import h5py
import numpy as np

from slic.core.acquisition.acquisition import Acquisition


# class using the BSQueue to avoid to reestablish a stream for each step.

class BSCAcquisition(Acquisition):
            
    def _acquire(self, filename, channels=None, data_base_dir=None, scan_info=None, n_pulses=100, **kwargs):

        queue =channels[0]  # abusing interface since BSAcquisition assume a list of channels

        # allocating space
        data={}
        chns = queue.channels
        for chn in chns:
            data[chn]={'data':np.zeros((n_pulses))}
        data['pulse_id']=np.zeros((n_pulses))

        # clear the queue
        queue.flush()
        for i in range(n_pulses):
            msg = queue.__next__()   # pull data from cache
            for chn in chns:
                data[chn]['data'][i] = msg[chn]
            data['pulse_id'][i]=msg['pid']

        # write out the data file
        hid = h5py.File(filename,'w')
        hid.create_dataset('pulse_id', data = data['pulse_id'])
        for chn in chns:
            gid = hid.create_group(chn)
            for key in data[chn].keys():
                gid.create_dataset(key, data = data[chn][key])
        hid.close()