#include <fs/gpt.h>
#include <ahci.h>
#include <mem.h>
#include <memory.h>
#include <vga.h>

struct gpt_header *read_gpt_disk(struct disk *disk) {
	uint16_t *gpt = kmalloc(512);
	if (!read(disk->port, 1, 1, gpt))
		return NULL;
	struct gpt_header *part = (void*) gpt;
	if (memcmp(part->sig, "EFI PART", 8) != 0) {
		vga_puts("not gpt");
		return NULL;
	}
	vga_puts("found gpt table on disk 0\n");

	vga_puts("number of partitions: ");
	vga_putn(part->number_partitions);
	vga_putc('\n');

	vga_puts("starting lba: ");
	vga_putn(part->first_lba);
	vga_putc('\n');

	vga_puts("size per entry: ");
	vga_putn(part->size_partitions);
	vga_putc('\n');

	return part;
}

struct gpt_entry *get_gpt_entry(struct disk *disk, struct gpt_header *header, size_t num) {
	if (num >= header->number_partitions)
		return NULL;
	uint16_t *data = kmalloc(512);
	if (!read(disk->port, header->first_lba + num, 1, data))
		return NULL;
	struct gpt_entry *entry = (void *) data;

	/*
	vga_puts("unique guid for first partition: ");
	vga_putx(entry->guid);
	vga_putc('\n');
	*/

	vga_puts("starting partition lba: ");
	vga_putn(entry->lba.start);
	vga_putc('\n');

	vga_puts("ending partition lba: ");
	vga_putn(entry->lba.end);
	vga_putc('\n');

	return entry;
}

char *read_gpt_entry(struct disk *disk, struct gpt_entry *entry) {
	uint16_t *data = kmalloc(512 * (entry->lba.end - entry->lba.start));
	uint16_t *ptr = data;
	for (size_t lba = entry->lba.start; lba < entry->lba.end; lba += 1024) {
		if (!read(disk->port, lba, entry->lba.end - lba < 1024 ? entry->lba.end - lba : 1024, ptr)) {
			vga_puts("failed to read disk");
			kfree(data);
			return NULL;
		}
		ptr += 1024 * 256;
	}

	return (char *)data;
}