#include <fstream>
#include "AssetManager.hpp" 
#include <experimental/filesystem>

namespace fs = std::experimental::filesystem::v1;

//const fs::path pathToAssets = "./assets/";
//const fs::path pathToAssetsList = "./items.json";
//const fs::path pathToTextureIndex = "./textures.json";
const std::string pathToAssetsList = "./items.json";
const std::string pathToTextureIndex = "./textures.json";

const fs::path pathToModels  = "./assets/minecraft/models/";

AssetManager::AssetManager() {
	LoadIds();
	LoadTextureResources();
    LoadBlockModels();
}

void AssetManager::LoadIds() {
	std::ifstream in(pathToAssetsList);
	nlohmann::json index;
	in >> index;
	for (auto &it:index) {
		unsigned short id = it["type"].get<int>();
		unsigned char state = it["meta"].get<int>();
		std::string blockName = it["text_type"].get<std::string>();
        assetIds[blockName] = BlockId{ id, state };
	}
	LOG(INFO) << "Loaded " << assetIds.size() << " ids";
}

AssetManager::~AssetManager() {
	delete textureAtlas;
}

//TODO: This function must be replaced with runtime texture atlas generating
void AssetManager::LoadTextureResources() {
	std::ifstream in(pathToTextureIndex);
	nlohmann::json index;
	in >> index;
	std::string filename = index["meta"]["image"].get<std::string>();
	float textureWidth = index["meta"]["size"]["w"].get<int>();
	float textureHeight = index["meta"]["size"]["h"].get<int>();
    size_t sizeName = 0,sizeTexture = 0;
	for (auto &it:index["frames"]) {
		auto frame = it["frame"];
		TextureCoordinates coord;
		coord.x = frame["x"].get<int>() / textureWidth;
		coord.y = frame["y"].get<int>() / textureHeight;
		coord.w = frame["w"].get<int>() / textureWidth;
		coord.h = frame["h"].get<int>() / textureHeight;
		std::string assetName = it["filename"].get<std::string>();
		assetName.insert(0, "minecraft/textures/");
		assetName.erase(assetName.length() - 4);
        assetName.shrink_to_fit();
        sizeName += sizeof(assetName) + assetName.capacity();
        sizeTexture += sizeof(coord);
		assetTextures[assetName] = coord;
	}
	textureAtlas = new Texture(filename);
	LOG(INFO) << "Texture atlas id is " << textureAtlas->texture;
}

TextureCoordinates AssetManager::GetTextureByAssetName(std::string AssetName) {
	if (assetTextures.find(AssetName) != assetTextures.end())
		return assetTextures[AssetName];
	else
		return TextureCoordinates{-1, -1, -1, -1};
}

std::string AssetManager::GetTextureAssetNameByBlockId(BlockTextureId block) {
	//Block sides: 0 - bottom, 1 - top, 2 - north, 3 - south, 4 - west, 5 - east 6 - every side
	const std::map<BlockTextureId, std::string> lookupTable = {
			{BlockTextureId(0, 0),     "minecraft/textures/blocks/air"},
			{BlockTextureId(1, 0),     "minecraft/textures/blocks/stone"},
			{BlockTextureId(1, 1),     "minecraft/textures/blocks/stone_granite"},

			{BlockTextureId(2, 0, 0),  "minecraft/textures/blocks/dirt"},
			{BlockTextureId(2, 0, 1),  "minecraft/textures/blocks/grass_top"},
			{BlockTextureId(2, 0, 2),  "minecraft/textures/blocks/grass_side"},
			{BlockTextureId(2, 0, 3),  "minecraft/textures/blocks/grass_side"},
			{BlockTextureId(2, 0, 4),  "minecraft/textures/blocks/grass_side"},
			{BlockTextureId(2, 0, 5),  "minecraft/textures/blocks/grass_side"},

			{BlockTextureId(3, 0),     "minecraft/textures/blocks/dirt"},
			{BlockTextureId(4, 0),     "minecraft/textures/blocks/cobblestone"},
			{BlockTextureId(5, 0),     "minecraft/textures/blocks/planks"},

