// testEngineLua.c -- Lua on a context thread, driven the way a host drives calog:
// register natives, open a context, fire-and-forget a script, and calogPump on the
// host thread to service the script's native calls. Verifies host-thread dispatch,
// the inline escape hatch, the sec-10 cross-thread callback, the error handler, and
// concurrent contexts. Built under ASan+UBSan.

#define _POSIX_C_SOURCE 200809L

#include "calog.h"

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

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

#define PUMP_LIMIT 4000   // ~2s at 0.5ms/iter, a generous upper bound

static CalogT          *calog        = NULL;
static _Atomic int64_t  reportedValue = 0;
static _Atomic uint64_t reportedCtxId = 0xFFFFu;
static _Atomic uint64_t inlineCtxId   = 0xFFFFu;
static _Atomic int32_t  bumpCount     = 0;
static _Atomic bool     scriptDone    = false;
static _Atomic int32_t  errorCount    = 0;
static _Atomic uint64_t errorCtxId    = 0;
static CalogFnT *_Atomic storedCb      = NULL;
static _Atomic int32_t  matchCount    = 0;
static _Atomic int32_t  mismatchCount = 0;
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 nativeAdd(CalogValueT *args, int32_t argCount, CalogValueT *result, void *userData);
static int32_t nativeBump(CalogValueT *args, int32_t argCount, CalogValueT *result, void *userData);
static int32_t nativeCheckRuntime(CalogValueT *args, int32_t argCount, CalogValueT *result, void *userData);
static int32_t nativeDone(CalogValueT *args, int32_t argCount, CalogValueT *result, void *userData);
static int32_t nativeGetAdder(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 nativeReportInline(CalogValueT *args, int32_t argCount, CalogValueT *result, void *userData);
static int32_t nativeSetCb(CalogValueT *args, int32_t argCount, CalogValueT *result, void *userData);
static void    onError(uint64_t contextId, const char *message, void *userData);
static void    pumpUntilDone(void);
static void    testConcurrentContexts(void);
static void    testContextLoad(void);
static void    testCrossThreadCallback(void);
static void    testForeignFunction(void);
static void    testHostAndInlineNatives(void);
static void    testScriptError(void);
static void    testSingleThreadMultiRuntime(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 nativeAdd(CalogValueT *args, int32_t argCount, CalogValueT *result, void *userData) {
    (void)userData;
    calogValueNil(result);
    if (argCount != 2 || args[0].type != calogIntE || args[1].type != calogIntE) {
        return calogFail(result, calogErrArgE, "add expects two integers");
    }
    calogValueInt(result, args[0].as.i + args[1].as.i);
    return calogOkE;
}


static int32_t nativeBump(CalogValueT *args, int32_t argCount, CalogValueT *result, void *userData) {
    (void)args;
    (void)argCount;
    (void)userData;
    atomic_fetch_add(&bumpCount, 1);
    calogValueNil(result);
    return calogOkE;
}


static int32_t nativeCheckRuntime(CalogValueT *args, int32_t argCount, CalogValueT *result, void *userData) {
    (void)args;
    (void)argCount;
    // userData is the runtime this native was registered under. Run from a script and
    // serviced by calogPump, it must see calogCurrent() == that runtime -- which holds
    // only if pump presents the pumping thread as the pumped runtime's host, so one
    // thread can host several runtimes.
    if (calogCurrent() == (CalogT *)userData) {
        atomic_fetch_add(&matchCount, 1);
    } else {
        atomic_fetch_add(&mismatchCount, 1);
    }
    calogValueNil(result);
    return calogOkE;
}


static int32_t nativeDone(CalogValueT *args, int32_t argCount, CalogValueT *result, void *userData) {
    (void)args;
    (void)argCount;
    (void)userData;
    atomic_store(&scriptDone, true);
    calogValueNil(result);
    return calogOkE;
}


static int32_t nativeGetAdder(CalogValueT *args, int32_t argCount, CalogValueT *result, void *userData) {
    CalogFnT *callable;
    int32_t   status;

    (void)args;
    (void)argCount;
    (void)userData;
    calogValueNil(result);
    // A host-owned function value handed to the script; calling it routes back here.
    status = calogFnFromNative(&callable, calog, nativeAdd, NULL);
    if (status != calogOkE) {
        return calogFail(result, status, "getAdder could not allocate");
    }
    calogValueFn(result, callable);
    return calogOkE;
}


