/***************************************************************************
 *                                                                         *
 *   LinuxSampler - modular, streaming capable sampler                     *
 *                                                                         *
 *   Copyright (C) 2003, 2004 by Benno Senoner and Christian Schoenebeck   *
 *   Copyright (C) 2005 - 2016 Christian Schoenebeck                       *
 *                                                                         *
 *   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; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 *   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, write to the Free Software           *
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston,                 *
 *   MA  02111-1307  USA                                                   *
 ***************************************************************************/

#ifndef __LS_EVENT_H__
#define __LS_EVENT_H__

#include "../../common/global.h"
#include "../../common/RTMath.h"
#include "../../common/RTAVLTree.h"
#include "../../common/Pool.h"
#include "../EngineChannel.h"

namespace LinuxSampler {

    // just symbol prototyping
    class Event;
    class SchedulerNode;
    class ScriptEvent;
    class ScheduledEvent;

    /**
     * Data type used to schedule events sample point accurately both within, as
     * well as beyond the scope of the current audio fragment cycle. The timing
     * reflected by this data type is consecutively running for a very long
     * time. Even with a sample rate of 96 kHz a scheduler time of this data
     * type will not wrap before 6 million years. So in practice such time
     * stamps are unique and will not repeat (unless the EventGenerator is
     * reset).
     */
    typedef uint64_t sched_time_t;

    /**
     * Generates Event objects and is responsible for resolving the position
     * in the current audio fragment each Event actually belongs to.
     */
    class EventGenerator {
        public:
            EventGenerator(uint SampleRate);
            void UpdateFragmentTime(uint SamplesToProcess);
            Event CreateEvent();
            Event CreateEvent(int32_t FragmentPos);

            template<typename T>
            void scheduleAheadMicroSec(RTAVLTree<T>& queue, T& node, int32_t fragmentPosBase, uint64_t microseconds);

            RTList<ScheduledEvent>::Iterator popNextScheduledEvent(RTAVLTree<ScheduledEvent>& queue, Pool<ScheduledEvent>& pool, sched_time_t end);
            RTList<ScriptEvent>::Iterator popNextScheduledScriptEvent(RTAVLTree<ScriptEvent>& queue, Pool<ScriptEvent>& pool, sched_time_t end);

            /**
             * Returns the scheduler time for the first sample point of the next
             * audio fragment cycle.
             */
            sched_time_t schedTimeAtCurrentFragmentEnd() const {
                return uiTotalSamplesProcessed + uiSamplesProcessed;
            }

        protected:
            typedef RTMath::time_stamp_t time_stamp_t;
            inline int32_t ToFragmentPos(time_stamp_t TimeStamp) {
                return int32_t (int32_t(TimeStamp - FragmentTime.begin) * FragmentTime.sample_ratio);
            }
            friend class Event;
        private:
            uint uiSampleRate;
            uint uiSamplesProcessed;
            struct __FragmentTime__ {
                time_stamp_t begin;        ///< Real time stamp of the beginning of this audio fragment cycle.
                time_stamp_t end;          ///< Real time stamp of the end of this audio fragment cycle.
                float        sample_ratio; ///< (Samples per cycle) / (Real time duration of cycle)
            } FragmentTime;
            sched_time_t uiTotalSamplesProcessed; ///< Total amount of sample points that have been processed since this EventGenerator object has been created. This is used to schedule instrument script events long time ahead in future (that is beyond the scope of the current audio fragment).
    };

    /**
     * Events are usually caused by a MIDI source or an internal modulation
     * controller like LFO or EG. An event should only be created by an
     * EventGenerator!
     *
     * @see EventGenerator, ScriptEvent
     */
    class Event {
        public:
            Event(){}
            enum type_t {
                type_note_on,
                type_note_off,
                type_pitchbend,
                type_control_change,
                type_sysex,           ///< MIDI system exclusive message
                type_cancel_release,  ///< transformed either from a note-on or sustain-pedal-down event
                type_release,         ///< transformed either from a note-off or sustain-pedal-up event
                type_channel_pressure, ///< a.k.a. aftertouch
                type_note_pressure, ///< polyphonic key pressure (aftertouch)
            } Type;
            union {
                /// Note-on and note-off event specifics
                struct _Note {
                    uint8_t Channel;     ///< MIDI channel (0..15)
                    uint8_t Key;         ///< MIDI key number of note-on / note-off event.
                    uint8_t Velocity;    ///< Trigger or release velocity of note-on / note-off event.
                    int8_t  Layer;       ///< Layer index (usually only used if a note-on event has to be postponed, e.g. due to shortage of free voices).
                    int8_t  ReleaseTrigger; ///< If new voice should be a release triggered voice (actually boolean field and usually only used if a note-on event has to be postponed, e.g. due to shortage of free voices).
                    void*   pRegion;     ///< Engine specific pointer to instrument region
                } Note;
                /// Control change event specifics
                struct _CC {
                    uint8_t Channel;     ///< MIDI channel (0..15)
                    uint8_t Controller;  ///< MIDI controller number of control change event.
                    uint8_t Value;       ///< Controller Value of control change event.
                } CC;
                /// Pitchbend event specifics
                struct _Pitch {
                    uint8_t Channel;     ///< MIDI channel (0..15)
                    int16_t Pitch;       ///< Pitch value of pitchbend event.
                } Pitch;
                /// MIDI system exclusive event specifics
                struct _Sysex {
                    uint Size;           ///< Data length (in bytes) of MIDI system exclusive message.
                } Sysex;
                /// Channel Pressure (aftertouch) event specifics
                struct _ChannelPressure {
                    uint8_t Channel; ///< MIDI channel (0..15)
                    uint8_t Controller; ///< Should always be assigned to CTRL_TABLE_IDX_AFTERTOUCH.
                    uint8_t Value;   ///< New aftertouch / pressure value for keys on that channel.
                } ChannelPressure;
                /// Polyphonic Note Pressure (aftertouch) event specifics
                struct _NotePressure {
                    uint8_t Channel; ///< MIDI channel (0..15)
                    uint8_t Key;     ///< MIDI note number where key pressure (polyphonic aftertouch) changed.
                    uint8_t Value;   ///< New pressure value for note.
                } NotePressure;
            } Param;
            /// Sampler format specific informations and variables.
            union {
                /// Gigasampler/GigaStudio format specifics.
                struct _Gig {
                    uint8_t DimMask; ///< May be used to override the Dimension zone to be selected for a new voice: each 1 bit means that respective bit shall be overridden by taking the respective bit from DimBits instead.
                    uint8_t DimBits; ///< Used only in conjunction with DimMask: Dimension bits that shall be selected.
                } Gig;
            } Format;
            EngineChannel* pEngineChannel; ///< Pointer to the EngineChannel where this event occured on, NULL means Engine global event (e.g. SysEx message).
            MidiInputPort* pMidiInputPort; ///< Pointer to the MIDI input port on which this event occured (NOTE: currently only for global events, that is SysEx messages)

