#include "DeckLinkSession.h"

#include "GlRenderConstants.h"

#include <cstring>

DeckLinkSession::~DeckLinkSession()
{
	ReleaseResources();
}

void DeckLinkSession::ReleaseResources()
{
	if (input != nullptr)
	{
		input->SetCallback(nullptr);
		if (captureDelegate != nullptr)
		{
			captureDelegate->Release();
			captureDelegate = nullptr;
		}
		input->Release();
		input = nullptr;
	}

	while (!outputVideoFrameQueue.empty())
	{
		IDeckLinkMutableVideoFrame* frameToRelease = outputVideoFrameQueue.front();
		if (frameToRelease != nullptr)
			frameToRelease->Release();
		outputVideoFrameQueue.pop_front();
	}

	if (output != nullptr)
	{
		if (keyer != nullptr)
		{
			keyer->Disable();
			keyer->Release();
			keyer = nullptr;
			externalKeyingActive = false;
		}
		output->SetScheduledFrameCompletionCallback(nullptr);
		if (playoutDelegate != nullptr)
		{
			playoutDelegate->Release();
			playoutDelegate = nullptr;
		}
		output->Release();
		output = nullptr;
	}

	if (playoutAllocator != nullptr)
	{
		playoutAllocator->Release();
		playoutAllocator = nullptr;
	}
}

bool DeckLinkSession::Start(unsigned outputHeight)
{
	totalPlayoutFrames = 0;
	if (!output)
	{
		MessageBoxA(NULL, "Cannot start playout because no DeckLink output device is available.", "DeckLink start failed", MB_OK | MB_ICONERROR);
		return false;
	}
	if (outputVideoFrameQueue.empty())
	{
		MessageBoxA(NULL, "Cannot start playout because the output frame queue is empty.", "DeckLink start failed", MB_OK | MB_ICONERROR);
		return false;
	}

	for (unsigned i = 0; i < kPrerollFrameCount; i++)
	{
		IDeckLinkMutableVideoFrame* outputVideoFrame = outputVideoFrameQueue.front();
		outputVideoFrameQueue.push_back(outputVideoFrame);
		outputVideoFrameQueue.pop_front();

		IDeckLinkVideoBuffer* outputVideoFrameBuffer;
		if (outputVideoFrame->QueryInterface(IID_IDeckLinkVideoBuffer, (void**)&outputVideoFrameBuffer) != S_OK)
		{
			MessageBoxA(NULL, "Could not query the preroll output frame buffer.", "DeckLink start failed", MB_OK | MB_ICONERROR);
			return false;
		}

		if (outputVideoFrameBuffer->StartAccess(bmdBufferAccessWrite) != S_OK)
		{
			outputVideoFrameBuffer->Release();
			MessageBoxA(NULL, "Could not write to the preroll output frame buffer.", "DeckLink start failed", MB_OK | MB_ICONERROR);
			return false;
		}

		void* pFrame;
		outputVideoFrameBuffer->GetBytes((void**)&pFrame);
		memset(pFrame, 0, outputVideoFrame->GetRowBytes() * outputHeight);

		outputVideoFrameBuffer->EndAccess(bmdBufferAccessWrite);
		outputVideoFrameBuffer->Release();

		if (output->ScheduleVideoFrame(outputVideoFrame, (totalPlayoutFrames * frameDuration), frameDuration, frameTimescale) != S_OK)
		{
			MessageBoxA(NULL, "Could not schedule a preroll output frame.", "DeckLink start failed", MB_OK | MB_ICONERROR);
			return false;
		}

		totalPlayoutFrames++;
	}

	if (input)
	{
		if (input->StartStreams() != S_OK)
		{
			MessageBoxA(NULL, "Could not start the DeckLink input stream.", "DeckLink start failed", MB_OK | MB_ICONERROR);
			return false;
		}
	}
	if (output->StartScheduledPlayback(0, frameTimescale, 1.0) != S_OK)
	{
		MessageBoxA(NULL, "Could not start DeckLink scheduled playback.", "DeckLink start failed", MB_OK | MB_ICONERROR);
		return false;
	}

	return true;
}

bool DeckLinkSession::Stop()
{
	if (keyer != nullptr)
	{
		keyer->Disable();
		externalKeyingActive = false;
	}

	if (input)
	{
		input->StopStreams();
		input->DisableVideoInput();
	}

	if (output)
	{
		output->StopScheduledPlayback(0, NULL, 0);
		output->DisableVideoOutput();
	}

	return true;
}