/* Copyright (C) 2021 Wildfire Games.
 * This file is part of 0 A.D.
 *
 * 0 A.D. is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * 0 A.D. is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "precompiled.h"

#include "SoundGroup.h"
#include "graphics/Camera.h"
#include "graphics/GameView.h"
#include "lib/rand.h"
#include "ps/CLogger.h"
#include "ps/ConfigDB.h"
#include "ps/CStr.h"
#include "ps/Filesystem.h"
#include "ps/Game.h"
#include "ps/Util.h"
#include "ps/XML/Xeromyces.h"
#include "simulation2/components/ICmpVisual.h"
#include "simulation2/system/Component.h"
#include "soundmanager/items/ISoundItem.h"
#include "soundmanager/SoundManager.h"

#include <algorithm>
#include <random>

extern CGame *g_Game;

#if CONFIG2_AUDIO

constexpr ALfloat DEFAULT_ROLLOFF = 0.5f;
constexpr ALfloat MAX_ROLLOFF = 0.7f;

/**
 * Low randomness, quite-a-lot-faster-than-std::mt19937 random number generator.
 * It matches the interface of UniformRandomBitGenerator for use in std::shuffle.
 */
class CFastRand
{
public:
	using result_type = u32;

	constexpr static result_type min() { return 0; }
	constexpr static result_type max() { return 0xFFFF; }

	static result_type Rand(result_type& seed)
	{
		// This is a mixed linear congruential random number generator.
		// The magic numbers are chosen so that they generate pseudo random numbers over a big enough period (0xFFFF).
		seed = 214013 * seed + 2531011;
		return (seed >> 16) & max();
	}

	static float RandFloat(result_type& seed, float min, float max)
	{
		return (static_cast<float>(Rand(seed)) / (0xFFFF)) * (max - min) + min;
	}

	CFastRand() {};
	CFastRand(result_type init) : m_Seed(init) {};

	result_type operator()()
	{
		return Rand(m_Seed);
	}

	result_type m_Seed;
};
#endif

void CSoundGroup::SetGain(float gain)
{
	m_Gain = std::min(gain, 1.0f);
}

void CSoundGroup::SetDefaultValues()
{
	m_CurrentSoundIndex = 0;
	m_Flags = 0;
	m_CurTime = 0.f;
	m_Gain = 0.7f;
	m_Pitch = 1.f;
	m_Priority = 60.f;
	m_PitchUpper = 1.1f;
	m_PitchLower = 0.9f;
	m_GainUpper = 1.f;
	m_GainLower = 0.8f;
	m_ConeOuterGain = 0.f;
	m_ConeInnerAngle = 360.f;
	m_ConeOuterAngle = 360.f;
	m_Decay = 3.f;
	m_Seed = 0;
	m_IntensityThreshold = 3.f;

	m_MinDist = 1.f;
	m_MaxDist = 350.f;
	// This is more than the default camera FOV: for now, our soundscape is not realistic anyways.
	m_MaxStereoAngle = static_cast<float>(M_PI / 6);
	if (CConfigDB::IsInitialised())
	{
		CFG_GET_VAL("sound.mindistance", m_MinDist);
		CFG_GET_VAL("sound.maxdistance", m_MaxDist);
		CFG_GET_VAL("sound.maxstereoangle", m_MaxStereoAngle);
	}
}

CSoundGroup::CSoundGroup()
{
	SetDefaultValues();
}

CSoundGroup::CSoundGroup(const VfsPath& pathnameXML)
{
	SetDefaultValues();
	LoadSoundGroup(pathnameXML);
}

CSoundGroup::~CSoundGroup()
{
	// clean up all the handles from this group.
	ReleaseGroup();
}

float CSoundGroup::RadiansOffCenter(const CVector3D& position, bool& onScreen, float& itemRollOff)
{
#if !CONFIG2_AUDIO
        UNUSED2(position);
        UNUSED2(onScreen);
        UNUSED2(itemRollOff);
	return 0.f;
#else
	const int screenWidth = g_Game->GetView()->GetCamera()->GetViewPort().m_Width;
	const int screenHeight = g_Game->GetView()->GetCamera()->GetViewPort().m_Height;
	const float xBufferSize = screenWidth * 0.1f;
	const float yBufferSize = 15.f;
	const float radianCap = m_MaxStereoAngle;

	float x, y;
	g_Game->GetView()->GetCamera()->GetScreenCoordinates(position, x, y);

