#!/usr/bin/env python3

import platform
import re
import os

import cli_function
import collections
import common
import copy
import shell_helpers
from shell_helpers import LF

class _Component:
    '''
    Yes, we are re-inventing a crappy dependency resolution system,
    reminescent of scons or apt or Buildroot. I can't believe it.

    The hard part is that we have optional dependencies as well...
    e.g. buildroot optionally depends on m5 to put m5 in the root filesystem,
    and buildroot optionally depends on qemu to build the qcow2 version
    of the image.
    '''
    def __init__(
        self,
        build_callback=None,
        supported_archs=None,
        dependencies=None,
        apt_get_pkgs=None,
        apt_build_deps=None,
        submodules=None,
        submodules_shallow=None,
        python2_pkgs=None,
        python3_pkgs=None,
    ):
        self.build_callback = build_callback
        self.supported_archs = supported_archs
        self.dependencies = dependencies or set()
        self.apt_get_pkgs = apt_get_pkgs or set()
        self.apt_build_deps = apt_build_deps or set()
        self.submodules = submodules or set()
        self.submodules_shallow = submodules_shallow or set()
        self.python2_pkgs = python2_pkgs or set()
        self.python3_pkgs = python3_pkgs or set()

    def build(self, arch):
        if (
            (self.build_callback is not None) and
            (self.supported_archs is None or arch in self.supported_archs)
        ):
            self.build_callback()

class Main(common.LkmcCliFunction):
    def __init__(self):
        super().__init__(
            description='''\
Build a component and all its dependencies.

Our build-* scripts don't build any dependencies to make iterative
development fast and more predictable.

It is currently not possible to configure indivitual components from the command line
when you build with this script. TODO.

Without any args, build only what is necessary for:
https://github.com/cirosantilli/linux-kernel-module-cheat#qemu-buildroot-setup

....
./%(prog)s
....

This is equivalent to:

....
./%(prog)s --arch x86_64 qemu-buildroot
....
''',
        )
        buildroot_component = _Component(
            self._build_file('build-buildroot'),
            submodules = {'buildroot'},
            # https://buildroot.org/downloads/manual/manual.html#requirement
            apt_get_pkgs={
                'bash',
                'bc',
                'binutils',
                'build-essential',
                'bzip2',
                'cpio',
                'g++',
                'gcc',
                'graphviz',
                'gzip',
                'make',
                'patch',
                'perl',
                'python-matplotlib',
                'python3',
                'rsync',
                'sed',
                'tar',
                'unzip',
            },
        )
        buildroot_overlay_qemu_component = copy.copy(buildroot_component)
        buildroot_overlay_qemu_component.dependencies = ['overlay', 'qemu']
        buildroot_overlay_gem5_component = copy.copy(buildroot_component)
        buildroot_overlay_gem5_component.dependencies = ['overlay-gem5']
        gem5_deps = {
            # TODO test it out on Docker and answer that question properly:
            # https://askubuntu.com/questions/350475/how-can-i-install-gem5
            'apt_get_pkgs': {
                'device-tree-compiler',
                'diod',
                'libgoogle-perftools-dev',
                'm4',
                'protobuf-compiler',
                'python-dev',
                'python-pip',
                # For prebuilt qcow2 unpack.
                'qemu-utils',
                'scons',
                'zlib1g-dev',
            },
            'python2_pkgs': {
                # Generate graphs of config.ini under m5out.
                'pydot',
            },
            'submodules': {'gem5'},
        }

