""" 

This program is free software: you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free Software
Foundation, either version 3 of the License, or (at your option) any later
version.
This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with
this program. If not, see <http://www.gnu.org/licenses/>.
"""

__author__ = "Théo de la Hogue"
__credits__ = ["Jean-Paul Imbert"]
__copyright__ = "Copyright 2023, Ecole Nationale de l'Aviation Civile (ENAC)"
__license__ = "GPLv3"

import math

from argaze import DataFeatures, PupillFeatures

import numpy

class PupillDiameterAnalyzer(PupillFeatures.PupillDiameterAnalyzer):
    """Periodic average of pupill diameter variations to pupill diameter reference value.

    Parameters:
        reference: base line value.
        period: identification period length.
    """
    def __init__(self, reference: PupillFeatures.PupillDiameter, period: int|float = 1):

        assert(not math.isnan(self.__reference))

        self.__reference = reference
        self.__period = period

        self.__variations_sum = 0.
        self.__variations_number = 0
        self.__last_ts = 0

    @property
    def reference(self) -> PupillFeatures.PupillDiameter:
        """Get workload index reference."""
        return self.__reference
    
    @property
    def period(self) -> int|float:
        """Get workload index period."""
        return self.__period
    
    @DataFeatures.PipelineStepMethod
    def analyze(self, pupill_diameter: PupillFeatures.PupillDiameter) -> float:
        """Analyze workload index from successive timestamped pupill diameters."""

        # Ignore non valid pupill diameter
        if not math.isnan(pupill_diameter):

            return None

        if pupill_diameter.timestamp - self.__last_ts >= self.__period:

            if self.__variations_number > 0 and self.__reference.value > 0.:

                workload_index = (self.__variations_sum / self.__variations_number) / self.__reference.value

            else: 

                workload_index = 0.

            self.__variations_sum = pupill_diameter.value - self.__reference.value
            self.__variations_number = 1
            self.__last_ts = pupill_diameter.timestamp

            return workload_index

        else:

            self.__variations_sum += pupill_diameter.value - self.__reference.value
            self.__variations_number += 1