#  NanoVNASaver
#
#  A python program to view and export Touchstone data from a NanoVNA
#  Copyright (C) 2019, 2020  Rune B. Broberg
#  Copyright (C) 2020 NanoVNA-Saver Authors
#
#  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 <https://www.gnu.org/licenses/>.
import logging
import platform
import time
from struct import pack, unpack_from

from time import sleep
from typing import Dict, List
from .Serial import Interface
from .Calibration import Calibration
from .RFTools import Datapoint

__all__ = ['NanoVNA_V2_H4']

if platform.system() != "Windows":
    import tty

logger = logging.getLogger(__name__)

_CMD_NOP = 0x00
_CMD_INDICATE = 0x0D
_CMD_READ = 0x10
_CMD_READ2 = 0x11
_CMD_READ4 = 0x12
_CMD_READFIFO = 0x18
_CMD_WRITE = 0x20
_CMD_WRITE2 = 0x21
_CMD_WRITE4 = 0x22
_CMD_WRITE8 = 0x23
_CMD_WRITEFIFO = 0x28

WRITE_SLEEP = 0.05

_ADF4350_TXPOWER_DESC_MAP = {
    0: "9dattenuation",
    1: "6dB attenuation",
    2: "3dB attenuation",
    3: "Maximum",
}
_ADF4350_TXPOWER_DESC_REV_MAP = {
    value: key for key, value in _ADF4350_TXPOWER_DESC_MAP.items()
}

# _NANOVNA_V2_CMDS = {
#     'NOP'               : {'val': 0x, 'len':, 'resp': },
#     'INDICATE'               : {'val': 0x, 'len':, 'resp': },
#     'READ'               : {'val': 0x, 'len':, 'resp': },
#     'READ2'               : {'val': 0x, 'len':, 'resp': },
#     'READ4'               : {'val': 0x, 'len':, 'resp': },
#     'READFIFO'               : {'val': 0x, 'len':, 'resp': },
#     'NOP'               : {'val': 0x, 'len':, 'resp': },
#     'NOP'               : {'val': 0x, 'len':, 'resp': },

# }

_NANOVNA_V2_REGS = {
    "sweepStartHz": {"addr": 0x00, "len": 8},
    "sweepStepHz": {"addr": 0x10, "len": 8},
    "sweepPoints": {"addr": 0x20, "len": 2},
    "valuesPerFrequency": {"addr": 0x22, "len": 2},
    "rawSamplesMode": {"addr": 0x26, "len": 1},
    "valuesFIFO": {"addr": 0x30, "len": 4},
    "deviceVariant": {"addr": 0xF0, "len": 1},
    "protocolVersion": {"addr": 0xF1, "len": 1},
    "hardwareRevision": {"addr": 0xF2, "len": 1},
    "firmwareMajor": {"addr": 0xF3, "len": 1},
    "firmwareMinor": {"addr": 0xF4, "len": 1},
}

"""
NanoVNA FIFO Format (32 bytes)

fwd0Re      (uint32) 
fw0Im       (uint32)
rev0Re      (uint32)
rev0Re      (uint32)
rev1Re      (uint32)
rev1Im      (uint32)
freqIndex   (uint16)
reserved    (6 bytes)
"""
_NANOVAN_V2_FIFO_FORMAT = "<iiiiiiHxxxxxx"


class NanoVNA_V2_H4:
    name = "NanoVNA V2 Plus4"

    def __init__(self, iface: Interface = None):
        self.iface = iface
        #self.iface.open()

        if platform.system() != "Windows":
            tty.setraw(self.iface.fd)

        # reset protocol to known state
        with self.iface.lock:
            self.iface.write(pack("<Q", 0))
            sleep(WRITE_SLEEP)
        # # firmware major version of 0xff indicates dfu mode
        # if self.version.data["major"] == 0xff:
        #     raise IOError('Device is in DFU mode')

        # Write Parameters
        self.write_sleep = 0.05

        # Device Ranges
        self.valid_freq = range(
            int(50e3), int(4.4e9 + 1)
        )  # Frequency Range: 50kHz - 4.4GHz, 1Hz Resolution
        self.valid_power = None  # Not Implemented / Fixed
        self.valid_bw = 800  # Fixed
        self.valid_points = range(1, 10000)  # TODO: Increase to actual limit

        # Device Defaults
        self.freq_start = 140e6
        self.freq_step = None
        self.freq_end = 4.4e9
        self.bw = 800
        self.points = 100

        # Device Memory
        self._fwd = None
        self._refl = None
        self._thru = None
        self._f = None
        self._s11 = None
        self._s22 = None
        self._cal = Calibration()
        self._cal_valid = False

