#pragma once

#ifndef KEYSTATE_INCLUDED

#define KEYSTATE_INCLUDED

// TnzTools includes

#include <tools/tooltimer.h>

// TnzCore includes

#include <tcommon.h>

#include <tsmartpointer.h>

// std includes

#include <map>

#include <set>

#include <algorithm>

#include <cmath>

#undef DVAPI

#undef DVVAR

#ifdef TNZTOOLS_EXPORTS

#define DVAPI DV_EXPORT_API

#define DVVAR DV_EXPORT_VAR

#else

#define DVAPI DV_IMPORT_API

#define DVVAR DV_IMPORT_VAR

#endif

//===================================================================

//*****************************************************************************************

//    TKeyState definition

//*****************************************************************************************

template<typename T>

class TKeyStateT : public TSmartObject {

public:

  typedef T Type;

  typedef TSmartPointerT<TKeyStateT> Pointer;

  struct Holder {

    Pointer state;

    TTimerTicks ticks;

    double timeOffset;

    explicit Holder(const Pointer &state = Pointer(), TTimerTicks ticks = 0, double timeOffset = 0.0):

      state(state), ticks(ticks), timeOffset(timeOffset) { }

    Pointer find(const Type &value) const

      { return state ? state->find(value) : Pointer(); }

    bool isEmpty() const

      { return !state || state->isEmpty(); }

    bool isPressed(const Type &value) const

      { return find(value); }

    double howLongPressed(const Type &value)

      { return howLongPressed(find(value), ticks, timeOffset); }

    static double howLongPressed(const Pointer &state, long ticks, double timeOffset) {

      return state

           ? std::max(TToolTimer::step, (ticks - state->ticks)*TToolTimer::step + timeOffset)

           : 0.0;

    }

  };

  static const Type& none() {

    static Type none;

    return none;

  }

  static const Pointer& empty() {

    static Pointer empty = new TKeyStateT();

	return empty;

  }

  const Pointer previous;

  const TTimerTicks ticks;

  const Type value;

private:

  TKeyStateT(const Pointer &previous, TTimerTicks ticks, const Type &value):

    previous(previous), ticks(ticks), value(value) { }

  Pointer makeChainWithout(const Pointer &state) {

    return state == this ? previous

         : previous ? Pointer(new TKeyStateT(previous->makeChainWithout(state), ticks, value))

         : this;

  }

public:

  TKeyStateT(): ticks(0), value(none()) { }

  Pointer find(const Type &value) {

    return value == none()      ? Pointer()

         : value == this->value ? this

         : previous             ? previous->find(value)

         :                        Pointer();

  }

  Pointer change(bool press, const Type &value, TTimerTicks ticks) {

    if (value == none())

      return Pointer(this);

    Pointer p = find(value);

    if (press == bool(p))

      return Pointer(this);

    if (ticks <= this->ticks)

      ticks = this->ticks + 1;

    if (press)

      return Pointer(new TKeyStateT((isEmpty() ? Pointer() : Pointer(this)), ticks, value));

    Pointer chain = makeChainWithout(p);

    return chain ? chain : Pointer(new TKeyStateT(Pointer(), ticks, none()));

  }

  bool isEmpty()

    { return value == none() && (!previous || previous->isEmpty()); }

  bool isPressed(const Type &value)

    { return find(value); }

  Pointer pressed(const Type &value, long ticks)

    { return change(true, value, ticks); }

  Pointer released(const Type &value, long ticks)

    { return change(false, value, ticks); }

};

//*****************************************************************************************

//    TKeyHistory definition

//*****************************************************************************************

template<typename T>

class TKeyHistoryT : public TSmartObject {

public:

  typedef T Type;

  typedef TSmartPointerT<TKeyHistoryT> Pointer;

  typedef TKeyStateT<Type> State;

  typedef typename TKeyStateT<Type>::Pointer StatePointer;

  typedef typename TKeyStateT<Type>::Holder StateHolder;

  typedef std::map<TTimerTicks, StatePointer> StateMap;

  typedef std::multiset<TTimerTicks> LockSet;

  class Holder {

  private:

