Patroneo/template/engine/sequencer.py

#! /usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Copyright 2022, Nils Hilbricht, Germany ( https://www.hilbricht.net )

This file is part of the Laborejo Software Suite ( https://www.laborejo.org ),

This 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 3 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, see <http://www.gnu.org/licenses/>.
"""

import logging; logger = logging.getLogger(__name__); logger.info("import")


#Standard Library
from typing import List, Dict, Tuple, Iterable, Union

#Third Party Modules
from template.calfbox import cbox

#Template Modules
from .data import Data
from .metronome import Metronome
from .duration import traditionalNumberToBaseDuration, MAXIMUM_TICK_DURATION

#Client Modules
from engine.config import *  #includes METADATA only. No other environmental setup is executed.
class Score(Data):
    """Manages and holds tracks
    Has a mutable list of Track instances. This is the official order. Rearranging happens here.
    Order ist reflected in JACK through metadata. UIs should adopt it as well.

    Score.TrackClass needs to be injected with your Track class.

    Score.TrackClass needs to have a SequencerInterface of type SequencerInterface

    self.tracks holds only active tracks. Which means tracks that produce sound
    That does not mean that they are visible or editable for the user.
    Does NOT hold deleted tracks in the undo storage. You need to hold these tracks in memory
    yourself before calling score.delete. For example Laborejo registers the Track instance
    in our history module which keeps the instance alive.

    Special Tracks do not need to be created here. E.g. a metronome can be just a track.

    """
    TrackClass = None

    def __init__(self, parentSession):
        assert Score.TrackClass
        super().__init__(parentSession)
        self.tracks = [] #see docstring
        self.tempoMap = TempoMap(parentData = self)
        self._template_processAfterInit()
        self._tracksFailedLookup = []

    def _template_processAfterInit(self): #needs a different name because there is an inherited class with the same method.
        """Call this after either init or instanceFromSerializedData"""
        if METADATA["metronome"]:
            self.metronome = Metronome(parentData=self) #Purely dynamic structure. No save/load. No undo/redo

    #Whole Score / Song

    def buildSongDuration(self, startEndTuple=None):
        """Set playback length for the entire score or a loop.
        Why is start the end-tick of the song?
        Starting from 0  would create an actual loop from the start to end.
        We want the song to play only once.
        The cbox way of doing that is to set the loop range to zero at the end of the track.
        Zero length is stop.
        """
        if startEndTuple is None:
            longestTrackDuration = max(track.sequencerInterface.cachedDuration for track in self.tracks)
            start = longestTrackDuration
            end = longestTrackDuration
        else:
            start, end = startEndTuple
        cbox.Document.get_song().set_loop(start, end)


    #Tracks
    def addTrack(self, name:str=""):
        """Create and add a new track. Not an existing one"""
        track = Score.TrackClass(parentData=self, name=name) # type: ignore  # mypy doesn't know that this is an injected class variable
        assert track.sequencerInterface
        self.tracks.append(track)
        return track

    def deleteTrack(self, track):
        track.sequencerInterface.prepareForDeletion()
        self.tracks.remove(track)
        return track #for undo

    def updateJackMetadataSorting(self):
        """Add this to you  "tracksChanged" or "numberOfTracksChanged" callback.
        Tell cbox to reorder the tracks by metadata. Deleted ports are automatically removed by JACK.

        It is advised to use this in a controlled manner. There is no Score-internal check if
        self.tracks changed and subsequent sorting. Multiple track changes in a row are common,
        therefore the place to update jack order is in the API, where the new track order is also
        sent to the UI.

        We also check if the track is 'deactivated' by probing track.cboxMidiOutUuid.
        Patroneo uses prepareForDeletion to deactive the tracks standalone track but keeps the
        interface around for later use.
        """
        order = {portName:index for index, portName in enumerate(track.sequencerInterface.cboxPortName() for track in self.tracks if track.sequencerInterface.cboxMidiOutUuid)}

        try:
            cbox.JackIO.Metadata.set_all_port_order(order)
        except Exception as e: #No Jack Meta Data or Error with ports.
            logger.error(e)