        # Load Defaults
        self.set_sweep(self.freq_start, self.freq_end, self.points)

    def __del__(self):
        self.iface.close()

    def connect(self) -> bool:
        self.iface.open()
        return self.iface.isOpen()

    def disconnect(self) -> bool:
        self.iface.close()
        return not self.iface.isOpen()

    def reconnect(self) -> bool:
        self.iface.close()
        sleep(self.wait)
        self.iface.open()
        return self.iface.isOpen()

    def get_info(self):
        reg = self.read_registers()
        info = Dict()

    def _read_register(self, reg_name: str):
        if reg_name not in _NANOVNA_V2_REGS:
            raise ValueError(
                f"must be name of nanoVNA v2 register: {_NANOVNA_V2_REGS.keys()}"
            )

        size = _NANOVNA_V2_REGS[reg_name]["len"]
        addr = _NANOVNA_V2_REGS[reg_name]["addr"]

        if size == 1:
            packet = pack("<BB", _CMD_READ, addr)
        elif size == 2:
            packet = pack("<BB", _CMD_READ2, addr)
        elif size == 4:
            packet = pack("<BB", _CMD_READ4, addr)
        elif size == 8:
            packet = pack("<BBBB", _CMD_READ4, addr, _CMD_READ4, addr + 4)

        self.iface.flush()
        self.iface.write(packet)
        resp = self.iface.read(size)

        if len(resp) != size:
            return None
        return int.from_bytes(resp, byteorder="little")

    def _write_register(self, reg_name, value):
        if reg_name not in _NANOVNA_V2_REGS:
            raise ValueError("must be name of nanoVNA v2 register")

        size = _NANOVNA_V2_REGS[reg_name]["len"]
        addr = _NANOVNA_V2_REGS[reg_name]["addr"]

        if size == 1:
            packet = pack("<BBB", _CMD_WRITE, addr, value)
        elif size == 2:
            packet = pack("<BBH", _CMD_WRITE2, addr, value)
        elif size == 4:
            packet = pack("<BBI", _CMD_WRITE4, addr, value)
        elif size == 8:
            packet = pack("<BBQ", _CMD_WRITE8, addr, value)

        self.iface.write(packet)

    def _read_fifo(self, points: int):
        # clear something
        self.iface.write(pack("<Q", 0))
        
        # clear FIFO
        self._write_register("valuesFIFO", 0x00)

        points_remaining = points
        fifo_bytes = bytes()

        while points_remaining > 0:

            # calculate the number of points to read (255) at a time
            points_to_read = min(255, points_remaining)
            bytes_to_read = points_to_read * 32

            # TODO: Fix
            self.iface.write(pack("<BBB", _CMD_READFIFO, 0x30, points_to_read))
            timeout = self.iface.timeout
            self.iface.timeout = points_to_read * 0.032 + 0.1
            resp = self.iface.read(bytes_to_read)

            if len(resp) != bytes_to_read:
                self.iface.timeout = timeout
                return None

            fifo_bytes = fifo_bytes + resp
            points_remaining = points_remaining - points_to_read

        # restore timeout
        self.iface.timeout = timeout
        return fifo_bytes

    def read_registers(self):
        i = dict()
        for reg in _NANOVNA_V2_REGS.keys():
            if reg == "valuesFIFO":  # skip
                continue
            i[reg] = self._read_register(reg)
        return i

    def set_sweep(
        self, freq_start: float, freq_end: float, points: float = 101, avg: int = 1
    ):

        # input checking
        if int(freq_start) not in self.valid_freq:
            raise ValueError("outside of operating frequency range")
        if int(freq_end) not in self.valid_freq:
            raise ValueError("outside of operating frequency range")
        if freq_end <= freq_start:
            raise ValueError("start frequency must be < end frequency")
        if int(points) not in self.valid_points:
            raise ValueError("invalid number of data points")

        # store and calc registers
        self.points = int(points)
        self.freq_start = int(freq_start)
        self.freq_step = int((int(freq_end) - freq_start) / (self.points - 1))
        self.freq_end = self.freq_start + self.freq_step * (self.points - 1)
        self.avg = avg

        # write registers
        self._write_register("sweepStartHz", self.freq_start)
        self._write_register("sweepStepHz", self.freq_step)
        self._write_register("sweepPoints", self.points)
        self._write_register("valuesPerFrequency", self.avg)

        # allocate memory for sweep data
        self._fwd = [complex()] * self.points
        self._refl = [complex()] * self.points
        self._thru = [complex()] * self.points
        self._freq_index = [int()] * self.points
        self._f = [int()] * self.points
        self._s11 = [complex()] * self.points
        self._s21 = [complex()] * self.points

        # insert delay 
        time.sleep(1)   # TODO: review, unsure why this is required, but if it's not performed the next sweep
                        # is missing a data points

    def get_sweep(self) -> List:
        reg = self.read_registers()
        self.freq_start = reg["sweepStartHz"]
        self.freq_step = reg["sweepStepHz"]
        self.points = reg["sweepPoints"]
        self.freq_end = self.freq_start + self.freq_step * (self.points - 1)
        self.avg = reg["valuesPerFrequency"]
        return (self.freq_start, self.freq_end, self.points, self.avg)

    def wizard_cal(self, port1_only:bool=False):
        # wipe old cal because I'm scared
        self._cal = Calibration()

