using NUnit.Framework;
using BaseGames.AI;

namespace BaseGames.Tests.EditMode.AI
{
    /// <summary>
    /// BrainGraph 框架健壮性/边界测试：构图校验、转换优先级、全局转换、
    /// 事件与条件优先、队列信号、自转换、trace 上限、Blackboard、dt 传递。
    /// 与 AiRuntimeTests（主干行为）互补，覆盖易回归的边角。
    /// </summary>
    public class AiFrameworkTests
    {
        // ── 构图校验（Build 应对错误声明抛异常，尽早暴露）──────────────────

        [Test]
        public void Build_Throws_WhenEntryNotSet()
        {
            var b = new BrainBuilder();
            b.State("A");
            Assert.Throws<System.InvalidOperationException>(() => b.Build());
        }

        [Test]
        public void Build_Throws_WhenEntryStateUndeclared()
        {
            var b = new BrainBuilder();
            b.Entry("Missing");
            b.State("A");
            Assert.Throws<System.InvalidOperationException>(() => b.Build());
        }

        // 局部转换指向未声明状态 → BrainBuilderTests.Build_UnknownTransitionTarget_Throws 已覆盖，此处不重复。

        [Test]
        public void Build_Throws_WhenGlobalTransitionTargetUndeclared()
        {
            var b = new BrainBuilder();
            b.Entry("A");
            b.State("A");
            b.Global().To("Ghost").OnEvent(AiSignal.Died);
            Assert.Throws<System.InvalidOperationException>(() => b.Build());
        }

        [Test]
        public void GlobalBuilder_Throws_WhenOnEventBeforeTo()
        {
            var b = new BrainBuilder();
            Assert.Throws<System.InvalidOperationException>(() => b.Global().OnEvent(AiSignal.Died));
        }

        [Test]
        public void GlobalBuilder_Throws_WhenWhenBeforeTo()
        {
            var b = new BrainBuilder();
            Assert.Throws<System.InvalidOperationException>(() => b.Global().When(c => true, "x"));
        }

        // ── 转换优先级 / 全局转换 ─────────────────────────────────────────

        [Test]
        public void ConditionTransition_FirstDeclaredWins()
        {
            var b = new BrainBuilder();
            b.Entry("A");
            b.State("A")
                .To("B").When(c => true, "first")
                .To("C").When(c => true, "second"); // 两者都真，先声明的 B 胜
            b.State("B"); b.State("C");
            var rt = new AiRuntime(b.Build(), new FakeAiContext());
            rt.Tick(0.1f);
            Assert.AreEqual("B", rt.CurrentStateName);
        }

        [Test]
        public void GlobalConditionTransition_Fires()
        {
            var b = new BrainBuilder();
            b.Entry("A");
            b.State("A"); b.State("Panic");
            b.Global().To("Panic").When(c => c.Vitals.HpBelow(0.3f), "lowHp");
            var ctx = new FakeAiContext();
            ctx.V.Hp = 0.1f;
            var rt = new AiRuntime(b.Build(), ctx);
            rt.Tick(0.1f);
            Assert.AreEqual("Panic", rt.CurrentStateName);
        }

        [Test]
        public void GlobalConditionTransition_TakesPriorityOverLocal()
        {
            var b = new BrainBuilder();
            b.Entry("A");
            b.State("A").To("B").When(c => true, "local");
            b.State("B"); b.State("G");
            b.Global().To("G").When(c => true, "global"); // 全局先评估
            var rt = new AiRuntime(b.Build(), new FakeAiContext());
            rt.Tick(0.1f);
            Assert.AreEqual("G", rt.CurrentStateName);
        }

        // ── 事件 vs 条件优先 / 队列信号 ───────────────────────────────────

        [Test]
        public void EventTransition_TakesPriorityOverCondition_SameTick()
        {
            var b = new BrainBuilder();
            b.Entry("A");
            b.State("A")
                .To("ByCond").When(c => true, "cond")   // 条件恒真
                .To("ByEvent").OnEvent(AiSignal.Died); // 事件优先(Tick 第1步)
            b.State("ByCond"); b.State("ByEvent");
            var rt = new AiRuntime(b.Build(), new FakeAiContext());
            rt.Send(AiSignal.Died);
            rt.Tick(0.1f);
            Assert.AreEqual("ByEvent", rt.CurrentStateName);
        }

        [Test]
        public void UnmatchedSignal_ConsumedThenConditionEvaluated()
        {
            var b = new BrainBuilder();
            b.Entry("A");
            b.State("A").To("B").When(c => c.Sensor.SeesPlayer(), "sees");
            b.State("B");
            var ctx = new FakeAiContext();
            ctx.S.Sees = true;
            var rt = new AiRuntime(b.Build(), ctx);
            rt.Send(AiSignal.Died); // A 无 Died 转换 → 被消费掉，不阻塞条件评估
            rt.Tick(0.1f);
            Assert.AreEqual("B", rt.CurrentStateName);
        }

