/* test_meow_cachegov.c — 宿主测试：SDK meow_cachegov（A：DONTNEED L0/L1 + refault 回退）。
 *
 * 背景（OOM_PAGECACHE_GOVERNANCE §2/§4，③混合）：A 的 DONTNEED/read_pos 热路径随 SDK 库；
 * 本测试用宿主桩：
 *   - 真实 posix_fadvise（文件数据完整性校验：drop 后文件内容不变、drop_finished 可再读）；
 *   - meow_log 桩捕获 "[cachegov] L1 drop off=.. len=.." 断言丢弃范围（[0, read_pos-keep_hot)）；
 *   - meow_cachegov_test_set_time_ms() 注入时钟驱动 refault 滚窗回退（放大 keep_hot→降L0→关A）；
 *   - MEOW_CACHEGOV_C_FILE 指向临时文件写入 fake C 状态，断言 download_paused/prefetch_paused。
 *
 * 编译（patch_v2/sdk 目录下）：
 *   gcc -Os -Wall -Wextra -I. -Iinclude -I../meow_launcherd -c meow_cachegov.c -o /tmp/cg.o
 *   gcc -Os -Wall -Wextra -I. -Iinclude -I../meow_launcherd test_meow_cachegov.c /tmp/cg.o -lpthread -o test_meow_cachegov
 * 运行：./test_meow_cachegov   （exit 0=PASS / 1=FAIL）
 */
#define _GNU_SOURCE
#include "meow_cachegov.h"

#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>

/* ---- meow_log 桩：捕获最近一条 [cachegov] 行，供断言 ---- */
static char g_last_log[512];
void meow_log(int lvl, const char *fmt, ...)
{
    (void)lvl;
    va_list ap; va_start(ap, fmt);
    vsnprintf(g_last_log, sizeof g_last_log, fmt, ap);
    va_end(ap);
    printf("  [cachegov.log] %s\n", g_last_log);
}
static int log_has(const char *needle) { return strstr(g_last_log, needle) != NULL; }

static int g_pass = 0, g_fail = 0;
static void check(const char *name, int cond)
{
    if (cond) { g_pass++; printf("PASS %s\n", name); }
    else { g_fail++; printf("FAIL %s\n", name); }
}

/* ---- read_pos 桩：由测试驱动当前读指针 ---- */
static uint64_t g_pos;
static uint64_t fake_read_pos(void *ctx) { (void)ctx; return g_pos; }

/* 建一个 size 字节的临时文件并填充确定性内容。 */
static int make_file(const char *path, size_t size)
{
    int fd = open(path, O_WRONLY | O_CREAT | O_TRUNC, 0644);
    if (fd < 0) return -1;
    for (size_t off = 0; off < size; off += 4096) {
        char tmp[4096];
        memset(tmp, (int)(off / 4096) & 0xFF, sizeof tmp);
        size_t n = (size - off) < sizeof tmp ? (size - off) : sizeof tmp;
        if (write(fd, tmp, n) != (ssize_t)n) { close(fd); return -1; }
    }
    close(fd);
    return 0;
}

/* 校验文件内容仍为确定性模式（drop 后数据完整）。 */
static int verify_file(const char *path, size_t size)
{
    int fd = open(path, O_RDONLY);
    if (fd < 0) return 0;
    char tmp[4096];
    size_t off = 0;
    int ok = 1;
    while (off < size) {
        size_t n = (size - off) < sizeof tmp ? (size - off) : sizeof tmp;
        ssize_t r = read(fd, tmp, n);
        if (r != (ssize_t)n) { ok = 0; break; }
        char expect[4096];
        memset(expect, (int)(off / 4096) & 0xFF, n);
        if (memcmp(tmp, expect, n) != 0) { ok = 0; break; }
        off += (size_t)n;
    }
    close(fd);
    return ok;
}

int main(void)
{
    char path[320], cfile[360];
    snprintf(path, sizeof path, "/tmp/meow_cg_%ld.bin", (long)getpid());
    snprintf(cfile, sizeof cfile, "/tmp/meow_cg_%ld.state", (long)getpid());
    setenv("MEOW_CACHEGOV_C_FILE", cfile, 1);
    unlink(path); unlink(cfile);

    const size_t size = 1024u * 1024u;   /* 1MB 测试文件 */
    check("make_file", make_file(path, size) == 0);

    /* 1) cfg：默认 + set/get 往返 */
    struct meow_cachegov_cfg c = {0};
    meow_cachegov_get_cfg(&c);
    check("cfg default enabled", c.enabled == 1);
    check("cfg default keep_hot=256KB", c.keep_hot_bytes == 256u * 1024u);
    struct meow_cachegov_cfg c2 = c;
    c2.keep_hot_bytes = 128u * 1024u;
    c2.drop_mode = 1;
    c2.refault_backoff = 2;
    check("set_cfg", meow_cachegov_set_cfg(&c2) == 0);
    meow_cachegov_get_cfg(&c);
    check("get_cfg roundtrip", c.keep_hot_bytes == 128u * 1024u && c.drop_mode == 1 && c.refault_backoff == 2);

