/**
 * Copyright (c) 2006-2017 LOVE Development Team
 *
 * This software is provided 'as-is', without any express or implied
 * warranty.  In no event will the authors be held liable for any damages
 * arising from the use of this software.
 *
 * Permission is granted to anyone to use this software for any purpose,
 * including commercial applications, and to alter it and redistribute it
 * freely, subject to the following restrictions:
 *
 * 1. The origin of this software must not be misrepresented; you must not
 *    claim that you wrote the original software. If you use this software
 *    in a product, an acknowledgment in the product documentation would be
 *    appreciated but is not required.
 * 2. Altered source versions must be plainly marked as such, and must not be
 *    misrepresented as being the original software.
 * 3. This notice may not be removed or altered from any source distribution.
 **/

#include "Image.h"

#include "graphics/Graphics.h"
#include "common/int.h"

// STD
#include <algorithm> // for min/max

namespace love
{
namespace graphics
{
namespace opengl
{

Image::Image(TextureType textype, PixelFormat format, int width, int height, int slices, const Settings &settings)
	: love::graphics::Image(Slices(textype), settings, false)
	, texture(0)
	, compressed(false)
	, usingDefaultTexture(false)
	, textureMemorySize(0)
{
	if (isPixelFormatCompressed(format))
		throw love::Exception("This constructor is only supported for non-compressed pixel formats.");

	if (textype == TEXTURE_VOLUME)
		depth = slices;
	else if (textype == TEXTURE_2D_ARRAY)
		layers = slices;

	init(format, width, height, settings);
}

Image::Image(const Slices &slices, const Settings &settings)
	: love::graphics::Image(slices, settings, true)
	, texture(0)
	, compressed(false)
	, usingDefaultTexture(false)
	, textureMemorySize(0)
{
	if (texType == TEXTURE_2D_ARRAY)
		this->layers = data.getSliceCount();
	else if (texType == TEXTURE_VOLUME)
		this->depth = data.getSliceCount();

	love::image::ImageDataBase *slice = data.get(0, 0);
	init(slice->getFormat(), slice->getWidth(), slice->getHeight(), settings);
}

Image::~Image()
{
	unloadVolatile();
}

void Image::init(PixelFormat fmt, int w, int h, const Settings &settings)
{
	pixelWidth = w;
	pixelHeight = h;

	width  = (int) (pixelWidth / settings.pixeldensity + 0.5);
	height = (int) (pixelHeight / settings.pixeldensity + 0.5);

	mipmapCount = mipmapsType == MIPMAPS_NONE ? 1 : getMipmapCount(w, h);
	format = fmt;
	compressed = isPixelFormatCompressed(format);

	if (compressed && mipmapsType == MIPMAPS_GENERATED)
		mipmapsType = MIPMAPS_NONE;

	if (getMipmapCount() > 1)
		filter.mipmap = defaultMipmapFilter;

	initQuad();
	loadVolatile();
}

void Image::generateMipmaps()
{
	if (getMipmapCount() > 1 && !isCompressed() &&
		(GLAD_ES_VERSION_2_0 || GLAD_VERSION_3_0 || GLAD_ARB_framebuffer_object || GLAD_EXT_framebuffer_object))
	{
		GLenum gltextype = OpenGL::getGLTextureType(texType);

		if (gl.bugs.generateMipmapsRequiresTexture2DEnable)
			glEnable(gltextype);

		glGenerateMipmap(gltextype);
	}
}

void Image::loadDefaultTexture()
{
	usingDefaultTexture = true;

	gl.bindTextureToUnit(this, 0, false);
	setFilter(filter);

	bool isSRGB = false;
	gl.rawTexStorage(texType, 1, PIXELFORMAT_RGBA8, isSRGB, 2, 2, 1);

	// A nice friendly checkerboard to signify invalid textures...
	GLubyte px[] = {0xFF,0xFF,0xFF,0xFF, 0xFF,0xA0,0xA0,0xFF,
	                0xFF,0xA0,0xA0,0xFF, 0xFF,0xFF,0xFF,0xFF};

	int slices = texType == TEXTURE_CUBE ? 6 : 1;
	Rect rect = {0, 0, 2, 2};
	for (int slice = 0; slice < slices; slice++)
		uploadByteData(PIXELFORMAT_RGBA8, px, sizeof(px), rect, 0, slice);
}

void Image::loadData()
{
	int mipcount = getMipmapCount();
	int slicecount = 1;

	if (texType == TEXTURE_VOLUME)
		slicecount = getDepth();
	else if (texType == TEXTURE_2D_ARRAY)
		slicecount = getLayerCount();
	else if (texType == TEXTURE_CUBE)
		slicecount = 6;

	if (!isCompressed())
		gl.rawTexStorage(texType, mipcount, format, sRGB, pixelWidth, pixelHeight, texType == TEXTURE_VOLUME ? depth : layers);

	if (mipmapsType == MIPMAPS_GENERATED)
		mipcount = 1;

	int w = pixelWidth;
	int h = pixelHeight;
	int d = depth;

