#!/usr/bin/env python3

import os
import pathlib
import subprocess

import common
from cli_function import Argument

class Main(common.BuildCliFunction):
    def do_get_arguments(self):
        return [
            Argument(
                'extra_scons_args',
                metavar='extra-scons-args',
                nargs='*',
            )
        ]

    def do_main(self, **kwargs):
        build_dir = self.get_build_dir(**kwargs)
        binaries_dir = os.path.join(kwargs['gem5_system_dir'], 'binaries')
        disks_dir = os.path.join(kwargs['gem5_system_dir'], 'disks')
        os.makedirs(binaries_dir, exist_ok=True)
        os.makedirs(disks_dir, exist_ok=True)
        if kwargs['gem5_source_dir'] is None:
            if not os.path.exists(os.path.join(kwargs['gem5_src_dir'], '.git')):
                if kwargs['gem5_src_dir'] == kwargs['gem5_default_src_dir']:
                    raise Exception('gem5 submodule not checked out')
                common.run_cmd([
                    'git', common.Newline,
                    '-C', kwargs['gem5_default_src_dir'], common.Newline,
                    'worktree', 'add', common.Newline,
                    '-b', os.path.join('wt', kwargs['gem5_build_id']), common.Newline,
                    kwargs['gem5_src_dir'], common.Newline,
                ])
        if kwargs['verbose']:
            verbose = ['--verbose', common.Newline]
        else:
            verbose = []
        if kwargs['arch'] == 'x86_64':
            dummy_img_path = os.path.join(disks_dir, 'linux-bigswap2.img')
            with open(dummy_img_path, 'wb') as dummy_img_file:
                zeroes = b'\x00' * (2 ** 16)
                for i in range(2 ** 10):
                    dummy_img_file.write(zeroes)
            common.run_cmd(['mkswap', dummy_img_path])
            with open(os.path.join(binaries_dir, 'x86_64-vmlinux-2.6.22.9'), 'w'):
                # This file must always be present, despite --kernel overriding that default and selecting the kernel.
                # I'm not even joking. No one has ever built x86 gem5 without the magic dist dir present.
                pass
        elif kwargs['arch'] == 'arm' or kwargs['arch'] == 'aarch64':
            gem5_system_src_dir = os.path.join(kwargs['gem5_src_dir'], 'system')

            # dtb
            dt_src_dir = os.path.join(gem5_system_src_dir, 'arm', 'dt')
            dt_build_dir = os.path.join(kwargs['gem5_system_dir'], 'arm', 'dt')
            common.run_cmd([
                'make', common.Newline,
                '-C', dt_src_dir, common.Newline,
            ])
            common.copy_dir_if_update_non_recursive(
                srcdir=dt_src_dir,
                destdir=dt_build_dir,
                filter_ext='.dtb',
            )

            # Bootloader 32.
            bootloader32_dir = os.path.join(gem5_system_src_dir, 'arm', 'simple_bootloader')
            # TODO use the buildroot cross compiler here, and remove the dependencies from configure.
            common.run_cmd([
                'make', common.Newline,
                '-C', bootloader32_dir, common.Newline,
                'CROSS_COMPILE=arm-linux-gnueabihf-', common.Newline,
            ])
            # bootloader
            common.cp(os.path.join(bootloader32_dir, 'boot_emm.arm'), binaries_dir)

            # Bootloader 64.
            bootloader64_dir = os.path.join(gem5_system_src_dir, 'arm', 'aarch64_bootloader')
            # TODO cross_compile is ignored because the make does not use CC...
            common.run_cmd([
                'make', common.Newline,
                '-C', bootloader64_dir, common.Newline
            ])
            common.cp(os.path.join(bootloader64_dir, 'boot_emm.arm64'), binaries_dir)
        common.run_cmd(
            (
                [
                    'scons', common.Newline,
                    '-j', str(kwargs['nproc']), common.Newline,
                    '--gold-linker', common.Newline,
                    '--ignore-style', common.Newline,
                    kwargs['gem5_executable'], common.Newline,
                ] +
                verbose +
                common.add_newlines(kwargs['extra_scons_args'])
            ),
            cwd=kwargs['gem5_src_dir'],
            extra_paths=[kwargs['ccache_dir']],
        )
        term_src_dir = os.path.join(kwargs['gem5_src_dir'], 'util/term')
        m5term_build = os.path.join(term_src_dir, 'm5term')
        common.run_cmd(['make', '-C', term_src_dir])
        if os.path.exists(kwargs['gem5_m5term']):
            # Otherwise common.cp would fail with "Text file busy" if you
            # tried to rebuild while running m5term:
            # https://stackoverflow.com/questions/16764946/what-generates-the-text-file-busy-message-in-unix/52427512#52427512
            os.unlink(kwargs['gem5_m5term'])
        common.cp(m5term_build, kwargs['gem5_m5term'])

    def get_build_dir(self, **kwargs):
        return kwargs['gem5_build_dir']

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