#ifndef TRANSPORT_H
#define TRANSPORT_H

#include <jack/jack.h>
#include <jack/midiport.h>
#include <stdint.h>
#include <stdbool.h>
#include <stdatomic.h>

#define MIDI_CLOCKS_PER_BEAT 24
#define BEATS_PER_BAR 4
#define DEFAULT_BPM 120.0

typedef enum {
    TRANSPORT_STOPPED,
    TRANSPORT_PLAYING,
    TRANSPORT_PAUSED
} TransportState;

typedef enum {
    CLOCK_SOURCE_INTERNAL,  // Master clock
    CLOCK_SOURCE_MIDI       // Slave to external MIDI clock
} ClockSource;

typedef struct {
    // State
    TransportState state;
    ClockSource clock_source;
    
    // Position
    uint32_t clock_count;
    uint32_t beat_position;   // 0-3
    uint32_t bar_position;
    uint32_t sample_position; // derived from clock at current sample rate
    
    // Internal clock generation
    double bpm;
    double samples_per_beat;
    double sample_accumulator;  // For precise BPM timing
    
    // Atomic mirrors for frontend reads
    atomic_int state_atomic;           // TransportState
    atomic_uint clock_count_atomic;
    atomic_uint beat_position_atomic;
    atomic_uint bar_position_atomic;
    atomic_uint sample_position_atomic;
    atomic_int clock_source_atomic;    // ClockSource
    double bpm_atomic;                 // Direct read for audio thread
    atomic_uint bpm_atomic_raw;        // Fixed-point (BPM * 100) for frontend reads
    
    // JACK ports for MIDI clock output (when master)
    jack_port_t *midi_clock_out_port;
    
    // Reference to engine for sample rate
    jack_nframes_t sample_rate;
} Transport;

// Lifecycle
void transport_init(Transport *transport, jack_nframes_t sample_rate);
void transport_cleanup(Transport *transport);

// Control
void transport_play(Transport *transport);
void transport_pause(Transport *transport);
void transport_stop(Transport *transport);
void transport_toggle_play(Transport *transport);

// Clock source
void transport_set_clock_source(Transport *transport, ClockSource source);
ClockSource transport_get_clock_source(Transport *transport);

// BPM (only relevant for internal clock)
void transport_set_bpm(Transport *transport, double bpm);
double transport_get_bpm(Transport *transport);

// Process function called from audio thread
// Returns number of MIDI clock ticks generated (for master mode)
int transport_process(Transport *transport, jack_nframes_t nframes, 
                      void *midi_clock_in_buf, void *midi_clock_out_buf);

// Reset position
void transport_reset(Transport *transport);


// Utility
const char* transport_state_to_string(TransportState state);
const char* clock_source_to_string(ClockSource source);

#endif // TRANSPORT_H