# SPDX-FileCopyrightText: 2023 John Park for Adafruit Industries
# SPDX-License-Identifier: MIT

#  Grand Central MIDI Knobs
#  for USB MIDI and optional UART MIDI
#  Reads analog inputs, sends out MIDI CC values
#   with Kattni Rembor and Jan Goolsbey for range and hysteresis code

import time
import board
import busio
from simpleio import map_range
from analogio import AnalogIn
from digitalio import DigitalInOut, Direction
import usb_midi
import adafruit_midi  # MIDI protocol encoder/decoder library
from adafruit_midi.control_change import ControlChange

# pick your USB MIDI out channel here, 1-16
MIDI_USB_channel = 1
# pick your classic MIDI channel for sending over UART serial TX/RX
CLASSIC_MIDI_channel = 2

midi_usb = adafruit_midi.MIDI(
    midi_out=usb_midi.ports[1], out_channel=MIDI_USB_channel - 1
)
#  use DIN-5 or TRS MIDI jack on TX/RX for classic MIDI
midi_uart = busio.UART(board.TX, board.RX, baudrate=31250, timeout=0.001)  # initialize UART
classic_midi = adafruit_midi.MIDI(
    midi_out=midi_uart, midi_in=midi_uart, out_channel=CLASSIC_MIDI_channel - 1, debug=False
)

led = DigitalInOut(board.D13)  # activity indicator
led.direction = Direction.OUTPUT

knob_count = 16  # Set the total number of potentiometers used

# Create the input objects list for potentiometers
knob = []
for k in range(knob_count):
    knobs = AnalogIn(
        getattr(board, "A{}".format(k))
    )  # get pin # attribute, use string formatting
    knob.append(knobs)

#  assignment of knobs to cc numbers
cc_number = [
    1,  # knob 1, mod wheel
    2,  # knob 2, breath control
    7,  # knob 3, volume
    10,  # knob 4 pan
    11,  # knob 5, expression
    53,  # knob 6
    54,  # knob 7
    73,  # knob 8
    74,  # knob 9, Filter frequency cutoff
    71,  # knob 10, Filter resonance
    58,  # knob 11
    59,  # knob 12
    60,  # knob 13
    61,  # knob 14
    62,  # knob 15
    63,  # knob 16
]

# CC range list defines the characteristics of the potentiometers
#  This list contains the input object, minimum value, and maximum value for each knob.
#   example ranges:
#   0 min, 127 max: full range control voltage
#   36 (C2) min, 84 (B5) max: 49-note keyboard
#   21 (A0) min, 108 (C8) max: 88-note grand piano
cc_range = [
    (0, 127),  # knob 0: C2 to B5: 49-note keyboard
    (0, 127),  # knob 1
    (0, 127),  # knob 2
    (0, 127),  # knob 3
    (0, 127),  # knob 4
    (0, 127),  # knob 5
    (0, 127),  # knob 6
    (0, 127),  # knob 7
    (0, 127),  # knob 8
    (0, 127),  # knob 9
    (0, 127),  # knob 10
    (0, 127),  # knob 11
    (0, 127),  # knob 12
    (0, 127),  # knob 13
    (0, 127),  # knob 14
    (0, 127),  # knob 15
]

print("---Grand Central MIDI Knobs---")
print("   USB MIDI channel: {}".format(MIDI_USB_channel))
print("   TRS MIDI channel: {}".format(CLASSIC_MIDI_channel))

# Initialize cc_value list with current value and offset placeholders
cc_value = []
for _ in range(knob_count):
    cc_value.append((0, 0))
last_cc_value = []
for _ in range(knob_count):
    last_cc_value.append((0, 0))

#  range_index converts an analog value (ctl) to an indexed integer
#  Input is masked to 8 bits to reduce noise then a scaled hysteresis offset
#  is applied. The helper returns new index value (idx) and input
#  hysteresis offset (offset) based on the number of control slices (ctrl_max).
def range_index(ctl, ctrl_max, old_idx, offset):
    if (ctl + offset > 65535) or (ctl + offset < 0):
        offset = 0
    idx = int(map_range((ctl + offset) & 0xFF00, 1200, 65500, 0, ctrl_max))
    if idx != old_idx:  # if index changed, adjust hysteresis offset
        # offset is 25% of the control slice (65536/ctrl_max)
        offset = int(
            0.25 * sign(idx - old_idx) * (65535 / ctrl_max)
        )  # edit 0.25 to adjust slices
    return idx, offset


def sign(x):  # determine the sign of x
    if x >= 0:
        return 1
    else:
        return -1


while True:
    # read all the knob values
    for i in range(knob_count):
        cc_value[i] = range_index(
            knob[i].value,
            (cc_range[i][1] - cc_range[i][0] + 1),
            cc_value[i][0],
            cc_value[i][1],
        )
        if cc_value[i] != last_cc_value[i]:  # only send if it changed
            # Form a MIDI CC message and send it:
            midi_usb.send(ControlChange(cc_number[i], cc_value[i][0] + cc_range[i][0]))
            classic_midi.send(
                ControlChange(cc_number[i], cc_value[i][0] + cc_range[i][0])
            )
            last_cc_value[i] = cc_value[i]
            led.value = True

    time.sleep(0.01)
    led.value = False