    def trackById(self, trackId:int):
        """Returns a track or None, if not found"""
        for track in self.tracks:
            if trackId == id(track):
                return track
        else:
            #Previously this crashed with a ValueError. However, after a rare bug that a gui widget focussed out because a track was deleted and then tried to send its value to the engine we realize that this lookup can gracefully return None.
            #Nothing will break: Functions that are not aware yet, that None is an option will crash when they try to access None as a track object. For this case we present the following logger error:
            if not trackId in self._tracksFailedLookup:
                logger.error(f"Track {trackId} not found. Current Tracks: {[id(tr) for tr in self.tracks]}")
                self._tracksFailedLookup.append(trackId) #prevent multiple error messages for the same track in a row.
                return None
                #raise ValueError(f"Track {trackId} not found. Current Tracks: {[id(tr) for tr in self.tracks]}")



    #Save / Load / Export
    def serialize(self)->dict:
        return {
            "tracks" : [track.serialize() for track in self.tracks],
            "tempoMap" : self.tempoMap.serialize(),
        }

    @classmethod
    def instanceFromSerializedData(cls, parentSession, serializedData):
        """The entry function to create a score from saved data. It is called by the session.

        This functions triggers a tree of other createInstanceFromSerializedData which finally
        return the score, which gets saved in the session.

        The serializedData is already converted to primitive python types from json,
        but nothing more. Here we create the actual objects."""
        self = cls.__new__(cls)
        Score.copyFromSerializedData(parentSession, serializedData, self)
        return self

    @staticmethod
    def copyFromSerializedData(parentSession, serializedData, childObject):
        """
        childObject is a Score or similar.

        Because this is an actual parent class we can't use instanceFromSerializedData in a child
        without actually creating an object. Long story short, use this to generate the data and
        use it in your child class. If the Data class is used standalone it still can be used."""
        childObject.parentSession = parentSession
        loadedTracks=[]
        for trackSrzData in serializedData["tracks"]:
            track = Score.TrackClass.instanceFromSerializedData(parentData=childObject, serializedData=trackSrzData)
            loadedTracks.append(track)

        childObject.tracks=loadedTracks
        childObject.tempoMap=TempoMap.instanceFromSerializedData(parentData=childObject, serializedData=serializedData["tempoMap"])
        childObject._template_processAfterInit()

    def export(self)->dict:
        return {
            "numberOfTracks" : len(self.tracks),
            #"duration" : self.
            }



class _Interface(object):
    #no load or save. Do that in the child classes.

    def __init__(self, parentTrack, name=None):
        self.parentTrack = parentTrack
        self.parentData = parentTrack.parentData
        self._name = self._isNameAvailable(name) if name else str(id(self))
        self._enabled = True
        self._processAfterInit()

    def _processAfterInit(self):
        self._cachedPatterns = [] #makes undo after delete possible
        self.calfboxTrack = cbox.Document.get_song().add_track()
        self.calfboxTrack.set_name(self.name) #only cosmetic and cbox internal. Useful for debugging, not used in jack.

        #Caches and other Non-Saved attributes
        self.cachedDuration = 0  #used by parentData.buildSongDuration to calculate the overall length of the song by checking all tracks.


    @property
    def name(self):
        return self._name

    @property
    def enabled(self)->bool:
        return self._enabled

    def _isNameAvailable(self, name:str):
        """Check if the name is free. If not increment"""
        name = ''.join(ch for ch in name if ch.isalnum() or ch in (" ", "_", "-")) #sanitize
        name = " ".join(name.split()) #remove double spaces
        while name in [tr.sequencerInterface.name for tr in self.parentData.tracks]:
            beforeLastChar = name[-2]
            lastChar = name[-1]
            if beforeLastChar==" " and lastChar.isalnum() and lastChar not in ("9", "z", "Z"):
                #Pattern is "Trackname A" or "Trackname 1" which can be incremented.
                name = name[:-1] + chr(ord(name[-1]) +1)
            else:
                name = name + " A"
        return name

    def _updatePlayback(self):
        self.parentData.buildSongDuration()
        cbox.Document.get_song().update_playback()

    def setTrack(self, blobs:Iterable):  #(bytes-blob, position, length)
        """Converts an Iterable of (bytes-blob, position, length) to cbox patterns, clips and adds
        them to an empty track, which replaces the current one.

