#include <algorithm>
#include <cstring>

#include "Common/GPU/thin3d.h"
#include "ext/jpge/jpgd.h"
#include "Common/UI/View.h"
#include "Common/UI/Context.h"
#include "Common/Render/DrawBuffer.h"

#include "Common/Data/Color/RGBAUtil.h"
#include "Common/Data/Format/ZIMLoad.h"
#include "Common/Data/Format/PNGLoad.h"
#include "Common/Math/math_util.h"
#include "Common/Math/curves.h"
#include "Common/File/VFS/VFS.h"
#include "Common/Log.h"
#include "Common/TimeUtil.h"
#include "Common/Render/ManagedTexture.h"

// For UI images loaded from disk, loaded into RAM, generally staged for upload.
// The reason for the separation is so that the image can be loaded and decompressed on a thread,
// and then only uploaded to the GPU on the main thread.
struct TempImage {
	~TempImage() {
		_dbg_assert_(levels[0] == nullptr);
	}
	Draw::DataFormat fmt = Draw::DataFormat::UNDEFINED;
	ImageFileType type = TYPE_UNKNOWN;
	uint8_t *levels[16]{};   // only free the first pointer, they all point to the same buffer.
	int zimFlags = 0;
	int width[16]{};
	int height[16]{};
	int numLevels = 0;

	bool LoadTextureLevels(const uint8_t *data, size_t size, ImageFileType typeSuggestion = DETECT);
	void Free() {
		if (levels[0]) {
			free(levels[0]);
			memset(levels, 0, sizeof(levels));
		}
	}
};

static Draw::DataFormat ZimToT3DFormat(int zim) {
	switch (zim) {
	case ZIM_RGBA8888: return Draw::DataFormat::R8G8B8A8_UNORM;
	default: return Draw::DataFormat::R8G8B8A8_UNORM;
	}
}

static ImageFileType DetectImageFileType(const uint8_t *data, size_t size) {
	if (size < 4) {
		return TYPE_UNKNOWN;
	}
	if (!memcmp(data, "ZIMG", 4)) {
		return ZIM;
	} else if (!memcmp(data, "\x89\x50\x4E\x47", 4)) {
		return PNG;
	} else if (!memcmp(data, "\xff\xd8\xff\xe0", 4) || !memcmp(data, "\xff\xd8\xff\xe1", 4)) {
		return JPEG;
	} else {
		return TYPE_UNKNOWN;
	}
}

bool TempImage::LoadTextureLevels(const uint8_t *data, size_t size, ImageFileType typeSuggestion) {
	if (typeSuggestion == DETECT) {
		typeSuggestion = DetectImageFileType(data, size);
	}
	if (typeSuggestion == TYPE_UNKNOWN) {
		ERROR_LOG(G3D, "File (size: %d) has unknown format", (int)size);
		return false;
	}

	type = typeSuggestion;
	numLevels = 0;
	zimFlags = 0;

	switch (typeSuggestion) {
	case ZIM:
		numLevels = LoadZIMPtr((const uint8_t *)data, size, width, height, &zimFlags, levels);
		fmt = ZimToT3DFormat(zimFlags & ZIM_FORMAT_MASK);
		break;

	case PNG:
		if (1 == pngLoadPtr((const unsigned char *)data, size, &width[0], &height[0], &levels[0])) {
			numLevels = 1;
			fmt = Draw::DataFormat::R8G8B8A8_UNORM;
			if (!levels[0]) {
				ERROR_LOG(IO, "pngLoadPtr failed (input size = %d)", (int)size);
				return false;
			}
		} else {
			ERROR_LOG(IO, "PNG load failed");
			return false;
		}
		break;

	case JPEG:
	{
		int actual_components = 0;
		unsigned char *jpegBuf = jpgd::decompress_jpeg_image_from_memory(data, (int)size, &width[0], &height[0], &actual_components, 4);
		if (jpegBuf) {
			numLevels = 1;
			fmt = Draw::DataFormat::R8G8B8A8_UNORM;
			levels[0] = (uint8_t *)jpegBuf;
		}
		break;
	}

	default:
		ERROR_LOG(IO, "Unsupported image format %d", (int)type);
		return false;
	}

	return numLevels > 0;
}

bool ManagedTexture::LoadFromFileData(const uint8_t *data, size_t dataSize, ImageFileType type, bool generateMips, const char *name) {
	generateMips_ = generateMips;
	using namespace Draw;

