#include <stdio.h>
#include <unistd.h>
#include <ctype.h>
#include <pthread.h>
#include <stdlib.h>
#include <sys/time.h>
#include <emscripten.h>

#include "stdio_impl.h"

static pthread_cond_t tyi_cond;
static pthread_mutex_t tyi_mutex;

#define TYI_BUF_SIZE 1000

static int tyi_buf [TYI_BUF_SIZE];
static unsigned tyi_rptr = 0;
static unsigned tyi_fptr = 0;

void tty_tyo(int ch) { MAIN_THREAD_EM_ASM((return tyo($0)), (int32_t)ch); }
void tty_puts(char *s) { for(;*s;s++)tty_tyo(*s); }
void whostate(char *s)  { MAIN_THREAD_EM_ASM((whostate(UTF8ToString($0))), s); }

static double now (void) {
    struct timeval tv;
    gettimeofday(&tv,0);
    return tv.tv_sec + 1e-6 * tv.tv_usec;
}

volatile int osint = 0;

void tty_intr (int ch) { osint = ch; }
void res (char *s) { (void)s; }

//char * ta = "(PUTD FIB (QUOTE (LAMBDA (N) ((LESSP N 2) N) (PLUS (FIB (PLUS N -2)) (FIB (PLUS N -1))))))\n";
static char *ta = "";

int tty_have_input (int c) {
    pthread_mutex_lock (&tyi_mutex); /* hmm */
    if (tyi_fptr == TYI_BUF_SIZE) {
        unsigned i;
        for (i = tyi_rptr; i < tyi_fptr; i++)
            tyi_buf[i-tyi_rptr] = tyi_buf[i];
        tyi_fptr -= tyi_rptr;
        tyi_rptr -= tyi_rptr;
    }
    if (tyi_fptr < TYI_BUF_SIZE)
        tyi_buf[tyi_fptr++] = c;
    pthread_cond_signal (&tyi_cond);
    pthread_mutex_unlock (&tyi_mutex);
    return tyi_fptr;
}

static size_t tty_write(FILE *fp, const unsigned char *buf, size_t n) {
    unsigned char *p;
    for (p = fp->wbase; p <  fp->wpos; p++) tty_tyo(*p);
    for (size_t i = 0; i < n; i++) tty_tyo(buf[i]);
    fp->wpos = fp->wbase;
    return n;
}

static size_t tty_read(FILE *fp, unsigned char *buf, size_t n) {
    static double t0 = -1;
    int ch;
    
    if (n == 0) return 0;       /* Huh? */

    if (fp == stdin) { fflush(stdout); fflush(stderr); }

    if(*ta) {
        ch = (unsigned char)*ta++;
        tty_tyo(ch);
    } else {

        pthread_mutex_lock (&tyi_mutex);
        if (tyi_rptr >= tyi_fptr) {
            static char buf [80];
            if (t0 < 0) {
                sprintf (buf, "Waiting for input");
            } else {
                sprintf (buf, "Waiting for input [Last command took %gs]",
                         now() - t0);
            }
            t0 = now();
            whostate(buf);
            while (tyi_rptr >= tyi_fptr) {
                pthread_cond_wait (&tyi_cond, &tyi_mutex);
            }
            whostate("Running");
        }
        ch = tyi_buf[tyi_rptr++];
        pthread_mutex_unlock (&tyi_mutex);
    }

    t0 = now();
    if (ch < 0) {
        fp->flags |= F_EOF;
        return 0;               /* EOF */
    } else {
        *buf = ch;
        return 1;
    }
}

void tty_init (void)
    /* This is supposed to be called at 'preRun' time. */
{
    if (0 != pthread_mutex_init(&tyi_mutex, 0)) abort();
    if (0 != pthread_cond_init(&tyi_cond, 0)) abort();
    stdout->write = tty_write;
    stderr->write = tty_write;
    stdin->read = tty_read;
}