/* -*- mode: c++ -*-
 * Kaleidoscope-OneShot -- One-shot modifiers and layers
 * Copyright (C) 2016-2022  Keyboard.io, Inc.
 *
 * This program is free software: you can redistribute it and/or modify it under
 * the terms of the GNU General Public License as published by the Free Software
 * Foundation, version 3.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program. If not, see <http://www.gnu.org/licenses/>.
 */

#pragma once

#include "kaleidoscope/Runtime.h"
#include <Kaleidoscope-Ranges.h>
#include "kaleidoscope/KeyAddrBitfield.h"

// ----------------------------------------------------------------------------
// Keymap macros

#define OSM(k) ::kaleidoscope::plugin::OneShotModifierKey(Key_ ## k)
#define OSL(n) ::kaleidoscope::plugin::OneShotLayerKey(n)

namespace kaleidoscope {
namespace plugin {

constexpr Key OneShotModifierKey(Key mod_key) {
  return Key(kaleidoscope::ranges::OSM_FIRST +
             mod_key.getKeyCode() - HID_KEYBOARD_FIRST_MODIFIER);
}

constexpr Key OneShotLayerKey(uint8_t layer) {
  return Key(kaleidoscope::ranges::OSL_FIRST + layer);
}

class OneShot : public kaleidoscope::Plugin {
 public:
  // Constructor
  // OneShot() {}

  // --------------------------------------------------------------------------
  // Configuration functions

  void enableStickablity() {}
  void enableStickability(Key key);
  template <typename... Keys>
  void enableStickability(Key key, Keys&&... keys) {
    enableStickability(key);
    enableStickability(keys...);
  }
  void enableStickabilityForModifiers();
  void enableStickabilityForLayers();

  void disableStickability() {}
  void disableStickability(Key key);
  template <typename... Keys>
  void disableStickability(Key key, Keys&&... keys) {
    disableStickability(key);
    disableStickability(keys...);
  }
  void disableStickabilityForModifiers();
  void disableStickabilityForLayers();

  void enableAutoModifiers() {
    auto_modifiers_ = true;
  }
  void enableAutoLayers() {
    auto_layers_ = true;
  }
  void enableAutoOneShot() {
    enableAutoModifiers();
    enableAutoLayers();
  }

  void disableAutoModifiers() {
    auto_modifiers_ = false;
  }
  void disableAutoLayers() {
    auto_layers_ = false;
  }
  void disableAutoOneShot() {
    disableAutoModifiers();
    disableAutoLayers();
  }

  void toggleAutoModifiers() {
    auto_modifiers_ = ! auto_modifiers_;
  }
  void toggleAutoLayers() {
    auto_layers_ = ! auto_layers_;
  }
  void toggleAutoOneShot() {
    if (auto_modifiers_ || auto_layers_) {
      disableAutoOneShot();
    } else {
      enableAutoOneShot();
    }
  }

  // --------------------------------------------------------------------------
  // Global test functions

  bool isActive() const;
  bool isSticky() const;

  // --------------------------------------------------------------------------
  // Single-key test functions
  bool isOneShotKey(Key key) const {
    return (key.getRaw() >= kaleidoscope::ranges::OS_FIRST &&
            key.getRaw() <= kaleidoscope::ranges::OS_LAST);
  }

  /// Determine if the given `key` is allowed to become sticky.
  bool isStickable(Key key) const;

  bool isStickableDefault(Key key) const;

  bool isTemporary(KeyAddr key_addr) const; // inline?
  bool isPending(KeyAddr key_addr) const;
  bool isSticky(KeyAddr key_addr) const; // inline?
  bool isActive(KeyAddr key_addr) const; // inline?

