#include <stdint.h>
#include <stddef.h>
#include "pci/pci.h"
#include "pci/qemu_pci_serial/qemu_pci_serial.h"
#include "io/io.h"
#include "sysdefs/dev.h"
#include "util/util.h"
#include "dev/dev.h"
#include "errors.h"
#include "hshtb.h"
#include "kprintf.h"

static QemuPciSerialDev QEMU_PCI_SERIAL_DEV;

// https://wiki.osdev.org/Serial_Ports

void _serial_init(uint16_t iobase) {
  io_out8(iobase+1, 0x00);
  io_out8(iobase+3, 0x80);
  io_out8(iobase+0, 0x03);
  io_out8(iobase+1, 0x00);
  io_out8(iobase+3, 0x03);
  io_out8(iobase+2, 0xC7);
  io_out8(iobase+4, 0x0B);
  io_out8(iobase+4, 0x1E);
  io_out8(iobase+0, 0xAE);

  if (io_in8(iobase+0) != 0xAE) {
    ERR("pci", "QEMU_PCI_SERIAL serial is faulty!\n");
    return;
  }

  io_out8(iobase+4, 0x0F);
}

int _serial_recvready(uint16_t iobase) {
  return io_in8(iobase+5) & 1;
}

uint8_t _serial_recvb(uint16_t iobase) {
  return io_in8(iobase);
}

int _serial_sendready(uint16_t iobase) {
  return io_in8(iobase+5) & 0x20;
}

void _serial_sendb(uint16_t iobase, uint8_t b) {
  io_out8(iobase, b);
}

int32_t qemu_pci_serial_dev_sendb(struct Dev *dev, uint8_t *buffer, size_t len, uint64_t pid) {
  (void)len; (void)pid;

  QemuPciSerialDev *qpsd = dev->extra;
  _serial_sendb(qpsd->iobase, buffer[0]);

  return E_OK;
}

int32_t qemu_pci_serial_dev_sendready(struct Dev *dev, uint8_t *buffer, size_t len, uint64_t pid) {
  (void)buffer; (void)len; (void)pid;

  QemuPciSerialDev *qpsd = dev->extra;

  return _serial_sendready(qpsd->iobase);
}

int32_t qemu_pci_serial_dev_recvb(struct Dev *dev, uint8_t *buffer, size_t len, uint64_t pid) {
  (void)buffer; (void)len; (void)pid;
  
  QemuPciSerialDev *qpsd = dev->extra;

  return _serial_recvb(qpsd->iobase);
}

int32_t qemu_pci_serial_dev_recvready(struct Dev *dev, uint8_t *buffer, size_t len, uint64_t pid) {
  (void)dev; (void)buffer; (void)len; (void)pid;
  
  QemuPciSerialDev *qpsd = dev->extra;

  return _serial_recvready(qpsd->iobase);
}

void pci_qemu_pci_serial_init(void) {
  PciDev dev = pci_getdev(0x1B36, 0x0002, -1);
  if (!dev.bits) {
    return;
  }
  
  uint32_t bar0 = pci_read(dev, PCI_BAR0);

  LOG("pci", "QEMU_PCI_SERIAL bar0=0x%x\n", bar0);
  
  uint16_t iobase = bar0 & 0xFFFFFFFC;
  LOG("pci", "QEMU_PCI_SERIAL iobase=0x%x\n", iobase);

  QEMU_PCI_SERIAL_DEV._magic = QEMU_PCI_SERIAL_MAGIC;
  QEMU_PCI_SERIAL_DEV.iobase = iobase;

  Dev *serialdev = NULL;
  HSHTB_ALLOC(DEVTABLE.devs, ident, "serialdev", serialdev);
  serialdev->fns[0] = &qemu_pci_serial_dev_sendb;
  serialdev->fns[1] = &qemu_pci_serial_dev_sendready;
  serialdev->fns[2] = &qemu_pci_serial_dev_recvb;
  serialdev->fns[3] = &qemu_pci_serial_dev_recvready;
  spinlock_init(&serialdev->spinlock);
  serialdev->extra = &QEMU_PCI_SERIAL_DEV;
  _serial_init(QEMU_PCI_SERIAL_DEV.iobase);
}