/* Copyright (c) 2013-2014 Jeffrey Pfau
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "gba-thread.h"

#include "arm.h"
#include "gba.h"
#include "gba-config.h"
#include "gba-serialize.h"

#include "debugger/debugger.h"

#include "util/patch.h"
#include "util/png-io.h"
#include "util/vfs.h"

#include "platform/commandline.h"

#include <signal.h>

static const float _defaultFPSTarget = 60.f;

#ifdef USE_PTHREADS
static pthread_key_t _contextKey;
static pthread_once_t _contextOnce = PTHREAD_ONCE_INIT;

static void _createTLS(void) {
	pthread_key_create(&_contextKey, 0);
}
#elif _WIN32
static DWORD _contextKey;
static INIT_ONCE _contextOnce = INIT_ONCE_STATIC_INIT;

static BOOL CALLBACK _createTLS(PINIT_ONCE once, PVOID param, PVOID* context) {
	UNUSED(once);
	UNUSED(param);
	UNUSED(context);
	_contextKey = TlsAlloc();
	return TRUE;
}
#endif

#ifndef DISABLE_THREADING
static void _changeState(struct GBAThread* threadContext, enum ThreadState newState, bool broadcast) {
	MutexLock(&threadContext->stateMutex);
	threadContext->state = newState;
	if (broadcast) {
		ConditionWake(&threadContext->stateCond);
	}
	MutexUnlock(&threadContext->stateMutex);
}

static void _waitOnInterrupt(struct GBAThread* threadContext) {
	while (threadContext->state == THREAD_INTERRUPTED) {
		ConditionWait(&threadContext->stateCond, &threadContext->stateMutex);
	}
}

static void _waitUntilNotState(struct GBAThread* threadContext, enum ThreadState oldState) {
	while (threadContext->state == oldState) {
		MutexUnlock(&threadContext->stateMutex);

		MutexLock(&threadContext->sync.videoFrameMutex);
		ConditionWake(&threadContext->sync.videoFrameRequiredCond);
		MutexUnlock(&threadContext->sync.videoFrameMutex);

		MutexLock(&threadContext->sync.audioBufferMutex);
		ConditionWake(&threadContext->sync.audioRequiredCond);
		MutexUnlock(&threadContext->sync.audioBufferMutex);

		MutexLock(&threadContext->stateMutex);
		ConditionWake(&threadContext->stateCond);
	}
}

static void _pauseThread(struct GBAThread* threadContext, bool onThread) {
	if (threadContext->debugger && threadContext->debugger->state == DEBUGGER_RUNNING) {
		threadContext->debugger->state = DEBUGGER_EXITING;
	}
	threadContext->state = THREAD_PAUSING;
	if (!onThread) {
		_waitUntilNotState(threadContext, THREAD_PAUSING);
	}
}
#endif

static void _changeVideoSync(struct GBASync* sync, bool frameOn) {
	// Make sure the video thread can process events while the GBA thread is paused
	MutexLock(&sync->videoFrameMutex);
	if (frameOn != sync->videoFrameOn) {
		sync->videoFrameOn = frameOn;
		ConditionWake(&sync->videoFrameAvailableCond);
	}
	MutexUnlock(&sync->videoFrameMutex);
}

#ifndef DISABLE_THREADING
static THREAD_ENTRY _GBAThreadRun(void* context) {
#ifdef USE_PTHREADS
	pthread_once(&_contextOnce, _createTLS);
#else
	InitOnceExecuteOnce(&_contextOnce, _createTLS, NULL, 0);
#endif

	struct GBA gba;
	struct ARMCore cpu;
	struct Patch patch;
	struct GBAThread* threadContext = context;
	struct ARMComponent* components[1] = {};
	int numComponents = 0;

	if (threadContext->debugger) {
		components[numComponents] = &threadContext->debugger->d;
		++numComponents;
	}

#if !defined(_WIN32) && defined(USE_PTHREADS)
	sigset_t signals;
	sigemptyset(&signals);
	pthread_sigmask(SIG_SETMASK, &signals, 0);
#endif

