_lastSet = {}  #midictlchannel:value7bit

currentFaders = {}  # midi control channel num : FaderUri

ctx = URIRef(showUri() + '/fade')

def compileCurrents(graph):

    currentFaders.clear()

    try:

        new = getChansToFaders(graph)

    except ValueError:

        return  # e.g. empty-graph startup

    currentFaders.update(new)

    mapping = g.value(L9['midiControl'], L9['map'])

    if mapping is None:

        raise ValueError('no :midiControl :map ?mapping')

    midiDev = g.value(mapping, L9['midiDev'])

    ourDev = 'bcf2000'

    if midiDev != Literal(ourDev):

def getCurMappedPage(g: SyncedGraph):

    mapping = getGraphMappingNode(g)

    return g.value(mapping, L9['outputs'])

    g.patchObject(ctx, mapping, L9.outputs, newPage)

def getChansToFaders(g: SyncedGraph) -> Dict[int, URIRef]:

    fadePage = getCurMappedPage(g)

    ret = []

    for f in g.objects(fadePage, L9.fader):

        columnLit = cast(Literal, g.value(f, L9['column']))

        col = int(columnLit.toPython())

        allPages = sorted(current.subjects(RDF.type, L9.FadePage), key=lambda fp: str(fp))

        mapping = getGraphMappingNode(current)

        curPage = current.value(mapping, L9.outputs)

    if curPage is None:

        curPage = allPages[0]

    idx = allPages.index(curPage)

    print('change from ', idx, newIdx)

    setCurMappedPage(g, mapping, newPage)

def writeHwValueToGraph(graph: SyncedGraph, ctx, fader: URIRef, strength: float):

    log.info(f'setFader(fader={fader}, strength={strength:.03f}')

    valueLit = decimalLiteral(round(strength, 3))

    with graph.currentState() as g:

        fadeSet = g.value(fader, L9['setting'])

    if fadeSet is None:

        nupdated = 0

        m = getChansToFaders(g)

        for midi_ctl_addr, f in m.items():

            fset = g.value(f, L9.setting)

            # could split this to a separate handler per fader

            value = g.value(fset, L9.value).toPython()

            hwgoal = int(value * 127)

            print(f'{f} {hwcurrent=} {hwgoal=}')

            if abs(hwcurrent - hwgoal) > 2:

                self.sendToBcf(midi_ctl_addr, hwgoal)

                nupdated += 1

        log.info(f'wrote to {nupdated} of {len(m)} mapped faders')