/*
 * Copyright (c) 2014-2016 Christian Schoenebeck
 *
 * http://www.linuxsampler.org
 *
 * This file is part of LinuxSampler and released under the same terms.
 * See README file for details.
 */

#include "InstrumentScriptVMFunctions.h"
#include "InstrumentScriptVM.h"
#include "../AbstractEngineChannel.h"

namespace LinuxSampler {
    
    // play_note() function

    InstrumentScriptVMFunction_play_note::InstrumentScriptVMFunction_play_note(InstrumentScriptVM* parent)
        : m_vm(parent)
    {
    }

    VMFnResult* InstrumentScriptVMFunction_play_note::exec(VMFnArgs* args) {
        int note = args->arg(0)->asInt()->evalInt();
        int velocity = (args->argsCount() >= 2) ? args->arg(1)->asInt()->evalInt() : 127;
        int sampleoffset = (args->argsCount() >= 3) ? args->arg(2)->asInt()->evalInt() : 0;
        int duration = (args->argsCount() >= 4) ? args->arg(3)->asInt()->evalInt() : 0; //TODO: -1 might be a better default value instead of 0

        if (note < 0 || note > 127) {
            errMsg("play_note(): argument 1 is an invalid note number");
            return errorResult(0);
        }

        if (velocity < 0 || velocity > 127) {
            errMsg("play_note(): argument 2 is an invalid velocity value");
            return errorResult(0);
        }

        if (sampleoffset < 0) {
            errMsg("play_note(): argument 3 may not be a negative sample offset");
            return errorResult(0);
        } else if (sampleoffset != 0) {
            wrnMsg("play_note(): argument 3 does not support a sample offset other than 0 yet");
        }

        if (duration < -1) {
            errMsg("play_note(): argument 4 must be a duration value of at least -1 or higher");
            return errorResult(0);
        }

        AbstractEngineChannel* pEngineChannel =
            static_cast<AbstractEngineChannel*>(m_vm->m_event->cause.pEngineChannel);

        Event e = m_vm->m_event->cause; // copy to get fragment time for "now"
        e.Init(); // clear IDs
        e.Type = Event::type_note_on;
        e.Param.Note.Key = note;
        e.Param.Note.Velocity = velocity;
        // make this new note dependent to the life time of the original note
        if (duration == -1) {
            if (m_vm->currentVMEventHandler()->eventHandlerType() != VM_EVENT_HANDLER_NOTE) {
                errMsg("play_note(): -1 for argument 4 may only be used for note event handlers");
                return errorResult(0);
            }
            e.Param.Note.ParentNoteID = m_vm->m_event->cause.Param.Note.ID;
        }

        const note_id_t id = pEngineChannel->ScheduleNoteMicroSec(&e, 0);

        // if a duration is supplied (and note-on event was scheduled
        // successfully above), then schedule a subsequent note-off event
        if (id && duration > 0) {
            e.Type = Event::type_note_off;
            e.Param.Note.Velocity = 127;
            pEngineChannel->ScheduleEventMicroSec(&e, duration);
        }

        // even if id is null, don't return an errorResult() here, because that
        // would abort the script, and under heavy load it may be considerable
        // that ScheduleNoteMicroSec() fails above, so simply ignore that
        return successResult( ScriptID::fromNoteID(id) );
    }

    // set_controller() function

    InstrumentScriptVMFunction_set_controller::InstrumentScriptVMFunction_set_controller(InstrumentScriptVM* parent)
        : m_vm(parent)
    {
    }

    VMFnResult* InstrumentScriptVMFunction_set_controller::exec(VMFnArgs* args) {
        int controller = args->arg(0)->asInt()->evalInt();
        int value      = args->arg(1)->asInt()->evalInt();

        AbstractEngineChannel* pEngineChannel =
            static_cast<AbstractEngineChannel*>(m_vm->m_event->cause.pEngineChannel);