	GBACreate(&gba);
	ARMSetComponents(&cpu, &gba.d, numComponents, components);
	ARMInit(&cpu);
	gba.sync = &threadContext->sync;
	threadContext->gba = &gba;
	gba.logLevel = threadContext->logLevel;
#ifdef USE_PTHREADS
	pthread_setspecific(_contextKey, threadContext);
#else
	TlsSetValue(_contextKey, threadContext);
#endif

	if (threadContext->audioBuffers) {
		GBAAudioResizeBuffer(&gba.audio, threadContext->audioBuffers);
	} else {
		threadContext->audioBuffers = GBA_AUDIO_SAMPLES;
	}

	if (threadContext->renderer) {
		GBAVideoAssociateRenderer(&gba.video, threadContext->renderer);
	}

	if (threadContext->rom) {
		GBALoadROM(&gba, threadContext->rom, threadContext->save, threadContext->fname);
		if (threadContext->bios) {
			GBALoadBIOS(&gba, threadContext->bios);
		}

		if (threadContext->patch && loadPatch(threadContext->patch, &patch)) {
			GBAApplyPatch(&gba, &patch);
		}
	}

	ARMReset(&cpu);

	if (threadContext->debugger) {
		threadContext->debugger->log = GBADebuggerLogShim;
		GBAAttachDebugger(&gba, threadContext->debugger);
		ARMDebuggerEnter(threadContext->debugger, DEBUGGER_ENTER_ATTACHED);
	}

	GBASIOSetDriverSet(&gba.sio, &threadContext->sioDrivers);

	gba.keySource = &threadContext->activeKeys;

	if (threadContext->startCallback) {
		threadContext->startCallback(threadContext);
	}

	_changeState(threadContext, THREAD_RUNNING, true);

	while (threadContext->state < THREAD_EXITING) {
		if (threadContext->debugger) {
			struct ARMDebugger* debugger = threadContext->debugger;
			ARMDebuggerRun(debugger);
			if (debugger->state == DEBUGGER_SHUTDOWN) {
				_changeState(threadContext, THREAD_EXITING, false);
			}
		} else {
			while (threadContext->state == THREAD_RUNNING) {
				ARMRunLoop(&cpu);
			}
		}

		int resetScheduled = 0;
		MutexLock(&threadContext->stateMutex);
		while (threadContext->state > THREAD_RUNNING && threadContext->state < THREAD_EXITING) {
			if (threadContext->state == THREAD_PAUSING) {
				threadContext->state = THREAD_PAUSED;
				ConditionWake(&threadContext->stateCond);
			}
			if (threadContext->state == THREAD_INTERRUPTING) {
				threadContext->state = THREAD_INTERRUPTED;
				ConditionWake(&threadContext->stateCond);
			}
			if (threadContext->state == THREAD_RESETING) {
				threadContext->state = THREAD_RUNNING;
				resetScheduled = 1;
			}
			while (threadContext->state == THREAD_PAUSED || threadContext->state == THREAD_INTERRUPTED) {
				ConditionWait(&threadContext->stateCond, &threadContext->stateMutex);
			}
		}
		MutexUnlock(&threadContext->stateMutex);
		if (resetScheduled) {
			ARMReset(&cpu);
		}
	}

	while (threadContext->state != THREAD_SHUTDOWN) {
		_changeState(threadContext, THREAD_SHUTDOWN, false);
	}

	if (threadContext->cleanCallback) {
		threadContext->cleanCallback(threadContext);
	}

	threadContext->gba = 0;
	ARMDeinit(&cpu);
	GBADestroy(&gba);

	threadContext->sync.videoFrameOn = false;
	ConditionWake(&threadContext->sync.videoFrameAvailableCond);
	ConditionWake(&threadContext->sync.audioRequiredCond);

	return 0;
}

void GBAMapOptionsToContext(const struct GBAOptions* opts, struct GBAThread* threadContext) {
	threadContext->bios = VFileOpen(opts->bios, O_RDONLY);
	threadContext->frameskip = opts->frameskip;
	threadContext->logLevel = opts->logLevel;
	threadContext->rewindBufferCapacity = opts->rewindBufferCapacity;
	threadContext->rewindBufferInterval = opts->rewindBufferInterval;
	threadContext->sync.audioWait = opts->audioSync;
	threadContext->sync.videoFrameWait = opts->videoSync;

