"""
Python Code for Power Supply
Hamamatsu c11204-02

"""
import serial
import binascii
import numpy as np
import time
import sys

# VARIABLES
V_conversion=1.812*10**(-3)     #voltage conversion factor
I_conversion=4.980*10**(-3)     #current conversion factor (mA)
STX = '02'          #start of text - fixed
ETX = '03'          #end of text - fixed
CR = '0D'           #delimiter - fixed

# SERIAL PORT
ser = serial.Serial('/dev/ttyUSB0')     # open serial port - linux
#ser = serial.Serial('COM6')             # open serial port - windows
ser.baudrate = 38400                    # set baudrate
ser.parity = serial.PARITY_EVEN         # set parity
ser.stopbits=serial.STOPBITS_ONE
ser.bytesize=serial.EIGHTBITS
print(ser.name)                         # check which port was really used

def convert(command):
    com = command.encode(encoding='utf-8', errors='strict')
    command_str = binascii.hexlify(com).decode('utf-8')
    sum_command = sum(bytearray(com))
    return (command_str, sum_command)

def checksum(sum_command,sum_voltage):
    #CHECKSUM CALCULATION
    CS=hex(int(STX,16)+sum_command+int(ETX,16)+sum_voltage)
    CS=CS.lstrip('0x')
    CS=CS.upper()
    CS=CS[-2:]
    CS_str,CS_sum=convert(CS)
    return(CS_str,CS_sum)

def setValue(voltage_dec):
    if voltage_dec > 58:
        print ("Voltage is too high")
        sys.exit()
    elif  voltage_dec < 40:
        print ("Voltage is too low")
        sys.exit()
    else:
        print (voltage_dec)
        voltage_conv=float(voltage_dec)/V_conversion
        voltage = int(round(voltage_conv))
        voltage_hex=hex(voltage) #convert voltage from decimal to hexadecimal number
        voltage_hex=voltage_hex.lstrip('0x')
        voltage_str,sum_voltage=convert(voltage_hex)
        command_str,sum_command=convert('HBV')
        CS_str,CS_sum = checksum(sum_command,sum_voltage)

    #FINAL COMMAND
    command_tosend = STX + command_str + voltage_str + ETX + CS_str + CR
    command_x =  "".join(chr(int(command_tosend[n : n+2],16)) for n in range(0, len(command_tosend), 2))
    print("send command:" + command_x)
    tx = ser.write(command_x.encode())
    rx = ser.read(3)
    print("read command:" + str(rx))

def getValue():
    command_str,sum_command=convert('HPO')
    CS_str,CS_sum = checksum(sum_command,0)

    #FINAL COMMAND
    command_tosend = STX + command_str + ETX + CS_str + CR
    print(command_tosend)
    command_x =  "".join(chr(int(command_tosend[n : n+2],16)) for n in range(0, len(command_tosend), 2))
    print(command_x)
    tx = ser.write(command_x.encode())
    rx = ser.read(28)
    #gets fucked somewhere around here due to python3 conversion
    volt_out= (int(rx[12:16], 16) * V_conversion)
    mA_out = (int(rx[17:21], 16) * I_conversion)
    print("Voltage (V): {0}".format(volt_out))
    print("Current (mA): {0}".format(mA_out))

def HighVoltageOn():
    command_str,sum_command=convert('HON')
    CS_str,CS_sum = checksum(sum_command,0)

    #FINAL COMMAND
    command_tosend = STX + command_str + ETX + CS_str + CR
    print(command_tosend)
    command_x =  "".join(chr(int(command_tosend[n : n+2],16)) for n in range(0, len(command_tosend), 2))
    print(command_x)
    tx = ser.write(command_x.encode())
    rx = ser.read(3)
    print("read command:" + str(rx))