jack-looper/dispatcher.h

#ifndef DISPATCHER_H
#define DISPATCHER_H

#include <stdint.h>
#include <stdbool.h>
#include <stdatomic.h>
#include <jack/jack.h>
#include <pthread.h>
#include "carla.h"

// ============================================================
// Application State - contains ALL application state
// ============================================================

#define MAX_SCENES 8
#define MAX_CHANNELS 8
#define MAX_CLIPS 512  // 8 grids * 8 scenes * 8 channels
#define GRID_ROWS MAX_SCENES
#define GRID_COLS MAX_CHANNELS
#define MAX_BUFFER_SIZE 441000  // 10 seconds at 44.1kHz
#define MAX_UNDO_HISTORY 256

#define CLIP_INDEX(scene, channel) ((scene) * MAX_CHANNELS + (channel))

typedef enum {
    CLIP_EMPTY,
    CLIP_RECORDING,
    CLIP_LOOPING,
    CLIP_STOPPED
} ClipState;

typedef enum {
    QUANTIZE_OFF,
    QUANTIZE_BEAT,
    QUANTIZE_BAR
} QuantizeMode;

typedef enum {
    TRANSPORT_STOPPED,
    TRANSPORT_PLAYING,
    TRANSPORT_PAUSED
} TransportState;

typedef enum {
    CLOCK_SOURCE_INTERNAL,
    CLOCK_SOURCE_MIDI
} ClockSource;

typedef struct {
    uint8_t note;
    uint8_t velocity;
    uint32_t timestamp;  // sample offset within the clip
} MidiEvent;

#define MAX_MIDI_EVENTS 44100  // ~1 second of dense MIDI data

typedef struct {
    ClipState state;
    MidiEvent *events;  // Dynamically allocated
    int event_count;
    int max_events;     // Allocated size
    int read_index;
    char channel_name[64];  // per-channel name for MIDI grid
} MidiClip;

typedef struct {
    ClipState state;
    float *buffer;
    size_t buffer_size;
    size_t write_position;
    size_t read_position;
} Clip;

typedef struct {
    // Transport state
    TransportState transport_state;
    ClockSource clock_source;
    uint32_t clock_count;
    uint32_t beat_position;
    uint32_t bar_position;
    uint32_t sample_position;
    double bpm;
    double samples_per_beat;
    double sample_accumulator;
    
    // Quantization
    QuantizeMode quantize_mode;
    jack_nframes_t quantize_threshold;
    
    // Clips
    Clip clips[MAX_CLIPS];
    
    // MIDI clips (separate grid)
    MidiClip midi_clips[MAX_CLIPS];
    bool show_midi_grid;             // View toggle: true = MIDI grid, false = Audio grid
    char channel_names[MAX_CHANNELS][64];  // Channel names for audio grid
    
    // Undo history
    struct {
        int undo_index;
        int redo_index;
        int count;
        ClipState prev_clip_states[MAX_UNDO_HISTORY];
        int prev_clip_indices[MAX_UNDO_HISTORY];
        size_t prev_buffer_sizes[MAX_UNDO_HISTORY];
        size_t prev_write_positions[MAX_UNDO_HISTORY];
        size_t prev_read_positions[MAX_UNDO_HISTORY];
        int batch_sizes[MAX_UNDO_HISTORY];  // NEW: track batch sizes
        int current_batch_size;              // NEW: current batch being recorded
    } undo;
    
    // Ring buffers for real-time recording (written by JACK callback, read by dispatcher)
    // Lock-free: single producer (JACK callback), single consumer (dispatcher thread)
    float record_buffer[MAX_CHANNELS][MAX_BUFFER_SIZE];
    atomic_size_t record_write_pos[MAX_CHANNELS];  // Only written by JACK callback
    atomic_size_t record_read_pos[MAX_CHANNELS];   // Only written by dispatcher thread
    
    // Carla host
    CarlaHost carla_host;
    
    // JACK info (needed by audio thread)
    jack_nframes_t sample_rate;
    bool running;
} AppState;

