/*
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/.
 */

#include "TextDrawable.hpp"
#include "Scene/Geometry.hpp"
#include "Scene/Material.hpp"
#include "Scene/Vertex.hpp"
#include "Scene/UniformBuffer.hpp"
#include "Scene/IFontAtlasGenerator.hpp"
#include "Base/Logger.hpp"
#include "Host/ResourceLoader.hpp"
#include "Image/ImageLoader.hpp"
#include "DataFormat.hpp"
#include "Base/Logger.hpp"
#include <fstream>
#include <utf8.h>

namespace OpenVulkano::Scene
{
	namespace
	{
		constexpr uint32_t MISSING_GLYPH_SYMBOL = '?';

		Shader MakeDefaultShader(FontAtlasType type)
		{
			Shader shader;
			shader.AddShaderProgram(ShaderProgramType::VERTEX, "Shader/text");
			shader.AddShaderProgram(ShaderProgramType::FRAGMENT, std::string(type.GetDefaultFragmentShader()));
			shader.AddVertexInputDescription(Vertex::GetVertexInputDescription());
			shader.AddDescriptorSetLayoutBinding(Texture::DESCRIPTOR_SET_LAYOUT_BINDING);
			DescriptorSetLayoutBinding desc = UniformBuffer::DESCRIPTOR_SET_LAYOUT_BINDING;
			desc.stageFlags = ShaderProgramType::FRAGMENT;
			shader.AddDescriptorSetLayoutBinding(desc);
			shader.alphaBlend = true;
			shader.cullMode = CullMode::NONE;
			return shader;
		}
	}

	Shader TextDrawable::DEFAULT_SHADER_BITMAP = MakeDefaultShader(FontAtlasType::BITMAP);
	Shader TextDrawable::DEFAULT_SHADER_SDF = MakeDefaultShader(FontAtlasType::SDF);
	Shader TextDrawable::DEFAULT_SHADER_MSDF = MakeDefaultShader(FontAtlasType::MSDF);

	TextDrawable::TextDrawable(const TextConfig& config) : m_cfg(config)
	{
		m_uniBuffer.Init(sizeof(TextConfig), &m_cfg, 3);
		m_uniBuffer.binding.stageFlags = ShaderProgramType::FRAGMENT;
	}

	TextDrawable::TextDrawable(const Array<char>& atlasMetadata, const TextConfig& config)
	    : TextDrawable(atlasMetadata, nullptr, config)
	{}

	TextDrawable::TextDrawable(const std::string& atlasMetadataFile, const TextConfig& config)
	    : TextDrawable(Utils::ReadFile(atlasMetadataFile), nullptr, config)
	{}

	TextDrawable::TextDrawable(const std::string& atlasMetadataFile, Texture* atlasTex, const TextConfig& config)
	    : TextDrawable(Utils::ReadFile(atlasMetadataFile), atlasTex, config)
	{}

	TextDrawable::TextDrawable(const Array<char>& atlasMetadata, Texture* atlasTex, const TextConfig& config)
		: m_cfg(config)
	{
		uint32_t isPacked;
		std::memcpy(&isPacked, atlasMetadata.Data() + (atlasMetadata.Size() - sizeof(uint32_t)), sizeof(uint32_t));
		uint64_t metadataBytes;
		std::memcpy(&metadataBytes, atlasMetadata.Data() + (atlasMetadata.Size() - sizeof(uint32_t) - sizeof(uint64_t)),
		            sizeof(uint64_t));
		uint64_t offsetToMetadata = atlasMetadata.Size() - metadataBytes - sizeof(uint32_t) - sizeof(uint64_t);
		m_atlasData = std::make_shared<AtlasData>();
		if (isPacked)
		{
			m_material.texture = &m_atlasData->texture;
			m_atlasData->img = Image::IImageLoader::loadData(reinterpret_cast<const uint8_t*>(atlasMetadata.Data()), offsetToMetadata);
			m_material.texture->format = m_atlasData->img->dataFormat;
			m_material.texture->resolution = m_atlasData->img->resolution;
			m_material.texture->size = m_atlasData->img->data.Size();
			m_material.texture->textureBuffer = m_atlasData->img->data.Data();
		}
		else
		{
			if (atlasTex == nullptr) { throw std::runtime_error("Atlas texture cannot be null with non-packed atlas metadata"); }
			m_atlasData->texture = *atlasTex;
			m_material.texture = atlasTex;
		}

		// metadata info
		size_t read_bytes = offsetToMetadata;
		size_t readMetadataBytes = 0;
		uint32_t unicode = 0;

		std::memcpy(&m_atlasData->meta, atlasMetadata.Data() + read_bytes, sizeof(AtlasMetadata));
		read_bytes += sizeof(AtlasMetadata);
		readMetadataBytes += sizeof(AtlasMetadata);
		while (readMetadataBytes < metadataBytes)
		{
			std::memcpy(&unicode, atlasMetadata.Data() + read_bytes, sizeof(uint32_t));
			read_bytes += sizeof(uint32_t);
			readMetadataBytes += sizeof(uint32_t);
			GlyphInfo& info = m_atlasData->glyphs[unicode];
			std::memcpy(&info, atlasMetadata.Data() + read_bytes, sizeof(GlyphInfo));
			read_bytes += sizeof(GlyphInfo);
			readMetadataBytes += sizeof(GlyphInfo);
		}
		m_uniBuffer.Init(sizeof(TextConfig), &m_cfg, 3);
		m_uniBuffer.binding.stageFlags = ShaderProgramType::FRAGMENT;
		if (m_atlasData->meta.atlasType == FontAtlasType::BITMAP)
		{
			m_material.texture->m_samplerConfig = &SamplerConfig::NEAREST;
		}
	}

