#!/usr/bin/env bash
# Offline-friendly helper to make a JDK available for benchmark builds.
# Order of preference:
# 1) Respect an existing JAVA_HOME when it contains javac.
# 2) Use javac from PATH when present.
# 3) Extract a vendored archive (jdk-21.0.1.tar.gz) into .jdk/ and use it.

ensure_bench_jdk() {
  # Re-use an explicitly provided JAVA_HOME when it already has javac.
  if [[ -n "${JAVA_HOME:-}" && -x "${JAVA_HOME}/bin/javac" ]]; then
    export PATH="${JAVA_HOME}/bin:${PATH}"
    return 0
  fi

  # Use any javac already on PATH.
  if command -v javac >/dev/null 2>&1; then
    return 0
  fi

  local script_dir bench_root cache_dir archive_dir archive_path candidate
  script_dir="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
  bench_root="$(cd "${script_dir}/../.." && pwd)"
  repo_root="$(cd "${bench_root}/../.." && pwd)"
  cache_dir="${bench_root}/.jdk"
  archive_dir="${cache_dir}/jdk-21.0.1+12"

  # Prefer an archive co-located with this script; fall back to the repo copy.
  for candidate in \
    "${script_dir}/jdk-21.0.1.tar.gz" \
    "${repo_root}/src/Sdk/StellaOps.Sdk.Generator/tools/jdk-21.0.1.tar.gz"
  do
    if [[ -f "${candidate}" ]]; then
      archive_path="${candidate}"
      break
    fi
  done

  if [[ -z "${archive_path:-}" ]]; then
    echo "[ensure_jdk] No JDK found. Set JAVA_HOME or place jdk-21.0.1.tar.gz under tools/java/." >&2
    return 1
  fi

  mkdir -p "${cache_dir}"
  if [[ ! -d "${archive_dir}" ]]; then
    tar -xzf "${archive_path}" -C "${cache_dir}"
  fi

  if [[ ! -x "${archive_dir}/bin/javac" ]]; then
    echo "[ensure_jdk] Extracted archive but javac not found under ${archive_dir}" >&2
    return 1
  fi

  export JAVA_HOME="${archive_dir}"
  export PATH="${JAVA_HOME}/bin:${PATH}"
}

# Allow running as a script for quick verification.
if [[ "${BASH_SOURCE[0]}" == "$0" ]]; then
  if ensure_bench_jdk; then
    java -version
  fi
fi