/**
 * Name: Ash Zahabiuon
 * Date: 5/26/2024
 * Assignment: Lab 2
 * Youtube: https://youtu.be/9DWMKz36roA
 *
 * This program:
 * When ran, pressing the button cycles through different LED combinations:
 * RED -> GREEN -> RED & GREEN -> RED -> GREEN (loops).
 */

#include <msp430.h>
#include <stdbool.h>

#define RED_LED_DIR P1DIR
#define GREEN_LED_DIR P1DIR
#define BUTTON_DIR P1DIR

#define RED_LED_OUT P1OUT
#define GREEN_LED_OUT P1OUT
#define BUTTON_IN P1IN

#define RED_LED_PIN BIT0
#define GREEN_LED_PIN BIT6
#define BUTTON_PIN BIT3

void initGPIO(void);
bool isButtonPressed(void);
void setRed(bool enable);
void setGreen(bool enable);

int main(void)
{
    WDTCTL = WDTPW + WDTHOLD; // Stop watchdog timer
    initGPIO();

    int ledState = 0;

    setRed(true);
    setGreen(false);

    for (;;)
    {
        if (isButtonPressed())
        {
            ledState = (ledState + 1) % 3;
            switch (ledState)
            {
                case 0:
                    setRed(false);
                    setGreen(true);
                    break;
                case 1:
                    setRed(true);
                    setGreen(true);
                    break;
                case 2:
                    setRed(true);
                    setGreen(false);
                    break;
            }
            while (isButtonPressed()); // Wait for button release
        }
    }
}

void initGPIO(void)
{
    RED_LED_DIR |= RED_LED_PIN; // Set P1.0 to output direction
    GREEN_LED_DIR |= GREEN_LED_PIN; // Set P1.6 to output direction
    BUTTON_DIR &= ~BUTTON_PIN; // Set P1.3 to input direction

    P1REN |= BUTTON_PIN; // Enable pull-up/down resistor on P1.3
    P1OUT |= BUTTON_PIN; // Set pull-up resistor on P1.3

    setRed(false);
    setGreen(false);
}

bool isButtonPressed(void)
{
    if (!(BUTTON_IN & BUTTON_PIN)) // If button is pressed
    {
        __delay_cycles(50000); // Debounce delay
        if (!(BUTTON_IN & BUTTON_PIN)) // If button is still pressed
        {
            return true;
        }
    }
    return false;
}

void setGreen(bool enable)
{
    if (enable)
    {
        RED_LED_OUT |= RED_LED_PIN;
    }
    else
    {
        RED_LED_OUT &= ~RED_LED_PIN;
    }
}

void setRed(bool enable)
{
    if (enable)
    {
        GREEN_LED_OUT |= GREEN_LED_PIN;
    }
    else
    {
        GREEN_LED_OUT &= ~GREEN_LED_PIN;
    }
}