module;

#include <array>
#include <cassert>
#include <utility>

export module VUI:Input;

import :InputCodes;
import :Keys;

namespace VUI {
struct WindowManager;
struct Window;
constexpr uint32_t DownMask = 1;
constexpr uint32_t RepeatMask = 1 << 2;

static std::array<uint8_t, std::to_underlying(KeyCodes::KEYLAST)> s_Keys{};

static constexpr std::array<KeyCodes, Keys> InputKeys = InitKeys();

export struct Input {
  static bool IsKeyDown(const KeyCodes key) {
    return s_Keys[std::to_underlying(key)] & DownMask;
  }

  static bool IsKeyPressed(const KeyCodes key) {
    const auto value = s_Keys[std::to_underlying(key)];
    return value & DownMask && !(value & RepeatMask);
  }

  static bool IsKeyRepeat(const KeyCodes key) {
    return s_Keys[std::to_underlying(key)] & RepeatMask;
  }

private:
  static void UpdateKey(uint32_t key, bool isDown);
  static void PostFrameUpdate();
  friend WindowManager;
  friend Window;
};

void Input::UpdateKey(const uint32_t key, const bool isDown) {
  assert(key < InputKeys.size() && "Keycode out of range");
  const uint8_t keyCode = std::to_underlying(InputKeys[key]);
  uint8_t value = s_Keys[keyCode];
  if (isDown) {
    value |= DownMask;
  } else {
    value &= ~(DownMask | RepeatMask);
  }
  s_Keys[keyCode] = value;
}

void Input::PostFrameUpdate() {
  for (uint8_t &s_key : s_Keys)
    s_key |= s_key & DownMask ? RepeatMask : 0;
}
} // namespace VUI