#!/usr/bin/env bash
# lesavka‑core.sh - one‑shot USB‑gadget bring‑up (Pi‑5 / Arch‑ARM)
# Presents:  • Boot‑protocol keyboard (hidg0)
#            • Boot‑protocol mouse    (hidg1)
#            • Stereo UAC2 speaker + microphone
set -euo pipefail

log() { printf '[lesavka-core] %s\n' "$*"; }
cleanup() { echo "" >"$G/UDC" 2>/dev/null || true; }

DISABLE_UAC=${LESAVKA_DISABLE_UAC:-}
DISABLE_UVC=${LESAVKA_DISABLE_UVC:-}
UVC_FALLBACK=${LESAVKA_UVC_FALLBACK:-1}
UVC_STREAMING_INTERVAL=${LESAVKA_UVC_STREAMING_INTERVAL:-1}
UVC_MAXPACKET=${LESAVKA_UVC_MAXPACKET:-1024}
UVC_MAXBURST=${LESAVKA_UVC_MAXBURST:-1}
UVC_INTERVAL=${LESAVKA_UVC_INTERVAL:-}
UVC_WIDTH=${LESAVKA_UVC_WIDTH:-1280}
UVC_HEIGHT=${LESAVKA_UVC_HEIGHT:-720}
UVC_FPS=${LESAVKA_UVC_FPS:-25}
UVC_DISABLE_IRQ=${LESAVKA_UVC_DISABLE_IRQ:-}
UVC_BULK=${LESAVKA_UVC_BULK:-}
MAX_SPEED=${LESAVKA_MAX_SPEED:-high-speed}

if [[ -z $UVC_INTERVAL ]]; then
    UVC_INTERVAL=$((10000000 / UVC_FPS))
fi
UVC_FRAME_SIZE=$((UVC_WIDTH * UVC_HEIGHT * 2))

wait_for_enum() {
    local tries=${1:-50}   # 50 x 100ms = 5s
    UDC_STATE="unknown"
    UDC_SPEED="unknown"
    for ((i=0; i<tries; i++)); do
        UDC_STATE=$(cat "/sys/class/udc/$UDC/state" 2>/dev/null || echo "unknown")
        UDC_SPEED=$(cat "/sys/class/udc/$UDC/current_speed" 2>/dev/null || echo "unknown")
        if [[ "$UDC_STATE" != "not attached" && "$UDC_STATE" != "unknown" ]]; then
            return 0
        fi
        sleep 0.1
    done
    return 1
}

exec 2> >(tee -a /tmp/lesavka-core.debug.$(date +%s).log)
set -x
echo "[lesavka-core] running: $0 (sha1sum=$(sha1sum "$0" | cut -d' ' -f1))"

#──────────────────────────────────────────────────
# 1.  Ensure overlay + kernel modules
#──────────────────────────────────────────────────
CFG=/boot/config.txt
grep -q 'dtoverlay=dwc2,dr_mode=peripheral' "$CFG" || echo 'dtoverlay=dwc2,dr_mode=peripheral' >> "$CFG"

modprobe dwc2 || { echo "dwc2 not in kernel; abort" >&2; exit 1; }
modprobe libcomposite || { echo "libcomposite not in kernel; abort" >&2; exit 1; }

modprobe -r uvcvideo 2>/dev/null || true
modprobe uvcvideo || { echo "uvcvideo not in kernel; abort" >&2; exit 1; }

udevadm control --reload
udevadm trigger --subsystem-match=video4linux
udevadm settle

#──────────────────────────────────────────────────
# 2.  Wait for UDC device to appear (max 10 s)
#──────────────────────────────────────────────────
log "⏳ waiting for UDC to register ..."
UDC=""
for _ in {1..100}; do                       # 100 × 100ms = 10s
    UDC=$(ls /sys/class/udc 2>/dev/null | head -n1) && [[ -n $UDC ]] && break
    sleep 0.1
done

if [[ -z $UDC ]]; then
    log "⚠️  UDC still absent - trying manual bind"
    for drv in dwc2 dwc3; do
        drv_root="/sys/bus/platform/drivers/$drv"
        [[ -d $drv_root ]] || continue
        for node in /sys/bus/platform/devices/*usb*; do
            node=${node##*/}               # strip path
            echo "$node" >"$drv_root/bind" 2>/dev/null || continue
        done
    done
    # re-check for another 5 s
    for i in {1..50}; do
        UDC=$(ls /sys/class/udc 2>/dev/null | head -n1) && [[ -n $UDC ]] && break
        sleep 0.1
    done
fi

