from mantid.kernel import *
from mantid.api import *
import mantid.simpleapi as api
import numpy as np

from dnsdata import DNSdata

class LoadDNSLegacy(PythonAlgorithm):
    """
    Load the DNS Legacy data file to the mantid workspace
    """
    def category(self):
        """
        """
        return 'DataHandling'

    def name(self):
        """
        """
        return "LoadDNSLegacy"

    def summary(self):
        return "Load the DNS Legacy data file to the mantid workspace."

    def PyInit(self):
        self.declareProperty(FileProperty("Filename", "", FileAction.Load, ['.d_dat']),
                "Name of DNS experimental data file.")
        self.declareProperty(WorkspaceProperty("OutputWorkspace","",direction=Direction.Output), 
                doc="Name of the workspace to store the loaded experimental data.")

        return


    def PyExec(self):
        # Input
        filename = self.getPropertyValue("Filename")
        outws = self.getPropertyValue("OutputWorkspace")

        # load data array from the given file
        data_array = np.loadtxt(filename)
        ndet = 24
        #nbins = 1
        
        dataX = np.zeros(ndet)
        dataY = data_array[0:ndet,1:]
        dataE = np.sqrt(dataY)
        
        # create workspace
        __temporary_workspace__ = api.CreateWorkspace(DataX=dataX, DataY=dataY, DataE=dataE, NSpec=ndet,UnitX="Wavelength")
        api.LoadInstrument(__temporary_workspace__, InstrumentName='DNS')

        # load run information
        metadata = DNSdata()
        metadata.read_legacy(filename)
        run = __temporary_workspace__.mutableRun()
        run.setStartAndEndTime(DateAndTime(metadata.start_time), DateAndTime(metadata.end_time))

        self.setProperty("OutputWorkspace", __temporary_workspace__)
        self.log().debug('LoadDNSLegacy: OK')
        api.DeleteWorkspace(__temporary_workspace__)
        

        return


def getEnergy(wavelength):
    """
    Calculates neutron energy in eV from the given wavelength in Angstrom
    """
    return  (1e-3*81.73 / wavelength**2)

# Register algorithm with Mantid
AlgorithmFactory.subscribe(LoadDNSLegacy)