        [Test]
        public void QueuedDuplicateSignals_TransitionOnce_RemainderConsumed()
        {
            // 注：原测试用两个不同信号验证"第一个匹配的先转"。AiSignal 现只有 Died 一个值，
            // 该形态暂不可表达；等将来出现第二个真实信号（如战斗激活）时恢复此覆盖。
            // 此处覆盖仍然成立的部分：残留信号被消费掉，不会重复触发转换。
            var b = new BrainBuilder();
            b.Entry("A");
            b.State("A").To("B").OnEvent(AiSignal.Died);
            b.State("B").OnEnter(c => c.Blackboard.Set("enters", c.Blackboard.Get<int>("enters") + 1));
            var ctx = new FakeAiContext();
            var rt = new AiRuntime(b.Build(), ctx);
            rt.Send(AiSignal.Died);
            rt.Send(AiSignal.Died);
            rt.Tick(0.1f);
            Assert.AreEqual("B", rt.CurrentStateName);
            rt.Tick(0.1f);
            Assert.AreEqual("B", rt.CurrentStateName);
            Assert.AreEqual(1, ctx.BB.Get<int>("enters")); // 残留信号被消费，未重入 B
        }

        // ── 自转换 / OnTick 时序 ──────────────────────────────────────────

        [Test]
        public void ConditionSelfTransition_DoesNotReenter()
        {
            var b = new BrainBuilder();
            b.Entry("A");
            b.State("A")
                .OnEnter(c => c.Blackboard.Set("enters", c.Blackboard.Get<int>("enters") + 1))
                .To("A").When(c => true, "self"); // 自转换
            var ctx = new FakeAiContext();
            var rt = new AiRuntime(b.Build(), ctx); // 构造进入 → enters=1
            rt.Tick(0.1f);                          // 自转换应 no-op，不重跑 OnEnter
            Assert.AreEqual(1, ctx.BB.Get<int>("enters"));
            Assert.AreEqual("A", rt.CurrentStateName);
        }

        [Test]
        public void TransitionWins_SkipsOnTick_SameFrame()
        {
            var b = new BrainBuilder();
            b.Entry("A");
            b.State("A")
                .Tick(c => c.Blackboard.Set("ticked", true))
                .To("B").When(c => true, "go");
            b.State("B");
            var ctx = new FakeAiContext();
            var rt = new AiRuntime(b.Build(), ctx);
            rt.Tick(0.1f); // 转换发生 → 当帧不应执行 A 的 OnTick
            Assert.AreEqual("B", rt.CurrentStateName);
            Assert.IsFalse(ctx.BB.Has("ticked"));
        }

        [Test]
        public void Tick_TwoArg_ReceivesDeltaTime()
        {
            var b = new BrainBuilder();
            b.Entry("A");
            b.State("A").Tick((c, dt) => c.Blackboard.Set("dt", dt)); // 无转换
            var ctx = new FakeAiContext();
            var rt = new AiRuntime(b.Build(), ctx);
            rt.Tick(0.25f);
            Assert.AreEqual(0.25f, ctx.BB.Get<float>("dt"), 1e-5f);
        }

        // ── trace 上限 / Blackboard / 挂起标志 ────────────────────────────

        [Test]
        public void Trace_CapsAtSixteen()
        {
            var b = new BrainBuilder();
            b.Entry("A");
            b.State("A").To("B").When(c => true, "toB");
            b.State("B").To("A").When(c => true, "toA"); // A↔B 每帧一次转换
            var rt = new AiRuntime(b.Build(), new FakeAiContext());
            for (int i = 0; i < 20; i++) rt.Tick(0.1f);
            Assert.AreEqual(16, rt.Trace.Count); // 环形缓冲上限 16
        }

        // Blackboard 基础 Set/Get/Has/Clear/Snapshot → BlackboardTests 已覆盖，此处不重复。

        [Test]
        public void IsSuspended_ClearedAfterEventWhileNotControllable()
        {
            var b = new BrainBuilder();
            b.Entry("A");
            b.State("A"); b.State("Dead");
            b.Global().To("Dead").OnEvent(AiSignal.Died);
            var ctx = new FakeAiContext();
            ctx.V.Controllable = false; // 受击中（若无事件本会挂起）
            var rt = new AiRuntime(b.Build(), ctx);
            rt.Send(AiSignal.Died);
            rt.Tick(0.1f);
            Assert.AreEqual("Dead", rt.CurrentStateName);
            Assert.IsFalse(rt.IsSuspended); // 事件推进转换后清挂起
        }

        [Test]
        public void State_Redeclaration_AccumulatesTransitions()
        {
            var b = new BrainBuilder();
            b.Entry("A");
            b.State("A").To("B").When(c => false, "t1"); // 第一次声明
            b.State("A").To("C").When(c => true, "t2");  // 再次 State("A") 应取同一状态，累加转换
            b.State("B"); b.State("C");
            var graph = b.Build();
            Assert.AreEqual(2, graph.GetState("A").Transitions.Count);
            var rt = new AiRuntime(graph, new FakeAiContext());
            rt.Tick(0.1f); // t1 假、t2 真 → C
            Assert.AreEqual("C", rt.CurrentStateName);
        }
    }
}