#include <stdint.h>
#include <stdbool.h>
#include "tm4c123gh6pm.h"

void GPIO_PORT_F_init(void)
{
    SYSCTL_RCGC2_R |= 0x00000020;       // Enable clock to GPIOF
    GPIO_PORTF_LOCK_R = 0x4C4F434B;     // Unlock commit register
    GPIO_PORTF_CR_R = 0x1F;             // Make PORTF0 configurable
    GPIO_PORTF_DEN_R = 0x1F;            // Set PORTF digital enable
    GPIO_PORTF_DIR_R = 0x0E;            // Set PF0, PF4 as input and PF1, PF2, PF3 as output
    GPIO_PORTF_PUR_R = 0x11;            // PORTF PF0 and PF4 is pulled up

    NVIC_EN0_R |= 1 << 30;              // Enable interrupt for PORTF
    GPIO_PORTF_IS_R = 0x00;             // Make it edge-sensitive
    GPIO_PORTF_IBE_R = 0x00;            // Trigger on one edge
    GPIO_PORTF_IEV_R = 0x00;            // Falling edge event
    GPIO_PORTF_IM_R |= 0x11;            // Unmask interrupts for PF0 and PF4
}
#define STCTRL *((volatile uint32_t *) 0xE000E010)              // Control and status
#define STRELOAD *((volatile uint32_t *) 0xE000E014)            // Reload value
#define STCURRENT *((volatile uint32_t *) 0xE000E018)           // Current value

#define COUNT_FLAG (1 << 16)                                    // Bit 16 of CSR automatically set to 1
#define ENABLE (1 << 0)                                         // Bit 0 of CSR to enable the timer
#define CLKINT (1 << 2)                                         // Bit 2 of CSR to specify CPU clock
#define CLOCK_HZ 16000000                                       // Clock frequency of EK-TM4C123GXL
#define INTEN (1 << 1)                                          // Bit 1 of CSR to enable interrupt
#define SYSTICK_RELOAD_VALUE(us) ((CLOCK_HZ / 1000000) * (us) - 1) // SysTick reload value in microseconds based on clock frequency

volatile int duty = 50;                                         // Initial duty cycle
const volatile int PWM_PERIOD = 1000000;                            // Period for 100kHz in microseconds (10ms)
volatile int ontime = 0;                                        // Variable to track on time
//volatile bool ledState = false; // State of the LED

void systick_setting(void)
{
    STRELOAD = SYSTICK_RELOAD_VALUE(PWM_PERIOD/100);            // Set reload value for 10 µs intervals (100 kHz)
    STCTRL  |= (CLKINT | ENABLE | INTEN);                       // Set internal clock, enable the timer
    STCURRENT = 0;                                              // Clear STCURRENT value
}

void delay(int us)                              // DEFINING DELAY FUNCTION
{
    STRELOAD = SYSTICK_RELOAD_VALUE(us);        // RELOAD VALUE FOR REQUIRED DELAY
    STCURRENT = 0;                              // Clear STCURRENT
    STCTRL |= (1 << 0) | (1 << 2);              // Enable SysTick
    while ((STCTRL & (1 << 16)) == 0);          // Wait until flag is set
    STCTRL &= 0x0;                              // Stop the timer
}

void SystickHandler(void)
{                                   // SysTick interrupt handler
    ontime++;
    if (ontime < duty)
    {
        GPIO_PORTF_DATA_R |= 0x02;  // LED should be ON
    }
    else
    {
        GPIO_PORTF_DATA_R &= ~0x02; // LED should be OFF
    }

    if (ontime >= 100)
    {
        ontime = 0;                 // Reset counter after one period
    }
}

void GPIOF_interruptHandler(void)
{
    delay(200000);                        // Debounce delay
    if (GPIO_PORTF_RIS_R & 0x01)          // Check if PF0 caused the interrupt (Switch 1)
    {
        duty += 5;                        // Increase duty cycle
        if (duty > 100) duty = 100;       // Limit to max 100%
        GPIO_PORTF_ICR_R = 0x01;          // Clear interrupt flag for PF0
       // systick_setting();
    }

    if (GPIO_PORTF_RIS_R & 0x10)
    {                                 // Check if PF0 caused the interrupt (Switch 1)
        duty -= 5;                    // Increase duty cycle
        if (duty < 0) duty = 0;       // Limit to max 100%
        GPIO_PORTF_ICR_R = 0x10;      // Clear interrupt flag for PF0
            //systick_setting();
     }
    systick_setting();
}