        Event e = m_vm->m_event->cause; // copy to get fragment time for "now"
        e.Init(); // clear IDs
        if (controller == CTRL_TABLE_IDX_AFTERTOUCH) {
            e.Type = Event::type_channel_pressure;
            e.Param.ChannelPressure.Value = value & 127;
        } else if (controller == CTRL_TABLE_IDX_PITCHBEND) {
            e.Type = Event::type_pitchbend;
            e.Param.Pitch.Pitch = value;
        } else if (controller >= 0 && controller <= 127) {
            e.Type = Event::type_control_change;
            e.Param.CC.Controller = controller;
            e.Param.CC.Value = value;
        } else {
            errMsg("set_controller(): argument 1 is an invalid controller");
            return errorResult();
        }

        const event_id_t id = pEngineChannel->ScheduleEventMicroSec(&e, 0);

        // even if id is null, don't return an errorResult() here, because that
        // would abort the script, and under heavy load it may be considerable
        // that ScheduleEventMicroSec() fails above, so simply ignore that
        return successResult( ScriptID::fromEventID(id) );
    }

    // ignore_event() function

    InstrumentScriptVMFunction_ignore_event::InstrumentScriptVMFunction_ignore_event(InstrumentScriptVM* parent)
        : m_vm(parent)
    {
    }

    bool InstrumentScriptVMFunction_ignore_event::acceptsArgType(int iArg, ExprType_t type) const {
        return type == INT_EXPR || type == INT_ARR_EXPR;
    }

    VMFnResult* InstrumentScriptVMFunction_ignore_event::exec(VMFnArgs* args) {
        AbstractEngineChannel* pEngineChannel =
                static_cast<AbstractEngineChannel*>(m_vm->m_event->cause.pEngineChannel);

        if (args->arg(0)->exprType() == INT_EXPR) {
            const ScriptID id = args->arg(0)->asInt()->evalInt();
            if (!id) {
                wrnMsg("ignore_event(): event ID argument may not be zero");
                // not errorResult(), because that would abort the script, not intentional in this case
                return successResult();
            }
            pEngineChannel->IgnoreEventByScriptID(id);
        } else if (args->arg(0)->exprType() == INT_ARR_EXPR) {
            VMIntArrayExpr* ids = args->arg(0)->asIntArray();
            for (int i = 0; i < ids->arraySize(); ++i) {
                const ScriptID id = ids->evalIntElement(i);     
                pEngineChannel->IgnoreEventByScriptID(id);
            }
        }

        return successResult();
    }

    // ignore_controller() function

    InstrumentScriptVMFunction_ignore_controller::InstrumentScriptVMFunction_ignore_controller(InstrumentScriptVM* parent)
        : m_vm(parent)
    {
    }

    VMFnResult* InstrumentScriptVMFunction_ignore_controller::exec(VMFnArgs* args) {
        const ScriptID id = (args->argsCount() >= 1) ? args->arg(0)->asInt()->evalInt() : m_vm->m_event->id;
        if (!id && args->argsCount() >= 1) {
            wrnMsg("ignore_controller(): event ID argument may not be zero");
            return successResult();
        }

        AbstractEngineChannel* pEngineChannel =
            static_cast<AbstractEngineChannel*>(m_vm->m_event->cause.pEngineChannel);

        pEngineChannel->IgnoreEventByScriptID(id);

        return successResult();
    }

    // note_off() function

    InstrumentScriptVMFunction_note_off::InstrumentScriptVMFunction_note_off(InstrumentScriptVM* parent)
        : m_vm(parent)
    {
    }

    bool InstrumentScriptVMFunction_note_off::acceptsArgType(int iArg, ExprType_t type) const {
        return type == INT_EXPR || type == INT_ARR_EXPR;
    }

    VMFnResult* InstrumentScriptVMFunction_note_off::exec(VMFnArgs* args) {
        AbstractEngineChannel* pEngineChannel =
            static_cast<AbstractEngineChannel*>(m_vm->m_event->cause.pEngineChannel);

        int velocity = (args->argsCount() >= 2) ? args->arg(1)->asInt()->evalInt() : 127;
        if (velocity < 0 || velocity > 127) {
            errMsg("note_off(): argument 2 is an invalid velocity value");
            return errorResult();
        }

        if (args->arg(0)->exprType() == INT_EXPR) {
            const ScriptID id = args->arg(0)->asInt()->evalInt();   
            if (!id) {
                wrnMsg("note_off(): note ID for argument 1 may not be zero");
                return successResult();
            }
            if (!id.isNoteID()) {
                wrnMsg("note_off(): argument 1 is not a note ID");
                return successResult();
            }