	TempImage image;
	if (!image.LoadTextureLevels(data, dataSize, type)) {
		return false;
	}

	_assert_(image.levels[0] != nullptr);

	int numLevels = image.numLevels;
	if (numLevels < 0 || numLevels >= 16) {
		ERROR_LOG(IO, "Invalid num_levels: %d. Falling back to one. Image: %dx%d", numLevels, image.width[0], image.height[0]);
		numLevels = 1;
	}

	// Free the old texture, if any.
	if (texture_) {
		delete texture_;
		texture_ = nullptr;
	}

	int potentialLevels = std::min(log2i(image.width[0]), log2i(image.height[0]));
	if (image.width[0] > 0 && image.height[0] > 0) {
		TextureDesc desc{};
		desc.type = TextureType::LINEAR2D;
		desc.format = image.fmt;
		desc.width = image.width[0];
		desc.height = image.height[0];
		desc.depth = 1;
		desc.mipLevels = generateMips ? potentialLevels : image.numLevels;
		desc.generateMips = generateMips && potentialLevels > image.numLevels;
		desc.tag = name;
		for (int i = 0; i < image.numLevels; i++) {
			desc.initData.push_back(image.levels[i]);
		}
		texture_ = draw_->CreateTexture(desc);
	}
	image.Free();
	return texture_ != nullptr;
}

bool ManagedTexture::LoadFromFile(const std::string &filename, ImageFileType type, bool generateMips) {
	generateMips_ = generateMips;
	size_t fileSize;
	uint8_t *buffer = g_VFS.ReadFile(filename.c_str(), &fileSize);
	if (!buffer) {
		filename_.clear();
		ERROR_LOG(IO, "Failed to read file '%s'", filename.c_str());
		return false;
	}
	bool retval = LoadFromFileData(buffer, fileSize, type, generateMips, filename.c_str());
	if (retval) {
		filename_ = filename;
	} else {
		filename_.clear();
		ERROR_LOG(IO, "Failed to load texture '%s'", filename.c_str());
	}
	delete[] buffer;
	return retval;
}

std::unique_ptr<ManagedTexture> CreateManagedTextureFromFile(Draw::DrawContext *draw, const char *filename, ImageFileType type, bool generateMips) {
	if (!draw)
		return std::unique_ptr<ManagedTexture>();
	// TODO: Load the texture on a background thread.
	ManagedTexture *mtex = new ManagedTexture(draw);
	if (!mtex->LoadFromFile(filename, type, generateMips)) {
		delete mtex;
		return std::unique_ptr<ManagedTexture>();
	}
	return std::unique_ptr<ManagedTexture>(mtex);
}

void ManagedTexture::DeviceLost() {
	INFO_LOG(G3D, "ManagedTexture::DeviceLost(%s)", filename_.c_str());
	if (texture_)
		texture_->Release();
	texture_ = nullptr;
}

void ManagedTexture::DeviceRestored(Draw::DrawContext *draw) {
    INFO_LOG(G3D, "ManagedTexture::DeviceRestored(%s)", filename_.c_str());

	draw_ = draw;

	_dbg_assert_(!texture_);
	if (texture_) {
		ERROR_LOG(G3D, "ManagedTexture: Unexpected - texture already present: %s", filename_.c_str());
		return;
	}

	// Vulkan: Can't load textures before the first frame has started.
	// Should probably try to lift that restriction again someday..
	loadPending_ = true;
}

Draw::Texture *ManagedTexture::GetTexture() {
	if (loadPending_) {
		if (!LoadFromFile(filename_, ImageFileType::DETECT, generateMips_)) {
			ERROR_LOG(IO, "ManagedTexture failed: '%s'", filename_.c_str());
		}
		loadPending_ = false;
	}
	return texture_;
}

// TODO: Remove the code duplication between this and LoadFromFileData
std::unique_ptr<ManagedTexture> CreateManagedTextureFromFileData(Draw::DrawContext *draw, const uint8_t *data, int size, ImageFileType type, bool generateMips, const char *name) {
	if (!draw)
		return std::unique_ptr<ManagedTexture>();
	ManagedTexture *mtex = new ManagedTexture(draw);
	if (mtex->LoadFromFileData(data, size, type, generateMips, name)) {
		return std::unique_ptr<ManagedTexture>(mtex);
	} else {
		// Best to return a null pointer if we fail!
		delete mtex;
		return std::unique_ptr<ManagedTexture>();
	}
}