        self.name_to_component_map = {
            'all': _Component(dependencies=[
                'all-linux',
                'all-baremetal',
            ]),
            'all-baremetal': _Component(dependencies=[
                    'qemu-baremetal',
                    'gem5-baremetal',
                    'baremetal-gem5-pbx',
                ],
                supported_archs=common.consts['crosstool_ng_supported_archs'],
            ),
            'all-linux': _Component(dependencies=[
                'qemu-gem5-buildroot',
                'gem5-debug',
                'gem5-fast',
                'qemu-user',
            ]),
            'baremetal': _Component(dependencies=[
                'baremetal-gem5',
                'baremetal-qemu',
            ]),
            'baremetal-qemu': _Component(
                self._build_file('build-baremetal', emulators=['qemu']),
                supported_archs=common.consts['crosstool_ng_supported_archs'],
                dependencies=['crosstool-ng'],
            ),
            'baremetal-gem5': _Component(
                self._build_file('build-baremetal', emulators=['gem5']),
                supported_archs=common.consts['crosstool_ng_supported_archs'],
                dependencies=['crosstool-ng'],
            ),
            'baremetal-gem5-pbx': _Component(
                self._build_file('build-baremetal', emulators=['gem5'], machine='RealViewPBX'),
                supported_archs=common.consts['crosstool_ng_supported_archs'],
                dependencies=['crosstool-ng'],
            ),
            'buildroot': buildroot_component,
            'buildroot-overlay-qemu': buildroot_overlay_qemu_component,
            'buildroot-overlay-gem5': buildroot_overlay_gem5_component,
            'copy-overlay': _Component(
                self._build_file('copy-overlay'),
            ),
            'crosstool-ng': _Component(
                self._build_file('build-crosstool-ng'),
                supported_archs=common.consts['crosstool_ng_supported_archs'],
                # http://crosstool-ng.github.io/docs/os-setup/
                apt_get_pkgs={
                    'bison',
                    'docbook2x',
                    'flex',
                    'gawk',
                    'gcc',
                    'gperf',
                    'help2man',
                    'libncurses5-dev',
                    'libtool-bin',
                    'make',
                    'python-dev',
                    'texinfo',
                },
                submodules={'crosstool-ng'},
            ),
            'gem5': _Component(
                self._build_file('build-gem5'),
                **gem5_deps
            ),
            'gem5-baremetal': _Component(dependencies=[
                'gem5',
                'baremetal-gem5',
            ]),
            'gem5-buildroot': _Component(dependencies=[
                'buildroot-overlay-gem5',
                'linux',
                'gem5',
            ]),
            'gem5-debug': _Component(
                self._build_file('build-gem5', gem5_build_type='debug'),
                **gem5_deps
            ),
            'gem5-fast': _Component(
                self._build_file('build-gem5', gem5_build_type='fast'),
                **gem5_deps
            ),
            'linux': _Component(
                self._build_file('build-linux', gem5_build_type='fast'),
                dependencies={'buildroot'},
                submodules_shallow={'linux'},
                apt_get_pkgs={
                    'bison',
                    'flex',
                    # Without this started failing in kernel 4.15 with:
                    # Makefile:932: *** "Cannot generate ORC metadata for CONFIG_UNWINDER_ORC=y, please install libelf-dev, libelf-devel or elfutils-libelf-devel".  Stop.
                    'libelf-dev',
                },
            ),
            'modules': _Component(
                self._build_file('build-modules'),
                dependencies=['buildroot', 'linux'],
            ),
            'm5': _Component(
                self._build_file('build-m5'),
                dependencies=['buildroot'],
                submodules={'gem5'},
            ),
            'overlay': _Component(dependencies=[
                'copy-overlay',
                'modules',
                'userland',
            ]),
            'overlay-gem5': _Component(dependencies=[
                'm5',
                'overlay',
            ]),
            'parsec-benchmark': _Component(
                submodules={'parsec-benchmark'},
                dependencies=['buildroot'],
            ),
            'qemu': _Component(
                self._build_file('build-qemu'),
                apt_build_deps={'qemu'},
                apt_get_pkgs={'libsdl2-dev'},
                submodules={'qemu'},
            ),
            'qemu-baremetal': _Component(dependencies=[
                'qemu',
                'baremetal-qemu',
            ]),
            'qemu-buildroot': _Component(dependencies=[
                'buildroot-overlay-qemu',
                'linux',
            ]),
            'qemu-gem5-buildroot': _Component(dependencies=[
                'qemu',
                'gem5-buildroot',
            ]),
            'qemu-user': _Component(
                self._build_file('build-qemu', user_mode=True),
                apt_build_deps = {'qemu'},
                apt_get_pkgs={'libsdl2-dev'},
                submodules={'qemu'},
            ),
            'release': _Component(dependencies=[
                'qemu-buildroot',
            ]),
            'test-gdb': _Component(dependencies=[
                    'all-baremetal',
                ],
                supported_archs=common.consts['crosstool_ng_supported_archs'],
            ),
            'userland': _Component(
                self._build_file('build-userland'),
                dependencies=['buildroot'],
            ),
        }
        self.component_to_name_map = {self.name_to_component_map[key]:key for key in self.name_to_component_map}

