#include "cpuboard.hpp"

#include <cstdio>

void Assigner::resetVoices() {
    // 0b81
    for (uint16_t i = 0x80; i < 0x85; i++) {
        ram[i + 8] = 0x80;  // 0b81 loop
        ram[i] = i + 0x88;  // 0b8b loop
    }
    ram[0x86] = 0x88;  // 0b96
}

void Assigner::clearNotes() {
    // 0b9e
    // loop over ff30 to ff3d zeroing out the "played notes" bits
    for (uint16_t hl = 0x30; hl < 0x3d; hl++) {
        ram[hl] = 0;
    }
}

void Assigner::voiceOn() {
    // 01e0 which we fall through to after scanning the key matrix

    b = 0x0d;       // bytes in scan table
    hl = 0x3d;      // ff3d, top of "enabled" notes
    de = 0x57;      // the key matrix is stored here
    ram[0xd0] = 0;  // unsure

h01eb:
    a = ram[hl + 0x10];  // read MIDI bitmap
    // 01ed
    // LTI B, $03; LTI B, $0B
    // I believe this selects only the key bitmap addresses from DE
    // 1f3 jr 01f7
    // 1f4 orax (DE) ; or in the bitmap at (DE) (keys pressed)

    // 1f7
    c = a;
    a ^= ram[hl];  // XRAX (HL), compare with already pressed

    if (a == 0) {
        // 01fa SK Z
    } else {
        // 01fc CALF $0A18;
        printf("new note change detected\n");
    }

    a = c;        // restore A
    ram[hl] = a;  // store bitfield at $ff30

    hl--;
    if (b > 0) {
        b--;
        goto h01eb;
    }

    // 0203
    if (ram[0xd0] != 0xff) {
        // skip
    } else {
        // 0206 CALF $0b9e
        clearNotes();
    }
}

void Assigner::noteOn() {
    // called from serial interrupt handler
    // sets or clears a bit in the "MIDI Key pressed" bitfield

    // note that RAM addresses normally set to 0xff40 are reduced to 0x0040

    // 06ca
    a = ram[0x3e];  // first byte is note value
    c = 0x40;       // fake velocity

    // bring note into range
    // 06cc
    if (a <= 0x17) a += 12;
    // 06d0
    if (a >= 0x6d) a -= 12;

    // 06d4 subtract transpose from ffbe

    // 06d7 mov b,a; slr b; slr b; slr b
    b = a >> 3;
    a &= 0x07;

    // 06e0 note on?
    if (ram[0x4e] != 0x90) goto h06f9;  // no, skip to note off
    // 06e4 velocity zero?
    if (c == 0) goto h06f9;  // yes, skip to note off

    // otherwise handle note on
    // 06e8 lxi hl,$0008; ldax (a+hl) for table of bits
    a = 1 << a;
    c = a;
    hl = 0x0040;      // note bit flags
    a = ram[hl + b];  // byte pointed to by upper part
    a |= c;           // or in the bit value
    ram[hl + b] = a;  // save it in RAM

    // 06f4 mviw $003f, $01 expect two bytes; jre $064c return from interrupt
    return;

h06f9:  // note off

    a = 0xff ^ (1 << a);
    c = a;
    hl = 0x0040;      // note bit flags
    a = ram[hl + b];  // byte pointed to by upper part
    a &= c;           // mask off the bit
    ram[hl + b] = a;  // save it in RAM

    return;
}