using System.Collections.Generic;
using NUnit.Framework;
using BaseGames.AI;
using BaseGames.Enemies;

namespace BaseGames.Tests.EditMode.AI
{
    public class PerceptionSkeletonTests
    {
        static AiRuntime Build(FakeAiContext ctx, IUnawareModule unaware = null, IEngagementModule engagement = null)
        {
            var b = new BrainBuilder();
            PerceptionSkeleton.Add(b,
                unaware    ?? new SinglePost(LocomotionMode.Patrol),
                engagement ?? new RushEngagement("rush", RushExit.OnLostTarget));
            return new AiRuntime(b.Build(), ctx);
        }

        // ── 升级 ──────────────────────────────────────────────────────────

        [Test]
        public void Unaware_ToEngagement_WhenInChaseZone()
        {
            var ctx = new FakeAiContext();
            var rt = Build(ctx);
            ctx.S.Chase = true;
            rt.Tick(0.1f);
            Assert.AreEqual(RushEngagement.Rush, rt.CurrentStateName);
        }

        [Test]
        public void Unaware_ToAlert_WhenInVision_AndHasAlert()
        {
            var ctx = new FakeAiContext { HasAlert = true };
            var rt = Build(ctx);
            ctx.S.Vision = true;
            rt.Tick(0.1f);
            Assert.AreEqual(PerceptionSkeleton.Alert, rt.CurrentStateName);
        }

        [Test]
        public void Unaware_StaysUnaware_WhenInVision_ButNoAlertState()
        {
            var ctx = new FakeAiContext { HasAlert = false };
            var rt = Build(ctx);
            ctx.S.Vision = true;
            rt.Tick(0.1f);
            Assert.AreEqual(SinglePost.Post, rt.CurrentStateName);
        }

        [Test]
        public void ChaseZone_BeatsAlert_WhenBothActive()
        {
            var ctx = new FakeAiContext { HasAlert = true };
            var rt = Build(ctx);
            ctx.S.Chase = true; ctx.S.Vision = true;
            rt.Tick(0.1f);
            Assert.AreEqual(RushEngagement.Rush, rt.CurrentStateName);
        }

        // 升级边必须优先于未发现层内部计时边
        [Test]
        public void UpgradeEdge_BeatsUnawareInternalDwellEdge()
        {
            var ctx = new FakeAiContext();
            var rt = Build(ctx, new AlternatingIdlePatrol(idleDwell: 1f, patrolDwell: 1f));
            Assert.AreEqual(AlternatingIdlePatrol.Idle, rt.CurrentStateName);
            ctx.S.Chase = true;
            rt.Tick(5f);   // 计时早已到点，但追击边优先
            Assert.AreEqual(RushEngagement.Rush, rt.CurrentStateName);
        }

        // ── 警觉 ──────────────────────────────────────────────────────────

        [Test]
        public void Alert_ToEngagement_WhenEnteringChaseZone()
        {
            var ctx = new FakeAiContext();
            var rt = Build(ctx);
            ctx.S.Vision = true; rt.Tick(0.1f);
            Assert.AreEqual(PerceptionSkeleton.Alert, rt.CurrentStateName);
            ctx.S.Chase = true; rt.Tick(0.1f);
            Assert.AreEqual(RushEngagement.Rush, rt.CurrentStateName);
        }

        [Test]
        public void Alert_ToRest_WhenLeavingVision()
        {
            var ctx = new FakeAiContext();
            var rt = Build(ctx);
            ctx.S.Vision = true; rt.Tick(0.1f);
            ctx.S.Vision = false; rt.Tick(0.1f);
            Assert.AreEqual(SinglePost.Post, rt.CurrentStateName);
        }

