#include <thread.h>
#include <thread-sync.h>

enum {
    C = 40,
    D = 42,
    E = 44,
    F = 45,
    G = 47,
    A = 49,
    B = 51,
    C0 = C - 12,
    D0 = D - 12,
    E0 = E - 12,
    F0 = F - 12,
    G0 = G - 12,
    A0 = A - 12,
    B0 = B - 12,
};

#define NPLAYER 3

mutex_t lk = MUTEX_INIT();

int n = -1;            // current beat
int done = NPLAYER;    // players finished current beat (init = all done)

int NOTES[3][8] = {
    {C, G0, A0, E0, F0, C0, F0, G0},
    {E, B0, C0, G0, A0, E0, A0, B0},
    {G, D,  E,  B0, C0, G0, C0, D0},
};

void T_player(int id) {
    int *notes, expect = 0;
    char cmd[128];

    switch (id) {
        case 1: notes = NOTES[0]; break;
        case 2: notes = NOTES[1]; break;
        case 3: notes = NOTES[2]; break;
    }

    while (1) {
        int ready;
        do {
            mutex_lock(&lk);
            ready = (n == expect);
            mutex_unlock(&lk);
        } while (!ready);

        int note = notes[expect % 8];

        sprintf(cmd,
            "ffplay -nodisp -autoexit"
            " -loglevel quiet"
            " piano_key_%d.wav", note);

        printf("player %d is playing note %d\n", id, expect);
        system(cmd);
        printf("player %d finished playing note %d\n", id, expect);

        mutex_lock(&lk);
        done++;
        mutex_unlock(&lk);
        expect++;
    }
}

void T_conductor() {
    char buf[32];
    while (1) {
        printf("\n(Ready) > ");
        fflush(stdout);
        fgets(buf, sizeof(buf), stdin);

        int all_done;
        do {
            mutex_lock(&lk);
            all_done = (done == NPLAYER);
            mutex_unlock(&lk);
        } while (!all_done);

        mutex_lock(&lk);
        done = 0;
        n++;
        mutex_unlock(&lk);
    }
}

int main() {
    for (int i = 0; i < NPLAYER; i++) {
        spawn(T_player);
    }
    spawn(T_conductor);
}