using NUnit.Framework;
using BaseGames.AI;
using BaseGames.Enemies;

namespace BaseGames.Tests.EditMode.AI
{
    public class ApproachAttackEngagementTests
    {
        const string Rest = "Rest";

        static AiRuntime RunAlone(FakeAiContext ctx)
        {
            var m = new ApproachAttackEngagement();
            var b = new BrainBuilder();
            AiStateFragments.Locomotion(b, Rest, LocomotionMode.Patrol);
            m.Build(b, Rest);
            b.Entry(m.EntryState);
            return new AiRuntime(b.Build(), ctx);
        }

        [Test]
        public void Approach_PursuesLastKnown()
        {
            var ctx = new FakeAiContext();
            ctx.S.Chase = true;
            ctx.S.Last = new UnityEngine.Vector2(5f, 1f);
            RunAlone(ctx);
            Assert.AreEqual(new UnityEngine.Vector2(5f, 1f), ctx.L.PursuedTo);
        }

        [Test]
        public void Approach_ToAttack_WhenEligibleAttackExists()
        {
            var ctx = new FakeAiContext();
            ctx.S.Chase = true;
            var rt = RunAlone(ctx);
            Assert.AreEqual(ApproachAttackEngagement.Approach, rt.CurrentStateName);
            ctx.C.Eligible = true;
            rt.Tick(0.1f);
            Assert.AreEqual(ApproachAttackEngagement.Attack, rt.CurrentStateName);
            CollectionAssert.Contains(ctx.C.Used, "best");
        }

        [Test]
        public void Attack_BackToApproach_WhenAbilityDone()
        {
            var ctx = new FakeAiContext();
            ctx.S.Chase = true; ctx.C.Eligible = true;
            var rt = RunAlone(ctx);
            rt.Tick(0.1f);
            Assert.AreEqual(ApproachAttackEngagement.Attack, rt.CurrentStateName);
            ctx.C.Running = null;                 // 招式打完
            rt.Tick(0.1f);
            Assert.AreEqual(ApproachAttackEngagement.Approach, rt.CurrentStateName);
        }

        [Test]
        public void Approach_ExitsToRest_WhenAllZonesLost()
        {
            var ctx = new FakeAiContext();
            ctx.S.Chase = true;
            var rt = RunAlone(ctx);
            ctx.S.Chase = false; ctx.S.Vision = false;
            rt.Tick(0.1f);
            Assert.AreEqual(Rest, rt.CurrentStateName);
        }

        // 有意的行为变更：攻击起手后打完，不中途收招
        [Test]
        public void Attack_CompletesEvenWhenPlayerLeavesAllZones()
        {
            var ctx = new FakeAiContext();
            ctx.S.Chase = true; ctx.C.Eligible = true;
            var rt = RunAlone(ctx);
            rt.Tick(0.1f);
            Assert.AreEqual(ApproachAttackEngagement.Attack, rt.CurrentStateName);

            ctx.S.Chase = false; ctx.S.Vision = false;   // 前摇中玩家跑掉
            // 真实系统里攻击射程远小于感知区，脱离全部感知区必然也脱离攻击射程，
            // HasEligibleAttack() 会随之变假。FakeCombat.Eligible 是裸字段不会联动，这里手工对齐。
            ctx.C.Eligible = false;
            rt.Tick(0.1f);
            Assert.AreEqual(ApproachAttackEngagement.Attack, rt.CurrentStateName); // 不中途收招

            ctx.C.Running = null;                         // 招式打完
            rt.Tick(0.1f);
            Assert.AreEqual(ApproachAttackEngagement.Approach, rt.CurrentStateName);
            rt.Tick(0.1f);
            Assert.AreEqual(Rest, rt.CurrentStateName);   // 再经 Approach 自然脱战
        }

        [Test]
        public void Attack_SelfHealsToApproach_WhenNothingActuallyTriggered()
        {
            // Attack 只有 attackDone 一条出边，安全性依赖："UseBestAttack 失败时不会留下运行中的能力"。
            // 若该不变量被破坏，敌人会永久卡在 Attack 里出不来。
            var ctx = new FakeAiContext();
            ctx.S.Chase = true;
            ctx.C.Eligible = true;
            ctx.C.BestAttackFails = true;         // 够得着，但触发失败
            var rt = RunAlone(ctx);
            rt.Tick(0.1f);
            Assert.AreEqual(ApproachAttackEngagement.Attack, rt.CurrentStateName);
            Assert.IsNull(ctx.C.Running);         // 什么都没启动

            rt.Tick(0.1f);
            Assert.AreEqual(ApproachAttackEngagement.Approach, rt.CurrentStateName); // 下一帧自愈
        }
    }
}