        [Test]
        public void Alert_FacesLastKnown()
        {
            var ctx = new FakeAiContext();
            ctx.S.Last = new UnityEngine.Vector2(7f, 2f);
            var rt = Build(ctx);
            ctx.S.Vision = true; rt.Tick(0.1f);
            Assert.AreEqual(new UnityEngine.Vector2(7f, 2f), ctx.L.FacedAt);
        }

        // ── 降级：追击后永不回警觉 ─────────────────────────────────────────

        [Test]
        public void AfterEngagement_GoesToRest_NeverBackToAlert()
        {
            var ctx = new FakeAiContext();
            var rt = Build(ctx);
            ctx.S.Chase = true; rt.Tick(0.1f);
            Assert.AreEqual(RushEngagement.Rush, rt.CurrentStateName);
            ctx.S.Chase = false; ctx.S.Vision = false; rt.Tick(0.1f);
            Assert.AreEqual(SinglePost.Post, rt.CurrentStateName);   // 不是 Alert
        }

        // ── 死亡 ──────────────────────────────────────────────────────────

        [Test]
        public void Died_TransitionsToDeath_FromAnyState()
        {
            var ctx = new FakeAiContext();
            var rt = Build(ctx);
            ctx.S.Chase = true; rt.Tick(0.1f);
            Assert.AreEqual(RushEngagement.Rush, rt.CurrentStateName);
            rt.Send(AiSignal.Died);
            rt.Tick(0.1f);
            Assert.AreEqual(PerceptionSkeleton.Death, rt.CurrentStateName);
        }

        // 真实死亡路径：PerformDeath 先 ForceState(Dead) 再发 Died，
        // 所以信号被处理时 IsControllable 已为假。事件边必须仍能通过。
        [Test]
        public void Died_WorksEvenWhenNotControllable()
        {
            var ctx = new FakeAiContext();
            var rt = Build(ctx);
            ctx.V.Controllable = false;      // 已是 Dead 物理态
            rt.Send(AiSignal.Died);
            rt.Tick(0.1f);
            Assert.AreEqual(PerceptionSkeleton.Death, rt.CurrentStateName);
        }

        [Test]
        public void Death_IsTerminal_NoConditionEdgesEvaluatedAfterwards()
        {
            var ctx = new FakeAiContext();
            var rt = Build(ctx);
            rt.Send(AiSignal.Died);
            rt.Tick(0.1f);
            ctx.V.Controllable = false;      // 死后不可控
            ctx.S.Chase = true;              // 即便玩家又进追逐区
            for (int i = 0; i < 10; i++) rt.Tick(0.1f);
            Assert.AreEqual(PerceptionSkeleton.Death, rt.CurrentStateName); // 也不复活
        }

        // ── 校验 ──────────────────────────────────────────────────────────

        sealed class BadUnaware : IUnawareModule
        {
            public string Entry => "X";
            public string Rest  => "NotInStates";
            public IReadOnlyList<string> States => new[] { "X" };
            public void Declare(BrainBuilder b) => AiStateFragments.Locomotion(b, "X", LocomotionMode.Idle);
            public void Link(BrainBuilder b) { }
        }

        sealed class UndeclaredUnaware : IUnawareModule
        {
            public string Entry => "Y";
            public string Rest  => "Y";
            public IReadOnlyList<string> States => new[] { "Y" };
            public void Declare(BrainBuilder b) { }   // 忘了声明行为
            public void Link(BrainBuilder b) { }
        }

        [Test]
        public void Throws_WhenRestNotInStates()
        {
            var b = new BrainBuilder();
            Assert.Throws<System.InvalidOperationException>(() => PerceptionSkeleton.Add(
                b, new BadUnaware(), new RushEngagement("rush")));
        }

        [Test]
        public void Throws_WhenUnawareStateNotDeclared()
        {
            var b = new BrainBuilder();
            Assert.Throws<System.InvalidOperationException>(() => PerceptionSkeleton.Add(
                b, new UndeclaredUnaware(), new RushEngagement("rush")));
        }

