From 4f3de714cd04ee5d99167f415843573d6bbd9f62 Mon Sep 17 00:00:00 2001
From: Aki <please@ignore.pl>
Date: Mon, 14 Nov 2022 00:32:08 +0100
Subject: Implemented naive turrets and targeting mechanics

Coupling between components, implementation of systems and behaviour of some
state-related methods should be refactored, but the overall look is nice.
---
 battles/include/kurator/battles/components.h |  7 ++++++
 battles/src/BaseBattle.cpp                   | 26 ++++++++++++++++++++-
 battles/src/TeamManager.cpp                  |  2 ++
 battles/src/scenarios.cpp                    | 35 ++++++++++++++--------------
 4 files changed, 52 insertions(+), 18 deletions(-)

diff --git a/battles/include/kurator/battles/components.h b/battles/include/kurator/battles/components.h
index 35a9251..8f5813b 100644
--- a/battles/include/kurator/battles/components.h
+++ b/battles/include/kurator/battles/components.h
@@ -44,5 +44,12 @@ struct HitPoints
 };
 
 
+struct TurretControl
+{
+	double reload;
+	entt::entity owner;
+};
+
+
 }  // namespace battles
 }  // namespace kurator
diff --git a/battles/src/BaseBattle.cpp b/battles/src/BaseBattle.cpp
index 4d80671..815c683 100644
--- a/battles/src/BaseBattle.cpp
+++ b/battles/src/BaseBattle.cpp
@@ -31,6 +31,12 @@ BaseBattle::BaseBattle(const Scenario& scenario) :
 		_registry.emplace<FloatingMovement>(entity, 0.4);
 		_registry.emplace<AIState>(entity, Point{0.0, 0.0});
 		_registry.emplace<HitPoints>(entity, ship.type.base_health_points);
+		for (const auto& turret_def : ship.turrets) {
+			const auto turret = _registry.create();
+			_registry.emplace<universe::TurretType>(turret, turret_def);
+			_registry.emplace<TurretControl>(turret, 0.0, entity);
+			_registry.emplace<Transform>(turret, Point{0.0, 0.0}, 0.0, entity);
+		}
 		manager.add(ship.team, entity);  // registry supports on construction events
 	}
 }
@@ -50,6 +56,8 @@ BaseBattle::update(const float dt)
 	for (auto&& [entity, team, transform, state, movement] : view.each()) {
 		if (!_registry.valid(state.target))
 			state.target = manager.random((team.id + 1) % 2);
+		if (!_registry.valid(state.target))
+			continue;
 		const auto target = _registry.get<Transform>(state.target);
 		const double speed = movement.speed * dt;
 		const Point diff = target.position - transform.position;
@@ -63,10 +71,26 @@ BaseBattle::update(const float dt)
 	}
 	auto view2 = _registry.view<HitPoints>();
 	for (auto&& [entity, points] : view2.each()) {
-		points.health -= dt;
 		if (points.health <= 0.0)
 			_registry.destroy(entity);
 	}
+	auto view3 = _registry.view<TurretControl, universe::TurretType>();
+	for (auto&& [entity, control, def] : view3.each()) {  // split into systems!
+		if (!_registry.valid(control.owner)) {
+			_registry.destroy(entity);
+			continue;
+		}
+		const auto& state = _registry.get<AIState>(control.owner);  // no checks
+		if (!_registry.valid(state.target))
+			continue;
+		if (control.reload > 0.0)
+			control.reload -= dt;
+		if (control.reload <= 0.0) {
+			auto& target_points = _registry.get<HitPoints>(state.target);
+			target_points.health -= def.base_damage;
+			control.reload = def.rate_of_fire;
+		}
+	}
 	manager.clear(_registry);  // registry supports on destructions events
 }
 
diff --git a/battles/src/TeamManager.cpp b/battles/src/TeamManager.cpp
index e4afeb3..9dc90e3 100644
--- a/battles/src/TeamManager.cpp
+++ b/battles/src/TeamManager.cpp
@@ -41,6 +41,8 @@ entt::entity
 TeamManager::random(int team)
 {
 	auto& members = teams.at(team);
+	if (members.size() == 0)
+		return entt::null;
 	std::uniform_int_distribution<Team::size_type> uniform{0, members.size() - 1};
 	return members.at(uniform(generator));
 }
diff --git a/battles/src/scenarios.cpp b/battles/src/scenarios.cpp
index cf348ca..3b35f44 100644
--- a/battles/src/scenarios.cpp
+++ b/battles/src/scenarios.cpp
@@ -17,26 +17,27 @@ example()
 {
 	const universe::ShipType halo {"halo", 6.0};
 	const universe::ShipType cube {"cube", 12.0};
-	const universe::ShipType bell {"bell", 20.0};
+	const universe::ShipType bell {"bell", 30.0};
+	const universe::TurretType cannon {"cannon", 1.0, 1.0, 0.5};
 	return {
 		"example",
 		{
-			{0, halo, {}},
-			{0, halo, {}},
-			{0, cube, {}},
-			{0, cube, {}},
-			{0, cube, {}},
-			{0, bell, {}},
-			{0, bell, {}},
-			{0, bell, {}},
-			{1, halo, {}},
-			{1, halo, {}},
-			{1, bell, {}},
-			{1, cube, {}},
-			{1, cube, {}},
-			{1, cube, {}},
-			{1, bell, {}},
-			{1, bell, {}},
+			{0, halo, {cannon}},
+			{0, halo, {cannon}},
+			{0, cube, {cannon, cannon}},
+			{0, cube, {cannon, cannon}},
+			{0, cube, {cannon, cannon}},
+			{0, bell, {cannon}},
+			{0, bell, {cannon}},
+			{0, bell, {cannon}},
+			{1, halo, {cannon}},
+			{1, halo, {cannon}},
+			{1, bell, {cannon}},
+			{1, cube, {cannon, cannon}},
+			{1, cube, {cannon, cannon}},
+			{1, cube, {cannon, cannon}},
+			{1, bell, {cannon}},
+			{1, bell, {cannon}},
 		},
 	};
 }
-- 
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