  // --------------------------------------------------------------------------
  // Public OneShot state control

  /// Put a key in the "pending" OneShot state.
  ///
  /// This function puts the key at `key_addr` in the "pending" OneShot state.
  /// This is appropriate to use when a key toggles on and you want it to behave
  /// like a OneShot key starting with the current event, and lasting until the
  /// key becomes inactive (cancelled by a subsequent keypress).
  void setPending(KeyAddr key_addr);

  /// Put a key directly in the "one-shot" state.
  ///
  /// This function puts the key at `key_addr` in the "one-shot" state.  This is
  /// usually the state of a OneShot key after it is released, but before it is
  /// cancelled by a subsequent keypress.  In most cases, you probably want to
  /// use `setPending()` instead, rather than calling this function explicitly,
  /// as OneShot will automatically cause any key in the "pending" state to
  /// progress to this state when it is (physically) released.
  void setOneShot(KeyAddr key_addr);

  /// Put a key in the "sticky" OneShot state.
  ///
  /// This function puts the key at `key_addr` in the "sticky" OneShot state.
  /// It will remain active until it is pressed again.
  void setSticky(KeyAddr key_addr);

  /// Clear any OneShot state for a key.
  ///
  /// This function clears any OneShot state of the key at `key_addr`.  It does
  /// not, however, release the key if it is held.
  void clear(KeyAddr key_addr);

  // --------------------------------------------------------------------------
  // Utility function for other plugins to cancel OneShot keys
  void cancel(bool with_stickies = false);

  // --------------------------------------------------------------------------
  // Timeout onfiguration functions
  void setTimeout(uint16_t ttl) {
    timeout_ = ttl;
  }
  void setHoldTimeout(uint16_t ttl) {
    hold_timeout_ = ttl;
  }
  void setDoubleTapTimeout(int16_t ttl) {
    double_tap_timeout_ = ttl;
  }

  // --------------------------------------------------------------------------
  // Plugin hook functions

  EventHandlerResult onNameQuery();
  EventHandlerResult onKeyEvent(KeyEvent &event);
  EventHandlerResult afterReportingState(const KeyEvent &event);
  EventHandlerResult afterEachCycle();

 private:

  // --------------------------------------------------------------------------
  // Constants
  static constexpr uint8_t oneshot_key_count = 16;
  static constexpr uint8_t oneshot_mod_count = 8;
  static constexpr uint8_t oneshot_layer_count = oneshot_key_count - oneshot_mod_count;
  static constexpr uint16_t stickable_modifiers_mask = uint16_t(uint16_t(-1) >> oneshot_layer_count);
  static constexpr uint16_t stickable_layers_mask = uint16_t(uint16_t(-1) << oneshot_mod_count);
  static constexpr KeyAddr invalid_key_addr = KeyAddr(KeyAddr::invalid_state);

  // --------------------------------------------------------------------------
  // Configuration variables
  uint16_t timeout_ = 2500;
  uint16_t hold_timeout_ = 250;
  int16_t double_tap_timeout_ = -1;

  uint16_t stickable_keys_ = -1;
  bool auto_modifiers_ = false;
  bool auto_layers_ = false;

  // --------------------------------------------------------------------------
  // State variables
  KeyAddrBitfield temp_addrs_;
  KeyAddrBitfield glue_addrs_;

  uint16_t start_time_ = 0;
  KeyAddr prev_key_addr_ = invalid_key_addr;

  // --------------------------------------------------------------------------
  // Internal utility functions
  bool hasTimedOut(uint16_t ttl) const {
    return Runtime.hasTimeExpired(start_time_, ttl);
  }
  bool hasDoubleTapTimedOut() const {
    // Derive the true double-tap timeout value if we're using the default.
    uint16_t dtto = (double_tap_timeout_ < 0) ? timeout_ : double_tap_timeout_;
    return hasTimedOut(dtto);
  }
  uint8_t getOneShotKeyIndex(Key oneshot_key) const;
  uint8_t getKeyIndex(Key key) const;
  Key decodeOneShotKey(Key oneshot_key) const;

  void pressKey(KeyAddr key_addr, Key oneshot_key);
  void holdKey(KeyAddr key_addr) const;
  void releaseKey(KeyAddr key_addr);
};

} // namespace plugin
} // namespace kaleidoscope

extern kaleidoscope::plugin::OneShot OneShot;