#!/bin/sh
set -eu

INBOX="${INBOX:-/inbox}"
DROP="${DROP:-/drop}"
STABLE_FOR="${STABLE_FOR:-5}"          # seconds with unchanged size to consider stable
SCAN_FALLBACK="${SCAN_FALLBACK:-60}"   # seconds between full scans (safety net)

echo "[mover] Watching inbox ${INBOX} -> ${DROP} (stable for ${STABLE_FOR}s)"

mkdir -p "$INBOX" "$DROP"

is_stable() {
  f="$1"
  [ -f "$f" ] || return 1
  size_a="$(stat -c%s "$f" 2>/dev/null || echo 0)"
  sleep "$STABLE_FOR"
  size_b="$(stat -c%s "$f" 2>/dev/null || echo 0)"
  [ "$size_a" -eq "$size_b" ]
}

move_file() {
  src="$1"
  [ -f "$src" ] || return 0
  rel="${src#$INBOX/}"
  dest_dir="$DROP/$(dirname "$rel")"
  dest="$dest_dir/$(basename "$rel")"
  mkdir -p "$dest_dir"
  mv -f -- "$src" "$dest"
  echo "[mover] Moved $(basename "$src")"
}

process_one() {
  f="$1"
  [ -f "$f" ] || return 0
  if is_stable "$f"; then
    move_file "$f"
  fi
}

scan_all() {
  find "$INBOX" -type f -size +0c -print0 | while IFS= read -r -d '' f; do
    process_one "$f"
  done
}

start_watcher() {
  if command -v inotifywait >/dev/null 2>&1; then
    echo "[mover] Starting inotify watcher"
    inotifywait -q -m -r -e close_write,moved_to,create --format '%w%f' "$INBOX" | \
      while IFS= read -r path; do
        process_one "$path"
      done &
    echo "[mover] Watcher pid $!"
  else
    echo "[mover] inotifywait not available; relying on periodic scans"
  fi
}

start_watcher

while :; do
  scan_all
  sleep "$SCAN_FALLBACK"
done