	if (opts->fpsTarget) {
		threadContext->fpsTarget = opts->fpsTarget;
	}

	if (opts->audioBuffers) {
		threadContext->audioBuffers = opts->audioBuffers;
	}
}

void GBAMapArgumentsToContext(const struct GBAArguments* args, struct GBAThread* threadContext) {
	if (args->dirmode) {
		threadContext->gameDir = VDirOpen(args->fname);
		threadContext->stateDir = threadContext->gameDir;
	} else {
		threadContext->rom = VFileOpen(args->fname, O_RDONLY);
#if ENABLE_LIBZIP
		threadContext->gameDir = VDirOpenZip(args->fname, 0);
#endif
	}
	threadContext->fname = args->fname;
	threadContext->patch = VFileOpen(args->patch, O_RDONLY);
}

bool GBAThreadStart(struct GBAThread* threadContext) {
	// TODO: error check
	threadContext->activeKeys = 0;
	threadContext->state = THREAD_INITIALIZED;
	threadContext->sync.videoFrameOn = true;
	threadContext->sync.videoFrameSkip = 0;

	threadContext->rewindBufferNext = threadContext->rewindBufferInterval;
	threadContext->rewindBufferSize = 0;
	if (threadContext->rewindBufferCapacity) {
		threadContext->rewindBuffer = calloc(threadContext->rewindBufferCapacity, sizeof(void*));
	} else {
		threadContext->rewindBuffer = 0;
	}

	if (!threadContext->fpsTarget) {
		threadContext->fpsTarget = _defaultFPSTarget;
	}

	if (threadContext->rom && !GBAIsROM(threadContext->rom)) {
		threadContext->rom->close(threadContext->rom);
		threadContext->rom = 0;
	}

	if (threadContext->gameDir) {
		threadContext->gameDir->rewind(threadContext->gameDir);
		struct VDirEntry* dirent = threadContext->gameDir->listNext(threadContext->gameDir);
		while (dirent) {
			struct Patch patchTemp;
			struct VFile* vf = threadContext->gameDir->openFile(threadContext->gameDir, dirent->name(dirent), O_RDONLY);
			if (!vf) {
				continue;
			}
			if (!threadContext->rom && GBAIsROM(vf)) {
				threadContext->rom = vf;
			} else if (!threadContext->patch && loadPatch(vf, &patchTemp)) {
				threadContext->patch = vf;
			} else {
				vf->close(vf);
			}
			dirent = threadContext->gameDir->listNext(threadContext->gameDir);
		}

	}

	if (!threadContext->rom) {
		threadContext->state = THREAD_SHUTDOWN;
		return false;
	}

	threadContext->save = VDirOptionalOpenFile(threadContext->stateDir, threadContext->fname, "sram", ".sav", O_CREAT | O_RDWR);

	MutexInit(&threadContext->stateMutex);
	ConditionInit(&threadContext->stateCond);

	MutexInit(&threadContext->sync.videoFrameMutex);
	ConditionInit(&threadContext->sync.videoFrameAvailableCond);
	ConditionInit(&threadContext->sync.videoFrameRequiredCond);
	MutexInit(&threadContext->sync.audioBufferMutex);
	ConditionInit(&threadContext->sync.audioRequiredCond);

	threadContext->interruptDepth = 0;

#ifndef _WIN32
	sigset_t signals;
	sigemptyset(&signals);
	sigaddset(&signals, SIGINT);
	sigaddset(&signals, SIGTRAP);
	pthread_sigmask(SIG_BLOCK, &signals, 0);
#endif