[[ -n $UDC ]] || { log "❌ UDC not present after manual bind"; exit 1; }
log "✅ UDC detected: $UDC"

#──────────────────────────────────────────────────
# 3.  (Re‑)create gadget
#──────────────────────────────────────────────────
mountpoint -q /sys/kernel/config || mount -t configfs none /sys/kernel/config
G=/sys/kernel/config/usb_gadget/lesavka

if [[ -d $G ]]; then
  echo '' >"$G/UDC" 2>/dev/null || true
  sleep 0.2
  # configfs doesn't allow unlinking attribute files; remove links then rmdir.
  find "$G" -type l -delete 2>/dev/null || true
  for dir in "$G/functions" "$G/configs" "$G/strings" "$G/os_desc" "$G/webusb"; do
    [[ -d $dir ]] || continue
    find "$dir" -mindepth 1 -depth -type d -exec rmdir {} \; 2>/dev/null || true
  done
fi

mkdir -p "$G"
echo 0x1d6b >"$G/idVendor"       # Linux Foundation
echo 0x0104 >"$G/idProduct"      # Multifunction Composite Gadget
echo 0x0200 >"$G/bcdUSB"
echo "$MAX_SPEED" >"$G/max_speed"

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

# ----------------------- HID keyboard (usb0) -----------------------
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"

# ----------------------- HID mouse (usb1) --------------------------
mkdir -p "$G/functions/hid.usb1"
echo 2 > "$G/functions/hid.usb1/protocol"   # Boot mouse
echo 1 > "$G/functions/hid.usb1/subclass"
echo 4 > "$G/functions/hid.usb1/report_length"
printf '\x05\x01\x09\x02\xa1\x01\x09\x01\xa1\x00'\
'\x05\x09\x19\x01\x29\x03\x15\x00\x25\x01\x95\x03\x75\x01\x81\x02'\
'\x95\x01\x75\x05\x81\x03'\
'\x05\x01\x09\x30\x09\x31\x09\x38\x15\x81\x25\x7f\x75\x08\x95\x03\x81\x06'\
'\xc0\xc0' >"$G/functions/hid.usb1/report_desc"

if [[ -z $DISABLE_UAC ]]; then
  # ---------- UAC2 function - speaker + mic, 2×48 kHz stereo ---------
  mkdir -p "$G/functions/uac2.usb0"
  U="$G/functions/uac2.usb0"
  # Playback (speaker)
  echo 0x3     >"$U/p_chmask"   # L+R
  echo 48000   >"$U/p_srate"
  echo 2       >"$U/p_ssize"    # 16 bit
  # Capture (microphone)
  echo 0x3     >"$U/c_chmask"
  echo 48000   >"$U/c_srate"
  echo 2       >"$U/c_ssize"
  # Optional: allocate a few extra request buffers
  echo 32      >"$U/req_number" 2>/dev/null || true
else
  log "🔇 UAC2 disabled (LESAVKA_DISABLE_UAC set)"
fi

if [[ -z $DISABLE_UVC ]]; then
  # ----------------------- UVC function (usb‑video) ------------------
  mkdir -p "$G/functions/uvc.usb0"
  F="$G/functions/uvc.usb0"
  echo "$UVC_STREAMING_INTERVAL" >"$F/streaming_interval"
  echo "$UVC_MAXPACKET" >"$F/streaming_maxpacket"
  echo "$UVC_MAXBURST" >"$F/streaming_maxburst"
  if [[ -n $UVC_BULK ]]; then
    echo 1 >"$F/streaming_bulk" 2>/dev/null || true
  fi

# ── 1.  FORMAT DESCRIPTOR (uncompressed YUY2, 16 bpp) ──────────────
  mkdir -p "$F/streaming/uncompressed/yuyv"
# GUID = {59555932-0000-0010-8000-00aa00389b71} (“YUY2”) little-endian
  printf '\x59\x55\x59\x32\x00\x00\x10\x00\x80\x00\x00\xaa\x00\x38\x9b\x71' \
      >"$F/streaming/uncompressed/yuyv/guidFormat"
  echo 16  >"$F/streaming/uncompressed/yuyv/bBitsPerPixel"

# ── 2.  FRAME DESCRIPTOR (480p @ 30 fps) ───────────────────────────
  mkdir -p "$F/streaming/uncompressed/yuyv/480p"
  echo "$UVC_WIDTH"  >"$F/streaming/uncompressed/yuyv/480p/wWidth"
  echo "$UVC_HEIGHT" >"$F/streaming/uncompressed/yuyv/480p/wHeight"
  echo "$UVC_FRAME_SIZE" >"$F/streaming/uncompressed/yuyv/480p/dwMaxVideoFrameBufferSize"
  echo "$UVC_INTERVAL" >"$F/streaming/uncompressed/yuyv/480p/dwDefaultFrameInterval"
  cat <<EOF >"$F/streaming/uncompressed/yuyv/480p/dwFrameInterval"
${UVC_INTERVAL}
$((UVC_INTERVAL * 2))
EOF

