#!/usr/bin/env bash
# navka-core.sh - background stealth daemon to present gadget as usb hub of genuine devices
# Proven Pi-5 configfs gadget: HID keyboard+mouse
# Still need Web Cam Support + stereo UAC2

# navka-core – one-shot gadget bring-up for Pi-5 / Arch-ARM
set -euo pipefail

# 1) Ensure the dwc2 peripheral overlay is active exactly once
CFG=/boot/config.txt
grep -q 'dtoverlay=dwc2,dr_mode=peripheral' "$CFG" || echo 'dtoverlay=dwc2,dr_mode=peripheral' >> "$CFG"

# 2) Load kernel modules (idempotent)
modprobe dwc2 || { echo "dwc2 not in kernel; abort" >&2; exit 1; }
modprobe libcomposite || { echo "libcomposite not in kernel; abort" >&2; exit 1; }

# 3) Mount configfs once
mountpoint -q /sys/kernel/config || mount -t configfs none /sys/kernel/config
G=/sys/kernel/config/usb_gadget/navka

# 4) Tear down any previous half-built gadget
if [[ -d $G ]]; then
  echo '' >"$G/UDC" 2>/dev/null || true
  sleep 0.2
  find "$G/configs" -type l -delete 2>/dev/null || true
  rm -rf "$G" 2>/dev/null || true
fi

# 5) Create gadget (boot-keyboard + UAC2 mic/spkr, 500 mA max)
mkdir -p "$G"
echo 0x1d6b >"$G/idVendor"       # Linux Foundation
echo 0x0104 >"$G/idProduct"      # Multifunction Composite Gadget
echo 0x0200 >"$G/bcdUSB"

mkdir -p "$G/strings/0x409"
echo "$(cat /proc/sys/kernel/random/uuid)" >"$G/strings/0x409/serialnumber"
echo "Navka"                               >"$G/strings/0x409/manufacturer"
echo "Navka Composite"                     >"$G/strings/0x409/product"

# HID (boot keyboard)
mkdir -p "$G/functions/hid.usb0"
echo 1  >"$G/functions/hid.usb0/protocol"
echo 1  >"$G/functions/hid.usb0/subclass"
echo 8  >"$G/functions/hid.usb0/report_length"
printf '\x05\x01\x09\x06\xa1\x01\x05\x07\x19\xe0\x29\xe7\x15\x00\x25\x01\x75\x01\x95\x08\x81\x02\x95\x01\x75\x08\x81\x01\x95\x05\x75\x01\x05\x08\x19\x01\x29\x05\x91\x02\x95\x01\x75\x03\x91\x01\x95\x06\x75\x08\x15\x00\x25\x65\x05\x07\x19\x00\x29\x65\x81\x00\xc0' \
  > "$G/functions/hid.usb0/report_desc"

# usb1 = mouse
mkdir -p "$G/functions/hid.usb1"
echo 2 > "$G/functions/hid.usb1/protocol"
echo 1 > "$G/functions/hid.usb1/subclass"
echo 4 > "$G/functions/hid.usb1/report_length"
printf '\x05\x01\x09\x06\xa1\x01\x05\x07\x19\xe0\x29\xe7\x15\x00\x25\x01\x75\x01\x95\x08\x81\x02\x95\x01\x75\x08\x81\x01\x95\x05\x75\x01\x05\x08\x19\x01\x29\x05\x91\x02\x95\x01\x75\x03\x91\x01\x95\x06\x75\x08\x15\x00\x25\x65\x05\x07\x19\x00\x29\x65\x81\x00\xc0' \
  > functions/hid.usb1/report_desc

# # -- UAC2 Audio
# mkdir -p $G/functions/uac2.usb0
# echo 48000 > $G/functions/uac2.usb0/c_srate
# echo 2     > $G/functions/uac2.usb0/c_ssize
# echo 2     > $G/functions/uac2.usb0/p_chmask

# -- Config
mkdir -p "$G/configs/c.1/strings/0x409"
echo 500 > "$G/configs/c.1/MaxPower"
echo "Config 1" > "$G/configs/c.1/strings/0x409/configuration"

# -- Bindings
ln -s $G/functions/hid.usb0  $G/configs/c.1/
# ln -s $G/functions/uac2.usb0 $G/configs/c.1/

# 6) Finally bind to first available UDC
echo $(ls /sys/class/udc | head -n1) > $G/UDC
echo "[navka-core] gadget ready on USB-C port"