            NoteBase* pNote = pEngineChannel->pEngine->NoteByID( id.noteID() );
            if (!pNote) return successResult();

            Event e = pNote->cause;
            e.Init(); // clear IDs
            e.CopyTimeFrom(m_vm->m_event->cause); // set fragment time for "now"
            e.Type = Event::type_note_off;
            e.Param.Note.Velocity = velocity;

            pEngineChannel->ScheduleEventMicroSec(&e, 0);
        } else if (args->arg(0)->exprType() == INT_ARR_EXPR) {
            VMIntArrayExpr* ids = args->arg(0)->asIntArray();
            for (int i = 0; i < ids->arraySize(); ++i) {
                const ScriptID id = ids->evalIntElement(i);
                if (!id || !id.isNoteID()) continue;

                NoteBase* pNote = pEngineChannel->pEngine->NoteByID( id.noteID() );
                if (!pNote) continue;

                Event e = pNote->cause;
                e.Init(); // clear IDs
                e.CopyTimeFrom(m_vm->m_event->cause); // set fragment time for "now"
                e.Type = Event::type_note_off;
                e.Param.Note.Velocity = velocity;

                pEngineChannel->ScheduleEventMicroSec(&e, 0);
            }
        }

        return successResult();
    }

    // set_event_mark() function

    InstrumentScriptVMFunction_set_event_mark::InstrumentScriptVMFunction_set_event_mark(InstrumentScriptVM* parent)
        : m_vm(parent)
    {
    }

    VMFnResult* InstrumentScriptVMFunction_set_event_mark::exec(VMFnArgs* args) {
        const ScriptID id = args->arg(0)->asInt()->evalInt();
        const int groupID = args->arg(1)->asInt()->evalInt();

        if (groupID < 0 || groupID >= INSTR_SCRIPT_EVENT_GROUPS) {
            errMsg("set_event_mark(): argument 2 is an invalid group id");
            return errorResult();
        }

        AbstractEngineChannel* pEngineChannel =
            static_cast<AbstractEngineChannel*>(m_vm->m_event->cause.pEngineChannel);

        // check if the event/note still exists
        switch (id.type()) {
            case ScriptID::EVENT: {
                RTList<Event>::Iterator itEvent = pEngineChannel->pEngine->EventByID( id.eventID() );
                if (!itEvent) return successResult();
                break;
            }
            case ScriptID::NOTE: {
                NoteBase* pNote = pEngineChannel->pEngine->NoteByID( id.noteID() );
                if (!pNote) return successResult();
                break;
            }
        }

        pEngineChannel->pScript->eventGroups[groupID].insert(id);

        return successResult();
    }

    // delete_event_mark() function

    InstrumentScriptVMFunction_delete_event_mark::InstrumentScriptVMFunction_delete_event_mark(InstrumentScriptVM* parent)
        : m_vm(parent)
    {
    }

    VMFnResult* InstrumentScriptVMFunction_delete_event_mark::exec(VMFnArgs* args) {
        const ScriptID id = args->arg(0)->asInt()->evalInt();
        const int groupID = args->arg(1)->asInt()->evalInt();

        if (groupID < 0 || groupID >= INSTR_SCRIPT_EVENT_GROUPS) {
            errMsg("delete_event_mark(): argument 2 is an invalid group id");
            return errorResult();
        }

        AbstractEngineChannel* pEngineChannel =
            static_cast<AbstractEngineChannel*>(m_vm->m_event->cause.pEngineChannel);

        pEngineChannel->pScript->eventGroups[groupID].erase(id);

        return successResult();
    }

    // by_marks() function

    InstrumentScriptVMFunction_by_marks::InstrumentScriptVMFunction_by_marks(InstrumentScriptVM* parent)
        : m_vm(parent)
    {
    }

    int InstrumentScriptVMFunction_by_marks::Result::arraySize() const {
        return eventGroup->size();
    }

    int InstrumentScriptVMFunction_by_marks::Result::evalIntElement(uint i) {
        return (*eventGroup)[i];
    }

