// testEngineJs.c -- a real Duktape (JavaScript) heap running on a CalogContextT
// thread, the fourth engine.
//
// Proves the CalogEngineT wiring and that the actor core drives JS exactly as it drives
// Lua/Squirrel: a JS script on jsCtx's thread calls a thread-agnostic native
// (report), a native owned by a different context (doubleIt, routed cross-thread),
// and -- exercising design.md sec 10 -- a JS closure captured on jsCtx's thread is
// invoked and released from the main thread, both marshalled back to the owner.
// Built under ASan+UBSan.

#include "calog.h"

#include <stdatomic.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

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

#define DOUBLE_EXPECTED 42
#define CALLBACK_INPUT  7
#define CALLBACK_EXPECTED 107

static CalogT         *broker        = NULL;
static CalogContextT  *jsCtx         = NULL;
static CalogContextT  *workerCtx     = NULL;
static _Atomic int64_t  reportedValue = 0;
static _Atomic uint32_t reportedCtxId = 0;
static _Atomic uint32_t doubleItCtxId = 0;
static CalogFnT *_Atomic storedCb     = NULL;
static int32_t          testsRun      = 0;
static int32_t          testsFailed   = 0;

static void    checkImpl(bool condition, const char *message, const char *file, int32_t line);
static int32_t nativeDoubleIt(CalogValueT *args, int32_t argCount, CalogValueT *result, void *userData);
static int32_t nativeReport(CalogValueT *args, int32_t argCount, CalogValueT *result, void *userData);
static int32_t nativeSetCb(CalogValueT *args, int32_t argCount, CalogValueT *result, void *userData);
static void    testCallbackAcrossContexts(void);
static void    testCrossContextFromScript(void);
static void    testScriptError(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 int32_t nativeDoubleIt(CalogValueT *args, int32_t argCount, CalogValueT *result, void *userData) {
    (void)userData;
    atomic_store(&doubleItCtxId, calogCurrentId());
    if (argCount != 1 || args[0].type != calogIntE) {
        return calogFail(result, calogErrArgE, "doubleIt expects one integer");
    }
    calogValueInt(result, args[0].as.i * 2);
    return calogOkE;
}


static int32_t nativeReport(CalogValueT *args, int32_t argCount, CalogValueT *result, void *userData) {
    (void)userData;
    if (argCount != 1 || args[0].type != calogIntE) {
        return calogFail(result, calogErrArgE, "report expects one integer");
    }
    atomic_store(&reportedCtxId, calogCurrentId());
    atomic_store(&reportedValue, args[0].as.i);
    calogValueNil(result);
    return calogOkE;
}


static int32_t nativeSetCb(CalogValueT *args, int32_t argCount, CalogValueT *result, void *userData) {
    (void)userData;
    calogValueNil(result);
    if (argCount != 1 || args[0].type != calogFnE) {
        return calogFail(result, calogErrArgE, "setCb expects one function");
    }
    // Runs on jsCtx's thread; the closure is owned by jsCtx. Retain it past this call.
    calogFnRetain(args[0].as.fn);
    atomic_store(&storedCb, args[0].as.fn);
    return calogOkE;
}


static void testCallbackAcrossContexts(void) {
    CalogFnT *callback;
    CalogValueT     arg;
    CalogValueT     result;
    int32_t    status;

    // Capture a JS closure on jsCtx's thread via setCb (owned by jsCtx).
    status = calogContextEval(jsCtx, "setCb(function(x) { return x + 100; })", &result);
    CHECK(status == calogOkE, "captured a JS closure as a CalogFnT on its owner thread");
    calogValueFree(&result);

    callback = atomic_load(&storedCb);
    CHECK(callback != NULL, "callback was stored");

    // Invoke from the MAIN thread: calogFnInvoke must marshal to jsCtx's thread
    // (design.md sec 10), so the closure runs on its owner heap, never here.
    calogValueInt(&arg, CALLBACK_INPUT);
    status = calogFnInvoke(callback, &arg, 1, &result);
    CHECK(status == calogOkE && result.type == calogIntE && result.as.i == CALLBACK_EXPECTED, "cross-thread callable invoke routed to the owner context");
    calogValueFree(&result);
    calogValueFree(&arg);

    // Release from the main thread: the registry-slot drop must run on jsCtx's heap.
    calogFnRelease(callback);
}


static void testCrossContextFromScript(void) {
    CalogValueT  result;
    int32_t status;

    status = calogContextEval(jsCtx, "report(doubleIt(21))", &result);
    CHECK(status == calogOkE, "JS script with a cross-context call ran without error");
    CHECK(atomic_load(&reportedValue) == DOUBLE_EXPECTED, "cross-context doubleIt result flowed back into the script");
    CHECK(atomic_load(&doubleItCtxId) == calogContextId(workerCtx), "doubleIt executed on the worker context's thread");
    CHECK(atomic_load(&reportedCtxId) == calogContextId(jsCtx), "report executed on the JS context's own thread");
    calogValueFree(&result);
}


static void testScriptError(void) {
    CalogValueT  result;
    int32_t status;

    status = calogContextEval(jsCtx, "@@@ not valid js @@@", &result);
    CHECK(status != calogOkE && result.type == calogStringE, "script error surfaced through result, not a crash");
    calogValueFree(&result);
}


int main(void) {
    const char *exposeNames[3];
    CalogConfigT   jsConfig;

    broker = calogCreate();
    if (broker == NULL) {
        printf("broker create failed\n");
        return 1;
    }

    calogContextCreate(broker, NULL, NULL, &workerCtx);

    exposeNames[0]       = "doubleIt";
    exposeNames[1]       = "report";
    exposeNames[2]       = "setCb";
    jsConfig.exposeNames = exposeNames;
    jsConfig.exposeCount = 3;
    calogContextCreate(broker, &calogJsEngine, &jsConfig, &jsCtx);

    // setCb is owned by jsCtx, so register it once jsCtx exists (for its id), before
    // calogContextStart exposes the names on the thread.
    calogRegister(broker, "doubleIt", nativeDoubleIt, NULL, calogContextId(workerCtx));
    calogRegister(broker, "report", nativeReport, NULL, 0);
    calogRegister(broker, "setCb", nativeSetCb, NULL, calogContextId(jsCtx));

    calogContextStart(workerCtx);
    calogContextStart(jsCtx);

    testCrossContextFromScript();
    testScriptError();
    testCallbackAcrossContexts();

    calogDestroy(broker);

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