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


static int32_t nativeReportInline(CalogValueT *args, int32_t argCount, CalogValueT *result, void *userData) {
    (void)args;
    (void)argCount;
    (void)userData;
    atomic_store(&inlineCtxId, calogCurrentId());   // should be the script's context id
    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");
    }
    calogFnRetain(args[0].as.fn);
    atomic_store(&storedCb, args[0].as.fn);
    return calogOkE;
}


static void onError(uint64_t contextId, const char *message, void *userData) {
    (void)message;
    (void)userData;
    atomic_store(&errorCtxId, contextId);
    atomic_fetch_add(&errorCount, 1);
}


// Pump the host thread until the running script signals done (or errors), bounded.
static void pumpUntilDone(void) {
    struct timespec ts = { 0, 500000 };   // 0.5 ms
    int             errorsBefore;
    int             i;

    errorsBefore = atomic_load(&errorCount);
    for (i = 0; i < PUMP_LIMIT; i++) {
        calogPump(calog);
        if (atomic_load(&scriptDone) || atomic_load(&errorCount) != errorsBefore) {
            calogPump(calog);   // one more sweep to drain trailing calls
            return;
        }
        nanosleep(&ts, NULL);
    }
}


static void testHostAndInlineNatives(void) {
    CalogContextT *ctx;

    ctx = calogContextOpen(calog, &calogLuaEngine);
    CHECK(ctx != NULL, "opened a Lua context");

    atomic_store(&scriptDone, false);
    calogContextEval(ctx, "report(42); reportInline(1); done()");
    pumpUntilDone();

    CHECK(atomic_load(&reportedValue) == 42, "host native received the argument");
    CHECK(atomic_load(&reportedCtxId) == 0, "default native ran on the host thread (id 0)");
    CHECK(atomic_load(&inlineCtxId) == calogContextId(ctx), "inline native ran on the script's own thread");

    calogContextClose(ctx);
}


static void testCrossThreadCallback(void) {
    CalogContextT *ctx;
    CalogFnT      *callback;
    CalogValueT    arg;
    CalogValueT    result;
    int32_t        status;

    ctx = calogContextOpen(calog, &calogLuaEngine);
    atomic_store(&scriptDone, false);
    atomic_store(&storedCb, NULL);
    calogContextEval(ctx, "setCb(function(x) return x + 100 end); done()");
    pumpUntilDone();

    callback = atomic_load(&storedCb);
    CHECK(callback != NULL, "a Lua closure was captured as a CalogFnT");

    // Invoke it from the host thread: it must marshal to the Lua context's thread
    // (sec 10). calogFnInvoke blocks-and-pumps the host queue while it waits.
    calogValueInt(&arg, 7);
    status = calogFnInvoke(callback, &arg, 1, &result);
    CHECK(status == calogOkE && result.type == calogIntE && result.as.i == 107, "cross-thread callable invoke routed to the owner");
    calogValueFree(&result);
    calogValueFree(&arg);
    calogFnRelease(callback);

    calogContextClose(ctx);
}


static void testForeignFunction(void) {
    CalogContextT *ctx;

    ctx = calogContextOpen(calog, &calogLuaEngine);
    atomic_store(&scriptDone, false);
    atomic_store(&reportedValue, 0);
    // The script receives a host-owned function value and calls it.
    calogContextEval(ctx, "report(getAdder()(2, 3)); done()");
    pumpUntilDone();

    CHECK(atomic_load(&reportedValue) == 5, "script called a foreign function value pushed in from the host");

    calogContextClose(ctx);
}


static void testScriptError(void) {
    CalogContextT *ctx;
    int32_t        before;

    ctx    = calogContextOpen(calog, &calogLuaEngine);
    before = atomic_load(&errorCount);
    atomic_store(&scriptDone, false);
    calogContextEval(ctx, "@@@ not valid lua @@@");
    pumpUntilDone();