        Simplest version is to send one blob at position 0 with its length."""
        #self.calfboxTrack.delete() #cbox clear data, not python structure
        #self.calfboxTrack = cbox.Document.get_song().add_track()
        #self.calfboxTrack.set_external_output(self.cboxMidiOutUuid)

        self.calfboxTrack.clear_clips()
        self._cachedPatterns = [] #makes undo after delete possible
        pos = 0
        for blob, pos, leng in blobs:
            if leng > 0:
                pat = cbox.Document.get_song().pattern_from_blob(blob, leng)
                t = (pat, pos, leng)
                self._cachedPatterns.append(t)

        length = 0
        for pattern, position, length in self._cachedPatterns:
            if length > 0:
                self.calfboxTrack.add_clip(position, 0, length, pattern) #pos, offset, length, pattern.


        self.cachedDuration = pos + length #use the last set values
        self._updatePlayback()

    def insertEmptyClip(self):
        """Convenience function to make recording into an empty song possible.
        Will be removed by self.setTrack."""
        blob = bytes()
        #We do not need any content #blob += cbox.Pattern.serialize_event(0, 0x80, 60, 64) # note off
        pattern = cbox.Document.get_song().pattern_from_blob(blob, MAXIMUM_TICK_DURATION) #blog, length
        self.calfboxTrack.add_clip(0, 0, MAXIMUM_TICK_DURATION, pattern) #pos, offset, length, pattern.
        self.cachedDuration = MAXIMUM_TICK_DURATION
        self._updatePlayback()

class _Subtrack(object):
    """Generates its own midi data and caches the resulting track but does not have a name
    nor its own jack midi port. Instead it is attached to an SequencerInterface.

    It is SequencerInterface because that has a jack midi port, and not Interface itself.

    Only used by SequencerInterface internally. Creation is done by its methods.
    This is not a child class because a top level class' code is easier to read.

    Intended usecase is to add CC messages as one subtrack per CC number (e.g. CC7 = Volume).

    Of course you could just put CCs together with notes in the main Interface
    and not use SubTracks. But where is the fun in that?"""

    def __init__(self, parentSequencerInterface):
        self._cachedPatterns = [] #makes undo after delete possible
        self.parentSequencerInterface = parentSequencerInterface
        self.calfboxSubTrack = cbox.Document.get_song().add_track()
        self.calfboxSubTrack.set_external_output(parentSequencerInterface.cboxMidiOutUuid)

    def prepareForDeletion(self):
        self.calfboxSubTrack.delete() #in place self deletion.
        self.calfboxSubTrack = None
        cbox.Document.get_song().update_playback()

    def recreateThroughUndo(self):
        assert self.calfboxSubTrack is None, self.calfboxSubTrack
        self.calfboxSubTrack = cbox.Document.get_song().add_track()
        for pattern, position, length in self._cachedPatterns:
            self.calfboxSubTrack.add_clip(position, 0, length, pattern) #pos, offset, length, pattern.
        cbox.Document.get_song().update_playback()

    def setSubtrack(self, blobs:Iterable): #(bytes-blob, position, length)
        """Does not add to the parents cached duration. Therefore it will not send data beyond
        its parent track length, except if another track pushes the overall duration beyond."""
        self.calfboxSubTrack.clear_clips()
        self._cachedPatterns = [] #makes undo after delete possible
        pos = 0
        for blob, pos, leng in blobs:
            if leng > 0:
                pat = cbox.Document.get_song().pattern_from_blob(blob, leng)
                t = (pat, pos, leng)
                self._cachedPatterns.append(t)

        length = 0
        for pattern, position, length in self._cachedPatterns:
            if length > 0:
                self.calfboxSubTrack.add_clip(position, 0, length, pattern) #pos, offset, length, pattern.

        cbox.Document.get_song().update_playback()


class SequencerInterface(_Interface): #Basically the midi part of a track.
    """A tracks name is the same as the jack midi-out ports name.

