#pragma once

#include <types.h>
#include "cpu/registers.h"

class InterruptHandler {
private:
  const uint8_t m_irq;

protected:
  InterruptHandler(uint8_t irq);
  ~InterruptHandler();

public:
  virtual cpu_state_t* trigger(cpu_state_t*);
};

class IDT {
  friend class InterruptHandler;

public:
  struct Pointer {
    uint16_t limit;
    uint32_t base;
  } __attribute__((packed));

  enum InterruptType : uint8_t {
    Null = 0,
    Task = 0b10000101,  // 32-bit task gate         selector points to TSS rather than a code segment
    Intr = 0b10001110,  // 32-bit interrupt         hardware interrupts are disabled while the handler runs
    Trap = 0b10001111,  // 32-bit trap gate         hardware interrupts remain active while the handler runs
  };

  class Entry {
  public:
    constexpr Entry() = default;
    Entry(void (*handler)(), uint16_t select, InterruptType t);

  private:
    uint16_t offset_0_15 = 0;            //  0-15 offset in the segment
    uint16_t selector = 0;               // 16-31 selector of the code segment
    [[maybe_unused]] uint8_t null = 0;   // 32-39 unused in protected mode
    InterruptType type = Null;           // 40-43 type
    uint16_t offset_16_31 = 0;           // 48-63 offset high
  } __attribute__((packed));

  IDT(const uint16_t selector);
  void enable() { asm volatile("sti"); }

private:
  static bool install(uint8_t, InterruptHandler*);
  static bool uninstall(uint8_t, InterruptHandler*);
};