			{BlockTextureId(7, 0),     "minecraft/textures/blocks/bedrock"},

			{BlockTextureId(17, 0, 0), "minecraft/textures/blocks/log_oak_top"},
			{BlockTextureId(17, 0, 1), "minecraft/textures/blocks/log_oak_top"},
			{BlockTextureId(17, 0, 2), "minecraft/textures/blocks/log_oak"},
			{BlockTextureId(17, 0, 3), "minecraft/textures/blocks/log_oak"},
			{BlockTextureId(17, 0, 4), "minecraft/textures/blocks/log_oak"},
			{BlockTextureId(17, 0, 5), "minecraft/textures/blocks/log_oak"},

			{BlockTextureId(17, 1, 0), "minecraft/textures/blocks/log_spruce_top"},
			{BlockTextureId(17, 1, 1), "minecraft/textures/blocks/log_spruce_top"},
			{BlockTextureId(17, 1, 2), "minecraft/textures/blocks/log_spruce"},
			{BlockTextureId(17, 1, 3), "minecraft/textures/blocks/log_spruce"},
			{BlockTextureId(17, 1, 4), "minecraft/textures/blocks/log_spruce"},
			{BlockTextureId(17, 1, 5), "minecraft/textures/blocks/log_spruce"},

			{BlockTextureId(17, 2, 0), "minecraft/textures/blocks/log_birch_top"},
			{BlockTextureId(17, 2, 1), "minecraft/textures/blocks/log_birch_top"},
			{BlockTextureId(17, 2, 2), "minecraft/textures/blocks/log_birch"},
			{BlockTextureId(17, 2, 3), "minecraft/textures/blocks/log_birch"},
			{BlockTextureId(17, 2, 4), "minecraft/textures/blocks/log_birch"},
			{BlockTextureId(17, 2, 5), "minecraft/textures/blocks/log_birch"},

			{BlockTextureId(17, 3, 0), "minecraft/textures/blocks/log_jungle_top"},
			{BlockTextureId(17, 3, 1), "minecraft/textures/blocks/log_jungle_top"},
			{BlockTextureId(17, 3, 2), "minecraft/textures/blocks/log_jungle"},
			{BlockTextureId(17, 3, 3), "minecraft/textures/blocks/log_jungle"},
			{BlockTextureId(17, 3, 4), "minecraft/textures/blocks/log_jungle"},
			{BlockTextureId(17, 3, 5), "minecraft/textures/blocks/log_jungle"},

			{BlockTextureId(18, 0),    "minecraft/textures/blocks/leaves_oak"},
			{BlockTextureId(18, 1),    "minecraft/textures/blocks/leaves_spruce"},
			{BlockTextureId(18, 2),    "minecraft/textures/blocks/leaves_birch"},
			{BlockTextureId(18, 3),    "minecraft/textures/blocks/leaves_jungle"},

			{BlockTextureId(61, 0, 0), "minecraft/textures/blocks/furnace_side"},
			{BlockTextureId(61, 0, 1), "minecraft/textures/blocks/furnace_top"},
			{BlockTextureId(61, 0, 2), "minecraft/textures/blocks/furnace_front_off"},
			{BlockTextureId(61, 0, 3), "minecraft/textures/blocks/furnace_side"},
			{BlockTextureId(61, 0, 4), "minecraft/textures/blocks/furnace_side"},
			{BlockTextureId(61, 0, 5), "minecraft/textures/blocks/furnace_side"},

			{BlockTextureId(62, 0, 0), "minecraft/textures/blocks/furnace_side"},
			{BlockTextureId(62, 0, 1), "minecraft/textures/blocks/furnace_top"},
			{BlockTextureId(62, 0, 2), "minecraft/textures/blocks/furnace_front_on"},
			{BlockTextureId(62, 0, 3), "minecraft/textures/blocks/furnace_side"},
			{BlockTextureId(62, 0, 4), "minecraft/textures/blocks/furnace_side"},
			{BlockTextureId(62, 0, 5), "minecraft/textures/blocks/furnace_side"},


			{BlockTextureId(31, 0),    "minecraft/textures/blocks/deadbush"},
			{BlockTextureId(31, 1),    "minecraft/textures/blocks/tallgrass"},
			{BlockTextureId(31, 2),    "minecraft/textures/blocks/fern"},
	};
	auto ret = lookupTable.find(block);
	if (ret == lookupTable.end())
		return "";
	else
		return ret->second;
}

