#include <dri/ata_pio/ata_pio.h>

#include <io.h>
#include <log.h>
#include <pic.h>

/* TODO: Rewrite all of this to work with dri_ide in the case of multiple
 * devices */

static ushort test_buffer[256];

void ata_pio_wait_bsy()
{
	while (inb(ATA_PORT_CMD) & ATA_BSY)
	{
	}
}

void ata_pio_wait_drq()
{
	while (!(inb(ATA_PORT_CMD) & ATA_RDY))
	{
	}
}

uint ata_pio_get_error()
{
	return inb(ATA_ERR);
}

static void ata_pio_send_init(uint lba, uchar num_sectors)
{
	outb(ATA_PORT_DRIVE_SEL, 0xe0 | (lba >> 24));
	outb(ATA_PORT_SECTOR_COUNT, num_sectors);
	outb(ATA_PORT_LBA_LOW, lba & 0xff);
	outb(ATA_PORT_LBA_MID, (lba >> 8) & 0xff);
	outb(ATA_PORT_LBA_HIGH, (lba >> 16) & 0xff);
}

void ata_pio_read_sectors(void *buffer, uint lba, uchar num_sectors)
{
	ushort *word_buffer = buffer;

	ata_pio_wait_bsy();
	ata_pio_send_init(lba, num_sectors);
	outb(ATA_PORT_CMD, ATA_CMD_READ);

	ata_pio_wait_bsy();
	
	if (inb(ATA_PORT_CMD) & ATA_ERR)
	{
		kprintf(ERROR "ATA_ERR on read\n");
		kpanic("Failed to read");
	}

	for (int i = 0; i < num_sectors * 256; i++)
	{
		word_buffer[i] = inw(ATA_PORT_DATA);
	}

	ata_pio_wait_bsy();
	outw(ATA_PORT_CMD, ATA_CMD_FLUSH_CACHE);
}

void ata_pio_write_sectors(uint lba, uchar num_sectors, ushort *buffer)
{
	ata_pio_wait_bsy();

	ata_pio_send_init(lba, num_sectors);
	outb(ATA_PORT_CMD, ATA_CMD_WRITE);

	ata_pio_wait_bsy();

	for (int i = 0; i < (num_sectors * 256); i++)
	{
		outw(ATA_PORT_DATA, buffer[i]);
	}

	ata_pio_wait_bsy();
	outw(ATA_PORT_CMD, ATA_CMD_FLUSH_CACHE);
}

static void print_buffer()
{
	for (int i = 0; i < 256; i++)
	{
		kprintf("%d ", test_buffer[i]);
		if (i % 16 == 0)
			kprintf("\n");
	}
}

void test_ata_pio()
{
	kprintf(INFO "Going to ata_pio_read_sectors\n");

	ata_pio_read_sectors(test_buffer, 0, 1);
	print_buffer();

	for (int i = 0; i < 256; i++)
		test_buffer[i] = i;

	// ata_pio_write_sectors(0, 1, test_buffer);

	// ata_pio_read_sectors(test_buffer, 0, 1);
	// print_buffer();
}

void ata_pio_handle_irq(struct registers *regs)
{
	// TODO: check that this IRQ came from the hard drive
	
	// TODO: use a lock and inform the scheduler that the thread waiting for
	// this can stop sleeping
	
	// Acknowledge the IRQ
	uchar status = inw(ATA_PORT_STATUS);

	kprintf(DEBUG "ATA PIO IRQ received %d (0x%x)\n", status, status);
}

void init_ata_pio()
{
	add_interrupt_handler(46, ata_pio_handle_irq);

/*
	// TODO: Consider adding this back.

	// 0xA0 for master, 0xB0 for slave
	outb(ATA_PORT_DRIVE_SEL, 0xA0);

	outb(ATA_PORT_LBA_LOW, 0);
	outb(ATA_PORT_LBA_MID, 0);
	outb(ATA_PORT_LBA_HIGH, 0);

	outb(ATA_PORT_CMD, ATA_CMD_IDENTIFY);

	if (inb(ATA_PORT_STATUS))
	{
		kprintf(OKAY "ATA drive exists\n");

		// Wait until either DRQ or ERR is set
		uchar status;
		while ((status = inb(ATA_PORT_STATUS)) & (ATA_DRQ | ATA_ERR))
		{
			if (status & ATA_ERR)
			{

			}
		}
	}
	else
	{
		kprintf(ERROR "ATA drive does not exist\n");
	}
*/
}