	MutexLock(&threadContext->stateMutex);
	ThreadCreate(&threadContext->thread, _GBAThreadRun, threadContext);
	while (threadContext->state < THREAD_RUNNING) {
		ConditionWait(&threadContext->stateCond, &threadContext->stateMutex);
	}
	MutexUnlock(&threadContext->stateMutex);

	return true;
}

bool GBAThreadHasStarted(struct GBAThread* threadContext) {
	bool hasStarted;
	MutexLock(&threadContext->stateMutex);
	hasStarted = threadContext->state > THREAD_INITIALIZED;
	MutexUnlock(&threadContext->stateMutex);
	return hasStarted;
}

void GBAThreadEnd(struct GBAThread* threadContext) {
	MutexLock(&threadContext->stateMutex);
	if (threadContext->debugger && threadContext->debugger->state == DEBUGGER_RUNNING) {
		threadContext->debugger->state = DEBUGGER_EXITING;
	}
	threadContext->state = THREAD_EXITING;
	ConditionWake(&threadContext->stateCond);
	MutexUnlock(&threadContext->stateMutex);
	MutexLock(&threadContext->sync.audioBufferMutex);
	threadContext->sync.audioWait = 0;
	ConditionWake(&threadContext->sync.audioRequiredCond);
	MutexUnlock(&threadContext->sync.audioBufferMutex);
}

void GBAThreadReset(struct GBAThread* threadContext) {
	MutexLock(&threadContext->stateMutex);
	_waitOnInterrupt(threadContext);
	threadContext->state = THREAD_RESETING;
	ConditionWake(&threadContext->stateCond);
	MutexUnlock(&threadContext->stateMutex);
}

void GBAThreadJoin(struct GBAThread* threadContext) {
	MutexLock(&threadContext->sync.videoFrameMutex);
	threadContext->sync.videoFrameWait = 0;
	ConditionWake(&threadContext->sync.videoFrameRequiredCond);
	MutexUnlock(&threadContext->sync.videoFrameMutex);

	ThreadJoin(threadContext->thread);

	MutexDeinit(&threadContext->stateMutex);
	ConditionDeinit(&threadContext->stateCond);

	MutexDeinit(&threadContext->sync.videoFrameMutex);
	ConditionWake(&threadContext->sync.videoFrameAvailableCond);
	ConditionDeinit(&threadContext->sync.videoFrameAvailableCond);
	ConditionWake(&threadContext->sync.videoFrameRequiredCond);
	ConditionDeinit(&threadContext->sync.videoFrameRequiredCond);

	ConditionWake(&threadContext->sync.audioRequiredCond);
	ConditionDeinit(&threadContext->sync.audioRequiredCond);
	MutexDeinit(&threadContext->sync.audioBufferMutex);

	int i;
	for (i = 0; i < threadContext->rewindBufferCapacity; ++i) {
		if (threadContext->rewindBuffer[i]) {
			GBADeallocateState(threadContext->rewindBuffer[i]);
		}
	}
	free(threadContext->rewindBuffer);

	if (threadContext->rom) {
		threadContext->rom->close(threadContext->rom);
		threadContext->rom = 0;
	}

	if (threadContext->save) {
		threadContext->save->close(threadContext->save);
		threadContext->save = 0;
	}

	if (threadContext->bios) {
		threadContext->bios->close(threadContext->bios);
		threadContext->bios = 0;
	}

	if (threadContext->patch) {
		threadContext->patch->close(threadContext->patch);
		threadContext->patch = 0;
	}

	if (threadContext->gameDir) {
		if (threadContext->stateDir == threadContext->gameDir) {
			threadContext->stateDir = 0;
		}
		threadContext->gameDir->close(threadContext->gameDir);
		threadContext->gameDir = 0;
	}

	if (threadContext->stateDir) {
		threadContext->stateDir->close(threadContext->stateDir);
		threadContext->stateDir = 0;
	}
}

bool GBAThreadIsActive(struct GBAThread* threadContext) {
	return threadContext->state >= THREAD_RUNNING && threadContext->state < THREAD_EXITING;
}

