/*
 * SDLImage.cpp, part of VCMI engine
 *
 * Authors: listed in file AUTHORS in main folder
 *
 * License: GNU General Public License v2.0 or later
 * Full text of license available in license.txt file, in main folder
 *
 */
#include "StdInc.h"
#include "SDLImage.h"

#include "SDLImageLoader.h"
#include "SDL_Extensions.h"

#include "../render/ColorFilter.h"
#include "../render/Colors.h"
#include "../render/CBitmapHandler.h"
#include "../render/CDefFile.h"
#include "../render/Graphics.h"
#include "../xBRZ/xbrz.h"
#include "../gui/CGuiHandler.h"
#include "../render/IScreenHandler.h"

#include <tbb/parallel_for.h>
#include <SDL_surface.h>
#include <SDL_image.h>

class SDLImageLoader;

int IImage::width() const
{
	return dimensions().x;
}

int IImage::height() const
{
	return dimensions().y;
}

SDLImageShared::SDLImageShared(const CDefFile * data, size_t frame, size_t group)
	: surf(nullptr),
	margins(0, 0),
	fullSize(0, 0),
	originalPalette(nullptr)
{
	SDLImageLoader loader(this);
	data->loadFrame(frame, group, loader);

	savePalette();
}

SDLImageShared::SDLImageShared(SDL_Surface * from)
	: surf(nullptr),
	margins(0, 0),
	fullSize(0, 0),
	originalPalette(nullptr)
{
	surf = from;
	if (surf == nullptr)
		return;

	savePalette();

	surf->refcount++;
	fullSize.x = surf->w;
	fullSize.y = surf->h;
}

SDLImageShared::SDLImageShared(const ImagePath & filename)
	: surf(nullptr),
	margins(0, 0),
	fullSize(0, 0),
	originalPalette(nullptr)
{
	surf = BitmapHandler::loadBitmap(filename);

	if(surf == nullptr)
	{
		logGlobal->error("Error: failed to load image %s", filename.getOriginalName());
		return;
	}
	else
	{
		savePalette();
		fullSize.x = surf->w;
		fullSize.y = surf->h;

		optimizeSurface();
	}
}

void SDLImageShared::draw(SDL_Surface * where, SDL_Palette * palette, const Point & dest, const Rect * src, const ColorRGBA & colorMultiplier, uint8_t alpha, EImageBlitMode mode) const
{
	if (!surf)
		return;

	Rect sourceRect(0, 0, surf->w, surf->h);

	Point destShift(0, 0);

	if(src)
	{
		if(src->x < margins.x)
			destShift.x += margins.x - src->x;

		if(src->y < margins.y)
			destShift.y += margins.y - src->y;

		sourceRect = Rect(*src).intersect(Rect(margins.x, margins.y, surf->w, surf->h));

		sourceRect -= margins;
	}
	else
		destShift = margins;

	destShift += dest;

	SDL_SetSurfaceColorMod(surf, colorMultiplier.r, colorMultiplier.g, colorMultiplier.b);
	SDL_SetSurfaceAlphaMod(surf, alpha);

	if (alpha != SDL_ALPHA_OPAQUE || (mode != EImageBlitMode::OPAQUE && surf->format->Amask != 0))
		SDL_SetSurfaceBlendMode(surf, SDL_BLENDMODE_BLEND);
	else
		SDL_SetSurfaceBlendMode(surf, SDL_BLENDMODE_NONE);

	if (palette && surf->format->palette)
		SDL_SetSurfacePalette(surf, palette);

	if(surf->format->palette && mode != EImageBlitMode::OPAQUE && mode != EImageBlitMode::COLORKEY)
	{
		CSDL_Ext::blit8bppAlphaTo24bpp(surf, sourceRect, where, destShift, alpha);
	}
	else
	{
		CSDL_Ext::blitSurface(surf, sourceRect, where, destShift);
	}

	if (surf->format->palette)
		SDL_SetSurfacePalette(surf, originalPalette);
}

void SDLImageShared::optimizeSurface()
{
	if (!surf)
		return;

	int left = surf->w;
	int top = surf->h;
	int right = 0;
	int bottom = 0;

