#!/bin/bash

# Configures USB gadgets per: https://www.kernel.org/doc/Documentation/usb/gadget_configfs.txt

# Exit on first error.
set -e

# Echo commands to stdout.
set -x

# Treat undefined environment variables as errors.
set -u

modprobe libcomposite

# Adapted from https://github.com/girst/hardpass-sendHID/blob/master/README.md

cd /sys/kernel/config/usb_gadget/
mkdir -p g1
cd g1

echo 0x1d6b > idVendor  # Linux Foundation
echo 0x0104 > idProduct # Multifunction Composite Gadget
echo 0x0100 > bcdDevice # v1.0.0
echo 0x0200 > bcdUSB    # USB2

STRINGS_DIR="strings/0x409"
mkdir -p "$STRINGS_DIR"
echo "6b65796d696d6570690" > "${STRINGS_DIR}/serialnumber"
echo "tinypilot" > "${STRINGS_DIR}/manufacturer"
echo "Multifunction USB Device" > "${STRINGS_DIR}/product"

# Keyboard
KEYBOARD_FUNCTIONS_DIR="functions/hid.keyboard"
mkdir -p "$KEYBOARD_FUNCTIONS_DIR"
echo 1 > "${KEYBOARD_FUNCTIONS_DIR}/protocol" # Keyboard
echo 1 > "${KEYBOARD_FUNCTIONS_DIR}/subclass" # Boot interface subclass
echo 8 > "${KEYBOARD_FUNCTIONS_DIR}/report_length"
# Write the report descriptor
D=$(mktemp)

{
  echo -ne \\x05\\x01       # Usage Page (Generic Desktop Ctrls)
  echo -ne \\x09\\x06       # Usage (Keyboard)
  echo -ne \\xA1\\x01       # Collection (Application)
  echo -ne \\x05\\x08       #   Usage Page (LEDs)
  echo -ne \\x19\\x01       #   Usage Minimum (Num Lock)
  echo -ne \\x29\\x03       #   Usage Maximum (Scroll Lock)
  echo -ne \\x15\\x00       #   Logical Minimum (0)
  echo -ne \\x25\\x01       #   Logical Maximum (1)
  echo -ne \\x75\\x01       #   Report Size (1)
  echo -ne \\x95\\x03       #   Report Count (3)
  echo -ne \\x91\\x02       #   Output (Data,Var,Abs,No Wrap,Linear,Preferred State,No Null Position,Non-volatile)
  echo -ne \\x09\\x4B       #   Usage (Generic Indicator)
  echo -ne \\x95\\x01       #   Report Count (1)
  echo -ne \\x91\\x02       #   Output (Data,Var,Abs,No Wrap,Linear,Preferred State,No Null Position,Non-volatile)
  echo -ne \\x95\\x04       #   Report Count (4)
  echo -ne \\x91\\x01       #   Output (Const,Array,Abs,No Wrap,Linear,Preferred State,No Null Position,Non-volatile)
  echo -ne \\x05\\x07       #   Usage Page (Kbrd/Keypad)
  echo -ne \\x19\\xE0       #   Usage Minimum (0xE0)
  echo -ne \\x29\\xE7       #   Usage Maximum (0xE7)
  echo -ne \\x95\\x08       #   Report Count (8)
  echo -ne \\x81\\x02       #   Input (Data,Var,Abs,No Wrap,Linear,Preferred State,No Null Position)
  echo -ne \\x75\\x08       #   Report Size (8)
  echo -ne \\x95\\x01       #   Report Count (1)
  echo -ne \\x81\\x01       #   Input (Const,Array,Abs,No Wrap,Linear,Preferred State,No Null Position)
  echo -ne \\x19\\x00       #   Usage Minimum (0x00)
  echo -ne \\x29\\x91       #   Usage Maximum (0x91)
  echo -ne \\x26\\xFF\\x00  #   Logical Maximum (255)
  echo -ne \\x95\\x06       #   Report Count (6)
  echo -ne \\x81\\x00       #   Input (Data,Array,Abs,No Wrap,Linear,Preferred State,No Null Position)
  echo -ne \\xC0            # End Collection
} >> "$D"
cp "$D" "${KEYBOARD_FUNCTIONS_DIR}/report_desc"

