#include <types.h>
#include <port_io.h>
#include <stdio.h>

#include <scheduler.h>

#include <drivers/pit.h>


#define PIT_CHANNEL0       0x40
#define PIT_COMMAND        0x43
#define PIT_IRQ_LINE       0
#define PIT_FREQUENCY_BASE 1193182

volatile uint64_t pit_ticks = 0;
bool pit_initialized = false;

void pit_init(void)
{
  printf("pit_initialized addr = %x\n", &pit_initialized);
  
#ifdef _DEBUG
  printf("[ PIT ] Initializing the PIT...\n");
#endif

  uint16_t divisor = (uint16_t) 1193;

  /* Send command byte */
  outb(PIT_COMMAND, 0x36);  /* Channel 0, low/high byte, mode 3 (square wave), binary */

  /* Send divisor low and high byte */
  outb(PIT_CHANNEL0, (uint8_t)(divisor & 0xFF));        /* Low byte */
  outb(PIT_CHANNEL0, (uint8_t)((divisor >> 8) & 0xFF)); /* High byte */
  
  pit_initialized = true;
  
#ifdef _DEBUG
  printf("[ PIT ] PIT Initialized\n");
#endif
}

registers_t* pit_handler(registers_t* regs)
{
  pit_ticks++;
  return regs;
}

void pit_sleep(uint64_t ms)
{
  uint64_t target = pit_ticks + ms;
  while (pit_ticks < target)
  {
    asm volatile ("hlt");
  }
}

/*void pit_sleep(uint64_t ms)
{
  extern task_t* current_task;
  
  current_task->wakeup_tick = pit_ticks + ms;
  current_task->state = TASK_SLEEPING;

  asm volatile("int $32");*/ /* force reschedule immediately */
/*}
*/