/*
 * Deskflow -- mouse and keyboard sharing utility
 * SPDX-FileCopyrightText: (C) 2012 - 2016 Symless Ltd.
 * SPDX-FileCopyrightText: (C) 2005 Chris Schoeneman
 * SPDX-License-Identifier: GPL-2.0-only WITH LicenseRef-OpenSSL-Exception
 */

#pragma once

#include "base/String.h"
#include "deskflow/KeyTypes.h"

#include <map>
#include <set>
#include <vector>

namespace deskflow {

//! Key map
/*!
This class provides a keyboard mapping.
*/
class KeyMap
{
public:
  // Class used for testing
  friend class KeyMapTests;

  KeyMap();
  virtual ~KeyMap() = default;

  //! KeyID synthesis info
  /*!
  This structure contains the information necessary to synthesize a
  keystroke that generates a KeyID (stored elsewhere).  \c m_sensitive
  lists the modifiers that the key is affected by and must therefore
  be in the correct state, which is listed in \c m_required.  If the
  key is mapped to a modifier, that modifier is in \c m_generates and
  is not in \c m_sensitive.
  */
  struct KeyItem
  {
  public:
    KeyID m_id{};                  //!< KeyID
    int32_t m_group{};             //!< Group for key
    KeyButton m_button{};          //!< Button to generate KeyID
    KeyModifierMask m_required{};  //!< Modifiers required for KeyID
    KeyModifierMask m_sensitive{}; //!< Modifiers key is sensitive to
    KeyModifierMask m_generates{}; //!< Modifiers key is mapped to
    bool m_dead{};                 //!< \c true if this is a dead KeyID
    bool m_lock{};                 //!< \c true if this locks a modifier
    uint32_t m_client{};           //!< Client data

  public:
    bool operator==(const KeyItem &) const = default;
  };

  //! The KeyButtons needed to synthesize a KeyID
  /*!
  An ordered list of \c KeyItems produces a particular KeyID.  If
  the KeyID can be synthesized directly then there is one entry in
  the list.  If dead keys are required then they're listed first.
  A list is the minimal set of keystrokes necessary to synthesize
  the KeyID, so it doesn't include no-ops.  A list does not include
  any modifier keys unless the KeyID is a modifier, in which case
  it has exactly one KeyItem for the modifier itself.
  */
  using KeyItemList = std::vector<KeyItem>;

  //! A keystroke
  class Keystroke
  {
  public:
    enum class KeyType
    {
      Button, //!< Synthesize button
      Group   //!< Set new group
    };

    Keystroke(KeyButton, bool press, bool repeat, uint32_t clientData);
    Keystroke(int32_t group, bool absolute, bool restore);

  public:
    struct Button
    {
    public:
      KeyButton m_button{}; //!< Button to synthesize
      bool m_press{};       //!< \c true iff press
      bool m_repeat{};      //!< \c true iff for an autorepeat
      uint32_t m_client{};  //!< Client data
    };
    struct Group
    {
    public:
      int32_t m_group{}; //!< Group/offset to change to/by
      bool m_absolute{}; //!< \c true iff change to, else by
      bool m_restore{};  //!< \c true iff for restoring state
    };
    union Data
    {
    public:
      Button m_button;
      Group m_group;
    };

    KeyType m_type{};
    Data m_data{};
  };

  //! A sequence of keystrokes
  using Keystrokes = std::vector<Keystroke>;

  //! A mapping of a modifier to keys for that modifier
  using ModifierToKeys = std::multimap<KeyModifierMask, KeyItem>;

  //! A set of buttons
  using ButtonToKeyMap = std::map<KeyButton, const KeyItem *>;

  //! Callback type for \c foreachKey
  using ForeachKeyCallback = void (*)(KeyID, int32_t group, KeyItem &, void *userData);

  //! @name manipulators
  //@{

  //! Swap with another \c KeyMap
  virtual void swap(KeyMap &) noexcept;

  //! Add a key entry
  /*!
  Adds \p item to the entries for the item's id and group.  The
  \c m_dead member is set automatically.
  */
  void addKeyEntry(const KeyItem &item);