    CHECK(atomic_load(&errorCount) == before + 1, "a fire-and-forget script error reached the error handler");
    CHECK(atomic_load(&errorCtxId) == calogContextId(ctx), "the error names the failing context");

    calogContextClose(ctx);
}


static void testConcurrentContexts(void) {
    CalogContextT  *ctxs[3];
    struct timespec ts = { 0, 500000 };
    int32_t         i;

    atomic_store(&bumpCount, 0);
    for (i = 0; i < 3; i++) {
        ctxs[i] = calogContextOpen(calog, &calogLuaEngine);
        calogContextEval(ctxs[i], "bump(); bump(); bump()");
    }
    for (i = 0; i < PUMP_LIMIT && atomic_load(&bumpCount) < 9; i++) {
        calogPump(calog);
        nanosleep(&ts, NULL);
    }
    CHECK(atomic_load(&bumpCount) == 9, "three concurrent contexts all dispatched to the host thread");
    for (i = 0; i < 3; i++) {
        calogContextClose(ctxs[i]);
    }
}


static void testContextLoad(void) {
    CalogContextT  *ctx;
    struct timespec ts = { 0, 500000 };
    FILE           *file;
    int32_t         i;

    // Registration makes the Lua engine (extension "lua") a load candidate.
    calogRegisterEngine(calog, &calogLuaEngine);

    // A file whose extension matches a registered engine is found, loaded, and run.
    file = fopen("calogLoadTest.lua", "wb");
    CHECK(file != NULL, "wrote a temporary .lua script");
    if (file != NULL) {
        fputs("bump()", file);
        fclose(file);
    }
    atomic_store(&bumpCount, 0);
    ctx = calogContextLoad(calog, "calogLoadTest");
    CHECK(ctx != NULL, "calogContextLoad opened a context for the matching .lua file");
    for (i = 0; i < PUMP_LIMIT && atomic_load(&bumpCount) < 1; i++) {
        calogPump(calog);
        nanosleep(&ts, NULL);
    }
    CHECK(atomic_load(&bumpCount) == 1, "the loaded script ran on its new context");
    if (ctx != NULL) {
        calogContextClose(ctx);
    }
    remove("calogLoadTest.lua");

    // No file with a registered extension exists -> NULL.
    ctx = calogContextLoad(calog, "calogNoSuchScript");
    CHECK(ctx == NULL, "calogContextLoad returns NULL when no file matches");
}


static void testSingleThreadMultiRuntime(void) {
    CalogT         *calogB;
    CalogContextT  *ctxA;
    CalogContextT  *ctxB;
    struct timespec ts = { 0, 500000 };
    int32_t         i;

    // This one thread now hosts TWO runtimes. Each runs a script that calls a native
    // registered under a different runtime; pumping each in turn must make calogCurrent()
    // resolve to the runtime being pumped -- not whichever was created last.
    calogB = calogCreate();
    CHECK(calogB != NULL, "created a second runtime on this same thread");
    calogRegister(calog, "checkRuntime", nativeCheckRuntime, calog);
    calogRegister(calogB, "checkRuntime", nativeCheckRuntime, calogB);

    atomic_store(&matchCount, 0);
    atomic_store(&mismatchCount, 0);
    ctxA = calogContextOpen(calog, &calogLuaEngine);
    ctxB = calogContextOpen(calogB, &calogLuaEngine);
    calogContextEval(ctxA, "checkRuntime()");
    calogContextEval(ctxB, "checkRuntime()");

    for (i = 0; i < PUMP_LIMIT && (atomic_load(&matchCount) + atomic_load(&mismatchCount)) < 2; i++) {
        calogPump(calog);
        calogPump(calogB);
        nanosleep(&ts, NULL);
    }
    CHECK(atomic_load(&matchCount) == 2, "one thread pumped two runtimes; each native saw its own runtime");
    CHECK(atomic_load(&mismatchCount) == 0, "no native resolved to the wrong runtime while sharing a host thread");

    calogContextClose(ctxA);
    calogContextClose(ctxB);
    calogDestroy(calogB);
}


int main(void) {
    calog = calogCreate();
    if (calog == NULL) {
        printf("calog create failed\n");
        return 1;
    }
    calogSetErrorHandler(calog, onError, NULL);
    calogRegister(calog, "report", nativeReport, NULL);
    calogRegister(calog, "setCb", nativeSetCb, NULL);
    calogRegister(calog, "done", nativeDone, NULL);
    calogRegister(calog, "bump", nativeBump, NULL);
    calogRegister(calog, "getAdder", nativeGetAdder, NULL);
    calogRegisterInline(calog, "reportInline", nativeReportInline, NULL);

    testHostAndInlineNatives();
    testCrossThreadCallback();
    testForeignFunction();
    testScriptError();
    testConcurrentContexts();
    testSingleThreadMultiRuntime();
    testContextLoad();

    calogDestroy(calog);

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