# Mouse
MOUSE_FUNCTIONS_DIR="functions/hid.mouse"
mkdir -p "$MOUSE_FUNCTIONS_DIR"
echo 0 > "${MOUSE_FUNCTIONS_DIR}/protocol"
echo 0 > "${MOUSE_FUNCTIONS_DIR}/subclass"
echo 5 > "${MOUSE_FUNCTIONS_DIR}/report_length"
# Write the report descriptor
D=$(mktemp)
{
echo -ne \\x05\\x01      # USAGE_PAGE (Generic Desktop)
echo -ne \\x09\\x02      # USAGE (Mouse)
echo -ne \\xA1\\x01      # COLLECTION (Application)
                         #   8-buttons
echo -ne \\x05\\x09      #   USAGE_PAGE (Button)
echo -ne \\x19\\x01      #   USAGE_MINIMUM (Button 1)
echo -ne \\x29\\x08      #   USAGE_MAXIMUM (Button 8)
echo -ne \\x15\\x00      #   LOGICAL_MINIMUM (0)
echo -ne \\x25\\x01      #   LOGICAL_MAXIMUM (1)
echo -ne \\x95\\x08      #   REPORT_COUNT (8)
echo -ne \\x75\\x01      #   REPORT_SIZE (1)
echo -ne \\x81\\x02      #   INPUT (Data,Var,Abs)
                         #   x,y absolute coordinates
echo -ne \\x05\\x01      #   USAGE_PAGE (Generic Desktop)
echo -ne \\x09\\x30      #   USAGE (X)
echo -ne \\x09\\x31      #   USAGE (Y)
echo -ne \\x16\\x00\\x00 #   LOGICAL_MINIMUM (0)
echo -ne \\x26\\xFF\\x7F #   LOGICAL_MAXIMUM (32767)
echo -ne \\x75\\x10      #   REPORT_SIZE (16)
echo -ne \\x95\\x02      #   REPORT_COUNT (2)
echo -ne \\x81\\x02      #   INPUT (Data,Var,Abs)
                         #   vertical wheel
echo -ne \\x09\\x38      #   USAGE (wheel)
echo -ne \\x15\\x81      #   LOGICAL_MINIMUM (-127)
echo -ne \\x25\\x7F      #   LOGICAL_MAXIMUM (127)
echo -ne \\x75\\x08      #   REPORT_SIZE (8)
echo -ne \\x95\\x01      #   REPORT_COUNT (1)
echo -ne \\x81\\x06      #   INPUT (Data,Var,Rel)
                         #   horizontal wheel
echo -ne \\x05\\x0C      #   USAGE_PAGE (Consumer Devices)
echo -ne \\x0A\\x38\\x02 #   USAGE (AC Pan)
echo -ne \\x15\\x81      #   LOGICAL_MINIMUM (-127)
echo -ne \\x25\\x7F      #   LOGICAL_MAXIMUM (127)
echo -ne \\x75\\x08      #   REPORT_SIZE (8)
echo -ne \\x95\\x01      #   REPORT_COUNT (1)
echo -ne \\x81\\x06      #   INPUT (Data,Var,Rel)
echo -ne \\xC0           # END_COLLECTION
} >> "$D"
cp "$D" "${MOUSE_FUNCTIONS_DIR}/report_desc"

CONFIG_INDEX=1
CONFIGS_DIR="configs/c.${CONFIG_INDEX}"
mkdir -p "$CONFIGS_DIR"
echo 250 > "${CONFIGS_DIR}/MaxPower"

CONFIGS_STRINGS_DIR="${CONFIGS_DIR}/strings/0x409"
mkdir -p "$CONFIGS_STRINGS_DIR"
echo "Config ${CONFIG_INDEX}: ECM network" > "${CONFIGS_STRINGS_DIR}/configuration"

ln -s "$KEYBOARD_FUNCTIONS_DIR" "${CONFIGS_DIR}/"
ln -s "$MOUSE_FUNCTIONS_DIR" "${CONFIGS_DIR}/"
ls /sys/class/udc > UDC

chmod 777 /dev/hidg0
chmod 777 /dev/hidg1