// Copyright 2019 The SwiftShader Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//    http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include "Thread.hpp"

#include "Context.hpp"
#include "EventListener.hpp"
#include "File.hpp"

namespace vk {
namespace dbg {

Thread::Thread(ID id, Context *ctx)
    : id(id)
    , ctx(ctx)
{}

void Thread::setName(const std::string &name)
{
	marl::lock lock(mutex);
	name_ = name;
}

std::string Thread::name() const
{
	marl::lock lock(mutex);
	return name_;
}

void Thread::onLocationUpdate(marl::lock &lock)
{
	auto location = frames.back()->location;

	if(state_ == State::Running)
	{
		if(location.file->hasBreakpoint(location.line))
		{
			ctx->serverEventBroadcast()->onLineBreakpointHit(id);
			state_ = State::Paused;
		}
	}

	switch(state_)
	{
	case State::Paused:
		lock.wait(stateCV, [this]() REQUIRES(mutex) { return state_ != State::Paused; });
		break;

	case State::Stepping:
		{
			bool pause = false;

			{
				auto frame = pauseAtFrame.lock();
				pause = !frame;             // Pause if there's no pause-at-frame...
				if(frame == frames.back())  // ... or if we've reached the pause-at-frame
				{
					pause = true;
					pauseAtFrame.reset();
				}
			}

			if(pause)
			{
				ctx->serverEventBroadcast()->onThreadStepped(id);
				state_ = State::Paused;
				lock.wait(stateCV, [this]() REQUIRES(mutex) { return state_ != State::Paused; });
			}
		}
		break;

	case State::Running:
		break;
	}
}

void Thread::enter(const std::shared_ptr<File> &file, const std::string &function, const UpdateFrame &f)
{
	std::shared_ptr<Frame> frame;
	bool isFunctionBreakpoint;
	{
		auto lock = ctx->lock();
		frame = lock.createFrame(file, function);
		isFunctionBreakpoint = lock.isFunctionBreakpoint(function);
	}

	{
		marl::lock lock(mutex);
		frames.push_back(frame);

		if(f) { f(*frame); }

		if(isFunctionBreakpoint)
		{
			ctx->serverEventBroadcast()->onFunctionBreakpointHit(id);
			state_ = State::Paused;
		}

		onLocationUpdate(lock);
	}
}

void Thread::exit(bool isStep /* = false */)
{
	marl::lock lock(mutex);
	frames.pop_back();
	if(isStep)
	{
		onLocationUpdate(lock);
	}
}

void Thread::update(bool isStep, const UpdateFrame &f)
{
	marl::lock lock(mutex);
	auto &frame = *frames.back();
	if(isStep)
	{
		auto oldLocation = frame.location;
		f(frame);
		if(frame.location != oldLocation)
		{
			onLocationUpdate(lock);
		}
	}
	else
	{
		f(frame);
	}
}

Frame Thread::frame() const
{
	marl::lock lock(mutex);
	return *frames.back();
}

std::vector<Frame> Thread::stack() const
{
	marl::lock lock(mutex);
	std::vector<Frame> out;
	out.reserve(frames.size());
	for(auto frame : frames)
	{
		out.push_back(*frame);
	}
	return out;
}

size_t Thread::depth() const
{
	marl::lock lock(mutex);
	return frames.size();
}

Thread::State Thread::state() const
{
	marl::lock lock(mutex);
	return state_;
}

void Thread::resume()
{
	{
		marl::lock lock(mutex);
		state_ = State::Running;
	}
	stateCV.notify_all();
}

void Thread::pause()
{
	marl::lock lock(mutex);
	state_ = State::Paused;
}

void Thread::stepIn()
{
	marl::lock lock(mutex);
	state_ = State::Stepping;
	pauseAtFrame.reset();
	stateCV.notify_all();
}

void Thread::stepOver()
{
	marl::lock lock(mutex);
	state_ = State::Stepping;
	pauseAtFrame = frames.back();
	stateCV.notify_all();
}

void Thread::stepOut()
{
	marl::lock lock(mutex);
	state_ = State::Stepping;
	pauseAtFrame = (frames.size() > 1) ? frames[frames.size() - 2] : nullptr;
	stateCV.notify_all();
}

}  // namespace dbg
}  // namespace vk