    The main purpose of the child class is to manage its musical data and regulary
    fill self.calfboxTrack with musical data:

    Create one ore more patterns, distribute them into clips, add clips to the cboxtrack.

    buffer = bytes()
    buffer += cbox.Pattern.serialize_event(startTick, 0x90, pitch, velocity) # note on
    buffer += cbox.Pattern.serialize_event(endTick-1, 0x80, pitch, velocity) # note off  #-1 ticks to create a small logical gap. Does not affect next note on.
    pattern = cbox.Document.get_song().pattern_from_blob(buffer, oneMeasureInTicks)
    self.calfboxTrack.add_clip(index*oneMeasureInTicks, 0, oneMeasureInTicks, pattern) #pos, pattern-internal offset, length, pattern.

    Use caches to optimize performance. This is mandatory!
        self.cachedDuration = the maximum track length. Used to determine the song playback duration.

    """

    def _processAfterInit(self):
        #Create midi out and cbox track
        logger.info(f"Creating empty SequencerInterface instance for {self._name}")
        super()._processAfterInit()
        self.cboxMidiOutUuid = cbox.JackIO.create_midi_output(self._name)
        self.calfboxTrack.set_external_output(self.cboxMidiOutUuid)
        cbox.JackIO.rename_midi_output(self.cboxMidiOutUuid, self._name)

        self._subtracks = {} #arbitrary key: _Subtrack(). This is not in Interface itself because Subtracks assume a jack midi out.
        self.enable(self._enabled)


    def enable(self, enabled):
        """This is "mute", more or less. It only disables the note parts, not CCs or other subtracks.
        This means if you switch this on again during playback you will have the correct context."""
        if enabled:
            #self.calfboxTrack.set_external_output(self.cboxMidiOutUuid) #Old version. Does not prevent hanging notes.
            self.calfboxTrack.set_mute(0)
        else:
            #self.calfboxTrack.set_external_output("") #Old version. Does not prevent hanging notes.
            self.calfboxTrack.set_mute(1)

        self._enabled = bool(enabled)
        cbox.Document.get_song().update_playback()

    @_Interface.name.setter # type: ignore
    def name(self, value):
        if not value in (track.sequencerInterface.name for track in self.parentData.tracks):
            self._name = self._isNameAvailable(value)
            if self.cboxMidiOutUuid: #we could be deactivated
                cbox.JackIO.rename_midi_output(self.cboxMidiOutUuid, self._name)

    def cboxPortName(self)->str:
        """Return the complete jack portname:  OurName:PortName"""
        portname = cbox.JackIO.status().client_name + ":" + self.name
        return portname

    def prepareForDeletion(self):
        """Called by score right before this track gets deleted.

        This does not mean the track is gone. It can be recovered by
        undo. That is why we bother setting calfboxTrack to None
        again.
        """
        if not self.calfboxTrack: #maybe non-template part deactivated it, like Patroneo groups
            return

        try:
            portlist = cbox.JackIO.get_connected_ports(self.cboxPortName())
        except: #port not found.
            portlist = []

        self._beforeDeleteThisJackMidiWasConnectedTo = portlist

        self.calfboxTrack.set_external_output("")
        cbox.JackIO.delete_midi_output(self.cboxMidiOutUuid)
        self.calfboxTrack.delete() #in place self deletion.
        self.calfboxTrack = None
        self.cboxMidiOutUuid = None
        #we leave cachedDuration untouched
        self._updatePlayback()

    def recreateThroughUndo(self):
        """Brings this track back from the dead, in-place.
        Assumes this track instance was not in the score but
        somewhere in memory. self.prepareForDeletion() was called
        in the past which deleted the midi output but not the cbox-midi
         data it generated and held"""
        #Recreate Calfbox Midi Data
        assert self.calfboxTrack is None, self.calfboxTrack
        self.calfboxTrack = cbox.Document.get_song().add_track()
        self.calfboxTrack.set_name(self.name) #only cosmetic and cbox internal. Useful for debugging, not used in jack.
        for pattern, position, length in self._cachedPatterns:
            self.calfboxTrack.add_clip(position, 0, length, pattern) #pos, offset, length, pattern.
        #self.cachedDuration is still valid

        #Create MIDI and reconnect Jack
        self.cboxMidiOutUuid = cbox.JackIO.create_midi_output(self.name)
        cbox.JackIO.rename_midi_output(self.cboxMidiOutUuid, self._name)
        self.calfboxTrack.set_external_output(self.cboxMidiOutUuid)
        for port in self._beforeDeleteThisJackMidiWasConnectedTo:
            try:
                cbox.JackIO.port_connect(self.cboxPortName(), port)
            except: #external connected synth is maybe gone. Prevent crash.
                logger.warning(f"Previously external connection {port} is gone. Can't connect anymore." )

