#include <hilbert/kernel/terminal.hpp>
#include <hilbert/kernel/input.hpp>
#include <hilbert/kernel/panic.hpp>

using namespace hilbert::kernel;

struct [[gnu::packed]] exception_info_t {

  uint64_t rax;
  uint64_t rbx;
  uint64_t rcx;
  uint64_t rdx;
  uint64_t rdi;
  uint64_t rsi;
  uint64_t rbp;
  uint64_t rsp;
  uint64_t r8;
  uint64_t r9;
  uint64_t r10;
  uint64_t r11;
  uint64_t r12;
  uint64_t r13;
  uint64_t r14;
  uint64_t r15;

  uint64_t cr2;
  uint64_t cr3;
  uint64_t rip;
  uint64_t rflags;

  uint64_t error;
  uint8_t has_error;//0 or 1
  uint8_t exception_number;

};

extern exception_info_t exception_info;

static const char *exception_types[] = {
  "division error",
  "",
  "non-maskable interrupt",
  "",
  "",
  "",
  "invalid opcode",
  "",
  "double fault (uh oh)",
  "",
  "",
  "",
  "stack fault",
  "general protection fault",
  "page fault",
  ""
};

static const char *flag_names[] = {
  " cf",
  "",
  " pf",
  "",
  " af",
  "",
  " zf",
  " sf",
  " tf",
  " if",
  " df",
  " of",
  "",
  "",
  " nt",
  " md"
};

static void print_line(const char *r1, const char *r2, uint64_t r1v, uint64_t r2v) {
  terminal::put_string_sz("\n  ");
  terminal::put_string_sz(r1);
  terminal::put_string_sz(": 0x");
  terminal::put_int_hex(r1v, 16);
  terminal::put_string_sz("  ");
  terminal::put_string_sz(r2);
  terminal::put_string_sz(": 0x");
  terminal::put_int_hex(r2v, 16);
}

extern "C" [[noreturn]] void print_exception() {

  terminal::put_string_sz("exception handler:\n  type: ");
  terminal::put_string_sz(exception_types[exception_info.exception_number]);
  terminal::put_string_sz(" (0x");
  terminal::put_int_hex(exception_info.exception_number, 2);
  terminal::put_char(')');

  if (exception_info.has_error == 1) {
    terminal::put_string_sz("\n  error code: 0x");
    terminal::put_int_hex(exception_info.error, 16);
  }

  terminal::put_string_sz("\n  flags:");
  if (exception_info.rflags == 0)
    terminal::put_string_sz(" [none]");
  else
    for (int i = 0; i < 16; ++i)
      if (((exception_info.rflags >> i) & 1) == 1)
        terminal::put_string_sz(flag_names[i]);

  if (exception_info.exception_number == 0x0e) {
    terminal::put_string_sz("\n  cr2: 0x");
    terminal::put_int_hex(exception_info.cr2, 16);
  }

  print_line("cr3", "rip", exception_info.cr3, exception_info.rip);
  print_line("rax", "rbx", exception_info.rax, exception_info.rbx);
  print_line("rcx", "rdx", exception_info.rcx, exception_info.rdx);
  print_line("rdi", "rsi", exception_info.rdi, exception_info.rsi);
  print_line("rbp", "rsp", exception_info.rbp, exception_info.rsp);
  print_line("r8 ", "r9 ", exception_info.r8 , exception_info.r9 );
  print_line("r10", "r11", exception_info.r10, exception_info.r11);
  print_line("r12", "r13", exception_info.r12, exception_info.r13);
  print_line("r14", "r15", exception_info.r14, exception_info.r15);

  while (1)
    asm ("hlt");

}

static uint32_t current_flags = 0;

#define SETBIT(field, bit, cond) \
  field = (cond) ? (field | (bit)) : (field & ~(bit));

static void got_key(uint32_t key) {

  input::key_queue->insert(current_flags | key);

  if (key == (input::BREAK | 0x77))
    current_flags ^= input::NUM_LOCK;

  else if (key == (input::BREAK | 0x58))
    current_flags ^= input::CAPS_LOCK;

  else if ((key & 0xff) == 0xa7)
    SETBIT(current_flags, input::RIGHT_WIN, !(key & input::BREAK))

  else if ((key & 0xff) == 0x9f)
    SETBIT(current_flags, input::LEFT_WIN, !(key & input::BREAK))

  else if ((key & 0xff) == 0x91)
    SETBIT(current_flags, input::RIGHT_ALT, !(key & input::BREAK))

  else if ((key & 0xff) == 0x11)
    SETBIT(current_flags, input::LEFT_ALT, !(key & input::BREAK))

  else if ((key & 0xff) == 0x94)
    SETBIT(current_flags, input::RIGHT_CTRL, !(key & input::BREAK))

  else if ((key & 0xff) == 0x14)
    SETBIT(current_flags, input::LEFT_CTRL, !(key & input::BREAK))

  else if ((key & 0xff) == 0x59)
    SETBIT(current_flags, input::RIGHT_SHIFT, !(key & input::BREAK))

  else if ((key & 0xff) == 0x12)
    SETBIT(current_flags, input::LEFT_SHIFT, !(key & input::BREAK))

}

static uint8_t key_so_far[8];
uint8_t key_so_far_len = 0;

extern "C" void on_keyboard_interrupt(uint8_t byte) {

  key_so_far[key_so_far_len++] = byte;

  if (key_so_far_len == 1) {
    if (byte != 0xe0 && byte != 0xe1 && byte != 0xf0) {
      got_key(byte);
      key_so_far_len = 0;
    }
  }

  else if (key_so_far_len == 2) {
    if (key_so_far[0] == 0xe0 && byte != 0xf0 && byte != 0x12) {
      got_key(byte | 0x80);
      key_so_far_len = 0;
    }
    else if (key_so_far[0] == 0xf0) {
      got_key(input::BREAK | byte);
      key_so_far_len = 0;
    }
  }

  else if (key_so_far_len == 3) {
    if (key_so_far[0] == 0xe0 && key_so_far[1] == 0xf0 && byte != 0x7c) {
      got_key(input::BREAK | byte | 0x80);
      key_so_far_len = 0;
    }
  }

  else if (key_so_far_len == 4) {
    if (key_so_far[0] == 0xe0 && key_so_far[1] == 0x12 &&
        key_so_far[2] == 0xe0 && byte == 0x7c) {
      got_key(0xe0);
      key_so_far_len = 0;
    }
  }

  else if (key_so_far_len == 6) {
    if (key_so_far[0] == 0xe0 && key_so_far[1] == 0xf0 &&
        key_so_far[2] == 0x7c && key_so_far[3] == 0xe0 &&
        key_so_far[4] == 0xf0 && byte == 0x12) {
      got_key(input::BREAK | 0xe0);
      key_so_far_len = 0;
    }
  }

  else if (key_so_far_len == 8) {
    if (key_so_far[0] == 0xe1 && key_so_far[1] == 0x14 &&
        key_so_far[2] == 0x77 && key_so_far[3] == 0xe1 &&
        key_so_far[2] == 0xf0 && key_so_far[3] == 0x14 &&
        key_so_far[4] == 0xf0 && byte == 0x77) {
      got_key(0xe1);
      got_key(input::BREAK | 0xe1);
    }
    key_so_far_len = 0;
  }

}