from pyps2000b import PS2000B
import globals as g


def set_devices():  # creates device objects for all PSUs
    g.XY_DEVICE = PS2000B.PS2000B(g.XY_PORT)
    g.Z_DEVICE = PS2000B.PS2000B(g.Z_PORT)
    g.X_AXIS = (g.XY_DEVICE, 0, g.RELAY_PINS[0], 0)  # (device, channel, arduino pin, axis index)
    g.Y_AXIS = (g.XY_DEVICE, 1, g.RELAY_PINS[1], 1)
    g.Z_AXIS = (g.Z_DEVICE, 0, g.RELAY_PINS[2], 2)


def activate_all():  # enables remote control and output on all PSUs and channels
    g.XY_DEVICE.enable_all()
    g.Z_DEVICE.enable_all()


def deactivate_all():  # disables remote control and output on all PSUs and channels
    g.XY_DEVICE.disable_all()
    g.Z_DEVICE.disable_all()


def setup_arduino():
    for pin in g.RELAY_PINS:
        g.ARDUINO.pinMode(pin, "Output")
        g.ARDUINO.digitalWrite(pin, "LOW")


def safe_arduino():  # sets output pins to low and closes serial connection
    for pin in g.RELAY_PINS:
        g.ARDUINO.digitalWrite(pin, "LOW")
    g.ARDUINO.close()


def print_status(axis):  # axis control variable, stored in globals.py
    device = axis[0]  # PSU
    channel = axis[1]  # output channel on the PSU
    print("%s, %0.2f V, %0.2f A"
          % (device.get_device_status_information(channel), device.get_voltage(channel), device.get_current(channel)))


def print_status_3():
    print("X-Axis:")
    print_status(g.X_AXIS)
    print("Y-Axis:")
    print_status(g.Y_AXIS)
    print("Z-Axis:")
    print_status(g.Z_AXIS)


def set_to_zero(device):
    device.voltage1 = 0
    device.current1 = 0
    device.current2 = 0
    device.current2 = 0


def set_field_simple(vector):  # forms magnetic field as specified by vector, w/o cancelling ambient field
    i_vec = vector/g.COIL_CONST
    set_current_vec(i_vec)


def set_field(vector):  # forms magnetic field as specified by vector, corrected for ambient field
    field = vector - g.AMBIENT_FIELD
    i_vec = field/g.COIL_CONST
    set_current_vec(i_vec)


def set_current_vec(i_vec):  # sets needed currents on each axis for given vector
    set_axis_current(g.X_AXIS, i_vec[0])
    set_axis_current(g.Y_AXIS, i_vec[1])
    set_axis_current(g.Z_AXIS, i_vec[2])


def set_axis_current(axis, value):  # sets current with correct polarity on one axis
    device = axis[0]
    channel = axis[1]
    ardPin = axis[2]
    axisIndex = axis[3]
    if abs(value) > g.MAX_AMPS[axisIndex]:  # prevent excessive currents
        set_to_zero(device)  # set currents and voltages to 0
        device.disable_all()  # disable outputs on PSU
        safe_arduino()  # set arduino pins to low and close serial link
        raise ValueError("Invalid current value. Tried %0.2fA, max. %0.2fA allowed" % (value, g.MAX_AMPS[axisIndex]))
    elif value >= 0:  # switch polarity as needed
        g.ARDUINO.digitalWrite(ardPin, "LOW")
    elif value < 0:
        g.ARDUINO.digitalWrite(ardPin, "HIGH")
    else:
        raise Exception("This should be impossible.")
    device.set_current(abs(value), channel)
    maxVoltage = min(max(1.1 * g.MAX_AMPS[axisIndex] * g.RESISTANCES[axisIndex], 12), g.MAX_VOLTS)  # limit voltage
    device.set_voltage(maxVoltage)