#include <stdio.h>
#include <string.h>
#include <stdint.h>

/* mock SnapRec (与 snapshot.h 一致, 64B) */
typedef struct {
    uint8_t  magic;
    uint8_t  len;
    uint8_t  flags;
    uint8_t  rsvd;
    uint32_t seq;
    uint32_t ts_ms;
    uint16_t boot_seq;
    uint16_t rsvd2;
    uint8_t  coils[48];
} SnapRec;

#define SNAP_COILS_MAX  4
#define SNAP_COIL_BYTES 12

int snap_rec_to_json(const SnapRec *r, char *buf, int buf_len)
{
    int coil_count = (r->len > (SNAP_COILS_MAX * SNAP_COIL_BYTES))
                     ? SNAP_COILS_MAX : (r->len / SNAP_COIL_BYTES);
    if (coil_count < 0) coil_count = 0;

    int pos = snprintf(buf, buf_len,
        "{\"seq\":%lu,\"boot_seq\":%u,\"ts_ms\":%lu,\"coil_count\":%u,\"channels\":[",
        (unsigned long)r->seq, (unsigned)r->boot_seq,
        (unsigned long)r->ts_ms, (unsigned)coil_count);

    int c;
    for (c = 0; c < coil_count; c++) {
        const uint8_t *p = &r->coils[c * SNAP_COIL_BYTES];
        uint8_t  cfg       = p[0];
        uint8_t  cond      = p[1];
        uint32_t freq      = (uint32_t)p[2] | ((uint32_t)p[3] << 8) | ((uint32_t)p[4] << 16);
        int32_t  variation = (int32_t)((uint32_t)p[5] | ((uint32_t)p[6] << 8) | ((uint32_t)p[7] << 16));
        uint32_t misc      = (uint32_t)p[8] | ((uint32_t)p[9] << 8)
                           | ((uint32_t)p[10] << 16) | ((uint32_t)p[11] << 24);
        uint8_t  freq_level  = (cfg >> 6) & 0x03;
        uint8_t  direction   = (cfg >> 5) & 0x01;
        uint8_t  freq_type   = (cfg >> 4) & 0x01;
        uint8_t  sensitivity = cfg & 0x0F;
        uint8_t  condition   = (cond >> 4) & 0x0F;
        uint8_t  loop_state  = (cond >> 3) & 0x01;   /* 0=normal 1=cut   */
        uint8_t  car_state   = (cond >> 2) & 0x01;   /* 0=nocar 1=car    */
        uint8_t  misc_type   = cond & 0x03;
        const char *fl = "high";
        const char *mt = "time";

        if (variation & 0x800000) variation |= (int32_t)0xFF000000;  /* 3B sign extend */

        if (freq_level == 1) fl = "mid_high";
        else if (freq_level == 2) fl = "mid_low";
        else if (freq_level == 3) fl = "low";

        if (misc_type == 1) mt = "cut_count";
        else if (misc_type == 2) mt = "flow_count";
        else if (misc_type == 3) mt = "relay_count";

        if (c > 0) pos += snprintf(buf + pos, buf_len - pos, ",");
        pos += snprintf(buf + pos, buf_len - pos,
            "{\"ch\":%u,\"freq_level\":\"%s\",\"direction\":%u,\"freq_type\":%u,"
            "\"sensitivity\":%u,\"condition\":%u,\"loop_ok\":%s,\"has_car\":%s,"
            "\"misc_type\":\"%s\",\"freq\":%lu,\"variation\":%ld,\"misc\":%lu}",
            (unsigned)(c + 1), fl, (unsigned)direction, (unsigned)freq_type,
            (unsigned)sensitivity, (unsigned)condition,
            loop_state ? "false" : "true", car_state ? "true" : "false",
            mt, (unsigned long)freq, (long)variation, (unsigned long)misc);
    }
    pos += snprintf(buf + pos, buf_len - pos, "]}");
    return pos;
}

#define CHECK(cond) do { if (!(cond)) { printf("FAIL %s:%d: %s\n", __FILE__, __LINE__, #cond); fails++; } else { passes++; } } while (0)

static int passes = 0, fails = 0;

int main(void)
{
    char buf[2048];
    SnapRec r;

    /* 用例1: 单线圈, 高频(00)/触发/实时频率/灵敏度2, 正常无车, 时间量
       freq=0x010F2A=69418, variation=+7, misc=0 */
    memset(&r, 0, sizeof(r));
    r.magic = 0xA6; r.len = 12; r.seq = 12345; r.ts_ms = 456789; r.boot_seq = 2;
    r.coils[0]  = 0x12;  /* freq_level=00  direction=0  freq_type=1  sens=0010 */
    r.coils[1]  = 0x00;  /* condition=0 loop_state=0 car_state=0 misc_type=00 */
    r.coils[2]  = 0x2A; r.coils[3] = 0x0F; r.coils[4] = 0x01;  /* 69418 */
    r.coils[5]  = 0x07; r.coils[6] = 0x00; r.coils[7] = 0x00;  /* +7 */
    r.coils[8]  = 0x00; r.coils[9] = 0x00; r.coils[10] = 0x00; r.coils[11] = 0x00;

