#include <assert.h>
#include <cpu/idt.h>
#include <cpu/io.h>
#include <drivers/pci.h>
#include <drivers/rtl8139.h>
#include <mmu.h>

#define RBSTART 0x30
#define CMD 0x37
#define IMR 0x3C

#define TSD0 0x10  // transmit status
#define TSAD0 0x20 // transmit start address

struct PCI_DEVICE rtl8139;
uint8_t device_buffer[8192 + 16];
uint32_t g_base_address;

uint8_t *send_buffers[4];

#define ROK (1 << 0)
#define TOK (1 << 2)

__attribute__((interrupt)) void rtl8139_handler(void *regs) {
  (void)regs;
  uint16_t status = inw(rtl8139.gen.base_mem_io + 0x3e);

  if (status & TOK) {
    kprintf("Packet sent\n");
  }
  if (status & ROK) {
    kprintf("Received packet\n");
  }

  outw(rtl8139.gen.base_mem_io + 0x3E, 0x5);
  EOI(0xB);
}

int rtl8139_send_data(const struct PCI_DEVICE *device, uint8_t *data,
                      uint16_t data_size) {
  // FIXME: It should block or fail if there is too little space for the
  // buffer
  if (data_size > 0x1000)
    return 0;
  static int loop = 0;
  if (loop > 3) {
    loop = 0;
  }
  memcpy(send_buffers[loop], data, data_size);
  outl(device->gen.base_mem_io + 0x20 + loop * 4,
       (uint32_t)virtual_to_physical(send_buffers[loop], NULL));
  outl(device->gen.base_mem_io + 0x10 + loop * 4, data_size);
  loop += 1;
  return 1;
}

uint8_t rtl8139_get_transmit_status(uint32_t base_address) {
  uint32_t status_register = inl(base_address + 0x3E);
  if ((status_register >> 3) & 0x1)
    kprintf("transmit error :(\n");
  uint8_t status = (status_register >> 2) & 0x1;
  outl(base_address + 0x3E, 0x5);
  return status;
}

void rtl8139_init(void) {
  if (!pci_populate_device_struct(0x10EC, 0x8139, &rtl8139)) {
    kprintf("RTL8139 not found :(\n");
    return;
  }
  kprintf("RTL8139 found at bus: %x slot: %x\n", rtl8139.bus, rtl8139.slot);

  uint8_t header_type = (pci_config_read32(&rtl8139, 0, 0xC) >> 16) & 0xFF;
  assert(0 == header_type);

  uint32_t base_address = rtl8139.gen.base_mem_io;
  uint8_t interrupt_line = pci_get_interrupt_line(&rtl8139);

  // Read the MAC address
  uint64_t mac_address;
  {
    uint32_t low_mac = inl(base_address);
    uint16_t high_mac = inw(base_address + 0x4);
    mac_address = ((uint64_t)high_mac << 32) | low_mac;
  }
  kprintf("mac_address: %x\n", mac_address);

  // Turning on the device
  outb(base_address + 0x52, 0x0);

  // Reset the device and clear the RX and TX buffers
  outb(base_address + CMD, 0x10);
  for (; 0 != (inb(base_address + CMD) & 0x10);)
    ;

  // Setupt the recieve buffer
  uint32_t rx_buffer = (uint32_t)virtual_to_physical(device_buffer, NULL);
  outl(base_address + RBSTART, rx_buffer);

  // Set IMR + ISR
  outw(base_address + IMR, (1 << 2) | (1 << 3));

  outb(base_address + 0x37, (1 << 2) | (1 << 3));

  // Configure the recieve buffer
  outl(base_address + 0x44,
       0xf | (1 << 7)); // (1 << 7) is the WRAP bit, 0xf is AB+AM+APM+AAP

  install_handler(rtl8139_handler, INT_32_INTERRUPT_GATE(0x0),
                  0x20 + interrupt_line);

  // ksbrk() seems to have the magical ability of disabling interrupts?
  // I have no fucking clue why that happens and it was a pain to debug.
  for (int i = 0; i < 4; i++)
    send_buffers[i] = ksbrk(0x1000);
  asm("sti");
  for (int i = 0; i < 10; i++) {
    char buffer[512];
    rtl8139_send_data(&rtl8139, (uint8_t *)buffer, 512);
  }
  for (;;)
    asm("sti");
}