	onScreen = true;
	float answer = 0.f;
	if (x < -xBufferSize)
	{
		onScreen = false;
		answer = -radianCap;
	}
	else if (x > screenWidth + xBufferSize)
	{
		onScreen = false;
		answer = radianCap;
	}
	else
	{
		if (x < 0 || x > screenWidth)
			itemRollOff = MAX_ROLLOFF;

		answer = radianCap * (x * 2 / screenWidth - 1);
	}

	if (y < -yBufferSize)
	{
		onScreen = false;
	}
	else if (y > screenHeight + yBufferSize)
	{
		onScreen = false;
	}
	else if (y < 0 || y > screenHeight)
	{
		itemRollOff = MAX_ROLLOFF;
	}

	return answer;
#endif // !CONFIG2_AUDIO
}

void CSoundGroup::UploadPropertiesAndPlay(size_t index, const CVector3D& position, entity_id_t source)
{
#if !CONFIG2_AUDIO
	UNUSED2(index);
	UNUSED2(position);
	UNUSED2(source);
#else
	if (!g_SoundManager)
		return;

	bool isOnscreen = false;
	ALfloat itemRollOff = DEFAULT_ROLLOFF;
	float offset = RadiansOffCenter(position, isOnscreen, itemRollOff);

	if (!isOnscreen && !TestFlag(eDistanceless) && !TestFlag(eOmnipresent))
		return;

	if (m_SoundGroups.empty())
		Reload();

	if (m_SoundGroups.size() <= index)
		return;

	CSoundData* sndData = m_SoundGroups[index];
	if (!sndData)
		return;

	ISoundItem* hSound = static_cast<CSoundManager*>(g_SoundManager)->ItemForEntity(source, sndData);
	if (!hSound)
		return;

	if (!TestFlag(eOmnipresent))
	{
		CVector3D origin = g_Game->GetView()->GetCamera()->GetOrientation().GetTranslation();
		float itemDist = (position - origin).Length();

		if (TestFlag(eDistanceless))
			itemRollOff = 0;

		if (sndData->IsStereo())
			LOGWARNING("OpenAL: stereo sounds can't be positioned: %s", sndData->GetFileName().string8());

		hSound->SetLocation(CVector3D(itemDist * sin(offset), 0, -itemDist * cos(offset)));
		hSound->SetRollOff(itemRollOff, m_MinDist, m_MaxDist);
	}

	CmpPtr<ICmpVisual> cmpVisual(*g_Game->GetSimulation2(), source);
	if (cmpVisual)
		m_Seed = cmpVisual->GetActorSeed();

	hSound->SetPitch(TestFlag(eRandPitch) ? CFastRand::RandFloat(m_Seed, m_PitchLower, m_PitchUpper) : m_Pitch);

	if (TestFlag(eRandGain))
		m_Gain = CFastRand::RandFloat(m_Seed, m_GainLower, m_GainUpper);

	hSound->SetCone(m_ConeInnerAngle, m_ConeOuterAngle, m_ConeOuterGain);
	static_cast<CSoundManager*>(g_SoundManager)->PlayGroupItem(hSound, m_Gain);
#endif // !CONFIG2_AUDIO
}

static void HandleError(const std::wstring& message, const VfsPath& pathname, Status err)
{
	// Open failed because sound is disabled (don't log this)
	if (err == ERR::AGAIN)
		return;

	LOGERROR("%s: pathname=%s, error=%s", utf8_from_wstring(message), pathname.string8(), GetStatusAsString(err).c_str());
}

void CSoundGroup::PlayNext(const CVector3D& position, entity_id_t source)
{
	if (m_Filenames.empty())
		return;

	m_CurrentSoundIndex = rand(0, m_Filenames.size());
	UploadPropertiesAndPlay(m_CurrentSoundIndex, position, source);
}

void CSoundGroup::Reload()
{
	m_CurrentSoundIndex = 0;
#if CONFIG2_AUDIO
	ReleaseGroup();

	if (!g_SoundManager)
		return;

	for (const std::wstring& filename : m_Filenames)
	{
		VfsPath absolutePath = m_Filepath / filename;
		CSoundData* itemData = CSoundData::SoundDataFromFile(absolutePath);
		if (!itemData)
			HandleError(L"error loading sound", absolutePath, ERR::FAIL);
		else
			m_SoundGroups.push_back(itemData->IncrementCount());
	}

