#include <string>

#include <glm/glm.hpp>
#include <rapidjson/document.h>
#include <rapidjson/schema.h>
#include <rapidjson/stringbuffer.h>
#include <rapidjson/error/en.h>
#include "aixlog.hpp"

#include "entity.h"
#include "hexgrid.h"
#include "hexlib.h"
#include "mesh.h"
#include "util.h"
#include "scene_loader.h"


struct slSceneDoc
{
	rapidjson::Document* doc;
};


// forward declarations
bool parseFile(rapidjson::Document* doc, const char* data_dir, const char* file_name);
glm::vec3 parseVec3(const rapidjson::Value& node);
glm::vec4 parseVec4(const rapidjson::Value& node);
uint32 parseHex32(std::string s);
bool validateScene(rapidjson::Document* schema_doc, rapidjson::Document* scene_doc,
		const char* scene_file);


// interface

slSceneDoc*
slLoadFile(const char* data_dir, const char* scene_file, const char* schema_file)
{
	LOG(INFO) << "Loading scene file: " << scene_file << "\n";
	rapidjson::Document schema_doc;
	slSceneDoc* sd = UTIL_ALLOC(1, slSceneDoc);
	sd->doc = new rapidjson::Document();

	bool retDoc = parseFile(sd->doc, data_dir, scene_file);
	bool retSchema = parseFile(&schema_doc, data_dir, schema_file);

	if (!retDoc || !retSchema || !validateScene(&schema_doc, sd->doc, scene_file)) {
		slFreeSceneDoc(sd);
		return nullptr;
	}

	return sd;
}

void
slFreeSceneDoc(slSceneDoc* sd)
{
	if (sd->doc != nullptr) {
		delete sd->doc;
		sd->doc = nullptr;
	}

	utilSafeFree(sd);
}

bool
slParseEntities(
		slSceneDoc* sd,
		Entity* entity_array,
		uint& entity_count,
		uint max_entities,
		const char* data_dir)
{
	const rapidjson::Value& entities = (*sd->doc)["entities"];
	if (entities.Size() > max_entities) {
		LOG(ERROR) << "entity count: " << entities.Size() << ", was more than max_entities: "
			<< max_entities << "\n";
		return false;
	}

	for (uint i = 0; i < entities.Size(); i++) {
		meMeshGroup mg;
		std::string model_path;
		model_path.append(data_dir).append("/").append(entities[i]["model_file"].GetString());

		if (meLoadFromFile(data_dir, model_path.c_str(), mg)) {
			Entity& e = entity_array[i];
			e.mesh_group = mg;
			e.scale = parseVec3(entities[i]["scale"]);
			e.translation = parseVec3(entities[i]["position"]);
		} else {
			LOG(ERROR) << "Error loading mesh file\n";
			meFreeMeshGroup(mg);
			return false;
		}

		entity_count++;
	}

	return true;
}

void
slParseCamera(slSceneDoc* sd, camera& cam)
{
	const rapidjson::Value& json_cam = (*sd->doc)["camera"];
	cameraInitPerspective(cam,
		parseVec3(json_cam["position"]),
		parseVec3(json_cam["target"]),
		parseVec3(json_cam["world_up"])
	);
}

void
slParseHexGrid(slSceneDoc* sd, hexgrid& hg)
{
	const rapidjson::Value& json_grid = (*sd->doc)["hex_grid"];

	std::string grid_type_str = json_grid["grid_type"].GetString();
	if (grid_type_str == "hexagon")
		hg.gridT = HEXAGON;
	else if (grid_type_str == "parallelogram")
		hg.gridT = PARALLELOGRAM;
	else if (grid_type_str == "rhombus")
		hg.gridT = RHOMBUS;
	else if (grid_type_str == "hash_map")
		hg.gridT = HASH_MAP;

