#include "memory.h"
#include "string.h"
#include "utils.h"

#include <stdint.h>

uint32_t *page_directory = &boot_page_directory;
uint32_t page_table_default[1024] __attribute__((aligned(PAGE_SIZE)));
uint32_t frame_zones_page_table[1024] __attribute__((aligned(PAGE_SIZE)));
uint32_t mem_size;
struct frame_zone *head;

static void lst_add_back(struct frame_zone **root, struct frame_zone *element)
{
	if (!*root) {
		*root = element;
		return;
	}
	struct frame_zone *it = *root;
	while (it->next)
		it = it->next;
	it->next = element;
}

static void add_frame_node(multiboot_memory_map_t *mmmt)
{
	static uint32_t index;

	/**
	 * # = kernel code
	 * - = blank
	 */

	uint64_t start_addr = mmmt->addr;
	uint64_t end_addr = mmmt->addr + mmmt->len;
	uint64_t len = mmmt->len;

	/** Kernel code cover all the block
	 *  this situation:
	 *  #######################
	 */
	if (KERNEL_START <= start_addr && KERNEL_END >= end_addr)
		return;

	/** Kernel code start on the block
	 *  this situation:
	 *  --------###############
	 */
	if (KERNEL_START > start_addr && KERNEL_START <= end_addr) {
		len = ROUND_FLOOR(KERNEL_START - start_addr, PAGE_SIZE);
	}
	/** Kernel code end on the block
	 *  this situation:
	 *  ###############--------
	 */
	if (KERNEL_START <= start_addr && KERNEL_END > start_addr &&
	    KERNEL_END <= end_addr) {
		len = ROUND_CEIL(len - (KERNEL_END - start_addr), PAGE_SIZE) -
		      PAGE_SIZE; // cringe but ROUND_FLOOR is un poquito crampte
		start_addr = ROUND_CEIL(KERNEL_END, PAGE_SIZE);
	}
	end_addr = ROUND_CEIL(start_addr + len, PAGE_SIZE);

	init_page_table(frame_zones_page_table, 0);
	page_directory[1022] =
	    ((uint32_t)frame_zones_page_table - HEAP_END) | 0x03;
	frame_zones_page_table[index] =
	    ((uint32_t)start_addr & PAGE_MASK) | INIT_FLAGS;

	struct frame_zone *current =
	    (struct frame_zone *)GET_PAGE_ADDR(1022, index++);

	current->frame_table = (uint8_t *)current + sizeof(struct frame_zone);

	/** 8 is cause we are using uint8_t
	    nb_frame = size / (PAGE_SIZE + 1 / 8)
	    cause we are using non decimal number
	    nb_frame = ((size * 8) / (PAGE_SIZE * 8 + 1))
	 */
	const uint32_t nb_frame = ((len * 8) / (PAGE_SIZE * 8 + 1));
	current->first_free_frame = 0;
	current->next = NULL;
	current->remaining_frames = nb_frame;
	current->total_frames = nb_frame;

	memset(current->frame_table, 0,
	       nb_frame * sizeof(*current->frame_table));

	uint32_t i = 1;
	for (; i < CEIL(nb_frame, PAGE_SIZE); i++)
		frame_zones_page_table[index + i] =
		    ((uint32_t)(start_addr + i * PAGE_SIZE) & PAGE_MASK) |
		    INIT_FLAGS;
	current->addr = (void *)start_addr + i * PAGE_SIZE;
	index += i - 1;
	lst_add_back(&head, current);
}

static void init_frame_zones(void)
{
	for (uint32_t i = 0; i < mmap_length; i++) {
		multiboot_memory_map_t *mmmt =
		    (multiboot_memory_map_t *)mmap_addr + i;
		if (mmmt->type == MULTIBOOT_MEMORY_AVAILABLE)
			add_frame_node(mmmt);
	}
}

void init_memory(multiboot_info_t *mbd, uint32_t magic)
{
	for (uint16_t i = 0; i < 0x300; i++)
		page_directory[i] = 0x02;
	init_page_table(page_table_default, 0);
	page_directory[0] = ((uint32_t)page_table_default - HEAP_END) | 0x03;
	init_multiboot(mbd, magic);
	init_frame_zones();
}