#!/usr/bin/env 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 0xa4ac > idProduct # USB HID
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" > "${STRINGS_DIR}/manufacturer"
echo "TinyPilot HID Keyboard Device" > "${STRINGS_DIR}/product"

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

chmod 777 /dev/hidg0