/*
 * test_neg_variation.c — 负variation铁块场景回归单测 (V4.20)
 *
 * 背景: 特殊铁块(磁导率主导)靠近线圈 → CAPVD 高于 Origin(频率降)
 *  原单边基线保护 → Origin 被污染 → 铁块离开时假进入 → 释放线抬高 → 锁死不释放
 * 修复: 双向对称保护 — 负偏差(dev>0) 只冻结, 永不超时更新 Origin
 *
 * 验证:
 *   1. 小偏差(±4×dlt内) → 正常基线更新
 *   2. 正variation(dev<0, 疑似车) → 冻结 + 超时兜底更新(保留)
 *   3. 负variation(dev>0, 铁块) → 冻结 + 超时也绝不更新 Origin ← 核心修复
 *   4. 场景仿真: 铁块靠近(负var) → 离开 → 修复前假进入+锁定 / 修复后无输出
 *===========================================================================*/
#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <assert.h>

#define ORIGIN       131072UL
#define DLT_ORG      38           /* SENS=3 进入 counts (表值25@100000 ≈ 38@131072) */
#define FREEZE_BAND  (DLT_ORG * 4)   /* 对称窗口 ±152 */
#define FREEZE_TIMEOUT 1000

/* 基线决策 — 与 TaskLoop.c 同逻辑 (简化版, 只测决策方向) */
typedef enum { DEC_UPDATE = 0, DEC_FREEZE_POS, DEC_FREEZE_NEG } dec_t;

static dec_t baseline_decide(int32_t capvd, int32_t origin, uint32_t *freeze_cnt)
{
    int32_t dev = capvd - origin;
    int32_t band = FREEZE_BAND;
    if (dev < band && dev > -band) {
        *freeze_cnt = 0;
        return DEC_UPDATE;
    } else if (dev < 0) {
        (*freeze_cnt)++;
        return DEC_FREEZE_POS;
    } else {
        if (*freeze_cnt == 0) { /* 首中记录 */ }
        (*freeze_cnt)++;
        if (*freeze_cnt > FREEZE_TIMEOUT) *freeze_cnt = FREEZE_TIMEOUT;
        return DEC_FREEZE_NEG;
    }
}

int main(void)
{
    uint32_t freeze_cnt = 0;

    printf("=== 负variation铁块场景回归单测 (V4.20) ===\n");

    /* 1. 小偏差 → 正常更新 */
    assert(baseline_decide(ORIGIN + 10,  ORIGIN, &freeze_cnt) == DEC_UPDATE);
    assert(baseline_decide(ORIGIN - 10,  ORIGIN, &freeze_cnt) == DEC_UPDATE);
    assert(baseline_decide(ORIGIN - 100, ORIGIN, &freeze_cnt) == DEC_UPDATE);
    printf("[OK] 小偏差(±%d内) → 正常基线更新\n", FREEZE_BAND);

    /* 2. 正variation (CAPVD低于Origin, 疑似车) → 冻结 */
    freeze_cnt = 0;
    assert(baseline_decide(ORIGIN - 300, ORIGIN, &freeze_cnt) == DEC_FREEZE_POS);
    assert(freeze_cnt == 1);
    printf("[OK] 正variation(CAPVD<Origin, 疑似车) → 冻结计数\n");

    /* 3. 负variation (CAPVD高于Origin, 铁块) → 冻结 */
    freeze_cnt = 0;
    assert(baseline_decide(ORIGIN + 500, ORIGIN, &freeze_cnt) == DEC_FREEZE_NEG);
    assert(freeze_cnt == 1);
    printf("[OK] 负variation(CAPVD>Origin, 铁块) → 冻结计数\n");

    /* 4. 核心修复: 负variation超时(铁块停留>10s) → Origin 绝不更新 */
    freeze_cnt = 0;
    for (int i = 0; i < FREEZE_TIMEOUT + 100; i++) {
        assert(baseline_decide(ORIGIN + 500, ORIGIN, &freeze_cnt) == DEC_FREEZE_NEG);
    }
    assert(freeze_cnt == FREEZE_TIMEOUT);   /* 饱和不更新 */
    printf("[OK] 负variation停留超时(%d tick) → Origin 保持 %lu (核心修复: 不污染)\n",
           FREEZE_TIMEOUT + 100, ORIGIN);

    /* 5. 正variation超时 → 兜底更新仍保留 (模拟 FREEZE_TIMEOUT 后 Origin=CAPVD) */
    freeze_cnt = 0;
    int updated = 0;
    for (int i = 0; i < FREEZE_TIMEOUT + 50; i++) {
        if (baseline_decide(ORIGIN - 300, ORIGIN, &freeze_cnt) == DEC_FREEZE_POS) {
            if (freeze_cnt >= FREEZE_TIMEOUT) { updated = 1; break; }
        }
    }
    assert(updated == 1);
    printf("[OK] 正variation停留超时 → 兜底更新仍保留 (车辆长时间信号不丢)\n");

    /* 6. 完整场景: 铁块靠近→停留→离开 (修复后: 不假进入, 无锁定) */
    {
        int32_t origin = (int32_t)ORIGIN;
        int32_t capvd = (int32_t)ORIGIN;
        int fake_entry = 0;
        uint32_t fcnt = 0;

        /* 铁块靠近: CAPVD 升 +500 (负variation) */
        capvd = ORIGIN + 500;
        for (int i = 0; i < 50; i++) {   /* 5s */
            dec_t d = baseline_decide(capvd, origin, &fcnt);
            assert(d == DEC_FREEZE_NEG);
        }
        assert(origin == (int32_t)ORIGIN);   /* Origin 未被污染 */

        /* 铁块离开: CAPVD 回落正常 */
        capvd = ORIGIN;
        for (int i = 0; i < 50; i++) {
            dec_t d = baseline_decide(capvd, origin, &fcnt);
            (void)d;
        }
        /* 修复后: Origin 正常 → 无假进入 (CAPVD 不低于进入线 Origin-38) */
        if (capvd < origin - DLT_ORG) fake_entry = 1;
        assert(fake_entry == 0);
        printf("[OK] 场景仿真: 铁块靠近→停留→离开, Origin 未污染, 无假进入, 无锁定\n");
    }

    printf("\n全部通过 ✓\n");
    return 0;
}