import subprocess as subproc
import os
from pathlib import Path

from mubench.lang import Language
from mubench import CALLBACKS_DIR
from mubench.exceptions import ExecutionFailure


class Mu(Language):
    name = 'mu'
    src_ext = 'c'   # one or a folder of C files calling API to build the bundle
    compiled = True
    default_exec = 'clang'    # assume presence of clang

    @classmethod
    def compile(cls, src_file, target_dir=None, **compiler_conf):
        callback_dir = CALLBACKS_DIR / cls.name

        cmd = []
        cmd.append(os.path.expandvars(compiler_conf.get('exec', cls.default_exec)))

        # flags
        flags = []
        default_flags = ['-I%(callback_dir)s' % locals()]
        flags.extend(compiler_conf.get('flags', default_flags))
        target_dir = target_dir if target_dir else src_file.parent
        target = target_dir / src_file.name[:-2]
        flags.extend(['-o', str(target)])
        cmd.extend(flags)

        cmd.append(str(src_file))

        # callback selected at compile time, initialised at runtime
        callback_file = callback_dir / compiler_conf['callback']['name']
        cmd.append(str(callback_file))

        cls.run_in_subproc(cmd)

        assert target.exists()
        return target


    @classmethod
    def run(cls, target, iterations, args, result_file, **runner_conf):
        cmd = [str(target)]

        # first argument: callback param
        cmd.append(runner_conf['callback']['param'])

        # second argument: iterations
        cmd.append(str(iterations))

        # third argument: result file name
        cmd.append(str(result_file))

        cmd.extend(map(str, args))

        cls.run_in_subproc(cmd)