#define MINIAUDIO_IMPLEMENTATION
#define MA_NO_DECODING
#define MA_NO_ENCODING
#define MA_NO_RESOURCE_MANAGER
#define MA_NO_NODE_GRAPH
#define MA_NO_ENGINE
#define MA_NO_GENERATION
#include "miniaudio.h"
#include "../xyw.h"

/* beeper device */
#define BEEPER_PITCH 0x0
#define BEEPER_LENGTH 0x2
#define BEEPER_LEVEL 0x4

/* 8-bit era constraints */
#define BEEPER_MAX_FREQ 0x2000   // 8192 Hz - typical PC speaker limit
#define BEEPER_MAX_LEVEL 0x0F    // 4-bit volume (0-15)
#define BEEPER_SAMPLE_RATE 22050 // Period-accurate low sample rate

// State for the beeper callback
typedef struct
{
    double phase;
    double phase_increment;
    float amplitude;
    ma_uint64 samples_remaining;
} beeper_state;

// Persistent audio device
static ma_device beeper_device;
static beeper_state beeper_st = {0};
static int beeper_device_initialized = 0;

// Audio callback to generate the square wave tone
static void beeper_callback(ma_device *device, void *output, const void *input, ma_uint32 frame_count)
{
    beeper_state *state = (beeper_state *)device->pUserData;
    float *out = (float *)output;

    (void)input;

    for (ma_uint32 i = 0; i < frame_count; i++)
    {
        if (state->samples_remaining == 0)
        {
            out[i] = 0.0f;
        }
        else
        {
            // Generate square wave sample (-amplitude or +amplitude)
            out[i] = (state->phase < MA_PI) ? state->amplitude : -state->amplitude;
            state->phase += state->phase_increment;
            if (state->phase >= MA_TAU)
                state->phase -= MA_TAU;
            state->samples_remaining--;
        }
    }
}

// Ensure the persistent audio device is initialized
static int beeper_ensure_device(void)
{
    if (beeper_device_initialized)
        return 1;

    ma_device_config config = ma_device_config_init(ma_device_type_playback);
    config.playback.format = ma_format_f32;
    config.playback.channels = 1;
    config.sampleRate = BEEPER_SAMPLE_RATE;
    config.dataCallback = beeper_callback;
    config.pUserData = &beeper_st;

    if (ma_device_init(NULL, &config, &beeper_device) != MA_SUCCESS)
        return 0;

    if (ma_device_start(&beeper_device) != MA_SUCCESS)
    {
        ma_device_uninit(&beeper_device);
        return 0;
    }

    beeper_device_initialized = 1;
    return 1;
}

// Helper function to play a tone with given frequency, duration, and level
static void beeper_play_tone(xyw_word freq, unsigned long duration_ms, xyw_byte level)
{
    if (!beeper_ensure_device())
        return;

    // Update tone parameters (callback will pick them up)
    beeper_st.phase = 0.0;
    beeper_st.phase_increment = MA_TAU * (double)freq / BEEPER_SAMPLE_RATE;
    beeper_st.amplitude = (float)level / (float)BEEPER_MAX_LEVEL;
    beeper_st.samples_remaining = (ma_uint64)(BEEPER_SAMPLE_RATE * duration_ms / 1000);

    // Wait for playback to complete
    while (beeper_st.samples_remaining > 0)
        ma_sleep(1);
}

void beeper_output(xyw_byte *data, xyw_byte addr, xyw_byte *error)
{
    (void)error;

    switch (addr)
    {
    case BEEPER_PITCH:
    case BEEPER_PITCH + 1:
    case BEEPER_LENGTH:
    case BEEPER_LENGTH + 1:
        // Just store the value, beep triggers on level write
        break;

    case BEEPER_LEVEL:
    {
        // Get pitch (2 bytes, big-endian)
        xyw_word pitch = XYW_PEEKW(&data[BEEPER_PITCH]);

        // Get length in 1/256 second units (2 bytes, big-endian)
        xyw_word length = XYW_PEEKW(&data[BEEPER_LENGTH]);

        // Get volume level (0-15)
        xyw_byte level = data[BEEPER_LEVEL];

        // Clamp to 8-bit era constraints
        if (pitch > BEEPER_MAX_FREQ)
            pitch = BEEPER_MAX_FREQ;
        if (level > BEEPER_MAX_LEVEL)
            level = BEEPER_MAX_LEVEL;

        // Only act if level > 0 and length > 0
        if (level > 0 && length > 0)
        {
            // Convert length from 1/256 seconds to milliseconds
            // 1/256 second = 1000/256 ms ≈ 3.90625 ms
            unsigned long duration_ms = ((unsigned long)length * 1000) / 256;
            if (duration_ms == 0)
                duration_ms = 1;

            // Pitch of 0 means silence (pause for the duration)
            if (pitch == 0)
                ma_sleep((ma_uint32)duration_ms);
            else
                beeper_play_tone(pitch, duration_ms, level);
        }
        break;
    }
    }
}

xyw_byte beeper_input(xyw_byte *data, xyw_byte addr, xyw_byte *error)
{
    (void)error;
    return data[addr];
}