#!/usr/bin/env bash
# Copyright: Julien Moutinho <julm+camera@sourcephile.fr>
# License: AGPL-3.0-or-later
#

cd "${0%/*}"
set -eu
shopt -s nullglob

ffmpeg_ () { local -; set -x; nice -19 time ffmpeg </dev/null -hide_banner -loglevel warning -stats -y "$@"; }
mv_ () { local -; mv -i >&2 "$@"; }
set -x
for dir in "$@"; do
  IFS=/ read -r user year cat month x <<<"$dir"
  listing=
  test -f "$dir" || listing=1
  if test -n "$listing"
  then
    test -n "$year" || exec "$0" "$user"/2*/src/*/
    test -n "$month" || exec "$0" "$user"/"$year"/src/*/
    pushd "$user/$year" >/dev/null
    test -d src/"$month" || { popd; continue; }
  else
    pushd "$user/$year" >/dev/null
  fi
  if test -n "$listing"
  then (cd src; find -L "$month" -type f -size +100M -printf '%f %p\n') | sort -t/ -k1.5 | cut -f2 -d ' '
  else printf '%s\n' "${dir#"$user/$year/$cat/"}"
  fi |
  while read -r src; do
    echo >&2 "$dir: processing $user/$year/src/$src"
    base=${src%.*}
    name=${base#*/}
    id=${name%%.*}
    mkdir -p {{tmp,wip}/reencode,old}/"${base%/*}"
    need_psize () {
      # Slow, but needed to make wide videos span two columns of the CSS grid
      IFS=' ' read -r width height rotation <<<"$(ffprobe -v error -select_streams v:0 -show_entries stream=width,height:stream_side_data=rotation -of csv=p=0:s='\ ' src/"$src")"
      case "$rotation" in
        (90|-90) w=$width; width=$height; height=$w;;
      esac
      if [ "$width" -gt "$height" ]
      then psize=$height
      else psize=$width
      fi
    }
    case "$src" in
      *.mp4|*.MOV)
        need_psize
        case $psize in
          480) crf=30;;
          720) crf=40;;
          1080) crf=50;;
          *) exit 3;;
        esac
        preset=5
        ext="preset=$preset.crf=$crf.av1.webm"
        need_opus () {
          test tmp/reencode/"$base".opus -nt src/"$src" || {
            ffmpeg_ -i src/"$src" \
              -map 0:a -c:a libopus -b:a 64k -application voip \
              wip/reencode/"$base".opus
            mv_ {wip,tmp}/reencode/"$base".opus
          }
        }
        test src/"$base.$ext" -nt src/"$src" || {
          need_opus
          ffmpeg_ -i src/"$src" -i tmp/reencode/"$base".opus \
            -map 0:v \
              -filter:v format=yuv420p \
              -c:v libsvtav1 -preset "$preset" -crf "$crf" \
                -svtav1-params input-depth=8:keyint=10s:enable-overlays=1:enable-tf=0:scd=1:scm=0:tune=0:fast-decode=1 \
            -map 1:a -c:a copy \
            wip/reencode/"$base.$ext"
          mv_ {wip/reencode,src}/"$base.$ext"
          mv_ {src,old}/"$src"
        }
        ;;
    esac
  done
  rm -vrf {tmp,wip}/reencode
  popd >/dev/null
done