    Pointer m_history;

    TTimerTicks m_ticks;

    double m_timeOffset;

    TTimerTicks m_heldTicks;

  public:

    Holder():

      m_ticks(), m_timeOffset(), m_heldTicks() { }

    Holder(const Pointer &history, TTimerTicks ticks, double timeOffset = 0.0):

      m_ticks(), m_timeOffset(), m_heldTicks()

      { set(history, ticks, timeOffset); }

    Holder(const Holder &other):

      m_ticks(), m_timeOffset(), m_heldTicks()

      { set(other); }

    ~Holder()

      { reset(); }

    Holder& operator= (const Holder &other)

      { set(other); return *this; }

    void set(const Pointer &history, TTimerTicks ticks, double timeOffset = 0.0) {

      TTimerTicks prevHeldTicks = m_heldTicks;

      Pointer prevHistory = m_history;

      m_history = history;

      m_ticks = ticks;

      m_timeOffset = timeOffset;

      m_heldTicks = (m_history ? m_history->holdTicks(m_ticks) : 0);

      if (prevHistory) prevHistory->releaseTicks(prevHeldTicks);

    }

    void set(const Holder &other)

      { set(other.history(), other.ticks(), other.timeOffset()); }

    void reset()

      { set(Pointer(), 0); }

    Pointer history() const

      { return m_history; }

    TTimerTicks ticks() const

      { return m_ticks; }

    double timeOffset() const

      { return m_timeOffset; }

    Holder offset(double timeOffset) const {

      return fabs(timeOffset) < TToolTimer::epsilon ? *this

           : Holder(m_history, m_ticks, m_timeOffset + timeOffset);

    }

    StateHolder get(double time) const {

      TTimerTicks dticks = (TTimerTicks)ceil(TToolTimer::frequency*(time + m_timeOffset - TConsts::epsilon));

      StatePointer state = m_history->get(m_ticks + dticks);

      return StateHolder(state, m_ticks, m_timeOffset + time);

    }

  };

private:

  StateMap m_states;

  LockSet m_locks;

  void autoRemove() {

    TTimerTicks ticks = m_states.rbegin()->first;

    if (!m_locks.empty())

      ticks = std::min(ticks, *m_locks.begin());

    while(true) {

      typename StateMap::iterator i = m_states.begin();

      ++i;

      if (i == m_states.end() || (!i->second->isEmpty() && i->first >= ticks)) break;

      m_states.erase(i);

    }

  }

  TTimerTicks holdTicks(TTimerTicks ticks)

    { return *m_locks.insert(std::max(ticks, m_states.begin()->first)); }

  void releaseTicks(TTimerTicks heldTicks) {

    typename LockSet::iterator i = m_locks.find(heldTicks);

    if (i == m_locks.end()) return;

    m_locks.erase(i);

    autoRemove();

  }

  StatePointer get(TTimerTicks ticks) {

    typename StateMap::iterator i = m_states.upper_bound(ticks);

    return i == m_states.begin() ? i->second : (--i)->second;

  }

public:

  TKeyHistoryT()

    { m_states[TTimerTicks()] = StatePointer(new State()); }

  StatePointer current() const

    { return m_states.rbegin()->second; }

  StatePointer change(bool press, Type value, TTimerTicks ticks)  {

    StatePointer state = current()->change(press, value, ticks);

    if (state != current() && ticks > m_states.rbegin()->first)

      m_states[state->ticks] = state;

    autoRemove();

    return current();

  }

  StatePointer pressed(Type value, TTimerTicks ticks)

    { return change(true, value, ticks); }

  StatePointer released(Type value, TTimerTicks ticks)

    { return change(false, value, ticks); }

  inline const StateMap& getStates() const

    { return m_states; }

  inline const LockSet& getLocks() const

    { return m_locks; }

};

#endif