/*
 * Copyright (C) 2023  Christopher J. Howard
 *
 * This file is part of Antkeeper source code.
 *
 * Antkeeper source code is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Antkeeper source code is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Antkeeper source code.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "game/systems/reproductive-system.hpp"
#include "game/components/ovary-component.hpp"
#include "game/components/scene-component.hpp"
#include "game/components/pose-component.hpp"
#include "game/components/rigid-body-component.hpp"
#include "game/components/egg-component.hpp"
#include "game/components/ant-genome-component.hpp"
#include <engine/math/fract.hpp>
#include <engine/math/interpolation.hpp>
#include <engine/scene/static-mesh.hpp>
#include <engine/debug/log.hpp>
#include <execution>

reproductive_system::reproductive_system(entity::registry& registry):
	updatable_system(registry)
{}

void reproductive_system::update(float t, float dt)
{
	auto ovary_group = registry.group<ovary_component>(entt::get<ant_genome_component, rigid_body_component, scene_component, pose_component>);
	std::for_each
	(
		std::execution::seq,
		ovary_group.begin(),
		ovary_group.end(),
		[&](auto entity_id)
		{
			auto& ovary = ovary_group.get<ovary_component>(entity_id);
			
			// Produce eggs
			if (ovary.egg_count < ovary.egg_capacity)
			{
				ovary.elapsed_egg_production_time += dt * m_time_scale;
				if (ovary.elapsed_egg_production_time >= ovary.egg_production_duration)
				{
					ovary.egg_count += static_cast<std::uint16_t>(ovary.elapsed_egg_production_time / ovary.egg_production_duration);
					ovary.egg_count = std::min(ovary.egg_count, ovary.egg_capacity);
					ovary.elapsed_egg_production_time = math::fract(ovary.elapsed_egg_production_time);
				}
			}
			
			// Oviposit egg
			if (ovary.ovipositor_egg_eid != entt::null || (ovary.ovipositing && ovary.egg_count))
			{
				// Get transform of ovipositor
				const auto& ovipositor_rigid_body = *ovary_group.get<rigid_body_component>(entity_id).body;
				const auto& ovipositor_pose = ovary_group.get<pose_component>(entity_id);
				const auto ovipositor_transform = ovipositor_rigid_body.get_transform() * ovipositor_pose.current_pose.get_absolute_transform(ovary.ovipositor_bone);
				
				// Advance oviposition time
				if (ovary.ovipositing)
				{
					ovary.elapsed_oviposition_time += dt * m_time_scale;
				}
				else
				{
					ovary.elapsed_oviposition_time -= dt * m_time_scale;
					ovary.elapsed_oviposition_time = std::max(0.0f, ovary.elapsed_oviposition_time);
				}
				
				// Determine position and orientation of egg
				const float t = std::min(ovary.elapsed_oviposition_time / ovary.oviposition_duration, 1.0f);
				auto egg_transform = ovipositor_transform;
				egg_transform.translation = egg_transform * math::lerp(ovary.oviposition_path.a, ovary.oviposition_path.b, t);
				
				if (ovary.ovipositor_egg_eid == entt::null)
				{
					// Get genome of parent entity
					const auto& parent_genome = ovary_group.get<ant_genome_component>(entity_id);
					
					// Get scene component of ovipositing entity
					const auto& ovipositor_scene = ovary_group.get<scene_component>(entity_id);
					
					
					// Construct egg rigid body
					auto egg_rigid_body = std::make_unique<physics::rigid_body>();
					egg_rigid_body->set_mass(0.0f);
					egg_rigid_body->set_transform(egg_transform);
					egg_rigid_body->set_previous_transform(egg_transform);
					
					// Construct egg scene object
					auto egg_scene_object = std::make_shared<scene::static_mesh>(parent_genome.genome->egg->phenes.front().model);
					
					// Construct egg entity
					ovary.ovipositor_egg_eid = registry.create();
					registry.emplace<rigid_body_component>(ovary.ovipositor_egg_eid, std::move(egg_rigid_body));
					registry.emplace<scene_component>(ovary.ovipositor_egg_eid, std::move(egg_scene_object), ovipositor_scene.layer_mask);
					registry.emplace<ant_genome_component>(ovary.ovipositor_egg_eid, parent_genome);
				}
				else
				{
					// Update position of egg rigid body
					auto& egg_rigid_body = *registry.get<rigid_body_component>(ovary.ovipositor_egg_eid).body;
					egg_rigid_body.set_transform(egg_transform);
				}
				
				if (ovary.elapsed_oviposition_time >= ovary.oviposition_duration)
				{
					// Construct egg component
					egg_component egg;
					egg.incubation_period = 5.0f;
					registry.emplace<egg_component>(ovary.ovipositor_egg_eid, std::move(egg));
					
					// Oviposition complete
					ovary.ovipositing = false;
					ovary.elapsed_oviposition_time = 0.0f;
					--ovary.egg_count;
					ovary.ovipositor_egg_eid = entt::null;
				}
			}
		}
	);
}