using NUnit.Framework;
using BaseGames.AI;

namespace BaseGames.Tests.EditMode.AI
{
    public class AiRuntimeTests
    {
        static AiGraph Graph()
        {
            var b = new BrainBuilder();
            b.Entry("Patrol");
            b.Global().To("Dead").OnEvent(AiSignal.Died);
            b.State("Patrol")
                .Tick(c => c.Locomotion.SetMode(LocomotionMode.Patrol))
                .To("Chase").When(c => c.Sensor.SeesPlayer(), "SeesPlayer");
            b.State("Chase")
                .OnEnter(c => c.Locomotion.Face(c.Sensor.LastKnown))
                .OnExit(c => c.Locomotion.Stop())
                .Tick(c => c.Locomotion.MoveTo(c.Sensor.LastKnown))
                .To("Search").When(c => c.Sensor.LostFor(2f), "LostFor(2s)");
            b.State("Search")
                .To("Patrol").After(3f);
            b.State("Dead");
            return b.Build();
        }

        [Test]
        public void StartsAtEntry()
        {
            var rt = new AiRuntime(Graph(), new FakeAiContext());
            Assert.AreEqual("Patrol", rt.CurrentStateName);
        }

        [Test]
        public void Tick_RunsCurrentStateTickAction()
        {
            var ctx = new FakeAiContext();
            var rt = new AiRuntime(Graph(), ctx);
            rt.Tick(0.1f);
            CollectionAssert.Contains(ctx.L.Calls, "SetMode:Patrol");
        }

        [Test]
        public void ConditionTransition_FiresAndRunsEnterExit()
        {
            var ctx = new FakeAiContext();
            var rt = new AiRuntime(Graph(), ctx);
            ctx.S.Sees = true;
            rt.Tick(0.1f);
            Assert.AreEqual("Chase", rt.CurrentStateName);
            CollectionAssert.Contains(ctx.L.Calls, "Face"); // Chase.OnEnter
        }

        [Test]
        public void Gate_SuspendsDecisionWhenNotControllable()
        {
            var ctx = new FakeAiContext();
            var rt = new AiRuntime(Graph(), ctx);
            ctx.S.Sees = true;
            ctx.V.Controllable = false;   // 受击中
            rt.Tick(0.1f);
            Assert.AreEqual("Patrol", rt.CurrentStateName); // 未转换
            Assert.IsTrue(rt.IsSuspended);
            CollectionAssert.DoesNotContain(ctx.L.Calls, "SetMode:Patrol"); // Tick 也不跑
        }

        [Test]
        public void Gate_ResumesAndReevaluatesWhenControllable()
        {
            var ctx = new FakeAiContext();
            var rt = new AiRuntime(Graph(), ctx);
            ctx.S.Sees = true;
            ctx.V.Controllable = false;
            rt.Tick(0.1f);
            ctx.V.Controllable = true;    // 恢复
            rt.Tick(0.1f);
            Assert.AreEqual("Chase", rt.CurrentStateName);
        }

        [Test]
        public void After_UsesStateTimer()
        {
            var ctx = new FakeAiContext();
            var rt = new AiRuntime(Graph(), ctx);
            ctx.S.Sees = true; rt.Tick(0.1f);                 // -> Chase
            ctx.S.Sees = false; ctx.S.LostForValue = 5f; rt.Tick(0.1f); // -> Search
            Assert.AreEqual("Search", rt.CurrentStateName);
            rt.Tick(1f); rt.Tick(1f);
            Assert.AreEqual("Search", rt.CurrentStateName);   // 未满 3s
            rt.Tick(1.5f);
            Assert.AreEqual("Patrol", rt.CurrentStateName);   // 累计 >3s
        }

        [Test]
        public void Switch_RunsPreviousStateOnExit()
        {
            var ctx = new FakeAiContext();
            var rt = new AiRuntime(Graph(), ctx);
            ctx.S.Sees = true; rt.Tick(0.1f);                          // Patrol -> Chase
            ctx.S.Sees = false; ctx.S.LostForValue = 5f; rt.Tick(0.1f);// Chase -> Search (触发 Chase.OnExit)
            CollectionAssert.Contains(ctx.L.Calls, "Stop");
        }

        [Test]
        public void Construct_InvokesEntryOnEnter()
        {
            var b = new BrainBuilder();
            b.Entry("Start");
            b.State("Start").OnEnter(c => c.Locomotion.SetMode(LocomotionMode.Idle));
            var ctx = new FakeAiContext();
            var rt = new AiRuntime(b.Build(), ctx);
            CollectionAssert.Contains(ctx.L.Calls, "SetMode:Idle");
        }