	// locate fully-transparent area around image
	// H3 hadles this on format level, but mods or images scaled in runtime do not
	if (surf->format->palette)
	{
		for (int y = 0; y < surf->h; ++y)
		{
			const uint8_t * row = static_cast<uint8_t *>(surf->pixels) + y * surf->pitch;
			for (int x = 0; x < surf->w; ++x)
			{
				if (row[x] != 0)
				{
					// opaque or can be opaque (e.g. disabled shadow)
					top = std::min(top, y);
					left = std::min(left, x);
					right = std::max(right, x);
					bottom = std::max(bottom, y);
				}
			}
		}
	}
	else
	{
		for (int y = 0; y < surf->h; ++y)
		{
			for (int x = 0; x < surf->w; ++x)
			{
				ColorRGBA color;
				SDL_GetRGBA(CSDL_Ext::getPixel(surf, x, y), surf->format, &color.r, &color.g, &color.b, &color.a);

				if (color.a != SDL_ALPHA_TRANSPARENT)
				{
					 // opaque
					top = std::min(top, y);
					left = std::min(left, x);
					right = std::max(right, x);
					bottom = std::max(bottom, y);
				}
			}
		}
	}

	if (left == surf->w)
	{
		// empty image - simply delete it
		SDL_FreeSurface(surf);
		surf = nullptr;
		return;
	}

	if (left != 0 || top != 0 || right != surf->w - 1 || bottom != surf->h - 1)
	{
		// non-zero border found
		Rect newDimensions(left, top, right - left + 1, bottom - top + 1);
		SDL_Rect rectSDL = CSDL_Ext::toSDL(newDimensions);
		auto newSurface = CSDL_Ext::newSurface(newDimensions.dimensions(), surf);
		SDL_SetSurfaceBlendMode(surf, SDL_BLENDMODE_NONE);
		SDL_BlitSurface(surf, &rectSDL, newSurface, nullptr);

		if (SDL_HasColorKey(surf))
		{
			uint32_t colorKey;
			SDL_GetColorKey(surf, &colorKey);
			SDL_SetColorKey(newSurface, SDL_TRUE, colorKey);
		}

		SDL_FreeSurface(surf);
		surf = newSurface;

		margins.x += left;
		margins.y += top;
	}
}

std::shared_ptr<const ISharedImage> SDLImageShared::scaleInteger(int factor, SDL_Palette * palette, EImageBlitMode mode) const
{
	if (factor <= 0)
		throw std::runtime_error("Unable to scale by integer value of " + std::to_string(factor));

	if (!surf)
		return shared_from_this();

	if (palette && surf->format->palette)
		SDL_SetSurfacePalette(surf, palette);

	SDL_Surface * scaled = nullptr;

	// dump heuristics to differentiate tileable UI elements from map object / combat assets
	if (mode == EImageBlitMode::OPAQUE || mode == EImageBlitMode::COLORKEY || mode == EImageBlitMode::SIMPLE)
		scaled = CSDL_Ext::scaleSurfaceIntegerFactor(surf, factor, EScalingAlgorithm::XBRZ_OPAQUE);
	else
		scaled = CSDL_Ext::scaleSurfaceIntegerFactor(surf, factor, EScalingAlgorithm::XBRZ_ALPHA);

	auto ret = std::make_shared<SDLImageShared>(scaled);

	ret->fullSize.x = fullSize.x * factor;
	ret->fullSize.y = fullSize.y * factor;

	ret->margins.x = (int) round((float)margins.x * factor);
	ret->margins.y = (int) round((float)margins.y * factor);
	ret->optimizeSurface();