	hg.hex_size = json_grid["hex_size"].GetInt();
	glm::vec3 pos = parseVec3(json_grid["position"]);
	hg.position.x = pos.x;
	hg.position.y = pos.y;
	hg.position.z = pos.z;
	std::string fill_color_str = json_grid["fill_color"].GetString();
	hg.fill_color = std::stoul(fill_color_str, nullptr, 16);
	std::string selected_fill_color_str = json_grid["selected_fill_color"].GetString();
	hg.selected_fill_color = std::stoul(selected_fill_color_str, nullptr, 16);
	std::string hex_line_color_str = json_grid["hex_line_color"].GetString();
	hg.hex_line_color = std::stoul(hex_line_color_str, nullptr, 16);
	std::string orientation_str = json_grid["hexlib_orientation"].GetString();
	hg.hexlib_orientation = (orientation_str == "layout_flat") ? layout_flat : layout_pointy;
	Layout lo(hg.hexlib_orientation, Point(hg.hex_size, hg.hex_size), Point(hg.position.x, hg.position.y));
	hg.hexlib_layout = lo;

	if (hg.gridT == HEXAGON) {
		hg.hex_radius = json_grid["hex_radius"].GetInt();
	}

	hgCreateHexes(hg);
}


bool
slParseLights(slSceneDoc* sd, rg_point_light* lights, uint& num_lights, uint max_lights)
{
	const rapidjson::Value& json_lights = (*sd->doc)["lights"];

	if (json_lights.Size() > max_lights) {
		LOG(ERROR) << "Too many lights\n";
		return false;
	}

	num_lights = json_lights.Size();

	for (uint i = 0; i < num_lights; i++) {
		lights[i].position = parseVec3(json_lights[i]["position"]);
	}

	return true;
}


// internal

bool
parseFile(rapidjson::Document* doc, const char* data_dir, const char* file_name)
{
	bool ret = true;
	std::string file_path;
	file_path.append(data_dir).append("/").append(file_name);
	char* contents = utilDumpTextFile(file_path.c_str());

	if (contents == nullptr) {
		LOG(ERROR) << "Error reading file: " << file_name << "\n";
		ret = false;
	}

	rapidjson::ParseResult pr = doc->Parse(contents/*, rapidjson::kParseStopWhenDoneFlag*/);
	if (!pr || !doc->IsObject()) {
		LOG(ERROR) << "Error parrsing scene file: " << file_name << "\n";
		LOG(ERROR) << "Error desscription: " << rapidjson::GetParseError_En(pr.Code())
			<< " (" << pr.Offset() << ")\n";
		ret = false;
	}

	utilSafeFree(contents);

	return ret;
}

bool
validateScene(rapidjson::Document* schema_doc, rapidjson::Document* scene_doc, const char* scene_file)
{
	rapidjson::SchemaDocument schema(*schema_doc);
	rapidjson::SchemaValidator validator(schema);

	if (!scene_doc->Accept(validator)) {
		LOG(ERROR) << "Error validating scene file: " << scene_file << "\n";
		rapidjson::StringBuffer sb;
		validator.GetInvalidSchemaPointer().StringifyUriFragment(sb);
		LOG(ERROR) << "Invalid schema: " << sb.GetString() << "\n";
		LOG(ERROR) << "Invalid keyword:" << validator.GetInvalidSchemaKeyword() << "\n";
		sb.Clear();
		validator.GetInvalidDocumentPointer().StringifyUriFragment(sb);
		LOG(ERROR) << "Invalid Document: " << sb.GetString() << "\n";
		return false;
	}

	LOG(INFO) << "scene file: " << scene_file << " passed schema validation\n";

	return true;
}

glm::vec3
parseVec3(const rapidjson::Value& node)
{
	glm::vec3 v3;
	v3.x = node["x"].GetFloat();
	v3.y = node["y"].GetFloat();
	v3.z = node["z"].GetFloat();

	return v3;
}

glm::vec4
parseVec4(const rapidjson::Value& node)
{
	glm::vec4 v4;
	v4.x = node["x"].GetFloat();
	v4.y = node["y"].GetFloat();
	v4.z = node["z"].GetFloat();
	v4.w = node["w"].GetFloat();

	return v4;
}