#include "lcd.h"
#include "lab7.h"
#include "timer.h"
#include <stdbool.h>
#include "driverlib/interrupt.h"


enum {LOW, HIGH, DONE} state;
unsigned int overflow = 0;
unsigned int rising_time = 0; // start time of the return pulse
unsigned int falling_time = 0 ; // end time of the return pulse



unsigned int ping_read(void){

       //delta = rising_time - falling_time;
       send_pulse();
       if(falling_time < rising_time){
           overflow++;
           state = LOW;
           return rising_time - falling_time;
       }
       state = LOW;
       return falling_time - rising_time;
   }


void send_pulse() {

           GPIO_PORTB_DIR_R |= 0x8; // set PB3 as output
           GPIO_PORTB_AFSEL_R &= 0xFFF7; // turn off alternative function
           GPIO_PORTB_DATA_R |= 0x8; // set PB3 to high

           // wait at least 5 microseconds based on data sheet
           timer_waitMicros(6);
           GPIO_PORTB_DATA_R &= 0x7; // set PB3 to low
           GPIO_PORTB_AFSEL_R |= 0x0008; //turn off alternative function
           GPIO_PORTB_DIR_R &= 0x7; // set PB3 as input
           //timer_waitMicros(6);
   }

   void init(){

       SYSCTL_RCGCGPIO_R |= 0b000010;// Enable Port B clock
       GPIO_PORTB_DIR_R &= 0xF7;//Setting PB3 to output
       GPIO_PORTB_PUR_R |= 0x03;//Set pins' pull-up resists
       GPIO_PORTB_DEN_R |= 0x08; //Enable PB3

   }


   void TIMER3B_Handler(void) {

       if(TIMER3_RIS_R &= 0x400){
               if(state == LOW){
                   rising_time = TIMER3_TBR_R;
                   state = HIGH;
               }
               else if(state == HIGH){
                   falling_time = TIMER3_TBR_R;
                   state = DONE;
               }
           }
           TIMER3_ICR_R |= 0x400; //clear interrupts BIT 10
   }


      void clock_timer_init(void) {

       SYSCTL_RCGCGPIO_R |= 0x2;     //enable Clock on PortB
       GPIO_PORTB_DEN_R |= 0x8;     // set pin 3
       GPIO_PORTB_AFSEL_R |= 0x8; //turning on alternative function
       GPIO_PORTB_PCTL_R |= 0x7000; //enable TX and RX on pin 3
       SYSCTL_RCGCTIMER_R |= 0x8; //enable timer 3 clock
       TIMER3_CTL_R &= 0xEFF; //sets TBEN to 0, have to disable before you can change settings
       TIMER3_CTL_R |= 0xC00; //sets TBEvent to 11
       TIMER3_CFG_R |= 0x4; //set to 16 bit timer
       TIMER3_TBMR_R |= (0x3 | 0x4 | 0x10); //capture mode
       TIMER3_TBILR_R |= 0xFFFFFFFF;  //Set upper bound.
       TIMER3_ICR_R |= 0xF00; // clear interrupts
       TIMER3_IMR_R |= 0x400; //enable capture interrupt.
       NVIC_EN1_R |= 0x10; //enable bit 5
       IntRegister(INT_TIMER3B, TIMER3B_Handler); //register TIMER3B interrupt handler
       IntMasterEnable(); //intialize global interrupts
       TIMER3_CTL_R |= 0x100; //sets TBEN to 1, enables timer3B


   }

   unsigned int get_Overflow(){

       return overflow;
   }

   int main(void) {
       lcd_init();
       init();

       clock_timer_init();
       while(1) {
          timer_waitMillis(100);
         unsigned int pingHolder= ping_read() ;
      //lcd_setCursorPos(0, 0);
      lcd_printf("Distance: %d  \nPulse: %d \nOverflow: %d ", pingHolder/990, pingHolder, get_Overflow());
     // lcd_setCursorPos(0, 1);
     // lcd_printf("Pulse Width:  ", pingHolder);
      //lcd_setCursorPos(0, 2);
    // lcd_printf("Overflow: %d \n",get_Overflow());
    //  lcd_printf("Testing ");
       }
   }