#!/usr/bin/env bash
# Installa (via pkexec) una copia di ffmpeg con CAP_SYS_ADMIN, necessaria per kmsgrab.
# La capability e' confinata a QUELLA copia del binario, non a /usr/bin/ffmpeg.
#
#   ./setup-kmsgrab.sh            installa
#   ./setup-kmsgrab.sh --remove   rimuove
set -euo pipefail

DEST="/usr/local/libexec/ambilight/ffmpeg-kmsgrab"
SRC="$(command -v ffmpeg)"

say() { printf '\033[1;32m==>\033[0m %s\n' "$*"; }

if [ "${1:-}" = "--remove" ]; then
    say "Rimuovo $DEST"
    pkexec sh -c "rm -f '$DEST' && rmdir --ignore-fail-on-non-empty /usr/local/libexec/ambilight 2>/dev/null || true"
    say "Fatto."
    exit 0
fi

[ -x "$SRC" ] || { echo "ffmpeg non trovato" >&2; exit 1; }

say "Installo $SRC -> $DEST con cap_sys_admin+ep (pkexec chiedera' la password)"
pkexec sh -c "install -D -m 0755 -o root -g root '$SRC' '$DEST' \
    && setcap cap_sys_admin+ep '$DEST' \
    && echo '--- capability applicata:' && getcap '$DEST'"

say "Verifica rapida (1 frame, senza portal e senza indicatore nel vassoio)"
"$DEST" -hide_banner -loglevel error -nostdin \
    -f kmsgrab -device /dev/dri/card1 -i - \
    -vf "hwdownload,format=bgr0,scale=188:72:flags=bilinear,format=rgb24" \
    -frames:v 1 -f rawvideo -pix_fmt rgb24 /tmp/kmsgrab_probe.rgb
ls -l /tmp/kmsgrab_probe.rgb
python3 - <<'PY'
import numpy as np
a = np.frombuffer(open('/tmp/kmsgrab_probe.rgb','rb').read(), dtype=np.uint8)
print("frame:", a.size, "byte ->", a[:9].tolist(), "| media:", a.reshape(-1,3).mean(axis=0).round(1).tolist())
PY

cat <<EOF

Attiva il backend nel demone:

  ambilight-ctl set capture kmsgrab
  systemctl --user restart ambilight.service
  ambilight-ctl state      # controlla 'fps' e assenza di 'stream_error'

Per tornare al portal:  ambilight-ctl set capture portal
EOF