/* FluidSynth Metronome - Sequencer API example
 *
 * This code is in the public domain.
 *
 * To compile:
 *   gcc -o rendermetronome3 -lfluidsynth -lsndfile rendermetronome3.c
 *
 * To run:
 *   rendermetronome3 soundfont [beats [tempo]]
 *
 * [Pedro Lopez-Cabanillas <address@hidden>]
 */

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <fluidsynth.h>
#include <sndfile.h>

fluid_synth_t *synth;
fluid_sequencer_t *sequencer;
short synth_destination;
unsigned int time_marker;
unsigned int sample_rate = 44100;
/* default tempo, beats per minute */
#define TEMPO 120
unsigned int note_duration = 60000 / TEMPO;
/* metronome click/bell */
unsigned int weak_note = 33;
unsigned int strong_note = 34;
/* number of notes in one pattern */
unsigned int pattern_size = 4;
/* total sequence length in bars */
unsigned int pending_bars = 10;

/* schedule a note on message */
void
schedule_noteon (int chan, short key, unsigned int ticks)
{
    printf("metronome: noteon %d at %u\n", key, ticks);
    fluid_event_t *ev = new_fluid_event ();
    fluid_event_set_source (ev, -1);
    fluid_event_set_dest (ev, synth_destination);
    fluid_event_noteon (ev, chan, key, 127);
    fluid_sequencer_send_at (sequencer, ev, ticks, 1);
    delete_fluid_event (ev);
}

/* schedule the metronome pattern */
void
schedule_pattern ()
{
    int i, note_time;
    note_time = time_marker;
    for (i = 0; i < pattern_size; ++i) {
        schedule_noteon (9, i ? weak_note : strong_note, note_time);
        note_time += note_duration;
    }
    time_marker = note_time;
}

void
usage (char* prog_name)
{
    printf ("Usage: %s soundfont.sf2 [beats [tempo]]\n", prog_name);
    printf ("\t(optional) beats: number of pattern beats, default %d\n",
            pattern_size);
    printf ("\t(optional) tempo: BPM (Beats Per Minute), default %d\n", TEMPO);
}

int
main (int argc, char *argv[])
{
    int i, n;
    int total_bar_size, period_size;
    fluid_settings_t *settings;
    SNDFILE* sndfile;
    SF_INFO info;
    size_t buf_size;
    float* buf;

    if (argc < 2) {
        usage (argv[0]);
    } else {
        if (argc > 2) {
            n = atoi (argv[2]);
            if (n > 0) pattern_size = n;
        }
        if (argc > 3) {
            n = atoi (argv[3]);
            if (n > 0) note_duration = 60000 / n;
        }

        /* total bar size in frames */
        total_bar_size = note_duration * pattern_size * sample_rate / 1000;
        buf_size = 2 * total_bar_size * sizeof (float);
        printf ("metronome: buffer size = %d frames\n", total_bar_size);

        memset (&info, 0, sizeof (info));
        info.format = SF_FORMAT_WAV | SF_FORMAT_PCM_16;
        info.samplerate = sample_rate * 1.0;
        info.channels = 2;

        settings = new_fluid_settings ();
        fluid_settings_setnum(settings, "synth.gain", 2.0);
        fluid_settings_setnum(settings, "synth.sample-rate", sample_rate);
        fluid_settings_setint(settings, "synth.verbose", 1);

        /* create the synth and sequencer instances */
        synth = new_fluid_synth (settings);
        sequencer = new_fluid_sequencer2 (0);
        /* register the synth with the sequencer */
        synth_destination = fluid_sequencer_register_fluidsynth (sequencer, synth);
        /* load a SoundFont */
        n = fluid_synth_sfload (synth, argv[1], 1);
        if (n != -1) {
            buf = malloc(buf_size);
            sndfile = sf_open ("rendermetronome3.wav", SFM_WRITE, &info);
            sf_command (sndfile, SFC_SET_CLIPPING, NULL, SF_TRUE);
            sf_command (sndfile, SFC_SET_NORM_FLOAT, NULL, SF_TRUE);
            /* get the current time in ticks */
            time_marker = fluid_sequencer_get_tick (sequencer);
            /* schedule and render patterns */
            for (n = 0; n < pending_bars; ++n) {
                schedule_pattern ();
                fluid_synth_write_float (synth, total_bar_size, buf, 0, 2, buf, 1, 2);
                sf_writef_float (sndfile, buf, total_bar_size);
            }
            sf_close(sndfile);
            free(buf);
        }
        /* clean and exit */
        delete_fluid_sequencer (sequencer);
        delete_fluid_synth (synth);
        delete_fluid_settings (settings);
    }
    return 0;
}