// ============================================================
// Actions
// ============================================================

typedef enum {
    ACTION_TRIGGER_CLIP,
    ACTION_TRIGGER_SCENE,
    ACTION_RESET_CLIP,
    ACTION_SET_QUANTIZE_MODE,
    ACTION_SET_QUANTIZE_THRESHOLD,
    ACTION_TRANSPORT_PLAY,
    ACTION_TRANSPORT_PAUSE,
    ACTION_TRANSPORT_STOP,
    ACTION_TRANSPORT_TOGGLE_PLAY,
    ACTION_SET_CLOCK_SOURCE,
    ACTION_SET_BPM,
    ACTION_RESET_TRANSPORT,
    ACTION_UNDO,
    ACTION_REDO,
    ACTION_SAVE_CLIP,
    ACTION_LOAD_CLIP,
    ACTION_MIDI_NOTE_ON,
    ACTION_MIDI_SCENE_LAUNCH,
    ACTION_RACK_ADD_PLUGIN,
    ACTION_RACK_REMOVE_PLUGIN,
    ACTION_RACK_SET_PARAMETER,
    ACTION_RACK_SET_VOLUME,
    ACTION_RACK_BYPASS,
    ACTION_SAVE_PROJECT,
    ACTION_LOAD_PROJECT,
    ACTION_PROCESS_AUDIO,
    ACTION_QUIT,
    ACTION_SET_SHOW_MIDI_GRID,
    ACTION_MIDI_CLIP_TRIGGER,
    ACTION_MIDI_CLIP_RESET,
    ACTION_SET_CHANNEL_NAME
} ActionType;

typedef struct {
    ActionType type;
    union {
        struct { int clip_index; } trigger_clip;
        struct { int scene_index; } trigger_scene;
        struct { int clip_index; } reset_clip;
        struct { QuantizeMode mode; } set_quantize_mode;
        struct { jack_nframes_t threshold; } set_quantize_threshold;
        struct { ClockSource source; } set_clock_source;
        struct { double bpm; } set_bpm;
        struct { int clip_index; } save_clip;
        struct { int clip_index; char filename[256]; } load_clip;
        struct { int note; int velocity; int channel; jack_nframes_t time; } midi_note_on;
        struct { int scene_index; jack_nframes_t time; } midi_scene_launch;
        struct { int channel; char uri[512]; PluginType type; } rack_add_plugin;
        struct { int channel; int plugin_index; } rack_remove_plugin;
        struct { int channel; int plugin_index; int param_index; float value; } rack_set_parameter;
        struct { int channel; float volume; } rack_set_volume;
        struct { int channel; bool bypass; } rack_bypass;
        struct { char filename[512]; } save_project;
        struct { char filename[512]; } load_project;
        struct { jack_nframes_t nframes; } process_audio;
        struct { bool show; } set_show_midi_grid;
        struct { int clip_index; } midi_clip_trigger;
        struct { int clip_index; } midi_clip_reset;
        struct { int channel; char name[64]; } set_channel_name;
    } data;
} Action;

// ============================================================
// Dispatcher API
// ============================================================

// Thread-safe dispatch function - called by any thread
typedef void (*DispatchFn)(Action action);

// Subscriber callback - called after each state update (from dispatcher thread)
typedef void (*SubscriberFn)(AppState *state, void *user_data);

// Initialize the dispatcher with initial state
// Returns the dispatch function that consumers can call
DispatchFn dispatcher_init(AppState *initial_state);

// Register a subscriber (call before dispatcher_start)
void dispatcher_subscribe(SubscriberFn fn, void *user_data);

// Start the dispatcher thread
void dispatcher_start(void);

// Stop the dispatcher and cleanup
void dispatcher_stop(void);

// Get current state (thread-safe snapshot)
void dispatcher_get_state(AppState *out);

// Get pointer to dispatcher's state (for real-time threads that can't block)
// WARNING: This is NOT thread-safe. Only use in JACK process callback
// which is serialized per client.
AppState* dispatcher_get_state_ptr(void);

// ============================================================
// Reducer - pure function (takes pointer to avoid stack copy)
// ============================================================
void reducer(AppState *state, Action action);

#endif // DISPATCHER_H