/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * This program 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 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#include "ags/shared/gfx/bitmap.h"
#include "ags/engine/gfx/gfxfilter.h"
#include "ags/engine/gfx/gfx_driver_base.h"
#include "ags/engine/gfx/gfx_util.h"

namespace AGS3 {

using namespace AGS::Shared;

namespace AGS {
namespace Engine {

GraphicsDriverBase::GraphicsDriverBase()
	: _pollingCallback(nullptr)
	, _drawScreenCallback(nullptr)
	, _nullSpriteCallback(nullptr)
	, _initGfxCallback(nullptr) {
	// Initialize default sprite batch, it will be used when no other batch was activated
	_actSpriteBatch = 0;
	_spriteBatchDesc.push_back(SpriteBatchDesc());
}

bool GraphicsDriverBase::IsModeSet() const {
	return _mode.Width != 0 && _mode.Height != 0 && _mode.ColorDepth != 0;
}

bool GraphicsDriverBase::IsNativeSizeValid() const {
	return !_srcRect.IsEmpty();
}

bool GraphicsDriverBase::IsRenderFrameValid() const {
	return !_srcRect.IsEmpty() && !_dstRect.IsEmpty();
}

DisplayMode GraphicsDriverBase::GetDisplayMode() const {
	return _mode;
}

Size GraphicsDriverBase::GetNativeSize() const {
	return _srcRect.GetSize();
}

Rect GraphicsDriverBase::GetRenderDestination() const {
	return _dstRect;
}

void GraphicsDriverBase::BeginSpriteBatch(const Rect &viewport, const SpriteTransform &transform,
	const Point offset, GraphicFlip flip, PBitmap surface) {
	_spriteBatchDesc.push_back(SpriteBatchDesc(_actSpriteBatch, viewport, transform, offset, flip, surface));
	_actSpriteBatch = _spriteBatchDesc.size() - 1;
	InitSpriteBatch(_actSpriteBatch, _spriteBatchDesc[_actSpriteBatch]);
}

void GraphicsDriverBase::EndSpriteBatch() {
	_actSpriteBatch = _spriteBatchDesc[_actSpriteBatch].Parent;
}

void GraphicsDriverBase::ClearDrawLists() {
	ResetAllBatches();
	_actSpriteBatch = 0;
	_spriteBatchDesc.resize(1);
}

void GraphicsDriverBase::OnInit() {
}

void GraphicsDriverBase::OnUnInit() {
}

void GraphicsDriverBase::OnModeSet(const DisplayMode &mode) {
	_mode = mode;
}

void GraphicsDriverBase::OnModeReleased() {
	_mode = DisplayMode();
	_dstRect = Rect();
}

void GraphicsDriverBase::OnScalingChanged() {
	PGfxFilter filter = GetGraphicsFilter();
	if (filter)
		_filterRect = filter->SetTranslation(_srcRect.GetSize(), _dstRect);
	else
		_filterRect = Rect();
	_scaling.Init(_srcRect.GetSize(), _dstRect);
}

void GraphicsDriverBase::OnSetNativeRes(const GraphicResolution &native_res) {
	_srcRect = RectWH(0, 0, native_res.Width, native_res.Height);
	_srcColorDepth = native_res.ColorDepth;
	OnScalingChanged();

	// Adjust default sprite batch making it comply to native size
	_spriteBatchDesc[0].Viewport = RectWH(native_res);
	InitSpriteBatch(_actSpriteBatch, _spriteBatchDesc[_actSpriteBatch]);
}

void GraphicsDriverBase::OnSetRenderFrame(const Rect &dst_rect) {
	_dstRect = dst_rect;
	OnScalingChanged();
}

void GraphicsDriverBase::OnSetFilter() {
	_filterRect = GetGraphicsFilter()->SetTranslation(Size(_srcRect.GetSize()), _dstRect);
}


VideoMemoryGraphicsDriver::VideoMemoryGraphicsDriver()
	: _stageVirtualScreenDDB(nullptr)
	, _stageScreenDirty(false)
	, _fxIndex(0) {
	// Only to have something meaningful as default
	_vmem_a_shift_32 = 24;
	_vmem_r_shift_32 = 16;
	_vmem_g_shift_32 = 8;
	_vmem_b_shift_32 = 0;
}