        #Make it official
        self._updatePlayback()

    def setSubtrack(self, key, blobs:Iterable): #(bytes-blob, position, length)
        """Creates a new subtrack if key is unknown
        Forward  data to the real function

        Simplest version is to send one blob at position 0 with its length"""
        if not key in self._subtracks:
            self._subtracks[key] = _Subtrack(parentSequencerInterface=self)

        assert self._subtracks[key], key
        assert isinstance(self._subtracks[key], _Subtrack), type(self._subtracks[key])

        self._subtracks[key].setSubtrack(blobs)

    def deleteSubtrack(self, key):
        """Remove a subtrack.
        Return for a potential undo"""
        self._subtracks[key].prepareForDeletion()
        toDelete = self._subtracks[key]
        del self._subtracks[key]
        return toDelete


    #Save / Load / Export
    def serialize(self)->dict:
        """Generate Data to save as json"""
        return {
            "name" : self.name,
            "enabled" : self._enabled,
        }

    @classmethod
    def instanceFromSerializedData(cls, parentTrack, serializedData):
        self = cls.__new__(cls)
        self._name = serializedData["name"]
        self._enabled = serializedData["enabled"]

        self.parentTrack = parentTrack
        self.parentData = parentTrack.parentData
        self._processAfterInit()
        return self

    def export(self)->dict:
        return {
            "id" : id(self),
            "name" : self.name,
            "index" : self.parentData.tracks.index(self.parentTrack) if self.parentTrack in self.parentData.tracks else None ,  #could be a special track, like the metronome
            "cboxPortName" : self.cboxPortName(),
            "cboxMidiOutUuid" : self.cboxMidiOutUuid,
            "enabled" : self._enabled,
        }


class SfzInstrumentSequencerInterface(_Interface):
    """Like a midi output, only routes to an internal instrument.

    This is not a pure sfz sampler, but rather a track that ends in an instrument instead of a
    jack midi output."""

    def __init__(self, parentTrack, name:str, absoluteSfzPath:str):

        super().__init__(parentTrack, name) #includes processAfterInit
        self.scene = cbox.Document.get_engine().new_scene()
        self.scene.clear()
        self.scene.add_new_instrument_layer(name, "sampler") #"sampler" is the cbox sfz engine
        self.scene.status().layers[0].get_instrument().engine.load_patch_from_string(0, "", "", "") #fill with null instruments
        self.scene.set_enable_default_song_input(True)
        self.instrumentLayer = self.scene.status().layers[0].get_instrument()

        self.scene.status().layers[0].set_ignore_program_changes(1) #TODO: ignore different channels. We only want one channel per scene/instrument/port.

        newProgramNumber = 1
        program = self.instrumentLayer.engine.load_patch_from_file(newProgramNumber, absoluteSfzPath, name)
        self.instrumentLayer.engine.set_patch(10, newProgramNumber) #from 1. 10 is the channel #TODO: we want this to be on all channels.

        #TODO: Metronome is not compatible with current cbox. we need to route midi data from our cbox track explicitely to self.scene, which is not possible right now.
        self.calfboxTrack.set_external_output("")

        #Metadata
        l = f"{cbox.JackIO.status().client_name}:out_1"
        r = f"{cbox.JackIO.status().client_name}:out_2"
        self.portnameL = cbox.JackIO.status().client_name + ":" + name.title() + "-L"
        self.portnameR = cbox.JackIO.status().client_name + ":" + name.title() + "-R"

        luuid = cbox.JackIO.create_audio_output(name.title() + "-L")
        ruuid = cbox.JackIO.create_audio_output(name.title() + "-R")
        cbox.JackIO.Metadata.set_pretty_name(self.portnameL, name.title() + "-L")
        cbox.JackIO.Metadata.set_pretty_name(self.portnameR, name.title() + "-R")


        self.outputMergerRouter = cbox.JackIO.create_audio_output_router(luuid, ruuid)
        self.outputMergerRouter.set_gain(-1.0)
        self.instrumentLayer.get_output_slot(0).rec_wet.attach(self.outputMergerRouter) #output_slot is 0 based and means a pair.


    def enable(self, enabled):
        if enabled:
            self.scene.status().layers[0].set_enable(True)
        else:
            self.scene.status().layers[0].set_enable(False)
        self._enabled = bool(enabled) #this is redundant in the SfzInstrument, but the normal midi outs need this. So we stick to the convention.
        cbox.Document.get_song().update_playback()

    @property
    def enabled(self)->bool:
        return self._enabled

class TempoMap(object):
    """
    This is a singleton instance in Score. Don't subclass.

