#include "task.h"
#include "alloc.h"
#include "debug.h"
#include "kpanic.h"
#include "kprintf.h"
#include "memory.h"

#include <stdint.h>

uint32_t esp_backup;

static struct task *create_task(uint8_t owner_id)
{
	static uint32_t pid = 1;
	struct task *new_task = vmalloc(sizeof(struct task));
	if (!new_task)
		return NULL;
	new_task->next = current_task->next;
	new_task->prev = current_task;
	current_task->next = new_task;
	new_task->owner_id = owner_id;
	new_task->esp0 = alloc_pages(STACK_SIZE, NULL);
	if (!new_task->esp0) {
		vfree(new_task);
		return NULL;
	}
	new_task->esp = new_task->esp0 + STACK_SIZE;
	new_task->pid = pid++;
	new_task->heap = alloc_pages(4096, (void **)&new_task->cr3);
	if (!new_task->heap) {
		free_pages(new_task->esp0, STACK_SIZE);
		vfree(new_task);
		return NULL;
	}
	return new_task;
}

int create_kernel_task(void)
{
	struct task *new_task = vmalloc(sizeof(struct task));
	if (!new_task)
		return -1;
	new_task->status = RUN;
	new_task->owner_id = 0;
	new_task->pid = 0;
	new_task->heap = page_directory;
	new_task->cr3 = page_directory - KERNEL_START;
	new_task->prev = new_task;
	new_task->next = new_task;
	current_task = new_task;
	return 0;
}

void exec_fn(void (*fn)(void))
{
	struct task *new_task = create_task(OWNER_KERNEL);
	if (!new_task)
		kpanic("failed to create new task");
	new_task->status = RUN;
	new_task->eip = (uint32_t *)fn;
}

/*
 * Create task
 * Allocate new pd => kmalloc(4096)
 * Add pd address to the struct task
 *
 */