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.Mover.WalkRandom())
                .To("Chase").When(c => c.Sensor.SeesPlayer(), "SeesPlayer");
            b.State("Chase")
                .OnEnter(c => c.Mover.FacePlayer())
                .OnExit(c => c.Mover.Stop())
                .Tick(c => c.Mover.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.M.Calls, "WalkRandom");
        }

        [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.M.Calls, "FacePlayer"); // 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.M.Calls, "WalkRandom"); // 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.M.Calls, "Stop");
        }

        [Test]
        public void Construct_InvokesEntryOnEnter()
        {
            var b = new BrainBuilder();
            b.Entry("Start");
            b.State("Start").OnEnter(c => c.Mover.LookAround());
            var ctx = new FakeAiContext();
            var rt = new AiRuntime(b.Build(), ctx);
            CollectionAssert.Contains(ctx.M.Calls, "LookAround");
        }
    }
}