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

ROOT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/../.." && pwd)"
source "$ROOT_DIR/scripts/lib/process-tree.sh"

sleep 60 &
protected_pid="$!"
signal_process_snapshot "${protected_pid}|not-the-real-start-time" KILL
if ! kill -0 "$protected_pid" >/dev/null 2>&1; then
  echo "FAIL: identity mismatch killed an unrelated process" >&2
  exit 1
fi
kill "$protected_pid" >/dev/null 2>&1 || true
wait "$protected_pid" 2>/dev/null || true

sh -c 'sleep 60 & wait' &
parent_pid="$!"
sleep 0.1
child_pid="$(pgrep -P "$parent_pid" | head -n 1)"

if [[ -z "$child_pid" ]]; then
  echo "FAIL: dummy child process was not created" >&2
  stop_process_tree "$parent_pid" KILL
  exit 1
fi

stop_process_tree "$parent_pid"
wait "$parent_pid" 2>/dev/null || true
sleep 0.1

child_state="$(ps -o stat= -p "$child_pid" 2>/dev/null | xargs || true)"
if [[ -n "$child_state" && "$child_state" != Z* ]]; then
  echo "FAIL: child process $child_pid is still running ($child_state)" >&2
  stop_process_tree "$child_pid" KILL
  exit 1
fi

echo "PASS: process tree stopped"

PROCESS_TREE_TERM_WAIT_LOOPS=2
export PROCESS_TREE_TERM_WAIT_LOOPS
sh -c 'trap "" TERM; sh -c '\''trap "" TERM; sleep 60'\'' & wait' &
stubborn_parent_pid="$!"
sleep 0.1
stubborn_child_pid="$(pgrep -P "$stubborn_parent_pid" | head -n 1)"

stop_process_tree "$stubborn_parent_pid"
wait "$stubborn_parent_pid" 2>/dev/null || true
sleep 0.1

stubborn_child_state="$(ps -o stat= -p "$stubborn_child_pid" 2>/dev/null | xargs || true)"
if [[ -n "$stubborn_child_state" && "$stubborn_child_state" != Z* ]]; then
  echo "FAIL: TERM-resistant child process $stubborn_child_pid is still running ($stubborn_child_state)" >&2
  kill -KILL "$stubborn_child_pid" >/dev/null 2>&1 || true
  exit 1
fi

echo "PASS: TERM-resistant process tree escalated safely"

identity_marker="$(mktemp)"
rm -f "$identity_marker"
process_identity_token() {
  if [[ ! -f "$identity_marker" ]]; then
    touch "$identity_marker"
    echo "first identity"
  else
    echo "reused identity"
  fi
}

reused_snapshot="$(snapshot_process_tree 999999)"
rm -f "$identity_marker"
if [[ -n "$reused_snapshot" ]]; then
  echo "FAIL: snapshot retained a process tree after root identity changed" >&2
  exit 1
fi

echo "PASS: root identity change invalidates the snapshot"