From 61d16477b01bcfbe8c3a481a232658ac60309f57 Mon Sep 17 00:00:00 2001
From: Aki <please@ignore.pl>
Date: Thu, 27 Apr 2023 00:36:46 +0200
Subject: Extracted KeepAtRange action

It seems an abstraction level is of some kind is needed here. One thing
to handle "AI", another to handle primitive commands and their
execution.
---
 sim/src/BaseSimulation.cpp |  2 +-
 sim/src/Builder.cpp        |  2 +-
 sim/src/ai.cpp             | 69 ++++++++++++++++++++++++++++++++++++++++------
 sim/src/ai.h               |  2 +-
 sim/src/sim.cpp            |  6 +---
 5 files changed, 65 insertions(+), 16 deletions(-)

(limited to 'sim/src')

diff --git a/sim/src/BaseSimulation.cpp b/sim/src/BaseSimulation.cpp
index b1add54..2731c67 100644
--- a/sim/src/BaseSimulation.cpp
+++ b/sim/src/BaseSimulation.cpp
@@ -24,7 +24,7 @@ void
 BaseSimulation::operator()(State& ctx)
 {
 	pick_random_targets(ctx, manager);
-	keep_at_range(ctx);
+	take_actions(ctx);
 	FloatingMovement::update(ctx);
 	update_turrets(ctx);
 	shoot_at_targets(ctx);
diff --git a/sim/src/Builder.cpp b/sim/src/Builder.cpp
index 4cf0bc6..2b2bd24 100644
--- a/sim/src/Builder.cpp
+++ b/sim/src/Builder.cpp
@@ -42,7 +42,7 @@ Builder::operator()(const universe::ShipType& ship_type, const int team) const
 		ship_type.max_speed,
 		ship_type.max_speed * 2.0,
 		ship_type.max_speed * 3.0);
-	registry.emplace<AIShip>(entity, 15000.0, Point{0.0, 0.0});
+	registry.emplace<AIShip>(entity);
 	registry.emplace<HitPoints>(entity, ship_type);
 	return entity;
 }
diff --git a/sim/src/ai.cpp b/sim/src/ai.cpp
index 1f2a4ec..7a0f637 100644
--- a/sim/src/ai.cpp
+++ b/sim/src/ai.cpp
@@ -1,5 +1,10 @@
 #include "ai.h"
 
+#include <algorithm>
+#include <utility>
+
+#include <entt/entt.hpp>
+
 #include <kurator/sim/components.h>
 #include <kurator/sim/State.h>
 #include <kurator/sim/weapons.h>
@@ -13,6 +18,42 @@ namespace sim
 {
 
 
+static double find_worst_range(State& ctx, entt::entity ship);
+
+
+class KeepAtRange
+{
+public:
+	KeepAtRange(State& ctx_, AIShip& ai_, entt::entity self_, entt::entity target_, double distance_) :
+		ctx {ctx_},
+		ai {ai_},
+		self {std::move(self_)},
+		target {std::move(target_)},
+		distance {distance_}
+	{
+	}
+
+	void operator()()
+	{
+		if (!ctx.registry.valid(target)) {
+			if (ctx.registry.valid(ai.target))
+				ai.action = KeepAtRange(ctx, ai, self, ai.target, distance);
+			return;
+		}
+		const auto here = ctx.registry.get<Transform>(self).position;
+		const auto there = ctx.registry.get<Transform>(target).position;
+		const auto offset = there - here;
+		ai.destination = there - offset.normalized().scale(distance);
+	}
+private:
+	State& ctx;
+	AIShip& ai;
+	entt::entity self;
+	entt::entity target;
+	double distance;
+};
+
+
 void
 pick_random_targets(State& ctx, TeamManager& manager)
 {
@@ -20,20 +61,19 @@ pick_random_targets(State& ctx, TeamManager& manager)
 	for (auto&& [entity, team, ai] : view.each()) {
 		if (!ctx.registry.valid(ai.target))
 			ai.target = manager.random(team.id);
+		if (!ai.action)
+			ai.action = KeepAtRange(ctx, ai, entity, ai.target, find_worst_range(ctx, entity));
 	}
 }
 
 
 void
-keep_at_range(State& ctx)
+take_actions(State& ctx)
 {
-	auto view = ctx.registry.view<Transform, AIShip>();
-	for (auto&& [entity, self, ai] : view.each()) {
-		if (!ctx.registry.valid(ai.target))
-			continue;
-		const auto target = ctx.registry.get<Transform>(ai.target);
-		const auto offset = target.position - self.position;
-		ai.destination = target.position - offset.normalized().scale(ai.keep_at_range);
+	auto view = ctx.registry.view<AIShip>();
+	for (auto&& [_, ai] : view.each()) {
+		if (ai.action)
+			ai.action();
 	}
 }
 
@@ -56,5 +96,18 @@ shoot_at_targets(State& ctx)
 }
 
 
+double
+find_worst_range(State& ctx, entt::entity ship)
+{
+	double range = 20000.0;
+	auto turrets = ctx.registry.view<Turret>();
+	for (const auto& [_, turret] : turrets.each()) {
+		if (turret.owner == ship)
+			range = std::min(range, turret.type.optimal_range);
+	}
+	return range;
+}
+
+
 }  // namespace sim
 }  // namespace kurator
diff --git a/sim/src/ai.h b/sim/src/ai.h
index 9173891..d1e9c29 100644
--- a/sim/src/ai.h
+++ b/sim/src/ai.h
@@ -13,7 +13,7 @@ namespace sim
 
 
 void pick_random_targets(State& ctx, TeamManager& manager);
-void keep_at_range(State& ctx);
+void take_actions(State& ctx);
 void shoot_at_targets(State& ctx);
 
 
diff --git a/sim/src/sim.cpp b/sim/src/sim.cpp
index 740e6af..879f7fb 100644
--- a/sim/src/sim.cpp
+++ b/sim/src/sim.cpp
@@ -1,7 +1,6 @@
 #include <kurator/sim.h>
 
 #include <kurator/campaign/Scenario.h>
-#include <kurator/sim/ai.h>
 #include <kurator/sim/State.h>
 #include <kurator/sim/System.h>
 #include <kurator/universe/UniqueIdentifier.h>
@@ -26,11 +25,8 @@ load_scenario(const campaign::Scenario& scenario)
 	for (const auto& ship : scenario.ships) {
 		const auto entity = build(ship.loadout.type, ship.team);
 		ctx.registry.emplace<universe::UniqueIdentifier>(entity, ship.identifier);
-		auto& state = ctx.registry.get<AIShip>(entity);
-		for (const auto& turret_type : ship.loadout.turrets) {
+		for (const auto& turret_type : ship.loadout.turrets)
 			build(turret_type, entity);
-			state.keep_at_range = std::min(state.keep_at_range, turret_type.optimal_range);
-		}
 	}
 	return ctx;
 }
-- 
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