#include "debug/debug.h"

#include "common/port.h"
#include "scheduler/scheduler.h"

#define COM1 0x3f8

#define BOCHS_DBG 1

namespace {
bool is_transmit_empty() { return (inb(COM1 + 5) & 0x20) != 0; }

void dbgputchar(char c) {
  while (!is_transmit_empty());

  outb(COM1, c);
#if BOCHS_DBG
  outb(0xe9, c);
#endif
}

void dbg(const glcr::StringView& str) {
  for (uint64_t i = 0; i < str.size(); i++) {
    dbgputchar(str[i]);
  }
}

void AddProcPrefix() {
  if (gScheduler != nullptr) {
    auto t = gScheduler->CurrentThread();

    char buffer[16];
    glcr::FixedStringBuilder builder(buffer, 16);
    glcr::StrFormatIntoBuffer(builder, "[{}.{}] ", t->pid(), t->tid());
    dbg(builder);
  }
}

}  // namespace

void dbgln(const glcr::StringView& str) {
  AddProcPrefix();
  dbg(str);
  dbg("\n");
}

namespace {

// Helper function to write a byte to a specified COM1 register offset
void write_serial_port(uint16_t offset, uint8_t value) {
  outb(COM1 + offset, value);
}

// Helper function to read a byte from a specified COM1 register offset
uint8_t read_serial_port(uint16_t offset) { return inb(COM1 + offset); }

}  // namespace

namespace serial {

// Function to initialize the serial port with a given baud rate
void initialize(uint32_t baud_rate) {
  // Disable interrupts
  write_serial_port(1, 0x00);

  // Enable DLAB (Divisor Latch Access Bit) in Line Control Register (LCR)
  write_serial_port(3, read_serial_port(3) | 0x80);

  // Calculate the divisor
  // Baud rate = 115200 / divisor (approximately)
  uint16_t divisor = 115200 / baud_rate;

  // Set the low byte of the divisor
  write_serial_port(0, divisor & 0xFF);

  // Set the high byte of the divisor
  write_serial_port(1, (divisor >> 8) & 0xFF);

  // Clear DLAB and set data bits, stop bits, and parity
  // 8 data bits, 1 stop bit, no parity
  write_serial_port(3, 0x03);  // 00000011b

  // Enable FIFO, clear buffers, set trigger level (e.g., 1 byte)
  write_serial_port(2, 0xC7);  // 11000111b

  // Enable IRQs (optional, for interrupt-driven communication)
  // write_serial_port(1, 0x01);

  // Set Modem Control Register (MCR)
  // Enable RTS, DTR, OUT1, OUT2, loopback off, IRQs enabled
  write_serial_port(4, 0x0B);  // 00001011b
}

}  // namespace serial