	OpenGL::TextureFormat fmt = gl.convertPixelFormat(format, false, sRGB);

	for (int mip = 0; mip < mipcount; mip++)
	{
		if (isCompressed() && (texType == TEXTURE_2D_ARRAY || texType == TEXTURE_VOLUME))
		{
			size_t mipsize = 0;

			if (texType == TEXTURE_2D_ARRAY || texType == TEXTURE_VOLUME)
			{
				for (int slice = 0; slice < data.getSliceCount(mip); slice++)
					mipsize += data.get(slice, mip)->getSize();
			}

			GLenum gltarget = OpenGL::getGLTextureType(texType);
			glCompressedTexImage3D(gltarget, mip, fmt.internalformat, w, h, d, 0, mipsize, nullptr);
		}

		for (int slice = 0; slice < slicecount; slice++)
		{
			love::image::ImageDataBase *id = data.get(slice, mip);

			if (id != nullptr)
				uploadImageData(id, mip, slice);
		}

		w = std::max(w / 2, 1);
		h = std::max(h / 2, 1);

		if (texType == TEXTURE_VOLUME)
			d = std::max(d / 2, 1);
	}

	if (mipmapsType == MIPMAPS_GENERATED)
		generateMipmaps();
}

void Image::uploadByteData(PixelFormat pixelformat, const void *data, size_t size, const Rect &r, int level, int slice)
{
	OpenGL::TextureFormat fmt = OpenGL::convertPixelFormat(pixelformat, false, sRGB);
	GLenum gltarget = OpenGL::getGLTextureType(texType);

	if (texType == TEXTURE_CUBE)
		gltarget = GL_TEXTURE_CUBE_MAP_POSITIVE_X + slice;

	if (isPixelFormatCompressed(pixelformat))
	{
		if (r.x != 0 || r.y != 0)
			throw love::Exception("x and y parameters must be 0 for compressed images.");

		if (texType == TEXTURE_2D || texType == TEXTURE_CUBE)
			glCompressedTexImage2D(gltarget, level, fmt.internalformat, r.w, r.h, 0, size, data);
		else if (texType == TEXTURE_2D_ARRAY || texType == TEXTURE_VOLUME)
			glCompressedTexSubImage3D(gltarget, level, 0, 0, slice, r.w, r.h, 1, fmt.internalformat, size, data);
	}
	else
	{
		if (texType == TEXTURE_2D || texType == TEXTURE_CUBE)
			glTexSubImage2D(gltarget, level, r.x, r.y, r.w, r.h, fmt.externalformat, fmt.type, data);
		else if (texType == TEXTURE_2D_ARRAY || texType == TEXTURE_VOLUME)
			glTexSubImage3D(gltarget, level, r.x, r.y, slice, r.w, r.h, 1, fmt.externalformat, fmt.type, data);
	}
}

void Image::uploadImageData(love::image::ImageDataBase *d, int level, int slice)
{
	love::image::ImageData *id = dynamic_cast<love::image::ImageData *>(d);

	love::thread::EmptyLock lock;
	if (id != nullptr)
		lock.setLock(id->getMutex());

	Rect rect = {0, 0, d->getWidth(), d->getHeight()};
	uploadByteData(d->getFormat(), d->getData(), d->getSize(), rect, level, slice);
}

bool Image::loadVolatile()
{
	if (texture != 0)
		return true;

	OpenGL::TempDebugGroup debuggroup("Image load");

	if (!OpenGL::isPixelFormatSupported(format, false, true, sRGB))
	{
		const char *str;
		if (love::getConstant(format, str))
		{
			throw love::Exception("Cannot create image: "
			                      "%s%s images are not supported on this system.", sRGB ? "sRGB " : "", str);
		}
		else
			throw love::Exception("cannot create image: format is not supported on this system.");
	}
	else if (!isCompressed())
	{
		if (sRGB && !hasSRGBSupport())
			throw love::Exception("sRGB images are not supported on this system.");