GLuint AssetManager::GetTextureAtlas() {
	return textureAtlas->texture;    
}

TextureCoordinates AssetManager::GetTextureByBlock(BlockTextureId block) {
	std::string assetName = this->GetTextureAssetNameByBlockId(block);
	return this->GetTextureByAssetName(assetName);
}

const std::map<BlockTextureId, glm::vec4> &AssetManager::GetTextureAtlasIndexes() {
	if (!textureAtlasIndexes.empty())
		return textureAtlasIndexes;

	LOG(INFO) << "Initializing texture atlas...";
	for (int id = 1; id < 128; id++) {
		for (int state = 0; state < 16; state++) {
			BlockTextureId blockTextureId(id, state, 6);
			if (!this->GetTextureByBlock(blockTextureId) &&
			    !this->GetTextureByBlock(BlockTextureId(id, state, 0))) {
				continue;
			}
			if (this->GetTextureByBlock(blockTextureId)) {
				for (int i = 0; i < 6; i++) {
					TextureCoordinates tc = this->GetTextureByBlock(BlockTextureId(id, state, 6));
					textureAtlasIndexes[BlockTextureId(id, state, i)] = glm::vec4(tc.x, tc.y, tc.w, tc.h);
				}
			} else {
				for (int i = 0; i < 6; i++) {
					TextureCoordinates tc = this->GetTextureByBlock(BlockTextureId(id, state, i));
					textureAtlasIndexes[BlockTextureId(id, state, i)] = glm::vec4(tc.x, tc.y, tc.w, tc.h);
				}
			}
		}
	}
	LOG(INFO) << "Created " << textureAtlasIndexes.size() << " texture indexes";

	return textureAtlasIndexes;
}

AssetManager &AssetManager::Instance() {
	static AssetManager assetManager;
	return assetManager;
}

const BlockModel *AssetManager::GetBlockModelByBlockId(BlockId block) {
    block.state = 0;
    if (blockIdToBlockName.find(block) == blockIdToBlockName.end()) {
        std::string blockName = "";
        for (const auto& it : assetIds) {
            if (BlockId{ it.second.id,0 } == block) {
                blockName = it.first;
                break;
            }
        }
        if (blockName == "grass")
            blockName = "grass_normal";
        if (blockName == "torch")
            blockName = "normal_torch";
        if (blockName == "leaves")
            blockName = "oak_leaves";
        if (blockName == "tallgrass")
            blockName = "tall_grass";
        if (blockName == "log")
            blockName = "oak_bark";
        if (blockName == "snow_layer")
            blockName = "snow_height2";

        blockName = "block/" + blockName;

        if (blockName == "")
            return nullptr;

        blockIdToBlockName[block] = blockName;
    }

    std::string blockName = blockIdToBlockName[block];

    auto modelIt = models.find(blockName);
    if (modelIt == models.end())
        return nullptr;

    return &modelIt->second;
}

void AssetManager::LoadBlockModels() {

    std::function<void(std::string)> parseModel = [&](std::string ModelName) {
        if (models.find(ModelName) != models.end())
            return;

        fs::path ModelPath = pathToModels / fs::path(ModelName + ".json");
        std::ifstream in(ModelPath);
        if (!in.is_open())
            throw std::runtime_error("Trying to load unknown model \"" + ModelName + "\" at " + ModelPath.generic_string());
        nlohmann::json modelData;
        in >> modelData;
        BlockModel model;        

        if (modelData.find("parent") != modelData.end()) {
            if (models.find(modelData["parent"]) == models.end())
                parseModel(modelData["parent"].get<std::string>());

            model = models.find(modelData["parent"])->second;
        }

        model.BlockName = ModelName;

        if (model.BlockName == "block/block")
            model.IsBlock = true;

        if (model.BlockName == "block/thin_block" || model.BlockName=="block/leaves")
            model.IsBlock = false;

        if (modelData.find("ambientocclusion") != modelData.end())
            model.AmbientOcclusion = modelData["ambientocclusion"].get<bool>();

