#!/bin/bash

# 포트 번호와 IP 주소 정의
LOCAL_PORT=3311
REMOTE_IP=172.50.173.121
REMOTE_PORT=2211
SSH_HOST=100.20.151.224
SSH_PORT=2211
SSH_KEY=/home/admintool/USWest2-KeyPair.pem

# 함수: SSH 터널 시작
start_tunnel() {
    echo "Starting SSH tunnel..."

    # 기존 포트 사용 여부 확인
    if sudo lsof -i :$LOCAL_PORT > /dev/null 2>&1; then
        echo "Port $LOCAL_PORT is already in use."

        # 기존 포트에 대해 열려 있는 프로세스 찾기
        PIDS=$(sudo lsof -ti :$LOCAL_PORT)

        if [ -n "$PIDS" ]; then
            echo "Terminating existing connections..."
            for PID in $PIDS; do
                sudo kill -9 $PID
            done

            # 프로세스가 성공적으로 종료되었는지 확인
            sleep 1
            if ! ps -p $PIDS > /dev/null 2>&1; then
                echo "Existing connections terminated. Establishing new SSH tunnel..."
                sudo ssh -f -N -L $LOCAL_PORT:$REMOTE_IP:$REMOTE_PORT ubuntu@$SSH_HOST -p $SSH_PORT -i $SSH_KEY -o StrictHostKeyChecking=no

                # 결과 확인
                if [ $? -eq 0 ]; then
                    echo "SSH tunnel established successfully."
                else
                    echo "Failed to establish SSH tunnel."
                fi
            else
                echo "Failed to terminate existing connections. Unable to establish a new SSH tunnel."
            fi
        else
            echo "No existing PIDs found, but port $LOCAL_PORT is in use."
        fi
    else
        echo "Port $LOCAL_PORT is free. Establishing new SSH tunnel..."
        sudo ssh -f -N -L $LOCAL_PORT:$REMOTE_IP:$REMOTE_PORT ubuntu@$SSH_HOST -p $SSH_PORT -i $SSH_KEY -o StrictHostKeyChecking=no

        # 결과 확인
        if [ $? -eq 0 ]; then
            echo "SSH tunnel established successfully."
        else
            echo "Failed to establish SSH tunnel."
        fi
    fi
}

# 함수: SSH 터널 종료
stop_tunnel() {
    echo "Stopping SSH tunnel..."

    # 포트가 사용 중인지 확인하고 종료
    if sudo lsof -i :$LOCAL_PORT > /dev/null 2>&1; then
        # 기존 포트에 대해 열려 있는 프로세스 찾기
        PIDS=$(sudo lsof -ti :$LOCAL_PORT)
        for PID in $PIDS; do
            sudo kill -9 $PID
        done
        echo "SSH tunnel stopped."
    else
        echo "No SSH tunnel found on port $LOCAL_PORT."
    fi
}

# 함수: SSH 터널 상태 확인
status_tunnel() {
    echo "Checking SSH tunnel status..."

    if sudo lsof -i :$LOCAL_PORT > /dev/null 2>&1; then
        echo "SSH tunnel is running on port $LOCAL_PORT."
    else
        echo "No SSH tunnel is running on port $LOCAL_PORT."
    fi
}

# 파라미터에 따라 함수 호출
case "$1" in
    start)
        start_tunnel
        ;;
    stop)
        stop_tunnel
        ;;
    status)
        status_tunnel
        ;;
    *)
        echo "Usage: $0 {start|stop|status}"
        exit 1
        ;;
esac