# ── 3.  REQUIRED HEADER LINKS (per UVC gadget docs) ────────────────
  mkdir -p "$F/streaming/header/h"
  pushd "$F/streaming/header/h" >/dev/null
  ln -s ../../uncompressed/yuyv yuyv
  popd >/dev/null

  for s in fs hs ss; do
      mkdir -p "$F/streaming/class/$s"
      pushd "$F/streaming/class/$s" >/dev/null
      ln -s ../../header/h h
      popd >/dev/null
  done

# ── 4.  Video‑Control interface ─────────────────────────────────────
  mkdir -p "$F/control/header/h"
  set +e
  for s in fs hs ss; do
      mkdir -p "$F/control/class/$s" 2>/dev/null || continue
      pushd "$F/control/class/$s" >/dev/null
      ln -s ../../header/h h 2>/dev/null || true
      popd >/dev/null
  done
  set -e

  if [[ -n $UVC_DISABLE_IRQ ]]; then
    echo 0 >"$F/control/enable_interrupt_ep" 2>/dev/null || true
  fi

# optional: hide unsupported controls
  echo 0 >"$F/control/terminal/camera/default/bmControls"    2>/dev/null || true
  echo 0 >"$F/control/processing/default/bmControls"         2>/dev/null || true

# friendly label
  mkdir -p "$F/control/header/h/strings/0x409" 2>/dev/null || true
  echo "Lesavka UVC" >"$F/control/header/h/strings/0x409/label" 2>/dev/null || true
else
  log "📷 UVC disabled (LESAVKA_DISABLE_UVC set)"
fi

# ----------------------- configuration -----------------------------
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"
config_label="Config 1: HID"
if [[ -z $DISABLE_UAC ]]; then
  config_label+=" + UAC2"
fi
if [[ -z $DISABLE_UVC ]]; then
  config_label+=" + UVC"
fi
echo "$config_label" >"$G/configs/c.1/strings/0x409/configuration"

ln -s  $G/functions/hid.usb0  $G/configs/c.1/
ln -s  $G/functions/hid.usb1  $G/configs/c.1/
if [[ -z $DISABLE_UAC ]]; then
  ln -s  $U                   $G/configs/c.1/
fi
if [[ -z $DISABLE_UVC ]]; then
  ln -s  $G/functions/uvc.usb0  $G/configs/c.1/
fi

# mkdir -p $G/functions/hid.usb0/os_desc
# mkdir -p $G/functions/hid.usb1/os_desc
# mkdir -p $U/os_desc

# ---------- optional Microsoft OS descriptors ----------------------
# if [ -e "$G/os_desc/use" ]; then
#     echo 1        >"$G/os_desc/use"
#     echo 0xcd     >"$G/os_desc/b_vendor_code"
#     echo "MSFT100" >"$G/os_desc/qw_sign"

#     ln -s "$G/configs/c.1" "$G/os_desc"          # creates $G/os_desc/conf

#     echo "Lesavka Keyboard" >"$G/functions/hid.usb0/os_desc/interface"
#     echo "Lesavka Mouse"    >"$G/functions/hid.usb1/os_desc/interface"
#     echo "Lesavka Mic+Spkr" >"$U/os_desc/interface"
# fi

#──────────────────────────────────────────────────
# 4.  Bind gadget
#──────────────────────────────────────────────────
echo "$UDC" >"$G/UDC"
parts="hidg0,hidg1"
[[ -z $DISABLE_UAC ]] && parts+=",UAC2"
[[ -z $DISABLE_UVC ]] && parts+=",UVC"
log "🎉 gadget bound on $UDC ($parts)"

if wait_for_enum 50; then
    log "✅ UDC state is '$UDC_STATE' (speed=$UDC_SPEED)"
else
    log "⚠️  UDC state is '$UDC_STATE' (speed=$UDC_SPEED). Host not enumerated."
    if [[ -z $DISABLE_UVC && "$UVC_FALLBACK" != "0" ]]; then
        log "♻️  retrying without UVC (LESAVKA_UVC_FALLBACK=0 to disable)"
        exec env LESAVKA_DISABLE_UVC=1 LESAVKA_UVC_FALLBACK=0 "$0"
    fi
fi

exit 0