    /* 2) L1 drop：read_pos=512KB、keep_hot=128KB → drop [0, 384KB) off=0 len=384KB */
    check("register", meow_cachegov_register(path, size, fake_read_pos, NULL) == 0);
    g_pos = 512u * 1024u;
    meow_cachegov_tick();
    check("L1 drop off=0 len=384KB", log_has("L1 drop") && strstr(g_last_log, "off=0 len=393216"));
    check("L1 range bounded by read_pos-keep_hot (no L2)",
          !strstr(g_last_log, "off=393216") && strstr(g_last_log, "len=393216"));

    /* 3) L1 推进：read_pos=800KB → drop [384KB, 800-128KB=672KB) off=384KB len=288KB */
    g_pos = 800u * 1024u;
    meow_cachegov_tick();
    check("L1 drop off=384KB len=288KB", log_has("L1 drop") && strstr(g_last_log, "off=393216") && strstr(g_last_log, "len=294912"));

    /* 4) refault 回退档1（放大 keep_hot 翻倍）：3 次触发 2 次 → 0→1（每升降一档需间隔 ≥10s */
    meow_cachegov_test_set_time_ms(0);
    meow_cachegov_note_refault(); meow_cachegov_note_refault();
    meow_cachegov_tick();
    check("backoff -> 1 (refault*2)", meow_cachegov_backoff_level() == 1);
    check("file intact after backoff1", verify_file(path, size));
    /* 档1 且 keep_hot=128KB*2=256KB：read_pos=1000KB → drop 上界=744KB（已丢到 672KB） */
    g_pos = 1000u * 1024u;
    meow_cachegov_tick();
    check("backoff1 L1 keep_hot enlarged (no L2)", meow_cachegov_backoff_level() == 1);

    /* 5) 再 2 次（间隔 10s）→ 档2（L1 关，只 L0）→ download_paused=1 */
    meow_cachegov_test_set_time_ms(11000);
    meow_cachegov_note_refault(); meow_cachegov_note_refault();
    meow_cachegov_tick();
    check("backoff -> 2 (L1 off)", meow_cachegov_backoff_level() == 2);
    g_pos = 900u * 1024u;
    meow_cachegov_tick();   /* L1 off：应无新的 L1 drop 日志 */
    check("level2 no L1 drop (only L0)", !log_has("L1 drop"));
    check("download_paused @backoff>=2", meow_cachegov_download_paused() == 1);

    /* 6) 再 2 次（间隔 10s）→ 档3（A 全关）→ prefetch_paused=1 + drop_finished 不再丢页 */
    meow_cachegov_test_set_time_ms(22000);
    meow_cachegov_note_refault(); meow_cachegov_note_refault();
    meow_cachegov_tick();
    check("backoff -> 3 (A off)", meow_cachegov_backoff_level() == 3);
    check("prefetch_paused @backoff>=3", meow_cachegov_prefetch_paused() == 1);
    meow_cachegov_test_set_time_ms(23000);
    meow_cachegov_drop_finished(path);
    check("drop_finished skip @A-off", log_has("drop_finished skip"));
    check("file intact after A-off", verify_file(path, size));

    /* 7) C 侧降载：write fake C state dl_pause=1；滚窗干净逐级降回 0 后 download_paused 仍 =1 */
    {
        FILE *f = fopen(cfile, "w");
        check("write C state", f != NULL);
        if (f) { fputs("cached_kb=35000\ndirty_kb=1000\ndl_pause=1\nprefetch_pause=0\n", f); fclose(f); }
    }
    meow_cachegov_test_set_time_ms(33000);
    meow_cachegov_tick();               /* 3→2 */
    meow_cachegov_test_set_time_ms(44000);
    meow_cachegov_tick();               /* 2→1 */
    meow_cachegov_test_set_time_ms(55000);
    meow_cachegov_tick();               /* 1→0 */
    check("backoff de-escalated to 0", meow_cachegov_backoff_level() == 0);
    check("download_paused via C file", meow_cachegov_download_paused() == 1);

    /* 8) L0 drop_finished（A 正常态）：整文件 DONTNEED + 数据完整 + 注销条目 */
    unlink(cfile);
    meow_cachegov_register(path, size, fake_read_pos, NULL);
    meow_cachegov_test_set_time_ms(66000);
    meow_cachegov_drop_finished(path);
    check("drop_finished L0 log", log_has("drop_finished L0"));
    check("file intact after L0", verify_file(path, size));
    check("unregister removes entry", meow_cachegov_unregister(path) != 0);  /* 已注销 → 找不到 */

    /* 9) disable 时 drop/tick 均 no-op：数据仍完整 */
    c2.enabled = 0; meow_cachegov_set_cfg(&c2);
    meow_cachegov_register(path, size, fake_read_pos, NULL);
    g_pos = 512u * 1024u;
    meow_cachegov_tick();
    meow_cachegov_drop_finished(path);
    check("file intact when disabled", verify_file(path, size));

    unlink(path); unlink(cfile);
    printf("----\n%d passed, %d failed\n", g_pass, g_fail);
    return g_fail ? 1 : 0;
}