    VMFnResult* InstrumentScriptVMFunction_by_marks::errorResult() {
        m_result.eventGroup = NULL;
        m_result.flags = StmtFlags_t(STMT_ABORT_SIGNALLED | STMT_ERROR_OCCURRED);
        return &m_result;
    }

    VMFnResult* InstrumentScriptVMFunction_by_marks::successResult(EventGroup* eventGroup) {
        m_result.eventGroup = eventGroup;
        m_result.flags = STMT_SUCCESS;
        return &m_result;
    }

    VMFnResult* InstrumentScriptVMFunction_by_marks::exec(VMFnArgs* args) {
        int groupID = args->arg(0)->asInt()->evalInt();

        if (groupID < 0 || groupID >= INSTR_SCRIPT_EVENT_GROUPS) {
            errMsg("by_marks(): argument is an invalid group id");
            return errorResult();
        }

        AbstractEngineChannel* pEngineChannel =
            static_cast<AbstractEngineChannel*>(m_vm->m_event->cause.pEngineChannel);

        return successResult( &pEngineChannel->pScript->eventGroups[groupID] );
    }

    // change_vol() function

    InstrumentScriptVMFunction_change_vol::InstrumentScriptVMFunction_change_vol(InstrumentScriptVM* parent)
        : m_vm(parent)
    {
    }

    bool InstrumentScriptVMFunction_change_vol::acceptsArgType(int iArg, ExprType_t type) const {
        if (iArg == 0)
            return type == INT_EXPR || type == INT_ARR_EXPR;
        else
            return INT_EXPR;
    }

    VMFnResult* InstrumentScriptVMFunction_change_vol::exec(VMFnArgs* args) {
        int volume = args->arg(1)->asInt()->evalInt(); // volume change in milli dB
        bool relative = (args->argsCount() >= 3) ? (args->arg(2)->asInt()->evalInt() & 1) : false;

        AbstractEngineChannel* pEngineChannel =
            static_cast<AbstractEngineChannel*>(m_vm->m_event->cause.pEngineChannel);

        if (args->arg(0)->exprType() == INT_EXPR) {
            const ScriptID id = args->arg(0)->asInt()->evalInt();
            if (!id) {
                wrnMsg("change_vol(): note ID for argument 1 may not be zero");
                return successResult();
            }
            if (!id.isNoteID()) {
                wrnMsg("change_vol(): argument 1 is not a note ID");
                return successResult();
            }

            NoteBase* pNote = pEngineChannel->pEngine->NoteByID( id.noteID() );
            if (!pNote) return successResult();

            const float fVolumeLin = RTMath::DecibelToLinRatio(float(volume) / 1000.f);
            // commented out, performed by EngineBase::ProcessNoteSynthParam() for time accuracy behavior
            /*if (relative)
                pNote->Override.Volume *= fVolumeLin;
            else
                pNote->Override.Volume = fVolumeLin;*/

            Event e = m_vm->m_event->cause; // copy to get fragment time for "now"
            e.Init(); // clear IDs
            e.Type = Event::type_note_synth_param;
            e.Param.NoteSynthParam.NoteID   = id.noteID();
            e.Param.NoteSynthParam.Type     = Event::synth_param_volume;
            e.Param.NoteSynthParam.Delta    = fVolumeLin;
            e.Param.NoteSynthParam.Relative = relative;

            pEngineChannel->ScheduleEventMicroSec(&e, 0);
        } else if (args->arg(0)->exprType() == INT_ARR_EXPR) {
            VMIntArrayExpr* ids = args->arg(0)->asIntArray();
            for (int i = 0; i < ids->arraySize(); ++i) {
                const ScriptID id = ids->evalIntElement(i);
                if (!id || !id.isNoteID()) continue;

                NoteBase* pNote = pEngineChannel->pEngine->NoteByID( id.noteID() );
                if (!pNote) continue;

                const float fVolumeLin = RTMath::DecibelToLinRatio(float(volume) / 1000.f);
                // commented out, performed by EngineBase::ProcessNoteSynthParam() for time accuracy behavior
                /*if (relative)
                    pNote->Override.Volume *= fVolumeLin;
                else
                    pNote->Override.Volume = fVolumeLin;*/