        [Test]
        public void Throws_WhenModuleIsNull()
        {
            var b = new BrainBuilder();
            Assert.Throws<System.ArgumentNullException>(() => PerceptionSkeleton.Add(
                b, null, new RushEngagement("rush")));
        }

        // ── 模块组合：抽象的存在理由，必须端到端验证 ─────────────────────

        [Test]
        public void Skeleton_WithApproachAttack_EscalatesAndDisengages()
        {
            var ctx = new FakeAiContext();
            var rt = Build(ctx, new SinglePost(LocomotionMode.Patrol), new ApproachAttackEngagement());
            Assert.AreEqual(SinglePost.Post, rt.CurrentStateName);

            ctx.S.Chase = true; rt.Tick(0.1f);
            Assert.AreEqual(ApproachAttackEngagement.Approach, rt.CurrentStateName);

            ctx.C.Eligible = true; rt.Tick(0.1f);
            Assert.AreEqual(ApproachAttackEngagement.Attack, rt.CurrentStateName);

            ctx.C.Running = null; rt.Tick(0.1f);            // 招式打完
            Assert.AreEqual(ApproachAttackEngagement.Approach, rt.CurrentStateName);

            ctx.S.Chase = false; ctx.S.Vision = false; ctx.C.Eligible = false;
            rt.Tick(0.1f);
            Assert.AreEqual(SinglePost.Post, rt.CurrentStateName);   // 脱战回 Rest
        }

        [Test]
        public void Skeleton_WithDisguiseThenPatrol_DisengagesToPatrol_NotDisguise()
        {
            // 唯一 Entry != Rest 的未发现层：出生伪装静止，脱战只回巡逻，伪装态从此不可达。
            var ctx = new FakeAiContext();
            var rt = Build(ctx, new DisguiseThenPatrol());
            Assert.AreEqual(DisguiseThenPatrol.Disguise, rt.CurrentStateName);

            ctx.S.Chase = true; rt.Tick(0.1f);
            Assert.AreEqual(RushEngagement.Rush, rt.CurrentStateName);

            ctx.S.Chase = false; ctx.S.Vision = false; rt.Tick(0.1f);
            Assert.AreEqual(DisguiseThenPatrol.Patrol, rt.CurrentStateName);   // 不是 Disguise

            // 再交战一轮，仍然只回巡逻——伪装态不可逆
            ctx.S.Chase = true;  rt.Tick(0.1f);
            Assert.AreEqual(RushEngagement.Rush, rt.CurrentStateName);
            ctx.S.Chase = false; rt.Tick(0.1f);
            Assert.AreEqual(DisguiseThenPatrol.Patrol, rt.CurrentStateName);
        }

        [Test]
        public void EntryCanBeOverridden_ForEnemiesWithPrefixStates()
        {
            // 骨架注释承诺的出路：掉落链 / 出场链这类前置态，调 Add 之后再覆盖 Entry。
            var ctx = new FakeAiContext();
            var b = new BrainBuilder();
            PerceptionSkeleton.Add(b, new SinglePost(LocomotionMode.Patrol),
                                      new RushEngagement("rush", RushExit.OnLostTarget));
            AiStateFragments.Locomotion(b, "Ceiling", LocomotionMode.Idle)
                .To(SinglePost.Post).When(x => x.Sensor.SeesPlayer(), "landed");
            b.Entry("Ceiling");                              // 覆盖骨架设的入口

            var rt = new AiRuntime(b.Build(), ctx);
            Assert.AreEqual("Ceiling", rt.CurrentStateName);

            ctx.S.Sees = true; rt.Tick(0.1f);
            Assert.AreEqual(SinglePost.Post, rt.CurrentStateName);   // 落地后并入感知层

            ctx.S.Chase = true; rt.Tick(0.1f);
            Assert.AreEqual(RushEngagement.Rush, rt.CurrentStateName); // 升级边照常生效
        }
    }
}