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

#include "driverlib/sysctl.h"
#include "driverlib/gpio.h"
#include "driverlib/timer.h"
#include "driverlib/pin_map.h"
#include "inc/tm4c1294ncpdt.h"
#include "driverlib/interrupt.h"
#include "inc/hw_types.h"
#include "inc/hw_memmap.h"
#include "driverlib/fpu.h"
#include <math.h>
#include "driverlib/pwm.h"

#include "frequency.h"

// start a pwm test signal
void start_signal() {
  // configure M0PWM2, at GPIO PF2, BoosterPack 1 header C1 pin 2
  SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOF);
  GPIOPinTypePWM(GPIO_PORTF_BASE, GPIO_PIN_2 | GPIO_PIN_3);
  GPIOPinConfigure(GPIO_PF2_M0PWM2);
  GPIOPinConfigure(GPIO_PF3_M0PWM3);
  GPIOPadConfigSet(GPIO_PORTF_BASE, GPIO_PIN_2 | GPIO_PIN_3, GPIO_STRENGTH_2MA,
                   GPIO_PIN_TYPE_STD);
  // configure the PWM0 peripheral, gen 1, outputs 2 and 3
  SysCtlPeripheralEnable(SYSCTL_PERIPH_PWM0);
  // use system clock without division
  PWMClockSet(PWM0_BASE, PWM_SYSCLK_DIV_1);
  PWMGenConfigure(PWM0_BASE, PWM_GEN_1,
                  PWM_GEN_MODE_DOWN | PWM_GEN_MODE_NO_SYNC);
  gPWMPeriod = roundf((float)gSystemClock / PWM_FREQUENCY);
  set_pwm_period(gPWMPeriod);
  PWMOutputState(PWM0_BASE, PWM_OUT_2_BIT | PWM_OUT_3_BIT, true);
  PWMGenEnable(PWM0_BASE, PWM_GEN_1);
}

void set_pwm_period(uint32_t period) {
    PWMGenPeriodSet(PWM0_BASE, PWM_GEN_1,
                    gPWMPeriod);
    PWMPulseWidthSet(PWM0_BASE, PWM_OUT_2,
                     roundf((float)gPWMPeriod * 0.4f));
    PWMPulseWidthSet(PWM0_BASE, PWM_OUT_3,
                     roundf((float)gPWMPeriod * 0.4f));
}



void start_frequency_scan() {
    // config GPIO PD0 as timer input T0CCP0 at BoosterPack Connector #1 pin 14
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOD);
    GPIOPinTypeTimer(GPIO_PORTD_BASE, GPIO_PIN_0);
    GPIOPinConfigure(GPIO_PD0_T0CCP0);
    SysCtlPeripheralEnable(SYSCTL_PERIPH_TIMER0);
    TimerDisable(TIMER0_BASE, TIMER_BOTH);
    TimerConfigure(TIMER0_BASE, TIMER_CFG_SPLIT_PAIR | TIMER_CFG_A_CAP_TIME_UP);
    TimerControlEvent(TIMER0_BASE, TIMER_A, TIMER_EVENT_POS_EDGE);
    // use maximum load value
    TimerLoadSet(TIMER0_BASE, TIMER_A, 0xffff);
    // use maximum prescale value
    TimerPrescaleSet(TIMER0_BASE, TIMER_A, 0xff);
    TimerIntEnable(TIMER0_BASE, TIMER_CAPA_EVENT);
    TimerEnable(TIMER0_BASE, TIMER_A);
}

uint32_t previous;
void capture_handler() {
    TimerIntClear(TIMER0_BASE, TIMER_CAPA_EVENT);

    uint32_t current = TimerValueGet(TIMER0_BASE, TIMER_A);

    uint32_t delta = current - previous;
    gPeriod = delta;

    previous = current;
}