VideoMemoryGraphicsDriver::~VideoMemoryGraphicsDriver() {
	DestroyAllStageScreens();
}

bool VideoMemoryGraphicsDriver::UsesMemoryBackBuffer() {
	// Although we do use ours, we do not let engine draw upon it;
	// only plugin handling are allowed to request our mem buffer.
	// TODO: find better workaround?
	return false;
}

Bitmap *VideoMemoryGraphicsDriver::GetMemoryBackBuffer() {
	return nullptr;
}

void VideoMemoryGraphicsDriver::SetMemoryBackBuffer(Bitmap * /*backBuffer*/) {
	// do nothing, video-memory drivers don't use main back buffer, only stage bitmaps they pass to plugins
}

Bitmap *VideoMemoryGraphicsDriver::GetStageBackBuffer(bool mark_dirty) {
	_stageScreenDirty |= mark_dirty;
	return _stageVirtualScreen.get();
}

bool VideoMemoryGraphicsDriver::GetStageMatrixes(RenderMatrixes &rm) {
	rm = _stageMatrixes;
	return true;
}

IDriverDependantBitmap *VideoMemoryGraphicsDriver::CreateDDBFromBitmap(Bitmap *bitmap, bool hasAlpha, bool opaque) {
	IDriverDependantBitmap * ddb = CreateDDB(bitmap->GetWidth(), bitmap->GetHeight(), bitmap->GetColorDepth(), opaque);
	if (ddb)
		UpdateDDBFromBitmap(ddb, bitmap, hasAlpha);
	return ddb;
}

IDriverDependantBitmap *VideoMemoryGraphicsDriver::GetSharedDDB(uint32_t sprite_id, Bitmap *bitmap, bool hasAlpha, bool opaque) {
	const auto found = _txRefs.find(sprite_id);
	if (found != _txRefs.end()) {
		const auto &item = found->_value;
		if (!item.Data.expired())
			return CreateDDB(item.Data.lock(), item.Res.Width, item.Res.Height, item.Res.ColorDepth, opaque);
	}

	// Create and add a new element
	std::shared_ptr<TextureData> txdata(CreateTextureData(bitmap->GetWidth(), bitmap->GetHeight(), opaque));
	txdata->ID = sprite_id;
	UpdateTextureData(txdata.get(), bitmap, opaque, hasAlpha);
	// only add into the map when has valid sprite ID
	if (sprite_id != UINT32_MAX) {
		_txRefs[sprite_id] = TextureCacheItem(txdata,
			GraphicResolution(bitmap->GetWidth(), bitmap->GetHeight(), bitmap->GetColorDepth()));
	}
	return CreateDDB(txdata, bitmap->GetWidth(), bitmap->GetHeight(), bitmap->GetColorDepth(), opaque);
}

void VideoMemoryGraphicsDriver::UpdateSharedDDB(uint32_t sprite_id, Bitmap *bitmap, bool hasAlpha, bool opaque) {
	const auto found = _txRefs.find(sprite_id);
	if (found != _txRefs.end()) {
		auto txdata = found->_value.Data.lock();
		if (txdata)
			UpdateTextureData(txdata.get(), bitmap, opaque, hasAlpha);
	}
 }

 void VideoMemoryGraphicsDriver::ClearSharedDDB(uint32_t sprite_id) {
	const auto found = _txRefs.find(sprite_id);
	if (found != _txRefs.end())
		_txRefs.erase(found);
 }

 void VideoMemoryGraphicsDriver::DestroyDDB(IDriverDependantBitmap* ddb) {
	uint32_t sprite_id = ddb->GetRefID();
	DestroyDDBImpl(ddb);
	// Remove shared object from ref list if no more active refs left
	const auto found = _txRefs.find(sprite_id);
	if (found != _txRefs.end() && found->_value.Data.expired())
		_txRefs.erase(found);
}

PBitmap VideoMemoryGraphicsDriver::CreateStageScreen(size_t index, const Size &sz) {
	if (_stageScreens.size() <= index)
		_stageScreens.resize(index + 1);
	if (sz.IsNull())
		_stageScreens[index].reset();
	else if (_stageScreens[index] == nullptr || _stageScreens[index]->GetSize() != sz)
		_stageScreens[index].reset(new Bitmap(sz.Width, sz.Height, _mode.ColorDepth));
	return _stageScreens[index];
}

