# standard imports
import logging

logg = logging.getLogger(__name__)


class Processor:
    
    def __init__(self, metadata=None, outputs_writer=None, extensions=[]):
        self.token_address = None
        self.metadata = metadata
        self.extensions = extensions
        self.outputs = []
        self.__outputs_writer = outputs_writer


    def writer(self):
        return self.__outputs_writer


    def can_process(self):
        return self.token_address != None


    def process_metadata(self, writer=None):
        if not self.can_process():
            raise RuntimeError('incomplete processing state for metadata')


    def get_outputs(self):
        outputs = []
        for ext in self.extensions:
            outputs += ext.outputs
        outputs += self.outputs
        return outputs


    def process(self):
        tasks = [
            'metadata',
            ]

        for ext in self.extensions:
            token_address = ext.process()

            for task in tasks:
                a = getattr(self, task)
                if a == None:
                    logg.debug('skipping missing task receiver "{}"'.format(task))
                    continue
                v = a.process(token_address=token_address, writer=self.__outputs_writer)
                self.outputs.append(v)