Two leds blink with one button

[Railroader]

@thatperson13

    //turns red LED on if the button is pressed:    
    if(buttonState==HIGH && mes==0){
    digitalWrite(ledPin2, HIGH);
    delay(500); //half a second delay before red LED turns off 
    digitalWrite(ledPin2, LOW); 
    buttonState=LOW; 
    }
  //changes LED from red to green
    else if (buttonState==HIGH && mes==1){ 
    digitalWrite(ledPin,HIGH);
    delay(500);// half a second delay before turning off 
    digitalWrite(ledPin,LOW); 
    buttonState=LOW;
    }  
   if(buttonState==LOW){
     digitalWrite(ledPin, LOW);
     digitalWrite(ledPin2,LOW);

     } // switch statemnt for when the button isn't pressed the LEDS to stay on
     switch (mes) {
       case 1:
       if (buttonState == HIGH){
       buttonState = LOW;
         digitalWrite (ledPin2,HIGH);
       digitalWrite (ledPin,LOW);// after the button is let go turn on red LED and turn off green LED
      delay (100);
         break;
       }
       case 2:
       digitalWrite (ledPin,LOW);
       digitalWrite (ledPin2,HIGH); // second time after the button is let go green LED on red off

     }
    }

I would put all actions into the cases. The first case will look for the trigger to start the next level, next case. First doing some digitalWrite and some in a case is a mismash in my world. Being in one case looking for the criteria for the next case, performing a closing digitalWrite and stepping up the case variable looks better to me.