		// GL_EXT_sRGB doesn't support glGenerateMipmap for sRGB textures.
		if (sRGB && (GLAD_ES_VERSION_2_0 && GLAD_EXT_sRGB && !GLAD_ES_VERSION_3_0)
			&& mipmapsType != MIPMAPS_DATA)
		{
			mipmapsType = MIPMAPS_NONE;
			filter.mipmap = FILTER_NONE;
		}
	}

	// NPOT textures don't support mipmapping without full NPOT support.
	if ((GLAD_ES_VERSION_2_0 && !(GLAD_ES_VERSION_3_0 || GLAD_OES_texture_npot))
		&& (pixelWidth != nextP2(pixelWidth) || pixelHeight != nextP2(pixelHeight)))
	{
		mipmapsType = MIPMAPS_NONE;
		filter.mipmap = FILTER_NONE;
	}

	glGenTextures(1, &texture);
	gl.bindTextureToUnit(this, 0, false);

	bool loaddefault = false;

	int max2Dsize = gl.getMax2DTextureSize();
	int max3Dsize = gl.getMax3DTextureSize();

	if ((texType == TEXTURE_2D || texType == TEXTURE_2D_ARRAY) && (pixelWidth > max2Dsize || pixelHeight > max2Dsize))
		loaddefault = true;
	else if (texType == TEXTURE_2D_ARRAY && layers > gl.getMaxTextureLayers())
		loaddefault = true;
	else if (texType == TEXTURE_CUBE && (pixelWidth > gl.getMaxCubeTextureSize() || pixelWidth != pixelHeight))
		loaddefault = true;
	else if (texType == TEXTURE_VOLUME && (pixelWidth > max3Dsize || pixelHeight > max3Dsize || depth > max3Dsize))
		loaddefault = true;

	// Use a default texture if the size is too big for the system.
	if (loaddefault)
	{
		loadDefaultTexture();
		return true;
	}

	setFilter(filter);
	setWrap(wrap);
	setMipmapSharpness(mipmapSharpness);

	GLenum gltextype = OpenGL::getGLTextureType(texType);

	if (mipmapsType == MIPMAPS_NONE && (GLAD_ES_VERSION_3_0 || GLAD_VERSION_1_0))
		glTexParameteri(gltextype, GL_TEXTURE_MAX_LEVEL, 0);

	while (glGetError() != GL_NO_ERROR); // Clear errors.

	try
	{
		loadData();

		GLenum glerr = glGetError();
		if (glerr != GL_NO_ERROR)
			throw love::Exception("Cannot create image (OpenGL error: %s)", OpenGL::errorString(glerr));
	}
	catch (love::Exception &)
	{
		gl.deleteTexture(texture);
		texture = 0;
		throw;
	}

	size_t prevmemsize = textureMemorySize;
	textureMemorySize = 0;

	for (int slice = 0; slice < data.getSliceCount(0); slice++)
		textureMemorySize += data.get(slice, 0)->getSize();

	if (getMipmapCount() > 1)
		textureMemorySize *= 1.33334;

	gl.updateTextureMemorySize(prevmemsize, textureMemorySize);

	usingDefaultTexture = false;
	return true;
}

void Image::unloadVolatile()
{
	if (texture == 0)
		return;

	gl.deleteTexture(texture);
	texture = 0;

	gl.updateTextureMemorySize(textureMemorySize, 0);
	textureMemorySize = 0;
}

void Image::replacePixels(love::image::ImageDataBase *d, int slice, int mipmap, bool reloadmipmaps)
{
	// No effect if the texture hasn't been created yet.
	if (getHandle() == 0 || usingDefaultTexture)
		return;

	if (d->getFormat() != getPixelFormat())
		throw love::Exception("Pixel formats must match.");

	if (mipmap < 0 || (mipmapsType != MIPMAPS_DATA && mipmap > 0) || mipmap >= getMipmapCount())
		throw love::Exception("Invalid image mipmap index.");

	if (slice < 0 || (texType == TEXTURE_CUBE && slice >= 6)
		|| (texType == TEXTURE_VOLUME && slice >= std::max(getDepth() >> mipmap, 1))
		|| (texType == TEXTURE_2D_ARRAY && slice >= getLayerCount()))
	{
		throw love::Exception("Invalid image slice index.");
	}

	love::image::ImageDataBase *oldd = data.get(slice, mipmap);

	if (oldd == nullptr)
		throw love::Exception("Image does not store ImageData!");

	int w = d->getWidth();
	int h = d->getHeight();

	if (w != oldd->getWidth() || h != oldd->getHeight())
		throw love::Exception("Dimensions must match the texture's dimensions for the specified mipmap level.");

