#include "terrain.h"
#include "terrain/terrain_chunk.h"
#include "terrain/terrain_modifier.h"

void Terrain::_bind_methods() {
	BIND_PROPERTY(Variant::INT, side_length);
	BIND_PROPERTY(Variant::INT, chunk_size);
	BIND_PROPERTY(Variant::INT, detail);
	BIND_PROPERTY(Variant::INT, thread_count);
}

void Terrain::ready() {
	construct_chunk_grid();
}

void Terrain::_notification(int what) {
	switch (what) {
		default:
			return;
		case NOTIFICATION_READY:
			ready();
			return;
		case NOTIFICATION_EXIT_TREE:
			this->workload_lock.lock();
			this->threads_stop = true;
			this->workload_lock.unlock();
			for (Thread &thread : this->threads) {
				thread.wait_to_finish();
			}
			return;
	}
}

void Terrain::generate_meshes_thread(void *terrain) {
	Terrain *self{ static_cast<Terrain *>(terrain) };
	print_line("thread", Thread::get_caller_id(), "start");
	for (;;) {
		self->workload_lock.lock();
		if (self->threads_stop) {
			self->workload_lock.unlock();
			print_line(Thread::get_caller_id(), "exiting");
			break;
		}
		if (self->workload.is_empty()) {
			self->workload_lock.unlock();
			Thread::yield();
			continue;
		}
		TerrainChunkMesh *mesh{ self->workload[0] };
		self->workload.remove_at(0);
		self->workload_lock.unlock();
		if (!mesh->is_inside_tree()) {
			print_line(Thread::get_caller_id(), "mesh is outside tree, exiting");
			break;
		}
		mesh->update_mesh();
		Thread::yield();
	}
	print_line(Thread::get_caller_id(), "done");
	return;
}

void Terrain::construct_chunk_grid() {
	for (TerrainChunkMesh *mesh : this->meshes) {
		mesh->queue_free();
	}
	this->meshes.clear();
	size_t const chunks_per_side{ this->side_length / this->chunk_size };
	Vector3 const origin{ (float)this->chunk_size / 2.f, 0.f, (float)this->chunk_size / 2.f };
	for (size_t y{ 0 }; y < chunks_per_side; ++y) {
		for (size_t x{ 0 }; x < chunks_per_side; ++x) {
			TerrainChunkMesh *chunk{ memnew(TerrainChunkMesh) };
			chunk->set_size(this->chunk_size);
			chunk->set_detail(this->detail);
			chunk->set_terrain(this);
			chunk->set_position(origin + Vector3{ (float)this->chunk_size * (float)x, 0.f, (float)this->chunk_size * (float)y });
			add_child(chunk);
			chunk->set_owner(this);
			this->meshes.push_back(chunk);
		}
	}
}

float Terrain::height_at(Vector2 world_coordinate) {
	float height{ 0 };
	for (TerrainModifier *mod : this->modifiers) {
		if (!mod->is_inside_tree()) {
			return height;
		}
		height = mod->evaluate_at(world_coordinate, height);
	}
	return height;
}

void Terrain::set_side_length(size_t length) {
	this->side_length = length;
	if (is_inside_tree()) {
		construct_chunk_grid();
	}
}

size_t Terrain::get_side_length() const {
	return this->side_length;
}

void Terrain::set_chunk_size(size_t size) {
	this->chunk_size = size;
	if (is_inside_tree()) {
		construct_chunk_grid();
	}
}

size_t Terrain::get_chunk_size() const {
	return this->chunk_size;
}

void Terrain::set_detail(size_t detail) {
	this->detail = detail;
	if (is_inside_tree()) {
		construct_chunk_grid();
	}
}

size_t Terrain::get_detail() const {
	return this->detail;
}

void Terrain::set_thread_count(size_t num) {
	this->workload_lock.lock();
	this->threads_stop = true;
	this->workload_lock.unlock();
	for (Thread &thread : this->threads) {
		thread.wait_to_finish();
	}
	this->threads_stop = false;
	this->threads.resize_initialized(num);
	for (Thread &thread : this->threads) {
		thread.start(&self_type::generate_meshes_thread, this);
	}
}

size_t Terrain::get_thread_count() const {
	return this->threads.size();
}