    Main data structure is self._tempoMap = {positionInTicks:(bpmAsFloat, timesigUpper, timesigLower)}

    The tempo map is only active if the whole program is JACK Transport Master (via Cbox).
    If not we simply follow jack sync.

    All values are floats.

    TempoMap itself handles this global switch if you set isTransportMaster=True (it is a property)

    For simplicity reasons the tempo map only deals with quarter notes per minute internally.
    There are functions to convert to and from a number of other tempo formats.

    There are three recommended ways to change the tempo map:

    1) setTempoMap completely replaces the tempo map with a new supplied one

    2) If you want just one tempo use the convenience function setQuarterNotesPerMinute.
    This will override and delete(!) the current tempo map.
    You can retrieve it with getQuarterNotePerMinute.

    3) set isTransportMaster will trigger a rebuild of the tempo map as a side effect. It does not
    change the existing tempo map. Flipping the transport master back will reenable the old tempo Map

    If you want to incrementally change the tempo map, which is really not necessary because
    changing it completely is a very cheap operation, you can edit the dict _tempoMap directly.

    In case you have a complex tempo management yourself, like Laborejo, use it to setTempoMap and
    then don't worry about save and load. Treat it as a cache that conveniently restores the last
    setting after program startup. """



    def __init__(self, parentData):
        logger.info("Creating empty TempoMap instance")
        self.parentData = parentData
        self._tempoMap = {0:(120.0, 4, 4)} # 4/4, 120bpm. will not be used on startup, but is needed if transportMaster is switched on
        self._isTransportMaster = False
        self._processAfterInit()
        assert not cbox.Document.get_song().status().mtis

    def _processAfterInit(self):
        self.factor = 1.0 # not saved
        self.isTransportMaster = self._isTransportMaster #already triggers cbox settings through @setter.
        self._sanitize()

    def _updatePlayback(self):
        """A wrapper that not only calls update playback but forces JACK to call its BBT callback,
        so it gets the new tempo info even without transport running.

        That is a bit of a hack, but it works without disturbing anything too much."""
        cbox.Document.get_song().update_playback()
        pos = cbox.Transport.status().pos #can be None on program start
        if self.isTransportMaster and not cbox.Transport.status().playing: #pos can be 0
            if pos is None:
                #Yes, we destroy the current playback position. But we ARE timebase master, so that is fine.
                cbox.Transport.seek_samples(0)
            else: #default case
                cbox.Transport.seek_samples(pos)


    @property
    def isTransportMaster(self) -> bool:
        return self._isTransportMaster

    @isTransportMaster.setter
    def isTransportMaster(self, value:bool):
        logger.info(f"Jack Transport Master status: {value}")
        self._isTransportMaster = value
        if value:
            self._sendToCbox() #reactivate existing tempo map
            cbox.JackIO.external_tempo(False)
            cbox.JackIO.transport_mode(master = True, conditional = False) #conditional = only attempt to become a master (will fail if there is one already)
        else:
            self._clearCboxTempoMap() #clear cbox map but don't touch our own data.
            cbox.JackIO.external_tempo(True)
            try:
                cbox.JackIO.transport_mode(master = False)
            except Exception: #"Not a current timebase master"
                pass


        self._updatePlayback()

    def _sanitize(self):
        """Inplace modification of self.tempoMap. Remove zeros and convert to float values. """
        self._tempoMap = {int(key):(float(value), timesigNum, timesigDenom) for key, (value, timesigNum, timesigDenom) in self._tempoMap.items() if value > 0.0}
        #Don't use the following. Empty tempo maps are allowed, especially in jack transport slave mode. #Instead set a default tempo 120 on init explicitly
        #if not self._tempoMap:
            #logger.warning("Found invalid tempo map. Forcing to 120 bpm. Please correct manually")
            #self._tempoMap = {0, 120.0}

    def _clearCboxTempoMap(self):
        """Remove all cbox tempo values by iterating over all of them and set them to None, which is
        the secret cbox handshake to delete a tempo change on a specific position.

