#!/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}"
vglog() { local lvl="$1"; shift; printf 'ts=%s level=%s component=vgdeband %s\n' "$(date -Is)" "$lvl" "$*"; }
log() { vglog info "msg=\"$*\""; }
dur() { ffprobe -v error -show_entries format=duration -of csv=p=0 "$1" 2>/dev/null | cut -d. -f1; }
# Metrics (LOGGING.md): the same counters the sweep keeps, under component=vgdeband. No-ops if not installed.
if [[ -r "$(dirname "$0")/vgmetrics.sh" ]]; then
  VG_MET_COMPONENT=vgdeband
  . "$(dirname "$0")/vgmetrics.sh" && vgmet_init
else
  vgmet_add() { :; }; vgmet_set() { :; }; vgmet_time() { echo 0; }; vgmet_since() { echo 0; }
fi
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 $side ]] || { vglog info "event=skip reason=no_sidecar file=\"$f\""; 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")
  [[ $src == strip ]] || { vglog info "event=skip reason=source_$src file=\"$f\""; continue; }
  (( removed )) && { vglog info "event=skip reason=already_removed file=\"$f\""; continue; }
  fuser -s "$f" 2>/dev/null && { vglog info "event=skip reason=in_use file=\"$f\""; 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")
  vglog info "event=deband file=\"$f\" width=$w band_rows=$band timecode=\"$tc\""
  job_t0=$(vgmet_time)
  nice -n 15 ionice -c 3 ffmpeg -nostdin -hide_banner -loglevel error -y -i "$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 -threads "${ENCODE_THREADS:-2}" \
    -vf "crop=iw:ih-${band}:0:0" -fps_mode passthrough -c:a copy \
    "${tcargs[@]}" -movflags +faststart -f mp4 "$tmp"
  rc=$?; job_secs=$(vgmet_since "$job_t0"); d1=$(dur "$f"); d2=$(dur "$tmp")
  vgmet_add "seconds:encode:stream" "$job_secs"
  if (( rc == 0 )) && [[ -n $d1 && -n $d2 ]] && (( d2 >= d1 - 2 && d2 <= d1 + 2 )); then
    vgmet_add "jobs:encode:done:stream"; vgmet_add deband 1
    mv -f "$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 "$side" 2>/dev/null
    vglog info "event=done file=\"$f\""
  else
    rm -f "$tmp"; vgmet_add "jobs:encode:failed:stream"; vglog error "event=failed file=\"$f\" rc=$rc src_dur=${d1:-?} out_dur=${d2:-?}" >&2
  fi
done