#include "terrain_loader.h"

#include <boost/format.hpp>
#include <boost/filesystem/fstream.hpp>

#include <stdexcept>

TerrainLoader::TerrainLoader(fs::path root) {
	this->root = root;
}

TerrainLoader::~TerrainLoader() {
}
float *TerrainLoader::get_chunk(int64_t x, int64_t y, unsigned int width, unsigned int height) {
	if(has_chunk(x, y))
		return load_chunk(x, y, width, height);
	return NULL;
}

bool TerrainLoader::has_chunk(int64_t x, int64_t y) {
	return fs::exists(root / (boost::format("%d.%d.chunk") % x % y).str());
}

// TODO: Handle big-endian platforms
void TerrainLoader::save_chunk(float *chunk, int64_t x, int64_t y, unsigned int width, unsigned int height) {
	fs::path p = root / (boost::format("%d.%d.chunk") % x % y).str();
	fs::ofstream os(p, std::ios::out | std::ios::binary);

	uint64_t w = width;
	uint64_t h = height;
	os.write((const char*)&w, sizeof(w));
	os.write((const char*)&h, sizeof(h));

	os.write((const char*)chunk, width*height * sizeof(float));
	os.close();
}

// TODO: Handle big-endian platforms
// NOTE: assumes width <= chunk_size+1, likewise for height
float *TerrainLoader::load_chunk(int64_t x, int64_t y, unsigned int width, unsigned int height) {
	fs::path p = root / (boost::format("%d.%d.chunk") % x % y).str();
	fs::ifstream is(p, std::ios::in | std::ios::binary);

	uint64_t w, h;
	w = h = 0;
	is.read((char*)&w, sizeof(w));
	is.read((char*)&h, sizeof(h));

	// TODO: should return w and h, fix calling code
	if(w != width || h != height)
		throw std::runtime_error("width or height doesn't match");

	float *chunk = new float[width*height];
	is.read((char*)chunk, width*height*sizeof(float));
	is.close();

	return chunk;
}