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

script_dir="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
repo_root="$(cd "${script_dir}/.." && pwd)"

target_dir="${repo_root}/qortal/data"
target_file=""
legacy_default_args='-XX:MaxRAMPercentage=25 -XX:+UseG1GC -Xss1024k'
legacy_autosized_args='-XX:MaxRAMPercentage=66 -XX:+UseG1GC -Xss1024k'
gib_bytes=$((1024 * 1024 * 1024))
env_file=""
seed_args="${QORTAL_JVM_MEMORY_ARGS:-}"
managed_state_file=""

resolve_path() {
  local raw="${1:-}"
  if [[ -z "${raw}" ]]; then
    printf '%s' ""
    return 0
  fi
  if [[ "${raw}" == /* ]]; then
    printf '%s' "${raw}"
    return 0
  fi
  printf '%s' "${repo_root}/${raw}"
}

ensure_qortal_data_permissions() {
  local data_dir="${1:-}"
  if [[ "${EUID:-$(id -u)}" -ne 0 ]]; then
    return 0
  fi
  if [[ -z "${data_dir}" || ! -d "${data_dir}" ]]; then
    return 0
  fi

  chown -R 1000:100 "${data_dir}" >/dev/null 2>&1 || true
  chmod -R u+rwX,g+rwX "${data_dir}" >/dev/null 2>&1 || true
}

read_host_memory_bytes() {
  if [[ -r /proc/meminfo ]]; then
    awk '/^MemTotal:/ { print $2 * 1024; exit }' /proc/meminfo 2>/dev/null || true
  fi
}

read_cgroup_memory_bytes() {
  local cgroup_file=""
  local value=""

  for cgroup_file in /sys/fs/cgroup/memory.max /sys/fs/cgroup/memory/memory.limit_in_bytes; do
    [[ -r "${cgroup_file}" ]] || continue
    value="$(tr -d '\r\n' < "${cgroup_file}" 2>/dev/null || true)"
    case "${value}" in
      ""|"max")
        continue
        ;;
    esac
    if [[ "${value}" =~ ^[0-9]+$ ]] && [[ "${value}" -gt 0 ]]; then
      printf '%s' "${value}"
      return 0
    fi
  done

  return 1
}

resolve_available_memory_bytes() {
  local host_bytes=""
  local cgroup_bytes=""

  host_bytes="$(read_host_memory_bytes)"
  cgroup_bytes="$(read_cgroup_memory_bytes || true)"

  if [[ -n "${host_bytes}" && "${host_bytes}" -gt 0 ]]; then
    if [[ -n "${cgroup_bytes}" && "${cgroup_bytes}" -gt 0 && "${cgroup_bytes}" -lt "${host_bytes}" ]]; then
      printf '%s' "${cgroup_bytes}"
      return 0
    fi
    printf '%s' "${host_bytes}"
    return 0
  fi

  if [[ -n "${cgroup_bytes}" && "${cgroup_bytes}" -gt 0 ]]; then
    printf '%s' "${cgroup_bytes}"
    return 0
  fi

  return 1
}

compute_auto_qortal_args() {
  local total_bytes=""
  local target_bytes=""
  local percentage=""

  total_bytes="$(resolve_available_memory_bytes || true)"
  if [[ -z "${total_bytes}" || "${total_bytes}" -le 0 ]]; then
    printf '%s' "${legacy_autosized_args}"
    return 0
  fi

  target_bytes=$(( total_bytes * 66 / 100 ))
  if [[ "${total_bytes}" -ge $((6 * gib_bytes)) ]]; then
    if [[ "${target_bytes}" -lt $((4 * gib_bytes)) ]]; then
      target_bytes=$((4 * gib_bytes))
    fi
    if [[ "${target_bytes}" -gt $((8 * gib_bytes)) ]]; then
      target_bytes=$((8 * gib_bytes))
    fi
  fi