            inline int32_t FragmentPos() {
                if (iFragmentPos >= 0) return iFragmentPos;
                iFragmentPos = pEventGenerator->ToFragmentPos(TimeStamp);
                if (iFragmentPos < 0) iFragmentPos = 0; // if event arrived shortly before the beginning of current fragment
                return iFragmentPos;
            }
            inline void ResetFragmentPos() {
                iFragmentPos = -1;
            }
        protected:
            typedef EventGenerator::time_stamp_t time_stamp_t;
            Event(EventGenerator* pGenerator, EventGenerator::time_stamp_t Time);
            Event(EventGenerator* pGenerator, int32_t FragmentPos);
            friend class EventGenerator;
        private:
            EventGenerator* pEventGenerator; ///< Creator of the event.
            time_stamp_t    TimeStamp;       ///< Time stamp of the event's occurence.
            int32_t         iFragmentPos;    ///< Position in the current fragment this event refers to.
    };

    /**
     * Used to sort timing relevant objects (i.e. events) into timing/scheduler
     * queue. This class is just intended as base class and should be derived
     * for its actual purpose (for the precise data type being scheduled).
     */
    class SchedulerNode : public RTAVLNode {
    public:
        sched_time_t scheduleTime; ///< Time ahead in future (in sample points) when this object shall be processed. This value is compared with EventGenerator's uiTotalSamplesProcessed member variable.

        /// Required operator implementation for RTAVLTree class.
        inline bool operator==(const SchedulerNode& other) const {
            return this->scheduleTime == other.scheduleTime;
        }

        /// Required operator implementation for RTAVLTree class.
        inline bool operator<(const SchedulerNode& other) const {
            return this->scheduleTime < other.scheduleTime;
        }
    };

    /**
     * Used to sort delayed MIDI events into a timing/scheduler queue. This
     * object just contains the timing informations, the actual MIDI event is
     * pointed by member variable @c itEvent.
     */
    class ScheduledEvent : public SchedulerNode {
    public:
        Pool<Event>::Iterator itEvent; ///< Points to the actual Event object being scheduled.
    };

    class VMEventHandler;
    class VMExecContext;

    /** @brief Real-time instrument script event.
     *
     * Encapsulates one execution instance of a real-time instrument script for
     * exactly one script event handler (script event callback).
     *
     * This class derives from SchedulerNode for being able to be sorted efficiently
     * by the script scheduler if the script was either a) calling the wait()
     * script function or b) the script was auto suspended by the ScriptVM
     * because the script was executing for too long. In both cases the
     * scheduler has to sort the ScriptEvents in its execution queue according
     * to the precise time the respective script execution instance needs to be
     * resumed.
     */
    class ScriptEvent : public SchedulerNode {
    public:
        Event cause; ///< Original external event that triggered this script event (i.e. MIDI note on event, MIDI CC event, etc.).
        int id; ///< Unique ID of the external event that triggered this script event.
        VMEventHandler** handlers; ///< The script's event handlers (callbacks) to be processed (NULL terminated list).
        VMExecContext* execCtx; ///< Script's current execution state (polyphonic variables and execution stack).
        int currentHandler; ///< Current index in 'handlers' list above.
        int executionSlices; ///< Amount of times this script event has been executed by the ScriptVM runner class.
    };

    /**
     * Insert given @a node into the supplied timing @a queue with a scheduled
     * timing position given by @a fragmentPosBase and @a microseconds, where
     * @a microseconds reflects the amount microseconds in future from "now"
     * where the node shall be scheduled, and @a fragmentPos identifies the
     * sample point within the current audio fragment cycle which shall be
     * interpreted by this method to be "now".
     *
     * The meaning of @a fragmentPosBase becomes more important the larger
     * the audio fragment size, and vice versa it bcomes less important the
     * smaller the audio fragment size.
     *
     * @param queue - destination scheduler queue
     * @param node - node (i.e. event) to be inserted into the queue
     * @param fragmentPosBase - sample point in current audio fragment to be "now"
     * @param microseconds - timing of node from "now" (in microseconds)
     */
    template<typename T>
    void EventGenerator::scheduleAheadMicroSec(RTAVLTree<T>& queue, T& node, int32_t fragmentPosBase, uint64_t microseconds) {
        node.scheduleTime = uiTotalSamplesProcessed + fragmentPosBase + float(uiSampleRate) * (float(microseconds) / 1000000.f);
        queue.insert(node);
    }

} // namespace LinuxSampler

#endif // __LS_EVENT_H__