PBitmap VideoMemoryGraphicsDriver::GetStageScreen(size_t index) {
	if (index < _stageScreens.size())
		return _stageScreens[index];
	return nullptr;
}

void VideoMemoryGraphicsDriver::DestroyAllStageScreens() {
	if (_stageVirtualScreenDDB)
		this->DestroyDDB(_stageVirtualScreenDDB);
	_stageVirtualScreenDDB = nullptr;

	for (size_t i = 0; i < _stageScreens.size(); ++i)
		_stageScreens[i].reset();
	_stageVirtualScreen.reset();
}

bool VideoMemoryGraphicsDriver::DoNullSpriteCallback(int x, int y) {
	if (!_nullSpriteCallback)
		error("Unhandled attempt to draw null sprite");
	_stageScreenDirty = false;
	_stageVirtualScreen->ClearTransparent();
	// NOTE: this is not clear whether return value of callback may be
	// relied on. Existing plugins do not seem to return anything but 0,
	// even if they handle this event.
	_stageScreenDirty |= _nullSpriteCallback(x, y) != 0;
	if (_stageScreenDirty) {
		if (_stageVirtualScreenDDB)
			UpdateDDBFromBitmap(_stageVirtualScreenDDB, _stageVirtualScreen.get(), true);
		else
			_stageVirtualScreenDDB = CreateDDBFromBitmap(_stageVirtualScreen.get(), true);
		return true;
	}
	return false;
}

IDriverDependantBitmap *VideoMemoryGraphicsDriver::MakeFx(int r, int g, int b) {
	if (_fxIndex == _fxPool.size()) _fxPool.push_back(ScreenFx());
	ScreenFx &fx = _fxPool[_fxIndex];
	if (fx.DDB == nullptr) {
		fx.Raw = BitmapHelper::CreateBitmap(16, 16, _mode.ColorDepth);
		fx.DDB = CreateDDBFromBitmap(fx.Raw, false, true);
	}
	if (r != fx.Red || g != fx.Green || b != fx.Blue) {
		fx.Raw->Clear(makecol_depth(fx.Raw->GetColorDepth(), r, g, b));
		this->UpdateDDBFromBitmap(fx.DDB, fx.Raw, false);
		fx.Red = r;
		fx.Green = g;
		fx.Blue = b;
	}
	_fxIndex++;
	return fx.DDB;
}

void VideoMemoryGraphicsDriver::ResetFxPool() {
	_fxIndex = 0;
}

void VideoMemoryGraphicsDriver::DestroyFxPool() {
	for (auto &fx : _fxPool) {
		if (fx.DDB)
			DestroyDDB(fx.DDB);
		delete fx.Raw;
	}
	_fxPool.clear();
	_fxIndex = 0;
}


#define algetr32(c) getr32(c)
#define algetg32(c) getg32(c)
#define algetb32(c) getb32(c)
#define algeta32(c) geta32(c)

#define algetr16(c) getr16(c)
#define algetg16(c) getg16(c)
#define algetb16(c) getb16(c)

#define algetr8(c)  getr8(c)
#define algetg8(c)  getg8(c)
#define algetb8(c)  getb8(c)


__inline void get_pixel_if_not_transparent8(const unsigned char *pixel, unsigned char *red, unsigned char *green, unsigned char *blue, unsigned char *divisor) {
	if (pixel[0] != MASK_COLOR_8) {
		*red += algetr8(pixel[0]);
		*green += algetg8(pixel[0]);
		*blue += algetb8(pixel[0]);
		divisor[0]++;
	}
}

__inline void get_pixel_if_not_transparent16(const unsigned short *pixel, unsigned short *red, unsigned short *green, unsigned short *blue, unsigned short *divisor) {
	if (pixel[0] != MASK_COLOR_16) {
		*red += algetr16(pixel[0]);
		*green += algetg16(pixel[0]);
		*blue += algetb16(pixel[0]);
		divisor[0]++;
	}
}

__inline void get_pixel_if_not_transparent32(const unsigned int *pixel, unsigned int *red, unsigned int *green, unsigned int *blue, unsigned int *divisor) {
	if (pixel[0] != MASK_COLOR_32) {
		*red += algetr32(pixel[0]);
		*green += algetg32(pixel[0]);
		*blue += algetb32(pixel[0]);
		divisor[0]++;
	}
}