void GBAThreadInterrupt(struct GBAThread* threadContext) {
	MutexLock(&threadContext->stateMutex);
	++threadContext->interruptDepth;
	if (threadContext->interruptDepth > 1 || !GBAThreadIsActive(threadContext)) {
		MutexUnlock(&threadContext->stateMutex);
		return;
	}
	threadContext->savedState = threadContext->state;
	_waitOnInterrupt(threadContext);
	threadContext->state = THREAD_INTERRUPTING;
	if (threadContext->debugger && threadContext->debugger->state == DEBUGGER_RUNNING) {
		threadContext->debugger->state = DEBUGGER_EXITING;
	}
	ConditionWake(&threadContext->stateCond);
	_waitUntilNotState(threadContext, THREAD_INTERRUPTING);
	MutexUnlock(&threadContext->stateMutex);
}

void GBAThreadContinue(struct GBAThread* threadContext) {
	MutexLock(&threadContext->stateMutex);
	--threadContext->interruptDepth;
	if (threadContext->interruptDepth < 1 && GBAThreadIsActive(threadContext)) {
		threadContext->state = threadContext->savedState;
		ConditionWake(&threadContext->stateCond);
	}
	MutexUnlock(&threadContext->stateMutex);
}

void GBAThreadPause(struct GBAThread* threadContext) {
	bool frameOn = true;
	MutexLock(&threadContext->stateMutex);
	_waitOnInterrupt(threadContext);
	if (threadContext->state == THREAD_RUNNING) {
		_pauseThread(threadContext, false);
		frameOn = false;
	}
	MutexUnlock(&threadContext->stateMutex);

	_changeVideoSync(&threadContext->sync, frameOn);
}

void GBAThreadUnpause(struct GBAThread* threadContext) {
	MutexLock(&threadContext->stateMutex);
	_waitOnInterrupt(threadContext);
	if (threadContext->state == THREAD_PAUSED || threadContext->state == THREAD_PAUSING) {
		threadContext->state = THREAD_RUNNING;
		ConditionWake(&threadContext->stateCond);
	}
	MutexUnlock(&threadContext->stateMutex);

	_changeVideoSync(&threadContext->sync, true);
}

bool GBAThreadIsPaused(struct GBAThread* threadContext) {
	bool isPaused;
	MutexLock(&threadContext->stateMutex);
	_waitOnInterrupt(threadContext);
	isPaused = threadContext->state == THREAD_PAUSED;
	MutexUnlock(&threadContext->stateMutex);
	return isPaused;
}

void GBAThreadTogglePause(struct GBAThread* threadContext) {
	bool frameOn = true;
	MutexLock(&threadContext->stateMutex);
	_waitOnInterrupt(threadContext);
	if (threadContext->state == THREAD_PAUSED || threadContext->state == THREAD_PAUSING) {
		threadContext->state = THREAD_RUNNING;
		ConditionWake(&threadContext->stateCond);
	} else if (threadContext->state == THREAD_RUNNING) {
		_pauseThread(threadContext, false);
		frameOn = false;
	}
	MutexUnlock(&threadContext->stateMutex);

	_changeVideoSync(&threadContext->sync, frameOn);
}

void GBAThreadPauseFromThread(struct GBAThread* threadContext) {
	bool frameOn = true;
	MutexLock(&threadContext->stateMutex);
	_waitOnInterrupt(threadContext);
	if (threadContext->state == THREAD_RUNNING) {
		_pauseThread(threadContext, true);
		frameOn = false;
	}
	MutexUnlock(&threadContext->stateMutex);

	_changeVideoSync(&threadContext->sync, frameOn);
}

#ifdef USE_PTHREADS
struct GBAThread* GBAThreadGetContext(void) {
	pthread_once(&_contextOnce, _createTLS);
	return pthread_getspecific(_contextKey);
}
#elif _WIN32
struct GBAThread* GBAThreadGetContext(void) {
	InitOnceExecuteOnce(&_contextOnce, _createTLS, NULL, 0);
	return TlsGetValue(_contextKey);
}
#endif