	TextDrawable::TextDrawable(const std::shared_ptr<AtlasData>& atlasData, const TextConfig& config)
		: m_atlasData(atlasData), m_cfg(config)
	{
		if (!atlasData || !*atlasData) throw std::runtime_error("Cannot initialize text drawable with empty atlas data");
		m_uniBuffer.Init(sizeof(TextConfig), &m_cfg, 3);
		m_uniBuffer.binding.stageFlags = ShaderProgramType::FRAGMENT;
	}

	uint32_t TextDrawable::GetFallbackGlyph() const
	{
		if (m_atlasData->glyphs.find(MISSING_GLYPH_SYMBOL) != m_atlasData->glyphs.end())
		{
			return MISSING_GLYPH_SYMBOL;
		}
		Logger::RENDER->warn("Could not find glyph for character ? to use as fallback. Using first glyph instead");
		return m_atlasData->glyphs.begin()->first;
	}


	void TextDrawable::GenerateText(const std::string& text, const Math::Vector3f& pos)
	{
		if (text.empty()) return;
		const uint32_t fallbackGlyph = GetFallbackGlyph();

		m_text = text;

		size_t len = utf8::distance(text.begin(), text.end());
		m_geometry.Close();
		m_geometry.Init(len * 4, len * 6);
		AtlasMetadata* meta;
		std::map<uint32_t, GlyphInfo>* symbols;
		m_material.texture = &m_atlasData->texture;
		symbols = &m_atlasData->glyphs;
		meta = &m_atlasData->meta;

		double cursorX = pos.x;
		auto begin = text.begin();
		auto end = text.end();
		const double lineHeight = meta->lineHeight;
		double posY = pos.y;
		int i = 0;
		Math::Vector3f bmin(pos), bmax(pos);
		bool firstGlyph = true;
		while (begin != end)
		{
			uint32_t c = utf8::next(begin, end);
			if (c == '\n')
			{
				posY -= lineHeight;
				cursorX = pos.x;
				continue;
			}

			if (symbols->find(c) == symbols->end())
			{
				Logger::RENDER->warn("Could not find glyph for character {}, using fallback", c);
				c = fallbackGlyph;
			}

			uint32_t vIdx = i * 4;
			uint32_t indices[] = { 1 + vIdx, 2 + vIdx, 3 + vIdx, 1 + vIdx, 3 + vIdx, 0 + vIdx };
			GlyphInfo& info = symbols->at(c);

			// left bottom
			m_geometry.vertices[vIdx].position.x = info.xyz[0].x + cursorX;
			m_geometry.vertices[vIdx].position.y = posY - info.xyz[0].y;
			m_geometry.vertices[vIdx].position.z = info.xyz[0].z;
			m_geometry.vertices[vIdx].textureCoordinates = Math::Vector3f(info.uv[0], 0);

			// right bottom
			m_geometry.vertices[vIdx + 1].position.x = info.xyz[1].x + cursorX;
			m_geometry.vertices[vIdx + 1].position.y = posY - info.xyz[1].y;
			m_geometry.vertices[vIdx + 1].position.z = info.xyz[1].z;
			m_geometry.vertices[vIdx + 1].textureCoordinates = Math::Vector3f(info.uv[1], 0);

			// top right
			m_geometry.vertices[vIdx + 2].position.x = info.xyz[2].x + cursorX;
			m_geometry.vertices[vIdx + 2].position.y = posY + info.xyz[2].y;
			m_geometry.vertices[vIdx + 2].position.z = info.xyz[2].z;
			m_geometry.vertices[vIdx + 2].textureCoordinates = Math::Vector3f(info.uv[2], 0);

			// top left
			m_geometry.vertices[vIdx + 3].position.x = info.xyz[3].x + cursorX;
			m_geometry.vertices[vIdx + 3].position.y = posY + info.xyz[3].y;
			m_geometry.vertices[vIdx + 3].position.z = info.xyz[3].z;
			m_geometry.vertices[vIdx + 3].textureCoordinates = Math::Vector3f(info.uv[3], 0);
			m_geometry.SetIndices(indices, 6, 6 * i);
			// TODO: change to lower value(or ideally remove completely) to avoid overlapping and make less space between symbols
			// when setting for depth comparison operator will be available( <= )
			cursorX += info.advance + 0.08;
			if (firstGlyph)
			{
				bmin.x = m_geometry.vertices[vIdx].position.x;
				firstGlyph = false;
			}
			bmax.x = std::max(bmax.x, m_geometry.vertices[vIdx + 1].position.x);
			bmax.y = std::max(bmax.y, m_geometry.vertices[vIdx + 2].position.y);
			bmin.y = std::min(bmin.y, m_geometry.vertices[vIdx + 1].position.y);
			++i;
		}
		m_bbox.Init(bmin, bmax);
		SimpleDrawable::Init(nullptr, &m_geometry, &m_material, &m_uniBuffer);
	}

	void TextDrawable::SetAtlasData(const std::shared_ptr<AtlasData>& atlasData) 
	{
		if (!atlasData || !*atlasData) throw std::runtime_error("Cannot initialize text drawable with empty atlas data");
		m_atlasData = atlasData;
	}
}