#define VMEMCOLOR_RGBA(r,g,b,a) \
	( (((a) & 0xFF) << _vmem_a_shift_32) | (((r) & 0xFF) << _vmem_r_shift_32) | (((g) & 0xFF) << _vmem_g_shift_32) | (((b) & 0xFF) << _vmem_b_shift_32) )


void VideoMemoryGraphicsDriver::BitmapToVideoMem(const Bitmap *bitmap, const bool has_alpha, const TextureTile *tile,
        char *dst_ptr, const int dst_pitch, const bool usingLinearFiltering) {
	const int src_depth = bitmap->GetColorDepth();
	bool lastPixelWasTransparent = false;
	for (int y = 0; y < tile->height; y++) {
		lastPixelWasTransparent = false;
		const uint8_t *scanline_before = bitmap->GetScanLine(y + tile->y - 1);
		const uint8_t *scanline_at = bitmap->GetScanLine(y + tile->y);
		const uint8_t *scanline_after = bitmap->GetScanLine(y + tile->y + 1);
		unsigned int *memPtrLong = (unsigned int *)dst_ptr;

		for (int x = 0; x < tile->width; x++) {
			if (src_depth == 8) {
				const unsigned char *srcData = (const unsigned char *)&scanline_at[(x + tile->x) * sizeof(char)];
				if (*srcData == MASK_COLOR_8) {
					if (!usingLinearFiltering)
						memPtrLong[x] = 0;
					// set to transparent, but use the colour from the neighbouring
					// pixel to stop the linear filter doing black outlines
					else {
						unsigned char red = 0, green = 0, blue = 0, divisor = 0;
						if (x > 0)
							get_pixel_if_not_transparent8(&srcData[-1], &red, &green, &blue, &divisor);
						if (x < tile->width - 1)
							get_pixel_if_not_transparent8(&srcData[1], &red, &green, &blue, &divisor);
						if (y > 0)
							get_pixel_if_not_transparent8((const unsigned char *)&scanline_before[(x + tile->x) * sizeof(char)], &red, &green, &blue, &divisor);
						if (y < tile->height - 1)
							get_pixel_if_not_transparent8((const unsigned char *)&scanline_after[(x + tile->x) * sizeof(char)], &red, &green, &blue, &divisor);
						if (divisor > 0)
							memPtrLong[x] = VMEMCOLOR_RGBA(red / divisor, green / divisor, blue / divisor, 0);
						else
							memPtrLong[x] = 0;
					}
					lastPixelWasTransparent = true;
				} else {
					memPtrLong[x] = VMEMCOLOR_RGBA(algetr8(*srcData), algetg8(*srcData), algetb8(*srcData), 0xFF);
					if (lastPixelWasTransparent) {
						// update the colour of the previous tranparent pixel, to
						// stop black outlines when linear filtering
						memPtrLong[x - 1] = memPtrLong[x] & 0x00FFFFFF;
						lastPixelWasTransparent = false;
					}
				}
			} else if (src_depth == 16) {
				const unsigned short *srcData = (const unsigned short *)&scanline_at[(x + tile->x) * sizeof(short)];
				if (*srcData == MASK_COLOR_16) {
					if (!usingLinearFiltering)
						memPtrLong[x] = 0;
					// set to transparent, but use the colour from the neighbouring
					// pixel to stop the linear filter doing black outlines
					else {
						unsigned short red = 0, green = 0, blue = 0, divisor = 0;
						if (x > 0)
							get_pixel_if_not_transparent16(&srcData[-1], &red, &green, &blue, &divisor);
						if (x < tile->width - 1)
							get_pixel_if_not_transparent16(&srcData[1], &red, &green, &blue, &divisor);
						if (y > 0)
							get_pixel_if_not_transparent16((const unsigned short *)&scanline_before[(x + tile->x) * sizeof(short)], &red, &green, &blue, &divisor);
						if (y < tile->height - 1)
							get_pixel_if_not_transparent16((const unsigned short *)&scanline_after[(x + tile->x) * sizeof(short)], &red, &green, &blue, &divisor);
						if (divisor > 0)
							memPtrLong[x] = VMEMCOLOR_RGBA(red / divisor, green / divisor, blue / divisor, 0);
						else
							memPtrLong[x] = 0;
					}
					lastPixelWasTransparent = true;
				} else {
					memPtrLong[x] = VMEMCOLOR_RGBA(algetr16(*srcData), algetg16(*srcData), algetb16(*srcData), 0xFF);
					if (lastPixelWasTransparent) {
						// update the colour of the previous tranparent pixel, to
						// stop black outlines when linear filtering
						memPtrLong[x - 1] = memPtrLong[x] & 0x00FFFFFF;
						lastPixelWasTransparent = false;
					}
				}
			} else if (src_depth == 32) {
				const unsigned int *srcData = (const unsigned int *)&scanline_at[(x + tile->x) * sizeof(int)];
				if (*srcData == MASK_COLOR_32) {
					if (!usingLinearFiltering)
						memPtrLong[x] = 0;
					// set to transparent, but use the colour from the neighbouring
					// pixel to stop the linear filter doing black outlines
					else {
						unsigned int red = 0, green = 0, blue = 0, divisor = 0;
						if (x > 0)
							get_pixel_if_not_transparent32(&srcData[-1], &red, &green, &blue, &divisor);
						if (x < tile->width - 1)
							get_pixel_if_not_transparent32(&srcData[1], &red, &green, &blue, &divisor);
						if (y > 0)
							get_pixel_if_not_transparent32((const unsigned int *)&scanline_before[(x + tile->x) * sizeof(int)], &red, &green, &blue, &divisor);
						if (y < tile->height - 1)
							get_pixel_if_not_transparent32((const unsigned int *)&scanline_after[(x + tile->x) * sizeof(int)], &red, &green, &blue, &divisor);
						if (divisor > 0)
							memPtrLong[x] = VMEMCOLOR_RGBA(red / divisor, green / divisor, blue / divisor, 0);
						else
							memPtrLong[x] = 0;
					}
					lastPixelWasTransparent = true;
				} else if (has_alpha) {
					memPtrLong[x] = VMEMCOLOR_RGBA(algetr32(*srcData), algetg32(*srcData), algetb32(*srcData), algeta32(*srcData));
				} else {
					memPtrLong[x] = VMEMCOLOR_RGBA(algetr32(*srcData), algetg32(*srcData), algetb32(*srcData), 0xFF);
					if (lastPixelWasTransparent) {
						// update the colour of the previous tranparent pixel, to
						// stop black outlines when linear filtering
						memPtrLong[x - 1] = memPtrLong[x] & 0x00FFFFFF;
						lastPixelWasTransparent = false;
					}
				}
			}
		}