        self.add_argument(
            '--all',
            default=False,
            help='''\
Build absolutely everything for all archs.
'''
        )
        self.add_argument(
            '--download-dependencies',
            default=False,
            help='''\
Also download all dependencies required for a given build: Ubuntu packages,
Python packages and git submodules.
'''
        )
        self.add_argument(
            '--print-components',
            default=False,
            help='''\
Print the components that would be built, including dependencies, but don't
build them, nor show the build commands.
'''
        )
        self.add_argument(
            '--travis',
            default=False,
            help='''\
Extra args to pass to all scripts.
'''
        )
        self.add_argument(
            'components',
            choices=list(self.name_to_component_map.keys()) + [[]],
            default=[],
            nargs='*',
            help='''\
Which components to build. Default: qemu-buildroot
'''
        )

    def _build_file(self, component_file, **extra_args):
        '''
        Build something based on a component file that defines a Main class.
        '''
        def f():
            args = self.get_common_args()
            args.update(extra_args)
            args['print_time'] = False
            self.import_path_main(component_file)(**args)
        return f

    def timed_main(self):
        self.sh = shell_helpers.ShellHelpers(dry_run=self.env['dry_run'])

        # Decide components.
        components = self.env['components']
        if self.env['all']:
            components = ['all']
        elif components == []:
            components = ['qemu-buildroot']
        selected_components = []
        for component_name in components:
            todo = [component_name]
            while todo:
                current_name = todo.pop(0)
                component = self.name_to_component_map[current_name]
                selected_components.insert(0, component)
                todo.extend(component.dependencies)
        # Remove duplicates, keep only the first one of each.
        # https://stackoverflow.com/questions/7961363/removing-duplicates-in-lists/7961390#7961390
        collections.OrderedDict.fromkeys(selected_components)

