#!/bin/bash
# One-off / catch-up: remove the timecode overscan band from stream recordings that were published BEFORE the
# sweep learned to crop it. Re-encodes (libx264, frame timing preserved, audio copied), re-applies the timecode
# from the sidecar, replaces the file, marks the sidecar band_removed. Skips files whose sidecar already says so.
#   vgdeband.sh                      all of /srv/media/streams/*/*.mp4 with a strip sidecar
#   vgdeband.sh FILE.mp4 ...         just these
# Long: a 3 h 1440p60 night is a few hours of CPU. Run detached: sudo systemd-run --unit vgdeband -p Nice=15 \
#   -p IOSchedulingClass=idle /usr/local/bin/vgdeband.sh ; follow with journalctl -fu vgdeband
set -uo pipefail
ROOT="${MEDIA_ROOT:-/srv/media}"
log() { echo "$(date '+%F %T') $*"; }
dur() { ffprobe -v error -show_entries format=duration -of csv=p=0 "$1" 2>/dev/null | cut -d. -f1; }
if (( $# )); then files=("$@"); else mapfile -t files < <(find "$ROOT/streams" -mindepth 2 -maxdepth 2 -type f -name '*.mp4' | sort); fi
for f in "${files[@]}"; do
  side="${f%.*}.json"
  [[ -f $side ]] || { log "skip   $f (no sidecar)"; continue; }
  read -r src removed tc ctime < <(python3 -c '
import json,sys; d=json.load(open(sys.argv[1]))
print(d.get("source","none"), 1 if d.get("band_removed") else 0, d.get("timecode",""), d.get("timestamp",""))' "$side")
  [[ $src == strip ]] || { log "skip   $f (source=$src)"; continue; }
  (( removed )) && { log "skip   $f (band already removed)"; continue; }
  fuser -s "$f" 2>/dev/null && { log "skip   $f (in use)"; continue; }
  w=$(ffprobe -v error -select_streams v:0 -show_entries stream=width -of csv=p=0 "$f")
  band=$(python3 /usr/local/bin/vgstrip.py band "$w")
  tmp="$f.part"
  tcargs=(); [[ -n $tc ]] && tcargs=(-timecode "$tc" -write_tmcd 1); [[ -n $ctime ]] && tcargs+=(-metadata "creation_time=$ctime")
  log "deband $f  (${w}px wide -> crop ${band} rows; tc=$tc)"
  nice -n 15 ionice -c 3 ffmpeg -nostdin -hide_banner -loglevel error -y -i "$f" \
    -map 0:v:0 -map '0:a?' \
    -c:v libx264 -preset veryfast -crf 18 -maxrate 30M -bufsize 60M -pix_fmt yuv420p -profile:v high \
    -vf "crop=iw:ih-${band}:0:0" -fps_mode passthrough -c:a copy \
    "${tcargs[@]}" -movflags +faststart -f mp4 "$tmp"
  rc=$?; d1=$(dur "$f"); d2=$(dur "$tmp")
  if (( rc == 0 )) && [[ -n $d1 && -n $d2 ]] && (( d2 >= d1 - 2 && d2 <= d1 + 2 )); then
    mv -f "$tmp" "$f"; chown 1000:1000 "$f" 2>/dev/null
    python3 -c '
import json,sys; p=sys.argv[1]; d=json.load(open(p)); d["band_rows"]=int(sys.argv[2]); d["band_removed"]=True
json.dump(d, open(p,"w"))' "$side" "$band"; chown 1000:1000 "$side" 2>/dev/null
    log "done   $f"
  else
    rm -f "$tmp"; log "FAILED $f rc=$rc src_dur=${d1:-?} out_dur=${d2:-?} (file left untouched)" >&2
  fi
done