	// erase our own reference
	SDL_FreeSurface(scaled);

	if (surf->format->palette)
		SDL_SetSurfacePalette(surf, originalPalette);

	return ret;
}

std::shared_ptr<const ISharedImage> SDLImageShared::scaleTo(const Point & size, SDL_Palette * palette) const
{
	float scaleX = static_cast<float>(size.x) / fullSize.x;
	float scaleY = static_cast<float>(size.y) / fullSize.y;

	if (palette && surf->format->palette)
		SDL_SetSurfacePalette(surf, palette);

	auto scaled = CSDL_Ext::scaleSurface(surf, (int)(surf->w * scaleX), (int)(surf->h * scaleY), EScalingAlgorithm::BILINEAR);

	if (scaled->format && scaled->format->palette) // fix color keying, because SDL loses it at this point
		CSDL_Ext::setColorKey(scaled, scaled->format->palette->colors[0]);
	else if(scaled->format && scaled->format->Amask)
		SDL_SetSurfaceBlendMode(scaled, SDL_BLENDMODE_BLEND);//just in case
	else
		CSDL_Ext::setDefaultColorKey(scaled);//just in case

	auto ret = std::make_shared<SDLImageShared>(scaled);

	ret->fullSize.x = (int) round((float)fullSize.x * scaleX);
	ret->fullSize.y = (int) round((float)fullSize.y * scaleY);

	ret->margins.x = (int) round((float)margins.x * scaleX);
	ret->margins.y = (int) round((float)margins.y * scaleY);

	// erase our own reference
	SDL_FreeSurface(scaled);

	if (surf->format->palette)
		SDL_SetSurfacePalette(surf, originalPalette);

	return ret;
}

void SDLImageShared::exportBitmap(const boost::filesystem::path& path, SDL_Palette * palette) const
{
	if (!surf)
		return;

	if (palette && surf->format->palette)
		SDL_SetSurfacePalette(surf, palette);
	IMG_SavePNG(surf, path.string().c_str());
	if (palette && surf->format->palette)
		SDL_SetSurfacePalette(surf, originalPalette);
}

bool SDLImageShared::isTransparent(const Point & coords) const
{
	if (surf)
		return CSDL_Ext::isTransparent(surf, coords.x - margins.x, coords.y	- margins.y);
	else
		return true;
}

Rect SDLImageShared::contentRect() const
{
	auto tmpMargins = margins;
	auto tmpSize = Point(surf->w, surf->h);
	return Rect(tmpMargins, tmpSize);
}

const SDL_Palette * SDLImageShared::getPalette() const
{
	if (!surf)
		return nullptr;
	return surf->format->palette;
}

Point SDLImageShared::dimensions() const
{
	return fullSize;
}

std::shared_ptr<const ISharedImage> SDLImageShared::horizontalFlip() const
{
	if (!surf)
		return shared_from_this();

	SDL_Surface * flipped = CSDL_Ext::horizontalFlip(surf);
	auto ret = std::make_shared<SDLImageShared>(flipped);
	ret->fullSize = fullSize;
	ret->margins.x = margins.x;
	ret->margins.y = fullSize.y - surf->h - margins.y;
	ret->fullSize = fullSize;

	return ret;
}

std::shared_ptr<const ISharedImage> SDLImageShared::verticalFlip() const
{
	if (!surf)
		return shared_from_this();

	SDL_Surface * flipped = CSDL_Ext::verticalFlip(surf);
	auto ret = std::make_shared<SDLImageShared>(flipped);
	ret->fullSize = fullSize;
	ret->margins.x = fullSize.x - surf->w - margins.x;
	ret->margins.y = margins.y;
	ret->fullSize = fullSize;

	return ret;
}

// Keep the original palette, in order to do color switching operation
void SDLImageShared::savePalette()
{
	// For some images that don't have palette, skip this
	if(surf->format->palette == nullptr)
		return;

	if(originalPalette == nullptr)
		originalPalette = SDL_AllocPalette(surf->format->palette->ncolors);

	SDL_SetPaletteColors(originalPalette, surf->format->palette->colors, 0, surf->format->palette->ncolors);
}

SDLImageShared::~SDLImageShared()
{
	SDL_FreeSurface(surf);
	SDL_FreePalette(originalPalette);
}