#!/usr/bin/env bash
#
# extract_all.sh — Rebuild the original HERCULES dataset tree from its .tar.zst archives.
#
# Each per-robot / per-result folder in this dataset is stored as a .tar.zst archive
# (raw loose files would exceed the Hugging Face 10,000-files-per-folder limit).
# This script extracts every archive *in place*, reproducing the exact original
# directory layout, with original permissions and timestamps preserved.
#
# It is self-contained: it finds archives relative to its own location, so just run it
# from inside your downloaded copy of the dataset.
#
# Usage:
#   ./extract_all.sh             # extract everything; SKIP archives already extracted
#   ./extract_all.sh --force     # re-extract even if the target folder already exists
#   ./extract_all.sh --clean     # delete each .tar.zst after it extracts successfully
#   ./extract_all.sh --dry-run   # show what would happen, change nothing
#   ./extract_all.sh --help
#
# Requirements: tar + zstd   (Debian/Ubuntu: sudo apt install zstd)
#
set -u

FORCE=0; CLEAN=0; DRY=0
for a in "$@"; do
  case "$a" in
    --force)   FORCE=1 ;;
    --clean)   CLEAN=1 ;;
    --dry-run) DRY=1 ;;
    -h|--help) grep '^#' "${BASH_SOURCE[0]}" | sed 's/^# \{0,1\}//'; exit 0 ;;
    *) echo "ERROR: unknown argument: $a (use --help)"; exit 2 ;;
  esac
done

command -v tar  >/dev/null 2>&1 || { echo "ERROR: 'tar' not found";  exit 3; }
command -v zstd >/dev/null 2>&1 || { echo "ERROR: 'zstd' not found (sudo apt install zstd)"; exit 3; }

ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
echo "=== HERCULES extract_all ==="
echo "Dataset root : $ROOT"
echo "Mode         : $([ $DRY -eq 1 ] && echo 'DRY-RUN ')$([ $FORCE -eq 1 ] && echo 'FORCE ')$([ $CLEAN -eq 1 ] && echo 'CLEAN ')$([ $FORCE -eq 0 ] && echo '(skip already-extracted)')"
echo

OK=0; SKIP=0; FAIL=0

# Find every .tar.zst under the dataset root (handles spaces in folder names).
while IFS= read -r -d '' arc; do
  dir="$(dirname "$arc")"                  # extract here -> reproduces original tree
  base="$(basename "$arc")"
  target_name="${base%.tar.zst}"           # archive Drone1.tar.zst -> folder Drone1
  target="$dir/$target_name"
  rel="${arc#$ROOT/}"

  # skip if already extracted (unless --force)
  if [ "$FORCE" -eq 0 ] && [ -d "$target" ] && [ -n "$(find "$target" -mindepth 1 -print -quit 2>/dev/null)" ]; then
    echo "  [SKIP ] already extracted: $rel"
    SKIP=$((SKIP+1)); continue
  fi

  if [ "$DRY" -eq 1 ]; then
    echo "  [DRY  ] would extract $rel  ->  $dir/"
    OK=$((OK+1)); continue
  fi

  # verify integrity before touching anything (real run only)
  if ! zstd -t "$arc" >/dev/null 2>&1; then
    echo "  [FAIL ] integrity check failed, NOT extracting: $rel"
    FAIL=$((FAIL+1)); continue
  fi

  # extract preserving permissions + timestamps (no -m: keep stored mtimes)
  if tar --use-compress-program="zstd -d" -xpf "$arc" -C "$dir"; then
    echo "  [ OK  ] $rel"
    OK=$((OK+1))
    [ "$CLEAN" -eq 1 ] && rm -f "$arc" && echo "          (removed archive)"
  else
    echo "  [FAIL ] extraction error: $rel"
    FAIL=$((FAIL+1))
  fi
done < <(find "$ROOT" -type f -name '*.tar.zst' -print0 | sort -z)

echo
echo "=== Summary ==="
echo "Extracted : $OK"
echo "Skipped   : $SKIP  (already present; use --force to re-extract)"
echo "Failed    : $FAIL"
[ "$FAIL" -gt 0 ] && exit 1
echo "Done. The original folder structure has been restored."
exit 0