// testHooks.c -- validates the library lifecycle hooks: calogAtDestroy (a runtime-shutdown hook run
// in one of two phases around context teardown) and calogAtContext (per-context init/shutdown run on
// each context's own thread). A monotonic sequence counter records the order of every hook event so
// the phase ordering can be asserted: before-hook < context shutdowns < after-hook.

#define _POSIX_C_SOURCE 200809L

#include "calog.h"

#include <stdatomic.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <time.h>

#define CHECK(cond, msg) checkImpl((cond), (msg), __FILE__, __LINE__)

#define PUMP_LIMIT 4000

static _Atomic int32_t seqCounter       = 0;    // hands out a global order to every hook event
static _Atomic int32_t destroyBeforeSeq = -1;
static _Atomic int32_t destroyAfterSeq  = -1;
static _Atomic int32_t initCount        = 0;
static _Atomic int32_t shutdownCount    = 0;
static _Atomic int32_t firstShutdownSeq = -1;
static _Atomic int32_t lastShutdownSeq  = -1;
static _Atomic int64_t seenUserData     = 0;
static _Atomic bool    lateOpenSucceeded = false;   // a context opened DURING teardown (must not happen)
static _Atomic bool    lateEvalAccepted  = false;   // work queued onto a context that has stopped serving
static int32_t         testsRun         = 0;
static int32_t         testsFailed      = 0;
static int32_t         userToken        = 0x5A5A;
static CalogT         *calog             = NULL;   // file scope: the shutdown hook reaches it too

static void checkImpl(bool condition, const char *message, const char *file, int32_t line);
static void contextInitHook(CalogContextT *context, void *userData);
static void contextShutdownHook(CalogContextT *context, void *userData);
static void destroyAfterHook(void);
static void destroyBeforeHook(void);


static void checkImpl(bool condition, const char *message, const char *file, int32_t line) {
    testsRun++;
    if (!condition) {
        testsFailed++;
        printf("FAIL %s:%d  %s\n", file, line, message);
    }
}


static void contextInitHook(CalogContextT *context, void *userData) {
    (void)context;
    atomic_fetch_add(&seqCounter, 1);
    atomic_fetch_add(&initCount, 1);
    atomic_store(&seenUserData, (int64_t)*(int32_t *)userData);
}


static void contextShutdownHook(CalogContextT *context, void *userData) {
    CalogContextT *late;
    int32_t        seq;
    int32_t        expected;

    (void)userData;
    seq = atomic_fetch_add(&seqCounter, 1);
    atomic_fetch_add(&shutdownCount, 1);
    expected = -1;
    atomic_compare_exchange_strong(&firstShutdownSeq, &expected, seq);
    atomic_store(&lastShutdownSeq, seq);
    // This hook runs on the context's own thread while calogDestroy is walking the registry -- the
    // one window where a script (taskSpawn) could still ask for a context the teardown has already
    // walked past, then be freed with its thread running. Opening one has to be refused here.
    (void)context;
    late = calogContextOpen(calog, &calogLuaEngine);
    if (late != NULL) {
        atomic_store(&lateOpenSucceeded, true);
        calogContextClose(late);
    }
    // Same window, the other half: this hook runs AFTER serveLoop stopped serving and BEFORE the
    // interpreter is marked dead, so the context still resolves in the registry. Queueing work here
    // used to be accepted and then never served -- a fire-and-forget eval silently dropped, and a
    // blocking caller left waiting on a reply that could not come. It must be refused.
    if (calogContextEval(context, "local dropped = 1") == calogOkE) {
        atomic_store(&lateEvalAccepted, true);
    }
}


static void destroyAfterHook(void) {
    atomic_store(&destroyAfterSeq, atomic_fetch_add(&seqCounter, 1));
}


static void destroyBeforeHook(void) {
    atomic_store(&destroyBeforeSeq, atomic_fetch_add(&seqCounter, 1));
}


int main(void) {
    CalogContextT  *ctxA;
    CalogContextT  *ctxB;
    struct timespec ts = { 0, 500000 };
    int32_t         i;

    calog = calogCreate();
    if (calog == NULL) {
        printf("calog create failed\n");
        return 1;
    }
    calogAtDestroy(calog, destroyBeforeHook, calogDestroyBeforeContextsE);
    calogAtDestroy(calog, destroyAfterHook, calogDestroyAfterContextsE);
    calogAtContext(calog, contextInitHook, contextShutdownHook, &userToken);

    ctxA = calogContextOpen(calog, &calogLuaEngine);
    ctxB = calogContextOpen(calog, &calogLuaEngine);
    calogContextEval(ctxA, "local a = 1");
    calogContextEval(ctxB, "local b = 2");
    for (i = 0; i < PUMP_LIMIT; i++) {
        calogPump(calog);
        if (atomic_load(&initCount) >= 2) {
            break;
        }
        nanosleep(&ts, NULL);
    }

    CHECK(atomic_load(&initCount) == 2, "per-context init hook fired once per context");
    CHECK(atomic_load(&seenUserData) == 0x5A5A, "context hook received its registered userData");

    calogDestroy(calog);   // before-hook -> tear down contexts (their shutdown hooks) -> after-hook

    CHECK(atomic_load(&shutdownCount) == 2, "per-context shutdown hook fired once per context");
    CHECK(!atomic_load(&lateOpenSucceeded), "opening a context during teardown is refused, not registered too late");
    CHECK(!atomic_load(&lateEvalAccepted), "queueing work onto a context that has stopped serving is refused, not orphaned");
    CHECK(atomic_load(&destroyBeforeSeq) >= 0, "before-context destroy hook fired");
    CHECK(atomic_load(&destroyAfterSeq) >= 0, "after-context destroy hook fired");
    CHECK(atomic_load(&destroyBeforeSeq) < atomic_load(&firstShutdownSeq), "before-hook ran before context teardown");
    CHECK(atomic_load(&lastShutdownSeq) < atomic_load(&destroyAfterSeq), "after-hook ran after context teardown");

    printf("\n%d checks, %d failed\n", testsRun, testsFailed);
    fflush(stdout);
    if (testsFailed != 0) {
        return 1;
    }
    return 0;
}