/*
 * bench_inject — measure pog422_inject_burst tx_ns on the Pi.
 *
 *   make bench_inject
 *   ./bench_inject /dev/ttyXRUSB1 --len 12 --count 50
 */

#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <termios.h>
#include <unistd.h>

#include "pog422_inject.h"

static void usage(const char *argv0)
{
    fprintf(
        stderr,
        "Usage: %s <tty> [--len N] [--count N] [--pre-us N] [--post-us N] [--rt]\n",
        argv0
    );
}

static int open_port(const char *path)
{
    int fd = open(path, O_RDWR | O_NOCTTY | O_NONBLOCK);
    if (fd < 0) {
        return -1;
    }
    if (fcntl(fd, F_SETFL, fcntl(fd, F_GETFL) & ~O_NONBLOCK) != 0) {
        close(fd);
        return -1;
    }
    struct termios tio;
    if (tcgetattr(fd, &tio) != 0) {
        close(fd);
        return -1;
    }
    cfsetispeed(&tio, B57600);
    cfsetospeed(&tio, B57600);
    tio.c_cflag = CS8 | CLOCAL | CREAD;
    tio.c_iflag = 0;
    tio.c_oflag = 0;
    tio.c_lflag = 0;
    if (tcsetattr(fd, TCSANOW, &tio) != 0) {
        close(fd);
        return -1;
    }
    pog422_gpio7_rx(fd);
    return fd;
}

int main(int argc, char **argv)
{
    if (argc < 2) {
        usage(argv[0]);
        return 1;
    }

    const char *tty = argv[1];
    size_t frame_len = 12;
    int count = 50;
    uint32_t pre_us = 0;
    uint32_t post_us = 2500;
    int use_rt = 0;

    for (int i = 2; i < argc; i++) {
        if (strcmp(argv[i], "--len") == 0 && i + 1 < argc) {
            frame_len = (size_t)atoi(argv[++i]);
        } else if (strcmp(argv[i], "--count") == 0 && i + 1 < argc) {
            count = atoi(argv[++i]);
        } else if (strcmp(argv[i], "--pre-us") == 0 && i + 1 < argc) {
            pre_us = (uint32_t)atoi(argv[++i]);
        } else if (strcmp(argv[i], "--post-us") == 0 && i + 1 < argc) {
            post_us = (uint32_t)atoi(argv[++i]);
        } else if (strcmp(argv[i], "--rt") == 0) {
            use_rt = 1;
        } else {
            usage(argv[0]);
            return 1;
        }
    }

    int fd = open_port(tty);
    if (fd < 0) {
        fprintf(stderr, "open %s: %s\n", tty, strerror(errno));
        return 1;
    }

    uint8_t *frame = calloc(1, frame_len);
    if (!frame) {
        close(fd);
        return 1;
    }
    frame[0] = 0x05;
    if (frame_len > 1) {
        frame[1] = 0x0B;
    }
    if (frame_len > 2) {
        frame[frame_len - 1] = 0x0D;
    }

    pog422_inject_opts_t opts = {
        .pre_tx_us = pre_us,
        .post_hold_us = post_us,
        .flush_rx_before_tx = 0,
        .use_realtime = (uint8_t)use_rt,
        .rt_priority = 50,
    };

    printf(
        "pog422_inject %s  tty=%s  len=%zu  count=%d  air_us=%u\n",
        pog422_inject_version(),
        tty,
        frame_len,
        count,
        (unsigned)((frame_len * 11ull * 1000000ull) / 57600ull)
    );

    uint64_t min_tx = UINT64_MAX;
    uint64_t max_tx = 0;
    uint64_t sum_tx = 0;

    for (int n = 0; n < count; n++) {
        pog422_inject_result_t res;
        int rc = pog422_inject_burst(fd, frame, frame_len, &opts, &res);
        if (rc != 0) {
            fprintf(stderr, "burst %d failed err=%d\n", n, res.err);
            break;
        }
        if (res.tx_ns < min_tx) {
            min_tx = res.tx_ns;
        }
        if (res.tx_ns > max_tx) {
            max_tx = res.tx_ns;
        }
        sum_tx += res.tx_ns;
    }

    if (count > 0 && min_tx != UINT64_MAX) {
        printf(
            "tx_us: min=%.1f max=%.1f avg=%.1f\n",
            min_tx / 1000.0,
            max_tx / 1000.0,
            (sum_tx / (double)count) / 1000.0
        );
    }

    free(frame);
    close(fd);
    return 0;
}