  //! Add an alias key entry
  /*!
  If \p targetID with the modifiers given by \p targetRequired and
  \p targetSensitive is not available in group \p group then find an
  entry for \p sourceID with modifiers given by \p sourceRequired and
  \p sourceSensitive in any group with exactly one item and, if found,
  add a new item just like it except using id \p targetID.  This
  effectively makes the \p sourceID an alias for \p targetID (i.e. we
  can generate \p targetID using \p sourceID).
  */
  void addKeyAliasEntry(
      KeyID targetID, int32_t group, KeyModifierMask targetRequired, KeyModifierMask targetSensitive, KeyID sourceID,
      KeyModifierMask sourceRequired, KeyModifierMask sourceSensitive
  );

  //! Add a key sequence entry
  /*!
  Adds the sequence of keys \p keys (\p numKeys elements long) to
  synthesize key \p id in group \p group.  This looks up in the
  map each key in \p keys.  If all are found then each key is
  converted to the button for that key and the buttons are added
  as the entry for \p id.  If \p id is already in the map or at
  least one key in \p keys is not in the map then nothing is added
  and this returns \c false, otherwise it returns \c true.
  */
  bool addKeyCombinationEntry(KeyID id, int32_t group, const KeyID *keys, uint32_t numKeys);

  //! Enable composition across groups
  /*!
  If called then the keyboard map will allow switching between groups
  during key composition.  Not all systems allow that.
  */
  void allowGroupSwitchDuringCompose();

  //! Add a half-duplex button
  /*!
  Records that button \p button is a half-duplex key.  This is called
  when translating the system's keyboard map.  It's independent of the
  half-duplex modifier calls.
  */
  void addHalfDuplexButton(KeyButton button);

  //! Remove all half-duplex modifiers
  /*!
  Removes all half-duplex modifiers.  This is called to set user
  configurable half-duplex settings.
  */
  void clearHalfDuplexModifiers();

  //! Add a half-duplex modifier
  /*!
  Records that modifier key \p key is half-duplex.  This is called to
  set user configurable half-duplex settings.
  */
  virtual void addHalfDuplexModifier(KeyID key);

  //! Finish adding entries
  /*!
  Called after adding entries, this does some internal housekeeping.
  */
  virtual void finish();

  //! Iterate over all added keys items
  /*!
  Calls \p cb for every key item.
  */
  virtual void foreachKey(ForeachKeyCallback cb, void *userData);

  //@}
  //! @name accessors
  //@{

  //! Map key press/repeat to keystrokes.
  /*!
  Converts press/repeat of key \p id in group \p group with current
  modifiers as given in \p currentState and the desired modifiers in
  \p desiredMask into the keystrokes necessary to synthesize that key
  event in \p keys.  It returns the \c KeyItem of the key being
  pressed/repeated, or nullptr if the key cannot be mapped.
  */
  virtual const KeyItem *mapKey(
      Keystrokes &keys, KeyID id, int32_t group, ModifierToKeys &activeModifiers, KeyModifierMask &currentState,
      KeyModifierMask desiredMask, bool isAutoRepeat, const std::string &lang
  ) const;

  void setLanguageData(std::vector<std::string> layouts);

  //! Get number of groups
  /*!
  Returns the number of keyboard groups (independent layouts) in the map.
  */
  int32_t getNumGroups() const;

  //! Compute a group number
  /*!
  Returns the number of the group \p offset groups after group \p group.
  */
  int32_t getEffectiveGroup(int32_t group, int32_t offset) const;

  //! Find key entry compatible with modifiers
  /*!
  Returns the \c KeyItemList for the first entry for \p id in group
  \p group that is compatible with the given modifiers, or nullptr
  if there isn't one.  A button list is compatible with a modifiers
  if it is either insensitive to all modifiers in \p sensitive or
  it requires the modifiers to be in the state indicated by \p required
  for every modifier indicated by \p sensitive.
  */
  const KeyItemList *
  findCompatibleKey(KeyID id, int32_t group, KeyModifierMask required, KeyModifierMask sensitive) const;

  //! Test if modifier is half-duplex
  /*!
  Returns \c true iff modifier key \p key or button \p button is
  half-duplex.
  */
  virtual bool isHalfDuplex(KeyID key, KeyButton button) const;

  //! Test if modifiers indicate a command
  /*!
  Returns \c true iff the modifiers in \p mask contain any command
  modifiers.  A command modifier is used for keyboard shortcuts and
  hotkeys,  Rather than trying to synthesize a character, a command
  is trying to synthesize a particular set of buttons.  So it's not
  important to match the shift or AltGr state to achieve a character
  but it is important to match the modifier state exactly.
  */
  bool isCommand(KeyModifierMask mask) const;

