from pyps2000b import PS2000B
import globals as g


def set_devices():  # creates device objects for all PSUs
    g.xyDevice = PS2000B.PS2000B(g.xyPort)
    g.zDevice = PS2000B.PS2000B(g.zPort)
    g.xAxis = (g.xyDevice, 0, g.relayPins[0], 0)  # (device, channel, arduino pin, axis index)
    g.yAxis = (g.xyDevice, 1, g.relayPins[1], 1)
    g.zAxis = (g.zDevice, 0, g.relayPins[2], 2)


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


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


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


def print_status(axis):  # axis as (device, channel), e.g. g.xAxis
    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.xAxis)
    print("Y-Axis:")
    print_status(g.yAxis)
    print("Z-Axis:")
    print_status(g.zAxis)


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.ambientField
    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.xAxis, i_vec[0])
    set_axis_current(g.yAxis, i_vec[1])
    set_axis_current(g.zAxis, 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.maxAmps[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.maxAmps[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)
    device.set_voltage(1.1 * g.maxAmps[axisIndex] * g.resistances[axisIndex])  # set max voltage high enough