// http://hosted.cjmovie.net/TutMultitask.htm
//
//
#include "kernel.h"
#include "lib/logger/log.h"	// logger facilities
#include "lib/int/stdint.h"
#include "mem.h"
#include "timer.h"

#include "syscalls.h"
#include "fs/fs.h"
#include "fs/ext2.h"
#define FOOLOS_MODULE_NAME "task"

int started;

static uint32_t c1,c2,c3;

void task_test1()
{
    //ext2_check(EXT2_RAM_ADDRESS);
    //syscall_execve(15,0,0);
//    syscall_execve(18,0,0);
   
   while(1)
   {
    c1++;
   }
   

}

void task_test2()
{
   while(1)
   {
       c2++;

   }

}

void task_test3()
{
   while(1)
   {
       c3++;
   }

}

//////////////
//
typedef struct{        //Simple structure for a thread
      unsigned int esp0;   //Stack for kernel
        unsigned int esp3;   //Stack for process
} Thread;


Thread Threads[3];     //Space for our simple threads.
volatile int CurrentTask;  //The thread currenlty running (-1 == none) 


void task_create(int pid,void(*thread)())
{
     unsigned int *stack;

    Threads[pid].esp0 = pmmngr_alloc_block();
    stack = (unsigned int*)Threads[pid].esp0+4095; //This makes a pointer to the stack for us
    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"new task: stack: 0x%08X  thread: 0x%08X", stack, thread);

 //First, this stuff is pushed by the processor
 *--stack = 0x0202; //This is EFLAGS
 *--stack = 0x08;   //This is CS, our code segment
 *--stack = (uint32_t)thread; //This is EIP
 
 //Next, the stuff pushed by 'pusha'
 *--stack = 0; //EDI
 *--stack = 0; //ESI
 *--stack = 0; //EBP
 *--stack = 0; //Just an offset, no value
 *--stack = 0; //EBX
 *--stack = 0; //EDX
 *--stack = 0; //ECX
 *--stack = 0; //EAX
 
 //Now these are the data segments pushed by the IRQ handler
 /*
 *--stack = 0x10; //DS
 *--stack = 0x10; //ES
 *--stack = 0x10; //FS
 *--stack = 0x10; //GS
 */
 
 Threads[pid].esp0 = (uint32_t)stack; //Update the stack pointer


};

uint32_t task_switch_next(uint32_t oldesp)
{

    timer_tick();
  if(started!=0xabcde) return oldesp;
  if(CurrentTask!=-1)Threads[CurrentTask].esp0=oldesp;

  CurrentTask++;
  if(CurrentTask>2)CurrentTask=0;

  log(
    FOOLOS_MODULE_NAME,
    FOOLOS_LOG_FINE,
    "oldesp: 0x%08X saved / next task: %d (esp: 0x%08X) ",
    oldesp, 
    CurrentTask,
    Threads[CurrentTask].esp0);
 
//  return oldesp;
  return Threads[CurrentTask].esp0; //Return new stack pointer to ASM
}

void stack_trace(uint32_t *stack,int size)
{
    for(int i=size;i>=0;i--)
    {
	log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"stack: 0x%08X -> 0x%08X", stack, *stack);
	stack++;


    }
}

void task_init()
{


   CurrentTask=-1;

   log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"init multitasking.");
   task_create(0,task_test1);
   task_create(1,task_test2);
   task_create(2,task_test3);
   started=0xabcde;
}