        Keep our own local data intact."""
        song = cbox.Document.get_song()
        for mti in song.status().mtis: #Creates a new temporary list with newly created objects, safe to iterate and delete.
            song.delete_mti(mti.pos)
        self._updatePlayback()
        assert not song.status().mtis, song.status().mtis

    def _sendToCbox(self):
        """Send to cbox"""
        assert self.isTransportMaster
        assert self._tempoMap
        song = cbox.Document.get_song()
        for pos, (value, timesigNum, timesigDenom)  in self._tempoMap.items():
            song.set_mti(pos=pos, tempo=value*self.factor, timesig_denom=timesigDenom , timesig_num=timesigNum) #Tempo changes are fine to happen on the same tick as note on.
            #song.set_mti(pos=pos, tempo=value * self.factor) #Tempo changes are fine to happen on the same tick as note on.
        self._updatePlayback()

    def setTempoMap(self, tempoMap:dict):
        """All-in-one function for outside access"""
        if self._tempoMap != tempoMap:
            self._tempoMap = tempoMap
            self._sanitize()
            if self.isTransportMaster: #if not the data will be used later.
                self._clearCboxTempoMap() #keeps our own data so it can be send again.
                self._sendToCbox()

    def setFactor(self, factor:float):
        """Factor is from 1, not from the current one."""
        self.factor = round(factor, 4)
        self._sanitize()
        self._clearCboxTempoMap() #keeps our own data so it can be send again.
        self._sendToCbox() #uses the factor

    def setQuarterNotesPerMinute(self, quarterNotesPerMinute:float):
        """Simple tempo setter. Overrides all other tempo data.
        Works in tandem with self.setTimeSignature"""
        currentValue, timesigNum, timesigDenom = self._tempoMap[0]
        self.setTempoMap({0:(quarterNotesPerMinute, timesigNum, timesigDenom)})

    def setTimeSignature(self, timesigNum:int, timesigDenom:int):
        """Simple traditional timesig setter. Overrides all other timesig data.
        Works in tandem with self.setTimeSignature.
        """
        assert timesigNum > 0, timesigNum
        #assert timesigDenom in traditionalNumberToBaseDuration, (timesigDenom, traditionalNumberToBaseDuration) For Laborejo this makes sense, but Patroneo has a fallback option with irregular timesigs: 8 steps in groups of 3 to make a quarter is valid. Results in "8/12"
        currentValue, OLD_timesigNum, OLD_timesigDenom = self._tempoMap[0]
        self.setTempoMap({0:(currentValue, timesigNum, timesigDenom)})

    def getQuarterNotesPerMinute(self)->Union[float, None]:
        """This assumes there is only one tempo point"""
        if self.isTransportMaster:
            assert len(self._tempoMap) == 1, len(self._tempoMap)
            assert 0 in self._tempoMap, self._tempoMap
            return self._tempoMap[0][0] #second [0] is the tuple (tempo, timesig, timesig)
        else:
            logger.info("Requested Quarter Notes per Minute, but we are not transport master")
            return None

    #Save / Load / Export

    def serialize(self)->dict:
        """Generate Data to save as json"""
        return {
            "isTransportMaster" : self.isTransportMaster,
            "tempoMap" : self._tempoMap,
        }

    @classmethod
    def instanceFromSerializedData(cls, parentData, serializedData):
        logger.info("Loading TempoMap from saved file")
        self = cls.__new__(cls)
        self.parentData = parentData
        self._tempoMap = serializedData["tempoMap"]  #json saves dict-keys as strings. We revert back in sanitize()
        self._isTransportMaster = serializedData["isTransportMaster"]
        self._processAfterInit()
        return self

    def export(self)->dict:
        return {
            "id" : id(self),
            "isTransportMaster" : self.isTransportMaster,
            "tempoMap" : self._tempoMap,
            "mtis" : cbox.Document.get_song().status().mtis,
        }