Question Using MIDI piano as a keyboard (or just as an input method)

I am aware that plugins exist for making a MIDI piano compatible with unity for a game, but would it be possible to use each individual key as a designated button? (like keys on a keyboard). I know that this is at least possible outside of unity (like using external plugins or the fact that GarageBand is able to record MIDI instruments in real time), but I would like to know if it is even within the bounds of possibility to use a MIDI piano as an input method without a plugin.

Here is more or less what I was thinking that I want if it turns out to be possible to use a MIDI piano as an input method:

Code (CSharp):

1. private bool sustain_on;
2. public AudioSource piano;
3. public AudioClip pianokey_note_A;
4. void Start(){
5.     StartCoroutine(playpiano);
6.     piano = GetComponent<AudioSource>();
7. }
8. void Update()
9. {
10. if(Input.GetKeyDown(pianokey1) && sustain_on == false)
11. {
12.      piano.PlayOneShot(pianokey_note_A, 0.75f);
13. }
14. if(Input.GetKeyDown(pianokey1) && sustain_on == true)
15. {
16.      piano.PlayOneShot(pianokey_note_A, 0.75f);
17.      //but extend the length of the pianokey sound
18. }
19.  
20. // but with this method i would have to have over 160 if statements, so this would work but not be convenient

this is also pretty important that it be in a script, because the piano is going to be the sole controller of my game, so I need to have it be customizable.

-Thanks