        [Test]
        public void EventTransition_FiresOnSignal_EvenBeforeTick()
        {
            var ctx = new FakeAiContext();
            var rt = new AiRuntime(Graph(), ctx);
            rt.Send(AiSignal.Died);
            rt.Tick(0.1f);
            Assert.AreEqual("Dead", rt.CurrentStateName);
        }

        [Test]
        public void EventTransition_FiresEvenWhenNotControllable()
        {
            // 死亡等事件不受让位门限制（门只挡决策推进/条件评估，不挡事件）
            var ctx = new FakeAiContext();
            var rt = new AiRuntime(Graph(), ctx);
            ctx.V.Controllable = false;
            rt.Send(AiSignal.Died);
            rt.Tick(0.1f);
            Assert.AreEqual("Dead", rt.CurrentStateName);
        }

        [Test]
        public void Trace_RecordsTriggerReason()
        {
            var ctx = new FakeAiContext();
            var rt = new AiRuntime(Graph(), ctx);
            ctx.S.Sees = true;
            rt.Tick(0.1f);
            Assert.AreEqual(1, rt.Trace.Count);
            Assert.AreEqual("Patrol", rt.Trace[0].From);
            Assert.AreEqual("Chase", rt.Trace[0].To);
            StringAssert.Contains("SeesPlayer", rt.Trace[0].Trigger);
        }

        [Test]
        public void Reset_ReturnsToEntryAndClearsState()
        {
            var ctx = new FakeAiContext();
            var rt = new AiRuntime(Graph(), ctx);
            ctx.S.Sees = true; rt.Tick(0.1f); // -> Chase
            ctx.BB.Set("scratch", 42);
            rt.Reset();
            Assert.AreEqual("Patrol", rt.CurrentStateName);
            Assert.IsEmpty(rt.Trace);
            Assert.IsFalse(ctx.BB.Has("scratch"));
        }

        [Test]
        public void LocalEventTransition_Fires()
        {
            var b = new BrainBuilder();
            b.Entry("Idle");
            b.State("Idle").To("Flee").OnEvent(AiSignal.Died);
            b.State("Flee");
            var ctx = new FakeAiContext();
            var rt = new AiRuntime(b.Build(), ctx);
            rt.Send(AiSignal.Died);
            rt.Tick(0.1f);
            Assert.AreEqual("Flee", rt.CurrentStateName);
        }

        [Test]
        public void EventSelfTransition_DoesNotReenter()
        {
            var b = new BrainBuilder();
            b.Entry("Dead");
            int enterCount = 0;
            b.State("Dead").OnEnter(c => enterCount++);
            b.Global().To("Dead").OnEvent(AiSignal.Died);
            var ctx = new FakeAiContext();
            var rt = new AiRuntime(b.Build(), ctx);
            // 构造即进入 Dead → enterCount==1
            rt.Send(AiSignal.Died);
            rt.Tick(0.1f);   // 已在 Dead，自转换应 no-op，不再 +1
            Assert.AreEqual(1, enterCount);
            Assert.AreEqual("Dead", rt.CurrentStateName);
        }

        [Test]
        public void TwoRuntimes_ShareGraph_IndependentStateAndTimer()
        {
            var graph = Graph(); // 共享同一张不可变图
            var a = new FakeAiContext(); var rtA = new AiRuntime(graph, a);
            var b = new FakeAiContext(); var rtB = new AiRuntime(graph, b);

            // A 发现玩家推进，B 不动 —— 状态独立
            a.S.Sees = true; rtA.Tick(0.1f);
            Assert.AreEqual("Chase", rtA.CurrentStateName);
            Assert.AreEqual("Patrol", rtB.CurrentStateName);

            // 两者各自进入 Search（计时归零）
            a.S.Sees = false; a.S.LostForValue = 5f; rtA.Tick(0.1f);   // A -> Search
            b.S.Sees = true; rtB.Tick(0.1f);                           // B -> Chase
            b.S.Sees = false; b.S.LostForValue = 5f; rtB.Tick(0.1f);   // B -> Search

            // 只推进 A 的 After 计时越过 3s；B 计时独立、不动
            rtA.Tick(2f); rtA.Tick(2f);                                // A Search 计时 ~4 -> After -> Patrol
            Assert.AreEqual("Patrol", rtA.CurrentStateName);
            Assert.AreEqual("Search", rtB.CurrentStateName);           // B 独立，仍在 Search
        }
    }
}