GetObservingBlocks

class GetObservingBlocks(KPFFunction):
    '''Retrieve the OB associated with the given unique ID in the KPF-CC
    database.
    '''
    @classmethod
    def pre_condition(cls, args):
        OBid = args.get('OBid', None)
        if OBid is None:
            raise FailedPreCondition('OBid must be provided')

    @classmethod
    def perform(cls, args):
        params = {'id': args.get('OBid', '')}
        OBs = get_OBs_from_KPFCC_API(params)
        if args.get('show_history', False):
            print(f'# Observing History for {OBs[0].summary()}')
            for i,h in enumerate(OBs[0].History):
                print(f"- Observer: {h.get('observer')} (at {h.get('timestamp')})")
                start_times = h.get('exposure_start_times', [])
                if len(start_times) > 0:
                    print(f"  Start Times: {start_times}")
                exposure_times = h.get('exposure_times', [])
                if len(exposure_times) > 0:
                    print(f"  Exposure Times: {exposure_times}")
                comment = h.get('comment', '')
                if len(comment) > 0:
                    print(f"  Observer comment: {comment}")
        return OBs

    @classmethod
    def post_condition(cls, args):
        pass

    @classmethod
    def add_cmdline_args(cls, parser):
        parser.add_argument('OBid', type=str,
                            help='The unique identifier for the OB to retrieve.')
        parser.add_argument('--history', '--show_history', dest="show_history",
            default=False, action="store_true",
            help='Print history to screen?')
        return super().add_cmdline_args(parser)