  // Get the modifiers that indicate a command
  /*!
  Returns the modifiers that when combined with other keys indicate
  a command (e.g. shortcut or hotkey).
  */
  KeyModifierMask getCommandModifiers() const;

  //! Get buttons from modifier map
  /*!
  Put all the keys in \p modifiers into \p keys.
  */
  static void collectButtons(const ModifierToKeys &modifiers, ButtonToKeyMap &keys);

  //! Set modifier key state
  /*!
  Sets the modifier key state (\c m_generates and \c m_lock) in \p item
  based on the \c m_id in \p item.
  */
  static void initModifierKey(KeyItem &item);

  //! Test for a dead key
  /*!
  Returns \c true if \p key is a dead key.
  */
  static bool isDeadKey(KeyID key);

  //! Get corresponding dead key
  /*!
  Returns the dead key corresponding to \p key if one exists, otherwise
  return \c kKeyNone.  This returns \p key if it's already a dead key.
  */
  static KeyID getDeadKey(KeyID key);

  //! Get string for a key and modifier mask
  /*!
  Converts a key and modifier mask into a string representing the
  combination.
  */
  static std::string formatKey(KeyID key, KeyModifierMask);

  //! Parse a string into a key
  /*!
  Converts a string into a key.  Returns \c true on success and \c false
  if the string cannot be parsed.
  */
  static bool parseKey(const std::string &, KeyID &);

  //! Parse a string into a modifier mask
  /*!
  Converts a string into a modifier mask.  Returns \c true on success
  and \c false if the string cannot be parsed.  The modifiers plus any
  remaining leading and trailing whitespace is stripped from the input
  string.
  */
  static bool parseModifiers(std::string &, KeyModifierMask &);

  //@}

private:
  //! Ways to synthesize a key
  enum EKeystroke
  {
    kKeystrokePress,   //!< Synthesize a press
    kKeystrokeRelease, //!< Synthesize a release
    kKeystrokeRepeat,  //!< Synthesize an autorepeat
    kKeystrokeClick,   //!< Synthesize a press and release
    kKeystrokeModify,  //!< Synthesize pressing a modifier
    kKeystrokeUnmodify //!< Synthesize releasing a modifier
  };

  // A list of ways to synthesize a KeyID
  using KeyEntryList = std::vector<KeyItemList>;

  // computes the number of groups
  int32_t findNumGroups() const;

  // computes the map of modifiers to the keys that generate the modifiers
  void setModifierKeys();

  // maps a command key.  a command key is a keyboard shortcut and we're
  // trying to synthesize a button press with an exact sets of modifiers,
  // not trying to synthesize a character.  so we just need to find the
  // right button and synthesize the requested modifiers without regard
  // to what character they would synthesize.  we disallow multikey
  // entries since they don't make sense as hotkeys.
  const KeyItem *mapCommandKey(
      Keystrokes &keys, KeyID id, int32_t group, ModifierToKeys &activeModifiers, KeyModifierMask &currentState,
      KeyModifierMask desiredMask, bool isAutoRepeat, const std::string &lang
  ) const;

  // maps a character key.  a character key is trying to synthesize a
  // particular KeyID and isn't entirely concerned with the modifiers
  // used to do it.
  const KeyItem *mapCharacterKey(
      Keystrokes &keys, KeyID id, int32_t group, ModifierToKeys &activeModifiers, KeyModifierMask &currentState,
      KeyModifierMask desiredMask, bool isAutoRepeat, const std::string &lang
  ) const;

  // maps a modifier key
  const KeyItem *mapModifierKey(
      Keystrokes &keys, KeyID id, int32_t group, ModifierToKeys &activeModifiers, KeyModifierMask &currentState,
      KeyModifierMask desiredMask, bool isAutoRepeat, const std::string &lang
  ) const;

  // returns the index into \p entryList of the KeyItemList requiring
  // the fewest modifier changes between \p currentState and
  // \p desiredState.
  int32_t findBestKey(const KeyEntryList &entryList, KeyModifierMask desiredState) const;

  // gets the \c KeyItem used to synthesize the modifier who's bit is
  // given by \p modifierBit in group \p group and does not synthesize
  // the key \p button.
  const KeyItem *keyForModifier(KeyButton button, int32_t group, int32_t modifierBit) const;