		dst_ptr += dst_pitch;
	}
}

void VideoMemoryGraphicsDriver::BitmapToVideoMemOpaque(const Bitmap *bitmap, const bool has_alpha, const TextureTile *tile,
        char *dst_ptr, const int dst_pitch) {
	const int src_depth = bitmap->GetColorDepth();
	for (int y = 0; y < tile->height; y++) {
		const uint8_t *scanline_at = bitmap->GetScanLine(y + tile->y);
		unsigned int *memPtrLong = (unsigned int *)dst_ptr;

		for (int x = 0; x < tile->width; x++) {
			if (src_depth == 8) {
				const unsigned char *srcData = (const unsigned char *)&scanline_at[(x + tile->x) * sizeof(char)];
				memPtrLong[x] = VMEMCOLOR_RGBA(algetr8(*srcData), algetg8(*srcData), algetb8(*srcData), 0xFF);
			} else if (src_depth == 16) {
				const unsigned short *srcData = (const unsigned short *)&scanline_at[(x + tile->x) * sizeof(short)];
				memPtrLong[x] = VMEMCOLOR_RGBA(algetr16(*srcData), algetg16(*srcData), algetb16(*srcData), 0xFF);
			} else if (src_depth == 32) {
				const unsigned int *srcData = (const unsigned int *)&scanline_at[(x + tile->x) * sizeof(int)];
				if (has_alpha)
					memPtrLong[x] = VMEMCOLOR_RGBA(algetr32(*srcData), algetg32(*srcData), algetb32(*srcData), algeta32(*srcData));
				else
					memPtrLong[x] = VMEMCOLOR_RGBA(algetr32(*srcData), algetg32(*srcData), algetb32(*srcData), 0xFF);
			}
		}

		dst_ptr += dst_pitch;
	}
}

} // namespace Engine
} // namespace AGS
} // namespace AGS3