c64.music.h

/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * This program 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/>.
 *
 */

#include "audio/audiostream.h"
#include "audio/mixer.h"
#include "audio/softsynth/sid.h"
#include "common/debug.h"

namespace Freescape {

class DrillerSIDPlayer : public Audio::AudioStream {

    // --- Voice State Structure ---
    struct VoiceState {
        // Pointers & Indices
        const uint8_t *trackDataPtr;   // Pointer to current track data array
        uint8_t trackIndex;            // Index within trackDataPtr
        const uint8_t *patternDataPtr; // Pointer to current pattern data array
        uint8_t patternIndex;          // Index within patternDataPtr
        uint8_t instrumentIndex;       // Current instrument (0-21, scaled by 8 for lookup)

        // Playback Control & Tempo
        int8_t delayCounter;  // Counts down frames for note duration (maps to voiceX_ctrl2)
        uint8_t noteDuration; // Duration set by FD xx (maps to voiceX_something+2)
        uint8_t gateMask;     // Control gating/retriggering (maps to control3 behavior)

        // Note & Frequency
        uint8_t currentNote;     // Current raw note value (0-95)
        uint8_t portaTargetNote; // Target note for portamento
        uint16_t currentFreq;    // Current frequency being sent to SID
        uint16_t baseFreq;       // Note frequency without effects
        uint16_t targetFreq;     // Used for portamento target

        // Pulse Width
        uint16_t pulseWidth; // Current pulse width
        // Placeholder for PWM effects if needed later

        // ADSR
        uint8_t attackDecay;    // SID Attack / Decay register value
        uint8_t sustainRelease; // SID Sustain / Release register value

        // Effects State
        uint8_t effect;                  // Current active effect (0:None, 1:Arpeggio, 2:Vibrato, 3:Portamento Up, 4:Portamento Down, 5: PWM LFO?)
        uint8_t arpeggioIndex;           // Index in arpeggio table
        uint8_t arpeggioSpeed;           // Counter divisor for arpeggio step
        uint8_t arpeggioCounter;         // Counter for arpeggio step
        uint8_t arpeggioNoteOffsetIndex; // 0, 1, 2 for arpeggio notes

        int16_t vibratoDepth;         // Depth for vibrato effect
        uint8_t vibratoSpeed;         // Speed/delay for vibrato effect
        uint8_t vibratoDelay;         // Counter for vibrato step
        uint8_t vibratoDirection;     // 0: up, 1: down
        int16_t vibratoCurrentOffset; // Current frequency offset for vibrato

        int16_t portaSpeed; // Speed for portamento effect (positive for up, negative for down)

        // Hard Restart / Buzz Effect (from L1005, possibly instrument related)
        uint8_t hardRestartValue;   // Value from instrument table (a1+5)
        uint8_t hardRestartDelay;   // Counter for delay phase (voiceX_whatever+3)
        uint8_t hardRestartCounter; // Counter for frequency change phase (voiceX_whatever+4)
        bool hardRestartActive;     // Is the effect currently running?

        // From disassembly variables (mapping might need refinement)
        // voice1_whatever: 0CCE[5] - effect state? (arp, vib, porta)
        uint8_t whatever0; // 0CCE - Vibrato state? (0=off, 1=active, 3-4=sweep?)
        uint8_t whatever1; // 0CCF - Arpeggio state? (0=off, 1=active)
        uint8_t whatever2; // 0CD0 - Portamento type (0=off, 1=down(FB), 2=up(FC), 3=down H(FB), 4=up H(FC))?
        uint8_t whatever3; // 0CD1 - Hard restart delay counter
        uint8_t whatever4; // 0CD2 - Hard restart step counter

        // voice1_whatever2: 0CD4 - Vibrato direction toggle?
        uint8_t whatever2_vibDirToggle;

        // voice1_something: 0CE3[3] - Porta speed?, Note duration
        uint16_t portaStepRaw; // 0CE3/4 - Raw value from FB/FC command
        // uint8_t noteDuration // 0CE5 - Covered above

        // voice1_something_else: 0CE7[3] - PW Low, PW High? (ADSR in disassembly?) - Needs clarification
        uint8_t something_else[3]; // Re-add this array as it's used in the code logic

        // voice1_ctrl0: 0CF8 - ADSR lower nibble (Sustain/Release)
        uint8_t ctrl0; // Re-add this as it's used in the code logic

        // voice1_ctrl1: 0CF9 - Arpeggio table index / Arp speed upper nibble
        uint8_t arpTableIndex;
        uint8_t arpSpeedHiNibble;

        // voice1_ctrl2: 0CFE - Note delay counter (covered by delayCounter)

        // voice1_stuff: 0D14[7] - Current freq, base freq, hard restart freq store? Arp counter?
        uint16_t stuff_freq_porta_vib;    // 0D14/15 - Current frequency including porta/vib
        uint16_t stuff_freq_base;         // 0D16/17 - Base frequency of the note
        uint16_t stuff_freq_hard_restart; // 0D18/19 - Frequency stored during hard restart buzz
        uint8_t stuff_arp_counter;        // 0D1A - Arpeggio counter (0..speed-1)
        uint8_t stuff_arp_note_index;     // 0D1B - Index into arp notes (0, 1, 2)

        // voice1_things: 0D29[7] - Vibrato state/params
        uint8_t things_vib_state;        // 0D29 - Vibrato state (0=down1, 1=up, 2=down2, 3=sweepdown1, 4=sweepup)
        uint16_t things_vib_depth;       // 0D2A/2B - Vibrato depth
        uint8_t things_vib_delay_reload; // 0D2C - Vibrato delay reload value
        uint8_t things_vib_delay_ctr;    // 0D2D - Vibrato delay counter
        // 0D2E/F unused?
        uint8_t currentNoteSlideTarget; // 0D30 - Last played note (used for slide target?)