	Graphics::flushStreamDrawsGlobal();

	d->retain();
	oldd->release();

	data.set(slice, mipmap, d);

	OpenGL::TempDebugGroup debuggroup("Image replace pixels");

	gl.bindTextureToUnit(this, 0, false);

	uploadImageData(d, mipmap, slice);

	if (reloadmipmaps && mipmap == 0 && getMipmapCount() > 1)
		generateMipmaps();
}

void Image::replacePixels(const void *data, size_t size, const Rect &rect, int slice, int mipmap, bool reloadmipmaps)
{
	Graphics::flushStreamDrawsGlobal();

	OpenGL::TempDebugGroup debuggroup("Image replace pixels");

	gl.bindTextureToUnit(this, 0, false);

	uploadByteData(format, data, size, rect, mipmap, slice);

	if (reloadmipmaps && mipmap == 0 && getMipmapCount() > 1)
		generateMipmaps();
}

ptrdiff_t Image::getHandle() const
{
	return texture;
}

void Image::setFilter(const Texture::Filter &f)
{
	Texture::setFilter(f);

	if (!OpenGL::hasTextureFilteringSupport(getPixelFormat()))
	{
		filter.mag = filter.min = FILTER_NEAREST;

		if (filter.mipmap == FILTER_LINEAR)
			filter.mipmap = FILTER_NEAREST;
	}

	// We don't want filtering or (attempted) mipmaps on the default texture.
	if (usingDefaultTexture)
	{
		filter.mipmap = FILTER_NONE;
		filter.min = filter.mag = FILTER_NEAREST;
	}

	gl.bindTextureToUnit(this, 0, false);
	gl.setTextureFilter(texType, filter);
}

bool Image::setWrap(const Texture::Wrap &w)
{
	Graphics::flushStreamDrawsGlobal();

	bool success = true;
	bool forceclamp = texType == TEXTURE_CUBE;
	wrap = w;

	// If we only have limited NPOT support then the wrap mode must be CLAMP.
	if ((GLAD_ES_VERSION_2_0 && !(GLAD_ES_VERSION_3_0 || GLAD_OES_texture_npot))
		&& (pixelWidth != nextP2(pixelWidth) || pixelHeight != nextP2(pixelHeight) || depth != nextP2(depth)))
	{
		forceclamp = true;
	}

	if (forceclamp)
	{
		if (wrap.s != WRAP_CLAMP || wrap.t != WRAP_CLAMP || wrap.r != WRAP_CLAMP)
			success = false;

		wrap.s = wrap.t = wrap.r = WRAP_CLAMP;
	}

	if (!gl.isClampZeroTextureWrapSupported())
	{
		if (wrap.s == WRAP_CLAMP_ZERO) wrap.s = WRAP_CLAMP;
		if (wrap.t == WRAP_CLAMP_ZERO) wrap.t = WRAP_CLAMP;
		if (wrap.r == WRAP_CLAMP_ZERO) wrap.r = WRAP_CLAMP;
	}

	gl.bindTextureToUnit(this, 0, false);
	gl.setTextureWrap(texType, wrap);

	return success;
}

bool Image::setMipmapSharpness(float sharpness)
{
	if (!gl.isSamplerLODBiasSupported())
		return false;

	Graphics::flushStreamDrawsGlobal();

	float maxbias = gl.getMaxLODBias();
	if (maxbias > 0.01f)
		maxbias -= 0.0f;

	mipmapSharpness = std::min(std::max(sharpness, -maxbias), maxbias);

	gl.bindTextureToUnit(this, 0, false);

	// negative bias is sharper
	glTexParameterf(gl.getGLTextureType(texType), GL_TEXTURE_LOD_BIAS, -mipmapSharpness);

	return true;
}

bool Image::isFormatLinear() const
{
	return isGammaCorrect() && !sRGB;
}

bool Image::isCompressed() const
{
	return compressed;
}

Image::MipmapsType Image::getMipmapsType() const
{
	return mipmapsType;
}

bool Image::isFormatSupported(PixelFormat pixelformat)
{
	return OpenGL::isPixelFormatSupported(pixelformat, false, true, false);
}

bool Image::hasSRGBSupport()
{
	return GLAD_ES_VERSION_3_0 || GLAD_EXT_sRGB || GLAD_VERSION_2_1 || GLAD_EXT_texture_sRGB;
}

} // opengl
} // graphics
} // love