    snap_rec_to_json(&r, buf, sizeof(buf));
    printf("case1: %s\n", buf);
    CHECK(strstr(buf, "\"seq\":12345") != NULL);
    CHECK(strstr(buf, "\"boot_seq\":2") != NULL);
    CHECK(strstr(buf, "\"ts_ms\":456789") != NULL);
    CHECK(strstr(buf, "\"coil_count\":1") != NULL);
    CHECK(strstr(buf, "\"ch\":1") != NULL);
    CHECK(strstr(buf, "\"freq_level\":\"high\"") != NULL);
    CHECK(strstr(buf, "\"direction\":0") != NULL);
    CHECK(strstr(buf, "\"freq_type\":1") != NULL);
    CHECK(strstr(buf, "\"sensitivity\":2") != NULL);
    CHECK(strstr(buf, "\"condition\":0") != NULL);
    CHECK(strstr(buf, "\"loop_ok\":true") != NULL);
    CHECK(strstr(buf, "\"has_car\":false") != NULL);
    CHECK(strstr(buf, "\"misc_type\":\"time\"") != NULL);
    CHECK(strstr(buf, "\"freq\":69418") != NULL);
    CHECK(strstr(buf, "\"variation\":7") != NULL);
    CHECK(strstr(buf, "\"misc\":0") != NULL);

    /* 用例2: 4线圈全量 + 负 variation + 低频 + relay_count + 有车/断开
       ch1: 低频(11)/方向判别(1)/初始频率(0)/灵敏度0, condition=0xF, loop_state=1(断开), car_state=1(有车), misc_type=11(relay)
       freq=0x00C383=50051, variation=-10 (F6 FF FF), misc=128 */
    memset(&r, 0, sizeof(r));
    r.magic = 0xA6; r.len = 48; r.seq = 999; r.ts_ms = 1234; r.boot_seq = 3;
    r.coils[0] = 0xE8;  /* 11 1 0 0000 */
    r.coils[1] = 0xFF;  /* 1111 1 1 11 */
    r.coils[2] = 0x83; r.coils[3] = 0xC3; r.coils[4] = 0x00;  /* 50051 */
    r.coils[5] = 0xF6; r.coils[6] = 0xFF; r.coils[7] = 0xFF;  /* -10 */
    r.coils[8] = 0x80; r.coils[9] = 0x00; r.coils[10] = 0x00; r.coils[11] = 0x00;  /* 128 */
    /* ch2: 中高(01), 正常无车, cut_count */
    r.coils[12] = 0x50;  /* 01 0 1 0000 */
    r.coils[13] = 0x01;  /* 0000 0 0 01 */
    r.coils[14] = 0x00; r.coils[15] = 0x02; r.coils[16] = 0x00;  /* 512 */
    r.coils[17] = 0x01; r.coils[18] = 0x00; r.coils[19] = 0x00;  /* +1 */
    /* ch3: 中低(10), flow_count */
    r.coils[24] = 0xA0;  /* 10 1 0 0000 */
    r.coils[25] = 0x02;  /* 0000 0 0 10 */
    r.coils[26] = 0x00; r.coils[27] = 0x01; r.coils[28] = 0x00;  /* 256 */
    /* ch4: 高频, 空 */

    snap_rec_to_json(&r, buf, sizeof(buf));
    printf("case2: %s\n", buf);
    CHECK(strstr(buf, "\"coil_count\":4") != NULL);
    CHECK(strstr(buf, "\"freq_level\":\"low\"") != NULL);
    CHECK(strstr(buf, "\"direction\":1") != NULL);
    CHECK(strstr(buf, "\"freq_type\":0") != NULL);
    CHECK(strstr(buf, "\"sensitivity\":0") != NULL);
    CHECK(strstr(buf, "\"condition\":15") != NULL);
    CHECK(strstr(buf, "\"loop_ok\":false") != NULL);
    CHECK(strstr(buf, "\"has_car\":true") != NULL);
    CHECK(strstr(buf, "\"misc_type\":\"relay_count\"") != NULL);
    CHECK(strstr(buf, "\"freq\":50051") != NULL);
    CHECK(strstr(buf, "\"variation\":-10") != NULL);
    CHECK(strstr(buf, "\"misc\":128") != NULL);
    CHECK(strstr(buf, "\"freq_level\":\"mid_high\"") != NULL);
    CHECK(strstr(buf, "\"misc_type\":\"cut_count\"") != NULL);
    CHECK(strstr(buf, "\"freq_level\":\"mid_low\"") != NULL);
    CHECK(strstr(buf, "\"misc_type\":\"flow_count\"") != NULL);

    /* 用例3: len=0 边界 (空记录) */
    memset(&r, 0, sizeof(r));
    r.magic = 0xA6; r.len = 0;
    snap_rec_to_json(&r, buf, sizeof(buf));
    printf("case3: %s\n", buf);
    CHECK(strstr(buf, "\"coil_count\":0") != NULL);
    CHECK(strstr(buf, "\"channels\":[]") != NULL);

    printf("\nPASS=%d FAIL=%d\n", passes, fails);
    return fails ? 1 : 0;
}