#include "VideoIOBackendFactory.h"

#include "DeckLinkSession.h"
#include "VideoIOTypes.h"

#include <array>

namespace
{
struct VideoIOBackendRegistration
{
	VideoIOBackendDescriptor descriptor;
	VideoIODeviceFactory factory;
};

const std::array<VideoIOBackendRegistration, 1>& RegisteredBackends()
{
	static const std::array<VideoIOBackendRegistration, 1> backends = { {
		{
			{
				VideoIOBackendId::DeckLink,
				"decklink",
				"Blackmagic DeckLink",
				"Please install the Blackmagic DeckLink drivers to use the features of this application.",
				"This application requires the selected video I/O drivers installed."
			},
			[]() { return std::make_unique<DeckLinkSession>(); }
		}
	} };
	return backends;
}
}

const VideoIOBackendDescriptor* GetVideoIOBackendDescriptor(VideoIOBackendId backendId)
{
	for (const VideoIOBackendRegistration& registration : RegisteredBackends())
	{
		if (registration.descriptor.backendId == backendId)
			return &registration.descriptor;
	}
	return nullptr;
}

std::vector<VideoIOBackendDescriptor> ListVideoIOBackendDescriptors()
{
	std::vector<VideoIOBackendDescriptor> descriptors;
	descriptors.reserve(RegisteredBackends().size());
	for (const VideoIOBackendRegistration& registration : RegisteredBackends())
		descriptors.push_back(registration.descriptor);
	return descriptors;
}

std::unique_ptr<VideoIODevice> CreateVideoIODevice(VideoIOBackendId backendId, std::string& error)
{
	for (const VideoIOBackendRegistration& registration : RegisteredBackends())
	{
		if (registration.descriptor.backendId != backendId)
			continue;

		error.clear();
		return registration.factory ? registration.factory() : nullptr;
	}

	error = "Unsupported video I/O backend.";
	return nullptr;
}

bool IsVideoIOBackendUnavailableError(VideoIOBackendId backendId, const std::string& error)
{
	const VideoIOBackendDescriptor* descriptor = GetVideoIOBackendDescriptor(backendId);
	return descriptor != nullptr &&
		descriptor->unavailableMessage != nullptr &&
		*descriptor->unavailableMessage != '\0' &&
		error == descriptor->unavailableMessage;
}