from pathlib import Path

from .preprocessor import Preprocessor
from ..utils import raise_for_structure, canonical_jobspec


canonical_default = {
    'type': 'default',
    'data': canonical_jobspec}

@Preprocessor.register
class DefaultProcessor(Preprocessor):
    """
    Preprocessing for standard jobs. It passes the job onwards unchanged
    since the incoming job should already conform to the unified job format.
    """
    def validate(self, queueitem):
        raise_for_structure(queueitem, canonical_default)
        if 'upload_dir' in queueitem['data']:
            upload_dir = Path(queueitem['data']['upload_dir'])
            if not upload_dir.exists():
                raise ValueError('Specified upload_dir does not exist.')
        return True

    def _preprocess(self, job):
        jobid = job['jobid']
        jobspec = job['queueitem']['data']
        return {'jobid': jobid,
                'jobspec': jobspec}