#include <jack/jack.h>
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

static jack_port_t *output_port;
static jack_client_t *client;
static volatile int running = 1;
static double phase = 0.0;
static double freq = 440.0;
static int sample_rate = 48000;
static int total_samples = 0;
static int samples_written = 0;

int process(jack_nframes_t nframes, void *arg) {
    jack_default_audio_sample_t *out =
        (jack_default_audio_sample_t *)jack_port_get_buffer(output_port, nframes);
    if (!out) return 0;
    for (jack_nframes_t i = 0; i < nframes; i++) {
        out[i] = sin(2 * M_PI * phase);
        phase += freq / sample_rate;
        if (phase >= 1.0) phase -= 1.0;
        samples_written++;
        if (total_samples > 0 && samples_written >= total_samples) {
            running = 0;
            break;
        }
    }
    return 0;
}

void shutdown(void *arg) { running = 0; }

int main(int argc, char **argv) {
    if (argc < 3) {
        fprintf(stderr, "Usage: gen_tone <duration_seconds> <target_port> [frequency]\n");
        return 1;
    }
    double duration = atof(argv[1]);
    const char *target = argv[2];
    if (argc >= 4) freq = atof(argv[3]);

    jack_status_t status;
    client = jack_client_open("gen_tone", JackNoStartServer, &status);
    if (!client) { fprintf(stderr, "Cannot open JACK client\n"); return 1; }

    sample_rate = jack_get_sample_rate(client);
    total_samples = (int)(duration * sample_rate + 0.5);

    output_port = jack_port_register(client, "output",
                                     JACK_DEFAULT_AUDIO_TYPE,
                                     JackPortIsOutput, 0);
    if (!output_port) { fprintf(stderr, "Cannot register port\n"); return 1; }

    jack_set_process_callback(client, process, NULL);
    jack_on_shutdown(client, shutdown, NULL);
    if (jack_activate(client)) { fprintf(stderr, "Cannot activate client\n"); return 1; }

    // Connect to target
    const char **ports = jack_get_ports(client, target,
                                        JACK_DEFAULT_AUDIO_TYPE,
                                        JackPortIsInput);
    if (!ports || !ports[0]) {
        fprintf(stderr, "Target port '%s' not found\n", target);
        return 1;
    }
    if (jack_connect(client, jack_port_name(output_port), ports[0])) {
        fprintf(stderr, "Cannot connect port\n");
        return 1;
    }

    while (running) sleep(1);

    jack_client_close(client);
    return 0;
}