	if (TestFlag(eRandOrder))
		std::shuffle(m_SoundGroups.begin(), m_SoundGroups.end(), CFastRand(m_Seed));
#endif
}

void CSoundGroup::ReleaseGroup()
{
#if CONFIG2_AUDIO
	for (CSoundData* soundGroup : m_SoundGroups)
		CSoundData::ReleaseSoundData(soundGroup);

	m_SoundGroups.clear();
#endif
}

void CSoundGroup::Update(float UNUSED(TimeSinceLastFrame))
{
}

bool CSoundGroup::LoadSoundGroup(const VfsPath& pathnameXML)
{
	CXeromyces XeroFile;
	if (XeroFile.Load(g_VFS, pathnameXML, "sound_group") != PSRETURN_OK)
	{
		HandleError(L"error loading file", pathnameXML, ERR::FAIL);
		return false;
	}

#define EL(x) int el_##x = XeroFile.GetElementID(#x)
	EL(soundgroup);
	EL(gain);
	EL(looping);
	EL(omnipresent);
	EL(heardby);
	EL(distanceless);
	EL(pitch);
	EL(priority);
	EL(randorder);
	EL(randgain);
	EL(randpitch);
	EL(conegain);
	EL(coneinner);
	EL(coneouter);
	EL(sound);
	EL(gainupper);
	EL(gainlower);
	EL(pitchupper);
	EL(pitchlower);
	EL(path);
	EL(threshold);
	EL(decay);
#undef EL

	XMBElement root = XeroFile.GetRoot();

	if (root.GetNodeName() != el_soundgroup)
	{
		LOGERROR("Invalid SoundGroup format (unrecognised root element '%s')", XeroFile.GetElementString(root.GetNodeName()));
		return false;
	}

	XERO_ITER_EL(root, child)
	{
		int child_name = child.GetNodeName();

		if (child_name == el_gain)
		{
			SetGain(child.GetText().ToFloat());
		}
		else if (child_name == el_looping)
		{
			if (child.GetText().ToInt() == 1)
				SetFlag(eLoop);
		}
		else if (child_name == el_omnipresent)
		{
			if (child.GetText().ToInt() == 1)
				SetFlag(eOmnipresent);
		}
		else if (child_name == el_heardby)
		{
			if (child.GetText().FindInsensitive("owner") == 0)
				SetFlag(eOwnerOnly);
		}
		else if (child_name == el_distanceless)
		{
			if (child.GetText().ToInt() == 1)
				SetFlag(eDistanceless);
		}
		else if (child_name == el_pitch)
		{
			this->m_Pitch = child.GetText().ToFloat();
		}
		else if (child_name == el_priority)
		{
			this->m_Priority = child.GetText().ToFloat();
		}
		else if (child_name == el_randorder)
		{
			if (child.GetText().ToInt() == 1)
				SetFlag(eRandOrder);
		}
		else if (child_name == el_randgain)
		{
			if (child.GetText().ToInt() == 1)
				SetFlag(eRandGain);
		}
		else if (child_name == el_gainupper)
		{
			this->m_GainUpper = child.GetText().ToFloat();
		}
		else if (child_name == el_gainlower)
		{
			this->m_GainLower = child.GetText().ToFloat();
		}
		else if (child_name == el_randpitch)
		{
			if (child.GetText().ToInt() == 1)
				SetFlag(eRandPitch);
		}
		else if (child_name == el_pitchupper)
		{
			this->m_PitchUpper = child.GetText().ToFloat();
		}
		else if (child_name == el_pitchlower)
		{
			this->m_PitchLower = child.GetText().ToFloat();
		}
		else if (child_name == el_conegain)
		{
			this->m_ConeOuterGain = child.GetText().ToFloat();
		}
		else if (child_name == el_coneinner)
		{
			this->m_ConeInnerAngle = child.GetText().ToFloat();
		}
		else if (child_name == el_coneouter)
		{
			this->m_ConeOuterAngle = child.GetText().ToFloat();
		}
		else if (child_name == el_sound)
		{
			this->m_Filenames.push_back(child.GetText().FromUTF8());
		}
		else if (child_name == el_path)
		{
			m_Filepath = child.GetText().FromUTF8();
		}
		else if (child_name == el_threshold)
		{
			m_IntensityThreshold = child.GetText().ToFloat();
		}
		else if (child_name == el_decay)
		{
			m_Decay = child.GetText().ToFloat();
		}
	}
	return true;
}