/*
   tonewheel organ plugin

   Copyright 2025 Gordon JC Pearce <gordonjcp@gjcp.net>

   Permission to use, copy, modify, and/or distribute this software for any
   purpose with or without fee is hereby granted, provided that the above
   copyright notice and this permission notice appear in all copies.

   THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
   MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
   SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
   WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
   OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
   CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/

#include "assigner.hpp"

#define DEBUG

void Assigner::dumpTables() {
#ifdef DEBUG
    printf("table state is:\n");
    for (uint8_t i = 0; i < NUM_VOICES; i++) {
        uint8_t e = voiceTbl[i];
        uint8_t a = noteTbl[e];
        printf("%2d=%3d%c ", e, a & 0x7f, (a & 0x80) ? '^' : 'v');
    }
    printf("\n");
#endif
}

Assigner::Assigner() {
    d_debug("assigner constructor");

    // set up the assigner tables
    for (uint8_t i = 0; i < NUM_VOICES; i++) {
        voiceTbl[i] = i;
        noteTbl[i] = 0x80;
    }
}

void Assigner::handleMidi(MidiEvent *ev) {
    uint8_t status = ev->data[0];
    switch (status & 0xf0) {
        case 0x80:
            noteOff(ev->data[1]);
            dumpTables();
            break;
        case 0x90:
            // dumpTables();
            noteOn(ev->data[1]);
            dumpTables();
            break;
        case 0xb0:
            switch (ev->data[1]) {
                // maybe handle the following
                // CC   1 - modwheel
                // CC  64 - sustain
                default:
                    break;
            }
            break;  // nothing to do here except in special cases where we don't expect the host to pass on controls
        case 0xc0:  // program change
            break;
        case 0xe0:  // pitch bend;
            break;
        case 0xf0:  // sysex
            break;

        default:
            d_debug("unhandled MIDI event, status %02x value %02x\n", ev->data[0], ev->data[1]);
            break;
    }
}
void Assigner::noteOff(uint8_t note) {
    d_debug("note off %3d", note);

    uint8_t i, v;
    // scan for note in table
    for (i = 0; i < NUM_VOICES; i++) {
        if ((noteTbl[voiceTbl[i]] & 0x7f) == note) break;
    }
    if (i == NUM_VOICES) return;  // got note off for note that isn't in the table

    // get the voice at this slot
    // then move the rest down and place this at the end
    // and mark the note for this voice as "off" by setting bit 7
    v = voiceTbl[i];
    memmove(voiceTbl + i, voiceTbl + i + 1, NUM_VOICES - i - 1);
    voiceTbl[NUM_VOICES - 1] = v;
    noteTbl[v] |= 0x80;
}

void Assigner::noteOn(uint8_t note) {
    d_debug("note on %3d", note);

    int8_t i, a, v;

    // don't even attempt to steal voices
    // by overwriting the last voice in the table
    // we could actually do voice stealing
    if ((noteTbl[voiceTbl[NUM_VOICES - 1]] & 0x80) == 0x00) {
        d_debug("note table full");
        return;
    }

    // loop around the voices
    for (i = NUM_VOICES - 1; i >= 0; i--) {
        v = voiceTbl[i];
        a = noteTbl[v];

        // if this note is playing we've gone too far
        // we need to back up a slot and consider it for use
        if ((a & 0x80) == 0) {
            i++;

            // shunt them all up to the end
            v = voiceTbl[i];
            memmove(voiceTbl + 1, voiceTbl, i);
            voiceTbl[0] = v;
            break;  // note is already playing in table
        }

        if ((a & 0x7f) == note) {
            memmove(voiceTbl + 1, voiceTbl, i);
            voiceTbl[0] = v;
            a &= 0x7f;
            break;
        }
    }
    noteTbl[v] = note;

    // limit lowest note to C2 and highest note to C7
    while(note>96) note -= 12;
    while(note<36) note += 12;

    d_debug("send voice on note %3d to voice %d", note, v);
}