                Event e = m_vm->m_event->cause; // copy to get fragment time for "now"
                e.Init(); // clear IDs
                e.Type = Event::type_note_synth_param;
                e.Param.NoteSynthParam.NoteID   = id.noteID();
                e.Param.NoteSynthParam.Type     = Event::synth_param_volume;
                e.Param.NoteSynthParam.Delta    = fVolumeLin;
                e.Param.NoteSynthParam.Relative = relative;

                pEngineChannel->ScheduleEventMicroSec(&e, 0);
            }
        }

        return successResult();
    }

    // change_tune() function

    InstrumentScriptVMFunction_change_tune::InstrumentScriptVMFunction_change_tune(InstrumentScriptVM* parent)
        : m_vm(parent)
    {
    }

    bool InstrumentScriptVMFunction_change_tune::acceptsArgType(int iArg, ExprType_t type) const {
        if (iArg == 0)
            return type == INT_EXPR || type == INT_ARR_EXPR;
        else
            return INT_EXPR;
    }

    VMFnResult* InstrumentScriptVMFunction_change_tune::exec(VMFnArgs* args) {
        int tune = args->arg(1)->asInt()->evalInt(); // tuning change in milli cents
        bool relative = (args->argsCount() >= 3) ? (args->arg(2)->asInt()->evalInt() & 1) : false;

        AbstractEngineChannel* pEngineChannel =
            static_cast<AbstractEngineChannel*>(m_vm->m_event->cause.pEngineChannel);

        if (args->arg(0)->exprType() == INT_EXPR) {
            const ScriptID id = args->arg(0)->asInt()->evalInt();
            if (!id) {
                wrnMsg("change_tune(): note ID for argument 1 may not be zero");
                return successResult();
            }
            if (!id.isNoteID()) {
                wrnMsg("change_tune(): argument 1 is not a note ID");
                return successResult();
            }

            NoteBase* pNote = pEngineChannel->pEngine->NoteByID( id.noteID() );
            if (!pNote) return successResult();

            const float fFreqRatio = RTMath::CentsToFreqRatioUnlimited(float(tune) / 1000.f);
            // commented out, performed by EngineBase::ProcessNoteSynthParam() for time accuracy behavior
            /*if (relative) 
                pNote->Override.Pitch *= fFreqRatio;
            else
                pNote->Override.Pitch = fFreqRatio;*/

            Event e = m_vm->m_event->cause; // copy to get fragment time for "now"
            e.Init(); // clear IDs
            e.Type = Event::type_note_synth_param;
            e.Param.NoteSynthParam.NoteID   = id.noteID();
            e.Param.NoteSynthParam.Type     = Event::synth_param_pitch;
            e.Param.NoteSynthParam.Delta    = fFreqRatio;
            e.Param.NoteSynthParam.Relative = relative;

            pEngineChannel->ScheduleEventMicroSec(&e, 0);
        } else if (args->arg(0)->exprType() == INT_ARR_EXPR) {
            VMIntArrayExpr* ids = args->arg(0)->asIntArray();
            for (int i = 0; i < ids->arraySize(); ++i) {
                const ScriptID id = ids->evalIntElement(i);
                if (!id || !id.isNoteID()) continue;

                NoteBase* pNote = pEngineChannel->pEngine->NoteByID( id.noteID() );
                if (!pNote) continue;

                const float fFreqRatio = RTMath::CentsToFreqRatioUnlimited(float(tune) / 1000.f);
                // commented out, performed by EngineBase::ProcessNoteSynthParam() for time accuracy behavior
                /*if (relative) 
                    pNote->Override.Pitch *= fFreqRatio;
                else
                    pNote->Override.Pitch = fFreqRatio;*/

