavar='version', help='macOS deployment version for ARM64')
        group.add_argument('--verbose', action='store_true', help='enable verbose build output')
        group.add_argument('--jobs', help='number of parallel compilation jobs')

        group = parser.add_mutually_exclusive_group()
        group.add_argument('--disable-x64', action='store_true', help='disable x86_64 support')
        group.add_argument('--disable-arm', action='store_true', help='disable ARM64 support')

        return parser.parse_args(args)