#include "terrain_loader.h"

#include <noise/noise.h>
#include "noiseutils/noiseutils.h"
#include <boost/format.hpp>
#include <boost/filesystem/fstream.hpp>

#include <stdexcept>

using namespace noise;

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

TerrainLoader::~TerrainLoader() {
}

float *TerrainLoader::generate_heights(int x, int y, int width, int height) {
	const double scale_factor = 0.004;
	module::Perlin mod;
	mod.SetSeed(seed);

	utils::NoiseMap heightmap;
	utils::NoiseMapBuilderPlane heightmap_builder;

	heightmap_builder.SetSourceModule(mod);
	heightmap_builder.SetDestNoiseMap(heightmap);

	heightmap_builder.SetDestSize(width, height);
	heightmap_builder.SetBounds((double)x * scale_factor, (double)(x+width) * scale_factor,
			(double)y * scale_factor, (double)(y+height) * scale_factor);
	heightmap_builder.Build();

	float *heights = new float[width*height];
	for(int i = 0; i < width; i++) {
		for(int j = 0; j < height; j++) {
			heights[i*height + j] = 50*(1+heightmap.GetValue(i, j));
		}
	}

	save_chunk(heights, x, y, width, height);

	return heights;
}

float *TerrainLoader::get_chunk(int x, int y, int width, int height) {
	float *h;
	if(has_chunk(x, y))
		h = load_chunk(x, y, width, height);
	else
		h = generate_heights(x, y, width, height);
	return h;
}

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

// TODO: Handle big-endian platforms
void TerrainLoader::save_chunk(float *chunk, int x, int y, int width, 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(int x, int y, int width, 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;
}