        // voice1_two_ctr: 0D3E - Glide down timer? (Instrument related)
        uint8_t glideDownTimer;

        // Temp values during processing
        uint8_t waveform; // Current waveform for SID
        bool keyOn;       // Current key state (attack vs release)
        bool sync;        // Sync bit state
        bool ringMod;     // Ring mod bit state

        // Pulse width parts matching something_else (if it maps to PW)
        uint8_t pwLo() const { return something_else[0]; } // Example mapping
        uint8_t pwHi() const { return something_else[2]; } // Example mapping
        void setPwLo(uint8_t val) { something_else[0] = val; }
        void setPwHi(uint8_t val) { something_else[2] = val; }

        void reset() {
            trackDataPtr = nullptr;
            trackIndex = 0;
            patternDataPtr = nullptr;
            patternIndex = 0;
            instrumentIndex = 0;
            delayCounter = 0;
            noteDuration = 0;
            gateMask = 0xFF;
            currentNote = 0;
            portaTargetNote = 0;
            currentFreq = 0;
            baseFreq = 0;
            targetFreq = 0;
            pulseWidth = 0;
            attackDecay = 0;
            sustainRelease = 0;
            effect = 0;
            arpeggioIndex = 0;
            arpeggioSpeed = 0;
            arpeggioCounter = 0;
            arpeggioNoteOffsetIndex = 0;
            vibratoDepth = 0;
            vibratoSpeed = 0;
            vibratoDelay = 0;
            vibratoDirection = 0;
            vibratoCurrentOffset = 0;
            portaSpeed = 0;
            hardRestartValue = 0;
            hardRestartDelay = 0;
            hardRestartCounter = 0;
            hardRestartActive = false;
            waveform = 0x10; // Default to triangle?
            keyOn = false;
            sync = false;
            ringMod = false;

            // Reset mapped vars
            whatever0 = 0;
            whatever1 = 0;
            whatever2 = 0;
            whatever3 = 0;
            whatever4 = 0;
            whatever2_vibDirToggle = 0;
            portaStepRaw = 0;
            memset(something_else, 0, sizeof(something_else)); // Reset the array
            ctrl0 = 0;                                         // Reset the added member
            arpTableIndex = 0;
            arpSpeedHiNibble = 0;
            stuff_freq_porta_vib = 0;
            stuff_freq_base = 0;
            stuff_freq_hard_restart = 0;
            stuff_arp_counter = 0;
            stuff_arp_note_index = 0;
            things_vib_state = 0;
            things_vib_depth = 0;
            things_vib_delay_reload = 0;
            things_vib_delay_ctr = 0;
            currentNoteSlideTarget = 0;
            glideDownTimer = 0;
        }
    };

    // --- Member Variables ---
    Resid::SID *_sid;
    Audio::Mixer *_mixer;
    Audio::SoundHandle _soundHandle; // Changed from pointer
    int _sampleRate;
    float _cyclesPerSample;
    double _cycleCounter;

    // Player State
    enum PlayState { STOPPED,
                     PLAYING,
                     CHANGING_TUNE };
    PlayState _playState;
    uint8_t _targetTuneIndex; // Tune index requested via startMusic

    // Global Timing
    uint8_t _globalTempo;        // Tempo value for current tune (0xD10)
    uint8_t _globalTempoCounter; // Frame counter for tempo (0xD12)

    // Voice States
    VoiceState _voiceState[3];

    // Internal helpers
    uint8_t _tempControl3; // Temporary storage for gate mask (0xD13)
    // uint8_t _tempControl1; // Temp storage from instrument data (0xD11)

public:
    DrillerSIDPlayer(Audio::Mixer *mixer);
    ~DrillerSIDPlayer();
    void startMusic(int tuneIndex = 1);
    void stopMusic();

    int readBuffer(int16 *buffer, const int numSamples) override;

    bool isStereo() const override { return false; }
    bool endOfData() const override { return false; }
    int getRate() const override { return _sampleRate; }

private:
    void SID_Write(int reg, uint8_t data);
    void initSID();
    void playFrame();
    void handleChangeTune(int tuneIndex);
    void handleResetVoices();
    void playVoice(int voiceIndex, bool tempoTick);
    void applyNote(VoiceState &v, int sidOffset, const uint8_t *instA0, const uint8_t *instA1, int voiceIndex);
    void applyContinuousEffects(VoiceState &v, int sidOffset, const uint8_t *instA0, const uint8_t *instA1);
    void applyHardRestart(VoiceState &v, int sidOffset, const uint8_t *instA0, const uint8_t *instA1);
};

} // namespace Freescape