Help with Swtich code & RGB LED's

Hello, I am fairly new with coding, I have been using an Arduino to control some RGB Led's using the Neopixel Library. I have been somewhat successful with making them do a few different things but I want to get a little more complicated and am having some trouble understanding the coding process. What I am looking to accomplish is probably simple or maybe it cannot even be done I don't know. So here is what I want and If needed I can use multiple Arduino's I want to have one strip of RGB Led's scroll red from left to right then turn off momentary 500ms then repeat the scrolling, and at the same time a second strip of RGB Led's do the same thing in yellow while a single switch is pressed and continue looping until that switch is released. then if possible I would like to have another input pin read a +12v signal and turn just the red strip all red as long as there is a +12v signal present. I can use a relay instead of the +12v to just pull a pin go ground but if I can avoid a relay it simplifies wiring. I have been playing with the simple provided button cycler thats in the neopixel library but what I want to do is over my head on programming. Any help is appreciated.

// This is a demonstration on how to use an input device to trigger changes on your neo pixels.
// You should wire a momentary push button to connect from ground to a digital IO pin.  When you
// press the button it will change to a new pixel animation.  Note that you need to press the
// button once to start the first animation!

#include <Adafruit_NeoPixel.h>

#define BUTTON_PIN   2    // Digital IO pin connected to the button.  This will be
                          // driven with a pull-up resistor so the switch should
                          // pull the pin to ground momentarily.  On a high -> low
                          // transition the button press logic will execute.

#define PIXEL_PIN    6    // Digital IO pin connected to the NeoPixels.

#define PIXEL_COUNT 144

// Parameter 1 = number of pixels in strip,  neopixel stick has 8
// Parameter 2 = pin number (most are valid)
// Parameter 3 = pixel type flags, add together as needed:
//   NEO_RGB     Pixels are wired for RGB bitstream
//   NEO_GRB     Pixels are wired for GRB bitstream, correct for neopixel stick
//   NEO_KHZ400  400 KHz bitstream (e.g. FLORA pixels)
//   NEO_KHZ800  800 KHz bitstream (e.g. High Density LED strip), correct for neopixel stick
Adafruit_NeoPixel strip = Adafruit_NeoPixel(PIXEL_COUNT, PIXEL_PIN, NEO_GRB + NEO_KHZ800);

bool oldState = HIGH;
int showType = 0;

void setup() {
  pinMode(BUTTON_PIN, INPUT_PULLUP);
  strip.begin();
  strip.show(); // Initialize all pixels to 'off'
}

void loop() {
  // Get current button state.
  bool newState = digitalRead(BUTTON_PIN);

  // Check if state changed from high to low (button press).
  if (newState == LOW && oldState == HIGH) {
    // Short delay to debounce button.
    delay(20);
    // Check if button is still low after debounce.
    newState = digitalRead(BUTTON_PIN);
    if (newState == LOW) {
      showType++;
      if (showType > 4)
        showType=0;
      startShow(showType);
    }
  }

  // Set the last button state to the old state.
  oldState = newState;
}

void startShow(int i) {
  switch(i){
    case 1: colorwipe(strip.Color(175, 100, 0), 10);    // Yellow
           break;
    case 2: reversecolorwipe(strip.Color(255, 0, 0), 10);  // Red
            break;
    case 3: colorwipe(strip.Color(0, 255, 0), 10);  // Green
            break;
    case 4: colorwipe(strip.Color(0, 0, 255), 10);  // Blue
            break;
   
  }
}

// Fill the dots one after the other with a color
void colorwipe(uint32_t c, uint8_t wait) {
  for(uint16_t i=0; i<strip.numPixels(); i++) {
    strip.setPixelColor(i, c);
    strip.show();
    delay(wait);
  }

}
 void reversecolorwipe(uint32_t c, uint8_t wait) {
  for(int i=(strip.numPixels()-1); i>=0; i--) {
      strip.setPixelColor(i, c);
      strip.show();
      delay(wait);
  }
}

What I am looking to accomplish is probably simple or maybe it cannot even be done I don't know.

If you don't know that it can be done, what makes you think it is simple?

if possible I would like to have another input pin read a +12v signal and turn just the red strip all red as long as there is a +12v signal present.

Applying 12V to a pin will require a fan to dissipate the magic smoke that will escape.

Using a voltage divider to drop the voltage to 5V will work.

The code you posted does something. An explanation regarding what it actually does would be useful, as a starting point towards making it do what you want.