"""
SCons++ Bootstrapper
"""


import os
from pathlib import Path
import shutil
import subprocess
import sys
from SCons.Environment import Environment


Import('config')


_SPP_FOLDER_NAME = 'scons-plus-plus'
_SPP_DEFAULT_REPOSITORY = 'https://git.mewin.de/mewin/scons-plus-plus.git'
_SPP_DEFAULT_BRANCH = 'master'


spp_root: Path
spp_repository: str
spp_branch: str

def _main() -> Environment:
    global spp_root, spp_repository, spp_branch

    spp_root = config.get('SPP_ROOT')
    if spp_root is None:
        spp_root = _get_default_spp_root()
    elif not isinstance(spp_root, Path):
        spp_root = Path(str(spp_root))
    spp_root = spp_root.absolute()

    spp_repository = config.get('SPP_REPOSITORY', _SPP_DEFAULT_REPOSITORY)
    spp_branch = config.get('SPP_BRANCH', _SPP_DEFAULT_BRANCH)

    _printinfo(f'Using SCons++ root at: {spp_root}')

    if not spp_root.exists():
        _printinfo('SCons++ does not yet exist, downloading it.')
        _install_spp()

    spp_script = spp_root / 'SConscript'
    if not spp_script.exists():
        _printerr(f'SCons++ main script not found at {spp_script}!')
        sys.exit(1)
    return SConscript(spp_script, exports=['config'])

def _get_default_spp_root() -> Path:
    if os.name == 'posix':
        # follow XDG specification -> first try $XDG_DATA_HOME, then $HOME/.local/share
        data_home = os.environ.get('XDG_DATA_HOME')
        if data_home is not None:
            return Path(data_home, _SPP_FOLDER_NAME)
        home = os.environ.get('HOME')
        if home is not None:
            return Path(home, '.local', 'share', _SPP_FOLDER_NAME)
    elif os.name == 'nt':
        # just use LocalAppData, which should always be set on Windows
        return Path(os.environ['LocalAppData'], _SPP_FOLDER_NAME)
    _printinfo(f'Could not detect SCons++ root directory, falling back to ./{_SPP_FOLDER_NAME}.')
    return Path(_SPP_FOLDER_NAME)

def _install_spp() -> None:
    git_exe = shutil.which('git')
    if git_exe is None:
        _printerr('No git executable found, cannot install SCons++.')
        sys.exit(1)
    _exec_checked((git_exe, 'clone', '-b', spp_branch, '--progress', spp_repository, spp_root))

def _exec_checked(args: Sequence[str], **kwargs) -> None:
    subprocess.run(args, stdout=sys.stdout, stderr=sys.stderr, check=True, **kwargs)

if not GetOption('silent'):
    _printinfo = print
else:
    def _printinfo(*args): ...
def _printerr(*args) -> None:
    print(*args, file=sys.stderr)

env = _main()
Return('env')