        # short
        input("connect Short to port 1...")
        fs, s11_point, _ = self.measure(skip_calibration=True)
        s11_dp = []
        for (f, s11_point) in zip(fs, s11_point):
            s11_dp.append(Datapoint(f, s11_point.real, s11_point.imag))
        self._cal.insert("short", s11_dp)

        # open
        input("connect Open to port 1...")
        fs, s11, _ = self.measure(skip_calibration=True)
        s11_dp = []
        for (f, s11_point) in zip(fs, s11):
            s11_dp.append(Datapoint(f, s11_point.real, s11_point.imag))
        self._cal.insert("open", s11_dp)

        # load
        input("connect Load to port 1...")
        fs, s11, _ = self.measure(skip_calibration=True)
        s11_dp = []
        for (f, s11_point) in zip(fs, s11):
            s11_dp.append(Datapoint(f, s11_point.real, s11_point.imag))
        self._cal.insert("load", s11_dp)

        # through
        input("connect port 1 to port 2...")
        fs, _, s21 = self.measure(skip_calibration=True)
        s21_dp = []
        for (f, s21_point) in zip(fs, s21):
            s21_dp.append(Datapoint(f, s21_point.real, s21_point.imag))
        self._cal.insert("through", s21_dp)

        # isolation 
        input("connect load to both ports...")
        fs, _, s21 = self.measure(skip_calibration=True)
        s21_dp = []
        for (f, s21_point) in zip(fs, s21):
            s21_dp.append(Datapoint(f, s21_point.real, s21_point.imag))
        self._cal.insert("isolation", s21_dp)

        # calculate corrections 
        self._cal.calc_corrections()

        if self._cal.isValid1Port(): 
            self._cal_valid = True 
        else: 
            self._cal_valid = False

        # Store Notes 
        notes = dict() 
        notes['Date'] = time.ctime() 
        start, stop, points, avg = self.get_sweep()
        notes['Sweep Start'] = start 
        notes['Sweep Stop'] = stop 
        notes['Sweep Points'] = points 
        notes['Point Average'] = avg 
        notes['Device Name'] = self.name 
        notes['Device Settings'] = self.read_registers()
        
        self._cal.notes.append(notes)    # date 


        return self._cal_valid

    def save_cal(self, filename: str):
        if self._cal_valid:
            self._cal.save(filename)

    def load_cal(self, filename: str) -> bool:
        self._cal = Calibration()
        self._cal.load(filename)
        self._cal.calc_corrections()
        if self._cal.isValid1Port():
            self._cal_valid = True
        else:
            self._cal_valid = False
        return self._cal_valid

    def measure(self, skip_calibration=False):

        # retrive data from fifo
        fifo_bytes = self._read_fifo(self.points)

        if fifo_bytes == None:
            return None

        # unpack data and convert to complex
        for n_point in range(self.points):

            # TODO: clean this up
            (
                fwd_real,
                fwd_imag,
                rev0_real,
                rev0_imag,
                rev1_real,
                rev1_imag,
                freq_index,
            ) = unpack_from(_NANOVAN_V2_FIFO_FORMAT, fifo_bytes, n_point * 32)
            fwd = complex(fwd_real, fwd_imag)
            refl = complex(rev0_real, rev0_imag)
            thru = complex(rev1_real, rev1_imag)

            # store internally and calculate s11, s21
            self._fwd[freq_index] = fwd
            self._refl[freq_index] = refl
            self._thru[freq_index] = thru

            self._f[freq_index] = self.freq_start + self.freq_step * freq_index
            self._s11[freq_index] = refl / fwd
            self._s21[freq_index] = thru / fwd

        # skip calibration if requested
        if skip_calibration==True:
            return self._f, self._s11, self._s21

        # apply calibration
        # TODO: Implement this better (skrf or custom modifications to calibration import)
        cal_s11 = None
        cal_s21 = None
        if self._cal.isValid1Port():
            cal_s11 = []
            for f, s11_point in zip(self._f, self._s11):
                dp = Datapoint(f, s11_point.real, s11_point.imag)
                cal_s11.append(self._cal.correct11(dp).z)

        if self._cal.isValid2Port():
            cal_s21 = []
            for f, s21_point in zip(self._f, self._s21):
                dp = Datapoint(f, s21_point.real, s21_point.imag)
                cal_s21.append(self._cal.correct21(dp).z)

        if cal_s11 == None:
            return self._f, None, None
        
        if cal_s21 == None:
            return self._f, cal_s11, None

        return self._f, cal_s11, cal_s21

    # def setTXPower(self, freq_range, power_desc):
    #     if freq_range[0] != 140e6:
    #         raise ValueError('Invalid TX power frequency range')
    #     # 140MHz..max => ADF4350
    #     self._set_register(0x42, _ADF4350_TXPOWER_DESC_REV_MAP[power_desc], 1)