#!/usr/bin/env bash
set -euo pipefail

# Cleans up zellij sessions that are inactive:
# - sessions marked EXITED (resurrectable metadata)
# - running sessions with 0 attached clients
#
# Usage:
#   cleanup-zellij-inactive.sh            # delete inactive sessions
#   cleanup-zellij-inactive.sh --dry-run  # show what would be deleted

DRY_RUN=0

case "${1-}" in
  "" ) ;;
  -n|--dry-run) DRY_RUN=1 ;;
  -h|--help)
    cat <<'EOF'
cleanup-zellij-inactive.sh

Delete zellij sessions that are inactive:
- EXITED sessions are deleted
- running sessions with 0 attached clients are killed+deleted

Options:
  -n, --dry-run   Show what would be deleted
  -h, --help      Show this help
EOF
    exit 0
    ;;
  *)
    echo "Unknown option: $1" >&2
    echo "Use --help for usage" >&2
    exit 1
    ;;
esac

if ! command -v zellij >/dev/null 2>&1; then
  echo "zellij not found in PATH" >&2
  exit 1
fi

mapfile -t session_lines < <(zellij list-sessions --no-formatting 2>/dev/null || true)

if [ "${#session_lines[@]}" -eq 0 ]; then
  echo "No zellij sessions found"
  exit 0
fi

deleted=0
failed=0
kept=0

for line in "${session_lines[@]}"; do
  [ -z "$line" ] && continue

  name="${line%% *}"
  is_exited=0
  if [[ "$line" == *"EXITED"* ]]; then
    is_exited=1
  fi

  should_delete=0

  if [ "$is_exited" -eq 1 ]; then
    should_delete=1
  else
    # Running session: check attached clients
    clients_out="$(zellij --session "$name" action list-clients 2>/dev/null || true)"
    client_count="$(printf '%s\n' "$clients_out" | tail -n +2 | sed '/^\s*$/d' | wc -l | tr -d ' ')"
    if [ "$client_count" -eq 0 ]; then
      should_delete=1
    fi
  fi

  if [ "$should_delete" -eq 1 ]; then
    if [ "$DRY_RUN" -eq 1 ]; then
      echo "[dry-run] delete: $name"
      deleted=$((deleted + 1))
    else
      # --force also kills running sessions before deleting
      if zellij delete-session --force "$name" >/dev/null 2>&1; then
        echo "deleted: $name"
        deleted=$((deleted + 1))
      else
        echo "failed:  $name" >&2
        failed=$((failed + 1))
      fi
    fi
  else
    kept=$((kept + 1))
  fi
done

echo
if [ "$DRY_RUN" -eq 1 ]; then
  echo "Would delete: $deleted"
else
  echo "Deleted: $deleted"
  echo "Failed:  $failed"
fi
echo "Kept:    $kept"