                Event e = m_vm->m_event->cause; // copy to get fragment time for "now"
                e.Init(); // clear IDs
                e.Type = Event::type_note_synth_param;
                e.Param.NoteSynthParam.NoteID   = id.noteID();
                e.Param.NoteSynthParam.Type     = Event::synth_param_pitch;
                e.Param.NoteSynthParam.Delta    = fFreqRatio;
                e.Param.NoteSynthParam.Relative = relative;

                pEngineChannel->ScheduleEventMicroSec(&e, 0);
            }
        }

        return successResult();
    }

    // change_pan() function

    InstrumentScriptVMFunction_change_pan::InstrumentScriptVMFunction_change_pan(InstrumentScriptVM* parent)
        : m_vm(parent)
    {
    }

    bool InstrumentScriptVMFunction_change_pan::acceptsArgType(int iArg, ExprType_t type) const {
        if (iArg == 0)
            return type == INT_EXPR || type == INT_ARR_EXPR;
        else
            return INT_EXPR;
    }

    VMFnResult* InstrumentScriptVMFunction_change_pan::exec(VMFnArgs* args) {
        int pan = args->arg(1)->asInt()->evalInt();
        bool relative = (args->argsCount() >= 3) ? (args->arg(2)->asInt()->evalInt() & 1) : false;

        if (pan > 1000) {
            wrnMsg("change_pan(): argument 2 may not be larger than 1000");
            pan = 1000;
        } else if (pan < -1000) {
            wrnMsg("change_pan(): argument 2 may not be smaller than -1000");
            pan = -1000;
        }

        AbstractEngineChannel* pEngineChannel =
            static_cast<AbstractEngineChannel*>(m_vm->m_event->cause.pEngineChannel);

        if (args->arg(0)->exprType() == INT_EXPR) {
            const ScriptID id = args->arg(0)->asInt()->evalInt();
            if (!id) {
                wrnMsg("change_pan(): note ID for argument 1 may not be zero");
                return successResult();
            }
            if (!id.isNoteID()) {
                wrnMsg("change_pan(): argument 1 is not a note ID");
                return successResult();
            }

            NoteBase* pNote = pEngineChannel->pEngine->NoteByID( id.noteID() );
            if (!pNote) return successResult();

            const float fPan = float(pan) / 1000.f;
            // commented out, performed by EngineBase::ProcessNoteSynthParam() for time accuracy behavior
            /*if (relative) {
                pNote->Override.Pan = RTMath::RelativeSummedAvg(pNote->Override.Pan, fPan, ++pNote->Override.PanSources);
            } else {
                pNote->Override.Pan = fPan;
                pNote->Override.PanSources = 1; // only relevant on subsequent change_pan() calls on same note with 'relative' being set
            }*/

            Event e = m_vm->m_event->cause; // copy to get fragment time for "now"
            e.Init(); // clear IDs
            e.Type = Event::type_note_synth_param;
            e.Param.NoteSynthParam.NoteID   = id.noteID();
            e.Param.NoteSynthParam.Type     = Event::synth_param_pan;
            e.Param.NoteSynthParam.Delta    = fPan;
            e.Param.NoteSynthParam.Relative = relative;

            pEngineChannel->ScheduleEventMicroSec(&e, 0);
        } else if (args->arg(0)->exprType() == INT_ARR_EXPR) {
            VMIntArrayExpr* ids = args->arg(0)->asIntArray();
            for (int i = 0; i < ids->arraySize(); ++i) {
                const ScriptID id = ids->evalIntElement(i);
                if (!id || !id.isNoteID()) continue;

                NoteBase* pNote = pEngineChannel->pEngine->NoteByID( id.noteID() );
                if (!pNote) continue;

                const float fPan = float(pan) / 1000.f;
                // commented out, performed by EngineBase::ProcessNoteSynthParam() for time accuracy behavior
                /*if (relative) {
                    pNote->Override.Pan = RTMath::RelativeSummedAvg(pNote->Override.Pan, fPan, ++pNote->Override.PanSources);
                } else {
                    pNote->Override.Pan = fPan;
                    pNote->Override.PanSources = 1; // only relevant on subsequent change_pan() calls on same note with 'relative' being set
                }*/

