#!/bin/bash

# 查找空闲端口
find_free_port() {
  local start="${1:-10001}"
  local max="${2:-65535}"

  # 收集当前监听端口（TCP + UDP）
  local used_ports raw
  if command -v ss >/dev/null 2>&1; then
    raw=$(ss -lntu 2>/dev/null || true)
    used_ports=$(printf "%s\n" "$raw" | awk '{print $5}' | sed -n '2,$p' | sed -E 's/.*[:]//g' | sed '/^$/d')
  elif command -v netstat >/dev/null 2>&1; then
    raw=$(netstat -lntu 2>/dev/null || true)
    used_ports=$(printf "%s\n" "$raw" | awk '{print $4}' | sed -n '2,$p' | sed -E 's/.*[:]//g' | sed '/^$/d')
  elif command -v lsof >/dev/null 2>&1; then
    raw=$(lsof -i -P -n 2>/dev/null || true)
    used_ports=$(printf "%s\n" "$raw" | awk '/LISTEN/ {print $9}' | sed -E 's/.*[:]//g' | sed '/^$/d')
  else
    echo "Error: neither ss, netstat nor lsof is available to check listening ports." >&2
    return 2
  fi

  # 用关联数组记录已占用端口（需要 bash 4+）
  declare -A used_map
  local p
  for p in $used_ports; do
    # 过滤掉非数字
    if [[ $p =~ ^[0-9]+$ ]]; then
      used_map["$p"]=1
    fi
  done

  # 从 start 到 max 逐个检查
  for ((port = start; port <= max; port++)); do
    if [[ -z "${used_map[$port]}" ]]; then
      echo "$port"
      return 0
    fi
  done

  # 没找到可用端口
  echo "Error: No available port found in range $start-$max" >&2
  return 1
}

update_port(){
  local script_dir=$(cd "$(dirname "$0")"; pwd)
  local config_dir="$script_dir/../conf"
  source "$script_dir/utils/jq_util.sh"
  
  local port=$(find_free_port)
  modify_json_file "$config_dir/config.json" ".listen" ":$port"
  echo "设置端口成功"
}

update_port