#ifdef USE_PNG
void GBAThreadTakeScreenshot(struct GBAThread* threadContext) {
	unsigned stride;
	void* pixels = 0;
	struct VFile* vf = VDirOptionalOpenIncrementFile(threadContext->stateDir, threadContext->gba->activeFile, "screenshot", "-", ".png", O_CREAT | O_TRUNC | O_WRONLY);
	threadContext->gba->video.renderer->getPixels(threadContext->gba->video.renderer, &stride, &pixels);
	png_structp png = PNGWriteOpen(vf);
	png_infop info = PNGWriteHeader(png, VIDEO_HORIZONTAL_PIXELS, VIDEO_VERTICAL_PIXELS);
	PNGWritePixels(png, VIDEO_HORIZONTAL_PIXELS, VIDEO_VERTICAL_PIXELS, stride, pixels);
	PNGWriteClose(png, info);
	vf->close(vf);
}
#endif

#else
struct GBAThread* GBAThreadGetContext(void) {
	return 0;
}
#endif

void GBASyncPostFrame(struct GBASync* sync) {
	if (!sync) {
		return;
	}

	MutexLock(&sync->videoFrameMutex);
	++sync->videoFramePending;
	--sync->videoFrameSkip;
	if (sync->videoFrameSkip < 0) {
		do {
			ConditionWake(&sync->videoFrameAvailableCond);
			if (sync->videoFrameWait) {
				ConditionWait(&sync->videoFrameRequiredCond, &sync->videoFrameMutex);
			}
		} while (sync->videoFrameWait && sync->videoFramePending);
	}
	MutexUnlock(&sync->videoFrameMutex);

	struct GBAThread* thread = GBAThreadGetContext();
	if (!thread) {
		return;
	}

	if (thread->rewindBuffer) {
		--thread->rewindBufferNext;
		if (thread->rewindBufferNext <= 0) {
			thread->rewindBufferNext = thread->rewindBufferInterval;
			GBARecordFrame(thread);
		}
	}
	if (thread->stream) {
		thread->stream->postVideoFrame(thread->stream, thread->renderer);
	}
	if (thread->frameCallback) {
		thread->frameCallback(thread);
	}
}

bool GBASyncWaitFrameStart(struct GBASync* sync, int frameskip) {
	if (!sync) {
		return true;
	}

	MutexLock(&sync->videoFrameMutex);
	ConditionWake(&sync->videoFrameRequiredCond);
	if (!sync->videoFrameOn && !sync->videoFramePending) {
		return false;
	}
	if (sync->videoFrameOn && !sync->videoFramePending) {
		ConditionWait(&sync->videoFrameAvailableCond, &sync->videoFrameMutex);
	}
	sync->videoFramePending = 0;
	sync->videoFrameSkip = frameskip;
	return true;
}

void GBASyncWaitFrameEnd(struct GBASync* sync) {
	if (!sync) {
		return;
	}

	MutexUnlock(&sync->videoFrameMutex);
}

bool GBASyncDrawingFrame(struct GBASync* sync) {
	if (!sync) {
		return true;
	}

	return sync->videoFrameSkip <= 0;
}

void GBASyncSuspendDrawing(struct GBASync* sync) {
	if (!sync) {
		return;
	}

	_changeVideoSync(sync, false);
}

void GBASyncResumeDrawing(struct GBASync* sync) {
	if (!sync) {
		return;
	}

	_changeVideoSync(sync, true);
}

void GBASyncProduceAudio(struct GBASync* sync, bool wait) {
	if (!sync) {
		return;
	}

	if (sync->audioWait && wait) {
		// TODO loop properly in event of spurious wakeups
		ConditionWait(&sync->audioRequiredCond, &sync->audioBufferMutex);
	}
	MutexUnlock(&sync->audioBufferMutex);
}

void GBASyncLockAudio(struct GBASync* sync) {
	if (!sync) {
		return;
	}

	MutexLock(&sync->audioBufferMutex);
}

void GBASyncUnlockAudio(struct GBASync* sync) {
	if (!sync) {
		return;
	}

	MutexUnlock(&sync->audioBufferMutex);
}

void GBASyncConsumeAudio(struct GBASync* sync) {
	if (!sync) {
		return;
	}

	ConditionWake(&sync->audioRequiredCond);
	MutexUnlock(&sync->audioBufferMutex);
}