  percentage="$(awk -v target="${target_bytes}" -v total="${total_bytes}" 'BEGIN { if (total <= 0) { print "66"; exit } printf "%.2f", (target / total) * 100 }')"
  printf '%s' "-XX:MaxRAMPercentage=${percentage} -XX:+UseG1GC -Xss1024k"
}

while [[ $# -gt 0 ]]; do
  case "$1" in
    --target-dir)
      target_dir="${2:-}"
      shift 2
      ;;
    --target-dir=*)
      target_dir="${1#*=}"
      shift
      ;;
    --target-file)
      target_file="${2:-}"
      shift 2
      ;;
    --target-file=*)
      target_file="${1#*=}"
      shift
      ;;
    -h|--help)
      cat <<USAGE
Usage: ./scripts/ensure-qortal-start-args.sh [options] [env-file]

Initialize a Qortal node start-arguments.txt file.

Options:
  --target-dir <path>     Start args directory (default: ${repo_root}/qortal/data)
  --target-file <path>    Start args file path override
  env-file                Optional env file whose QORTAL_JVM_MEMORY_ARGS value overrides auto-sizing
  -h, --help              Show this help
USAGE
      exit 0
      ;;
    *)
      if [[ -z "${env_file}" ]]; then
        env_file="${1}"
        shift
      else
        echo "Unknown argument: $1" >&2
        exit 1
      fi
      ;;
  esac
done

target_dir="$(resolve_path "${target_dir}")"
if [[ -z "${target_file}" ]]; then
  target_file="${target_dir%/}/start-arguments.txt"
else
  target_file="$(resolve_path "${target_file}")"
  target_dir="$(dirname "${target_file}")"
fi
managed_state_file="${target_file}.mode"

if [[ -n "${env_file}" && -f "${env_file}" ]]; then
  if [[ "${env_file}" != /* ]]; then
    env_file="$(resolve_path "${env_file}")"
  fi
  value_from_env_file="$(grep -E '^QORTAL_JVM_MEMORY_ARGS=' "${env_file}" | tail -n1 | cut -d= -f2- || true)"
  if [[ -n "${value_from_env_file}" ]]; then
    seed_args="${value_from_env_file}"
  fi
fi

mkdir -p "${target_dir}"
ensure_qortal_data_permissions "${target_dir}"

auto_args="$(compute_auto_qortal_args)"
existing_args=""
existing_mode=""

if [[ -f "${target_file}" && -s "${target_file}" ]]; then
  existing_args="$(tr -d '\r' < "${target_file}" | sed 's/[[:space:]]*$//')"
fi
if [[ -f "${managed_state_file}" && -s "${managed_state_file}" ]]; then
  existing_mode="$(tr -d '\r' < "${managed_state_file}" | sed 's/[[:space:]]*$//')"
fi

if [[ -n "${seed_args}" ]]; then
  printf '%s\n' "${seed_args}" > "${target_file}"
  printf '%s\n' "manual" > "${managed_state_file}"
  if [[ "${existing_args}" == "${seed_args}" ]]; then
    echo "Using Qortal JVM start args from env: ${target_file}"
  else
    echo "Updated Qortal JVM start args from env: ${target_file}"
  fi
  exit 0
fi

if [[ -f "${target_file}" && -s "${target_file}" ]]; then
  if [[ "${existing_mode}" == "auto" || "${existing_args}" == "${legacy_default_args}" || "${existing_args}" == "${legacy_autosized_args}" ]]; then
    printf '%s\n' "${auto_args}" > "${target_file}"
    printf '%s\n' "auto" > "${managed_state_file}"
    echo "Updated auto-sized Qortal JVM start args: ${target_file}"
    exit 0
  fi

  echo "Using existing Qortal JVM start args: ${target_file}"
  exit 0
fi

printf '%s\n' "${auto_args}" > "${target_file}"
printf '%s\n' "auto" > "${managed_state_file}"
echo "Initialized auto-sized Qortal JVM start args: ${target_file}"