"""TCD1304 linear CCD driver for Open Spectrometer.



The sensor shall be connected to the PSLab as following:

Pin 1 of the sensorboard: master_clock --> SQ1 on PSLab

Pin 2: sh_clock --> SQ2

Pin 3: icg_clock --> SQ3

Pin 4: +5V --> PV1

Pin 5: GND --> GND

Pin 6: OS --> CH1

"""



import math

import time



from pslab.serial_handler import SerialHandler

from pslab.instrument.oscilloscope import Oscilloscope

from pslab.instrument.power_supply import PowerSupply

from pslab.instrument.waveform_generator import PWMGenerator



_OSCILLATOR_FREQUENCY = 128e6

_MICROSECONDS = 1e6





class TCD1304:

    """The TCD1304 is a linear CCD suitable for visible spectrum analysis."""



    _INTEGRATION_ELEMENTS = 3694

    _MIN_VOLTAGE_OUTPUT = 2

    _MAX_VOLTAGE_OUTPUT = 4

    _SAMPLES_PER_ELEMENT = 2



    def __init__(

        self,

        device: SerialHandler = None,

        integration_time: float = 10e-6,

        master_clock_frequency: float = 2e6,

    ):

        self._device = SerialHandler() if device is None else device

        self._pwmgen = PWMGenerator(self._device)

        self._scope = Oscilloscope(self._device)

        self._ps = PowerSupply(self._device)

        self.integration_time = integration_time

        self.master_clock_frequency = master_clock_frequency



        self.poweron()

        self._pwmgen.set_state(sq3=True)

        self._start_master_clock()

        self._start_sh_clock()



    def poweron(self):

        """Turn TCD1304 on."""

        self._ps.pv1 = 5



    def poweroff(self):

        """Turn TCD1304 off."""

        self._ps.pv1 = 0



    def _start_icg_clock(self):

        read_out_time = self._INTEGRATION_ELEMENTS * self.integration_time

        self._pwmgen.set_state(sq3=False)

        self._pwmgen.set_state(sq3=True)

        time.sleep(read_out_time)

        self._pwmgen.set_state(sq3=False)

        self._pwmgen.set_state(sq3=True)



    def _start_master_clock(self):

        prescaler = int(

            math.log(_OSCILLATOR_FREQUENCY / self.master_clock_frequency) / math.log(2)

        )

        self._pwmgen.map_reference_clock(["SQ1"], prescaler)



    def _start_sh_clock(self):

        self._pwmgen.generate(["SQ2"], 1 / self.integration_time, [0.5])



    def read_signal(self):

        """Start the ICG clock and read the analog output from the TCD1304."""

        self._scope.select_range("CH1", self._MAX_VOLTAGE_OUTPUT)

        self._scope.configure_trigger(channel="CH1", voltage=self._MIN_VOLTAGE_OUTPUT)

        self._scope.capture(

            channels=1,

            samples=self._INTEGRATION_ELEMENTS * self._SAMPLES_PER_ELEMENT,

            timegap=self.integration_time / self._SAMPLES_PER_ELEMENT * _MICROSECONDS,

            block=False,

        )

        self._start_icg_clock()

        (y,) = self._scope.fetch_data()

        return y