                Event e = m_vm->m_event->cause; // copy to get fragment time for "now"
                e.Init(); // clear IDs
                e.Type = Event::type_note_synth_param;
                e.Param.NoteSynthParam.NoteID   = id.noteID();
                e.Param.NoteSynthParam.Type     = Event::synth_param_pan;
                e.Param.NoteSynthParam.Delta    = fPan;
                e.Param.NoteSynthParam.Relative = relative;

                pEngineChannel->ScheduleEventMicroSec(&e, 0);
            }
        }

        return successResult();
    }

    #define VM_FILTER_PAR_MAX_VALUE 1000000

    // change_cutoff() function

    InstrumentScriptVMFunction_change_cutoff::InstrumentScriptVMFunction_change_cutoff(InstrumentScriptVM* parent)
        : m_vm(parent)
    {
    }

    bool InstrumentScriptVMFunction_change_cutoff::acceptsArgType(int iArg, ExprType_t type) const {
        if (iArg == 0)
            return type == INT_EXPR || type == INT_ARR_EXPR;
        else
            return INT_EXPR;
    }

    VMFnResult* InstrumentScriptVMFunction_change_cutoff::exec(VMFnArgs* args) {
        int cutoff = args->arg(1)->asInt()->evalInt();
        if (cutoff > VM_FILTER_PAR_MAX_VALUE) {
            wrnMsg("change_cutoff(): argument 2 may not be larger than 1000000");
            cutoff = VM_FILTER_PAR_MAX_VALUE;
        } else if (cutoff < 0) {
            wrnMsg("change_cutoff(): argument 2 may not be negative");
            cutoff = 0;
        }

        AbstractEngineChannel* pEngineChannel =
            static_cast<AbstractEngineChannel*>(m_vm->m_event->cause.pEngineChannel);

        if (args->arg(0)->exprType() == INT_EXPR) {
            const ScriptID id = args->arg(0)->asInt()->evalInt();
            if (!id) {
                wrnMsg("change_cutoff(): note ID for argument 1 may not be zero");
                return successResult();
            }
            if (!id.isNoteID()) {
                wrnMsg("change_cutoff(): argument 1 is not a note ID");
                return successResult();
            }

            NoteBase* pNote = pEngineChannel->pEngine->NoteByID( id.noteID() );
            if (!pNote) return successResult();

            const float fCutoff = float(cutoff) / float(VM_FILTER_PAR_MAX_VALUE);

            Event e = m_vm->m_event->cause; // copy to get fragment time for "now"
            e.Init(); // clear IDs
            e.Type = Event::type_note_synth_param;
            e.Param.NoteSynthParam.NoteID   = id.noteID();
            e.Param.NoteSynthParam.Type     = Event::synth_param_cutoff;
            e.Param.NoteSynthParam.Delta    = fCutoff;
            e.Param.NoteSynthParam.Relative = false;

            pEngineChannel->ScheduleEventMicroSec(&e, 0);
        } else if (args->arg(0)->exprType() == INT_ARR_EXPR) {
            VMIntArrayExpr* ids = args->arg(0)->asIntArray();
            for (int i = 0; i < ids->arraySize(); ++i) {
                const ScriptID id = ids->evalIntElement(i);
                if (!id || !id.isNoteID()) continue;

                NoteBase* pNote = pEngineChannel->pEngine->NoteByID( id.noteID() );
                if (!pNote) continue;

                const float fCutoff = float(cutoff) / float(VM_FILTER_PAR_MAX_VALUE);

                Event e = m_vm->m_event->cause; // copy to get fragment time for "now"
                e.Init(); // clear IDs
                e.Type = Event::type_note_synth_param;
                e.Param.NoteSynthParam.NoteID   = id.noteID();
                e.Param.NoteSynthParam.Type     = Event::synth_param_cutoff;
                e.Param.NoteSynthParam.Delta    = fCutoff;
                e.Param.NoteSynthParam.Relative = false;

                pEngineChannel->ScheduleEventMicroSec(&e, 0);
            }
        }

        return successResult();
    }

    // change_reso() function
    
    InstrumentScriptVMFunction_change_reso::InstrumentScriptVMFunction_change_reso(InstrumentScriptVM* parent)
        : m_vm(parent)
    {
    }

    bool InstrumentScriptVMFunction_change_reso::acceptsArgType(int iArg, ExprType_t type) const {
        if (iArg == 0)
            return type == INT_EXPR || type == INT_ARR_EXPR;
        else
            return INT_EXPR;
    }