  // fills \p keystrokes with the keys to synthesize the key in
  // \p keyItem taking the modifiers into account.  returns \c true
  // iff successful and sets \p currentState to the
  // resulting modifier state.
  bool keysForKeyItem(
      const KeyItem &keyItem, int32_t &group, ModifierToKeys &activeModifiers, KeyModifierMask &currentState,
      KeyModifierMask desiredState, KeyModifierMask overrideModifiers, bool isAutoRepeat, Keystrokes &keystrokes,
      const std::string &lang
  ) const;

  // fills \p keystrokes with the keys to synthesize the modifiers
  // in \p desiredModifiers from the active modifiers listed in
  // \p activeModifiers not including the key in \p keyItem.
  // returns \c true iff successful.
  bool keysToRestoreModifiers(
      const KeyItem &keyItem, int32_t group, ModifierToKeys &activeModifiers, KeyModifierMask &currentState,
      const ModifierToKeys &desiredModifiers, Keystrokes &keystrokes
  ) const;

  // fills \p keystrokes and \p undo with the keys to change the
  // current modifier state in \p currentState to match the state in
  // \p requiredState for each modifier indicated in \p sensitiveMask.
  // returns \c true iff successful and sets \p currentState to the
  // resulting modifier state.
  bool keysForModifierState(
      KeyButton button, int32_t group, ModifierToKeys &activeModifiers, KeyModifierMask &currentState,
      KeyModifierMask requiredState, KeyModifierMask sensitiveMask, KeyModifierMask notRequiredMask,
      Keystrokes &keystrokes
  ) const;

  // Adds keystrokes to synthesize key \p keyItem in mode \p type to
  // \p keystrokes and to undo the synthesis to \p undo.
  void addKeystrokes(
      EKeystroke type, const KeyItem &keyItem, ModifierToKeys &activeModifiers, KeyModifierMask &currentState,
      Keystrokes &keystrokes
  ) const;

  // Returns the number of modifiers indicated in \p state.
  static int32_t getNumModifiers(KeyModifierMask state);

  // Initialize key name/id maps
  static void initKeyNameMaps();

  // Ways to synthesize a KeyID over multiple keyboard groups
  using KeyGroupTable = std::vector<KeyEntryList>;

  void addGroupToKeystroke(Keystrokes &keys, int32_t &group, const std::string &lang) const;

  int32_t getLanguageGroupID(int32_t group, const std::string &lang) const;
  const KeyItemList *
  getKeyItemList(const KeyGroupTable &keyGroupTable, int32_t group, KeyModifierMask desiredMask) const;

  // not implemented
  KeyMap(const KeyMap &);
  KeyMap &operator=(const KeyMap &);

private:
  // Table of KeyID to ways to synthesize that KeyID
  using KeyIDMap = std::map<KeyID, KeyGroupTable>;

  // List of KeyItems that generate a particular modifier
  using ModifierKeyItemList = std::vector<const KeyItem *>;

  // Map a modifier to the KeyItems that synthesize that modifier
  using ModifierToKeyTable = std::vector<ModifierKeyItemList>;

  // A set of keys
  using KeySet = std::set<KeyID>;

  // A set of buttons
  using KeyButtonSet = std::set<KeyButton>;

  // Key maps for parsing/formatting
  using NameToKeyMap = std::map<std::string, KeyID, deskflow::string::CaselessCmp>;
  using NameToModifierMap = std::map<std::string, KeyModifierMask, deskflow::string::CaselessCmp>;
  using KeyToNameMap = std::map<KeyID, std::string>;
  using ModifierToNameMap = std::map<KeyModifierMask, std::string>;

  // KeyID info
  KeyIDMap m_keyIDMap;
  int32_t m_numGroups;
  ModifierToKeyTable m_modifierKeys;

  // composition info
  bool m_composeAcrossGroups;

  // half-duplex info
  KeyButtonSet m_halfDuplex; // half-duplex set by deskflow
  KeySet m_halfDuplexMods;   // half-duplex set by user

  // dummy KeyItem for changing modifiers
  KeyItem m_modifierKeyItem;

  // Language sync data
  std::vector<std::string> m_keyboardLayouts;

  // parsing/formatting tables
  static NameToKeyMap *s_nameToKeyMap;
  static NameToModifierMap *s_nameToModifierMap;
  static KeyToNameMap *s_keyToNameMap;
  static ModifierToNameMap *s_modifierToNameMap;
};

} // namespace deskflow