        if self.env['download_dependencies']:
            apt_get_pkgs = {
                # Core requirements for this repo.
                'git',
                'moreutils', # ts
                'python3-pip',
                'tmux',
                'vinagre',
                'wget',
            }
            # E.g. on an ARM host, the package gcc-arm-linux-gnueabihf
            # is called just gcc.
            processor = platform.processor()
            if processor != 'arm':
                apt_get_pkgs.update({
                    'gcc-arm-linux-gnueabihf',
                    'g++-arm-linux-gnueabihf',
                })
            if processor != 'aarch64':
                apt_get_pkgs.update({
                    'gcc-aarch64-linux-gnu',
                    'g++-aarch64-linux-gnu',
                })
            apt_build_deps = set()
            submodules = set()
            submodules_shallow = set()
            python2_pkgs = set()
            python3_pkgs = {
                'pexpect==4.6.0',
            }
            for component in selected_components:
                apt_get_pkgs.update(component.apt_get_pkgs)
                apt_build_deps.update(component.apt_build_deps)
                submodules.update(component.submodules)
                submodules_shallow.update(component.submodules_shallow)
                python2_pkgs.update(component.python2_pkgs)
                python3_pkgs.update(component.python3_pkgs)
            if apt_get_pkgs or apt_build_deps:
                if self.env['travis']:
                    interacive_pkgs = {
                        'libsdl2-dev',
                    }
                    apt_get_pkgs.difference_update(interacive_pkgs)
                if common.consts['in_docker']:
                    sudo = []
                    # https://askubuntu.com/questions/909277/avoiding-user-interaction-with-tzdata-when-installing-certbot-in-a-docker-contai
                    os.environ['DEBIAN_FRONTEND'] = 'noninteractive'
                    # https://askubuntu.com/questions/496549/error-you-must-put-some-source-uris-in-your-sources-list
                    sources_path = os.path.join('/etc', 'apt', 'sources.list')
                    with open(sources_path, 'r') as f:
                        sources_txt = f.read()
                    sources_txt = re.sub('^# deb-src ', 'deb-src ', sources_txt, flags=re.MULTILINE)
                    with open(sources_path, 'w') as f:
                        f.write(sources_txt)
                else:
                    sudo = ['sudo']
                if common.consts['in_docker'] or self.env['travis']:
                    y = ['-y']
                else:
                    y = []
                self.sh.run_cmd(
                    sudo + ['apt-get', 'update', LF]
                )
                if apt_get_pkgs:
                    self.sh.run_cmd(
                        sudo + ['apt-get', 'install'] + y + [LF] +
                        self.sh.add_newlines(sorted(apt_get_pkgs))
                    )
                if apt_build_deps:
                    self.sh.run_cmd(
                        sudo +
                        ['apt-get', 'build-dep'] + y + [LF] +
                        self.sh.add_newlines(sorted(apt_build_deps))
                    )
            if python2_pkgs:
                self.sh.run_cmd(
                    ['python', '-m', 'pip', 'install', '--user', LF] +
                    self.sh.add_newlines(sorted(python2_pkgs))
                )
            if python3_pkgs:
                # Not with pip executable directly:
                # https://stackoverflow.com/questions/49836676/error-after-upgrading-pip-cannot-import-name-main/51846054#51846054
                self.sh.run_cmd(
                    ['python3', '-m', 'pip', 'install', '--user', LF] +
                    self.sh.add_newlines(sorted(python3_pkgs))
                )
            git_cmd_common = ['git', 'submodule', 'update', '--init', '--recursive']
            if submodules:
                # == Other nice git options for when distros move to newer Git
                #
                # Currently not on Ubuntu 16.04:
                #
                # `--progress`: added on Git 2.10:
                #
                # * https://stackoverflow.com/questions/32944468/how-to-show-progress-for-submodule-fetching
                # * https://stackoverflow.com/questions/4640020/progress-indicator-for-git-clone
                #
                # `--jobs"`: https://stackoverflow.com/questions/26957237/how-to-make-git-clone-faster-with-multiple-threads/52327638#52327638
                self.sh.run_cmd(
                    git_cmd_common + ['--', LF] +
                    self.sh.add_newlines([os.path.join(common.consts['submodules_dir'], x) for x in sorted(submodules)])
                )
            if submodules_shallow:
                # == Shallow cloning.
                #
                # TODO Ideally we should shallow clone --depth 1 all of them.
                #
                # However, most git servers out there are crap or craply configured
                # and don't allow shallow cloning except for branches.
                #
                # So for now, let's shallow clone only the Linux kernel, which has by far
                # the largest .git repo history, and full clone the others.
                #
                # Then we will maintain a GitHub Linux kernel mirror / fork that always has a
                # lkmc branch, and point to it, so that it will always succeed.
                #
                # See also:
                #
                # * https://stackoverflow.com/questions/3489173/how-to-clone-git-repository-with-specific-revision-changeset
                # * https://stackoverflow.com/questions/2144406/git-shallow-submodules/47374702#47374702
                # * https://unix.stackexchange.com/questions/338578/why-is-the-git-clone-of-the-linux-kernel-source-code-much-larger-than-the-extrac
                #
                self.sh.run_cmd(
                    git_cmd_common + ['--depth', '1', '--', LF] +
                    self.sh.add_newlines([os.path.join(common.consts['submodules_dir'], x) for x in sorted(submodules_shallow)])
                )

        # Do the build.
        for component in selected_components:
            if self.env['print_components']:
                print(self.component_to_name_map[component])
            else:
                component.build(self.env['arch'])

if __name__ == '__main__':
    Main().cli()