        //models.Display

        if (modelData.find("textures") != modelData.end()) {
            for (nlohmann::json::iterator texture = modelData["textures"].begin(); texture != modelData["textures"].end(); ++texture) {
                model.Textures[texture.key()] = texture.value().get<std::string>();
            }
        }        

        if (modelData.find("elements") != modelData.end()) {
            model.Elements.clear();
            for (auto& it : modelData["elements"]) {
                BlockModel::ElementData element;

                auto vec = it["from"];
                Vector from (vec[0].get<int>(), vec[1].get<int>(), vec[2].get<int>());
                vec = it["to"];
                Vector to(vec[0].get<int>(), vec[1].get<int>(), vec[2].get<int>());

                element.from = from;
                element.to = to;
                
                if (it.find("rotation") != it.end()) {
                    vec = it["rotation"]["origin"];
                    Vector rotOrig(vec[0].get<int>(), vec[1].get<int>(), vec[2].get<int>());

                    element.rotationOrigin = rotOrig;
                    element.rotationAxis = (it["rotation"]["axis"].get<std::string>() == "x") ? BlockModel::ElementData::Axis::x : ((it["rotation"]["axis"].get<std::string>() == "y") ? BlockModel::ElementData::Axis::y : BlockModel::ElementData::Axis::z);
                    if (it["rotation"].find("angle") != it["rotation"].end())
                        element.rotationAngle = it["rotation"]["angle"].get<int>();

                    if (it["rotation"].find("rescale") != it["rotation"].end())
                        element.rotationRescale = it["rotation"]["rescale"].get<bool>();
                }
                
                if (it.find("shade") != it.end())
                    element.shade = it["shade"].get<bool>();

                for (nlohmann::json::iterator faceIt = it["faces"].begin(); faceIt != it["faces"].end(); ++faceIt) {
                    auto face = faceIt.value();
                    BlockModel::ElementData::FaceData faceData;

                    BlockModel::ElementData::FaceDirection faceDir;
                    if (faceIt.key() == "down")
                        faceDir = BlockModel::ElementData::FaceDirection::down;
                    else if (faceIt.key() == "up")
                        faceDir = BlockModel::ElementData::FaceDirection::up;
                    else if (faceIt.key() == "north")
                        faceDir = BlockModel::ElementData::FaceDirection::north;
                    else if (faceIt.key() == "south")
                        faceDir = BlockModel::ElementData::FaceDirection::south;
                    else if (faceIt.key() == "west")
                        faceDir = BlockModel::ElementData::FaceDirection::west;
                    else if (faceIt.key() == "east")
                        faceDir = BlockModel::ElementData::FaceDirection::east;
                                        
                    if (face.find("uv") != face.end()) {
                        BlockModel::ElementData::FaceData::Uv uv;
                        uv.x1 = face["uv"][0];
                        uv.y1 = face["uv"][1];
                        uv.x2 = face["uv"][2];
                        uv.y2 = face["uv"][3];
                        faceData.uv = uv;
                    }

                    BlockModel::ElementData::FaceDirection cullface = faceDir;
                    if (face.find("cullface") != face.end()) {
                        if (face["cullface"] == "down")
                            cullface = BlockModel::ElementData::FaceDirection::down;
                        else if (face["cullface"] == "up")
                            cullface = BlockModel::ElementData::FaceDirection::up;
                        else if (face["cullface"] == "north")
                            cullface = BlockModel::ElementData::FaceDirection::north;
                        else if (face["cullface"] == "south")
                            cullface = BlockModel::ElementData::FaceDirection::south;
                        else if (face["cullface"] == "west")
                            cullface = BlockModel::ElementData::FaceDirection::west;
                        else if (face["cullface"] == "east")
                            cullface = BlockModel::ElementData::FaceDirection::east;                        
                    }
                    faceData.cullface = cullface;
                    
                    faceData.texture = face["texture"].get<std::string>();                    

                    if (face.find("rotation") != face.end())
                        faceData.rotation = face["rotation"].get<int>();

                    if (face.find("tintindex") != face.end())
                        faceData.tintIndex = true;

                    element.faces[faceDir] = faceData;
                }

                model.Elements.push_back(element);
            }
        }

        models.insert(std::make_pair(ModelName, model));
    };

    fs::path pathToBlockModels = pathToModels.generic_string() + "/block/";

    for (auto& dirEntry : fs::recursive_directory_iterator(pathToBlockModels)) {
        if (dirEntry.path().extension() != ".json")
            continue;
        
        std::string modelName = dirEntry.path().stem().generic_string();

        parseModel("block/" + modelName);
    }
}

std::string AssetManager::GetAssetNameByBlockId(BlockId block) {
    for (auto& it : assetIds) {
        BlockId value = it.second;
        value.state = 0;
        if (value == block)
            return it.first;
    }
    return "#NF";
}