import shutil
from SCons.Script import *

def exists(env: Environment) -> bool:
    return shutil.which('dxc.exe') is not None

def generate(env : Environment):
    if not exists(env):
        return
    def _build(target, source, env):
        if len(target) != 1:
            env.Error('Invalid number of targets for DXC builder, must be 1.')
        if len(source) != 1:
            env.Error('Invalid number of sources for DXC builder, must be 1.')
        ext = source[0].name.split('.')[-1]
        profile = {
            'vs': 'vs_6_0',
            'ps': 'ps_6_0'
        }.get(ext.lower())
        if not profile:
            env.Error(f'Could not detect DXC shader profile from extension: {ext}')
        env.Execute(f'"$DXC" -O0 -Zi -E main -T {profile} -Fo "{target[0]}" -Fd "{target[0]}.pdb" "{source[0]}')
    dxc_builder = Builder(
        action=_build
    )
    env.AddMethod(_build, 'DXC')
    env['DXC'] = shutil.which('dxc.exe')
    env.Append(BUILDERS={'DXC': dxc_builder})