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

env_file="${1:-}"
if [[ -z "${env_file}" ]]; then
  echo "Usage: $0 <env-file>"
  exit 1
fi
if [[ ! -f "${env_file}" ]]; then
  echo "Missing env file: ${env_file}"
  exit 1
fi

set_kv() {
  local key="$1"
  local value="$2"
  local esc
  esc="${value//\\/\\\\}"
  esc="${esc//&/\\&}"
  esc="${esc//|/\\|}"
  if grep -q "^${key}=" "${env_file}"; then
    sed -i -E "s|^${key}=.*|${key}=${esc}|" "${env_file}"
  else
    echo "${key}=${value}" >> "${env_file}"
  fi
}

get_kv() {
  local key="$1"
  local value
  value="$(grep -E "^${key}=" "${env_file}" | tail -n1 | cut -d= -f2- || true)"
  echo "${value}"
}

is_valid_port() {
  local port="$1"
  [[ "${port}" =~ ^[0-9]+$ ]] || return 1
  (( port >= 1 && port <= 65535 ))
}

port_in_use() {
  local port="$1"
  if ! command -v ss >/dev/null 2>&1; then
    # If we cannot inspect sockets, do not block startup. Keep current/default value.
    return 1
  fi
  if ss -H -ltn 2>/dev/null | awk '{print $4}' | grep -E -q "(^|:|\\])${port}$"; then
    return 0
  fi
  if ss -H -lun 2>/dev/null | awk '{print $5}' | grep -E -q "(^|:|\\])${port}$"; then
    return 0
  fi
  return 1
}

port_set_is_free() {
  local api_port="$1"
  local gateway_port="$((api_port - 1))"
  local p2p_port="$((api_port + 1))"
  local qdn_port="$((api_port + 3))"
  if ! is_valid_port "${api_port}" || ! is_valid_port "${gateway_port}" || ! is_valid_port "${p2p_port}" || ! is_valid_port "${qdn_port}"; then
    return 1
  fi
  if port_in_use "${api_port}" || port_in_use "${gateway_port}" || port_in_use "${p2p_port}" || port_in_use "${qdn_port}"; then
    return 1
  fi
  return 0
}

pick_api_port() {
  local candidates=("$@")
  local candidate
  for candidate in "${candidates[@]}"; do
    if port_set_is_free "${candidate}"; then
      echo "${candidate}"
      return 0
    fi
  done
  return 1
}

# Preferred order requested for API:
# 12391, then 22391/32391/42391/52391, then 12291/22291/32291/42291/52291.
preferred_api=(
  12391
  22391 32391 42391 52391
  12291 22291 32291 42291 52291
)

configured_api="$(get_kv "QORTAL_NODE_API_HOST_PORT")"
selected_api=""

# Respect explicit non-default API port overrides and keep P2P in sync as API+1.
if is_valid_port "${configured_api}" && [[ "${configured_api}" != "12391" ]]; then
  selected_api="${configured_api}"
else
  if selected_api="$(pick_api_port "${preferred_api[@]}")"; then
    :
  else
    echo "Unable to find free Qortal Gateway/API/P2P/QDN port set in requested range/order." >&2
    exit 1
  fi
fi

selected_gateway="$((selected_api - 1))"
selected_p2p="$((selected_api + 1))"
selected_qdn="$((selected_api + 3))"

if ! is_valid_port "${selected_gateway}" || ! is_valid_port "${selected_p2p}" || ! is_valid_port "${selected_qdn}"; then
  echo "Computed invalid Qortal Gateway/P2P/QDN port from API port ${selected_api}: Gateway=${selected_gateway}, P2P=${selected_p2p}, QDN=${selected_qdn}" >&2
  exit 1
fi

set_kv "QORTAL_NODE_GATEWAY_HOST_PORT" "${selected_gateway}"
set_kv "QORTAL_NODE_API_HOST_PORT" "${selected_api}"
set_kv "QORTAL_NODE_P2P_HOST_PORT" "${selected_p2p}"
set_kv "QORTAL_NODE_QDN_HOST_PORT" "${selected_qdn}"
echo "Selected Qortal node host ports: Gateway=${selected_gateway}, API=${selected_api}, P2P=${selected_p2p}, QDN=${selected_qdn}"
if port_in_use "${selected_gateway}" || port_in_use "${selected_api}" || port_in_use "${selected_p2p}" || port_in_use "${selected_qdn}"; then
  echo "Note: selected Gateway/API/P2P/QDN port appears in use; this may be expected if qortal_node is already running."
fi

exit 0