    VMFnResult* InstrumentScriptVMFunction_change_reso::exec(VMFnArgs* args) {
        int resonance = args->arg(1)->asInt()->evalInt();
        if (resonance > VM_FILTER_PAR_MAX_VALUE) {
            wrnMsg("change_reso(): argument 2 may not be larger than 1000000");
            resonance = VM_FILTER_PAR_MAX_VALUE;
        } else if (resonance < 0) {
            wrnMsg("change_reso(): argument 2 may not be negative");
            resonance = 0;
        }

        AbstractEngineChannel* pEngineChannel =
            static_cast<AbstractEngineChannel*>(m_vm->m_event->cause.pEngineChannel);

        if (args->arg(0)->exprType() == INT_EXPR) {
            const ScriptID id = args->arg(0)->asInt()->evalInt();
            if (!id) {
                wrnMsg("change_reso(): note ID for argument 1 may not be zero");
                return successResult();
            }
            if (!id.isNoteID()) {
                wrnMsg("change_reso(): argument 1 is not a note ID");
                return successResult();
            }

            NoteBase* pNote = pEngineChannel->pEngine->NoteByID( id.noteID() );
            if (!pNote) return successResult();

            const float fResonance = float(resonance) / float(VM_FILTER_PAR_MAX_VALUE);

            Event e = m_vm->m_event->cause; // copy to get fragment time for "now"
            e.Init(); // clear IDs
            e.Type = Event::type_note_synth_param;
            e.Param.NoteSynthParam.NoteID   = id.noteID();
            e.Param.NoteSynthParam.Type     = Event::synth_param_resonance;
            e.Param.NoteSynthParam.Delta    = fResonance;
            e.Param.NoteSynthParam.Relative = false;

            pEngineChannel->ScheduleEventMicroSec(&e, 0);
        } else if (args->arg(0)->exprType() == INT_ARR_EXPR) {
            VMIntArrayExpr* ids = args->arg(0)->asIntArray();
            for (int i = 0; i < ids->arraySize(); ++i) {
                const ScriptID id = ids->evalIntElement(i);
                if (!id || !id.isNoteID()) continue;

                NoteBase* pNote = pEngineChannel->pEngine->NoteByID( id.noteID() );
                if (!pNote) continue;

                const float fResonance = float(resonance) / float(VM_FILTER_PAR_MAX_VALUE);

                Event e = m_vm->m_event->cause; // copy to get fragment time for "now"
                e.Init(); // clear IDs
                e.Type = Event::type_note_synth_param;
                e.Param.NoteSynthParam.NoteID   = id.noteID();
                e.Param.NoteSynthParam.Type     = Event::synth_param_resonance;
                e.Param.NoteSynthParam.Delta    = fResonance;
                e.Param.NoteSynthParam.Relative = false;

                pEngineChannel->ScheduleEventMicroSec(&e, 0);
            }
        }

        return successResult();
    }

    // event_status() function

    InstrumentScriptVMFunction_event_status::InstrumentScriptVMFunction_event_status(InstrumentScriptVM* parent)
        : m_vm(parent)
    {
    }

    VMFnResult* InstrumentScriptVMFunction_event_status::exec(VMFnArgs* args) {
        AbstractEngineChannel* pEngineChannel =
            static_cast<AbstractEngineChannel*>(m_vm->m_event->cause.pEngineChannel);

        const ScriptID id = args->arg(0)->asInt()->evalInt();
        if (!id) {
            wrnMsg("event_status(): note ID for argument 1 may not be zero");
            return successResult(EVENT_STATUS_INACTIVE);
        }
        if (!id.isNoteID()) {
            wrnMsg("event_status(): argument 1 is not a note ID");
            return successResult(EVENT_STATUS_INACTIVE);
        }

        NoteBase* pNote = pEngineChannel->pEngine->NoteByID( id.noteID() );
        return successResult(pNote ? EVENT_STATUS_NOTE_QUEUE : EVENT_STATUS_INACTIVE);
    }

} // namespace LinuxSampler