using System.Reflection;
using BumpCombat.Core;
using BumpCombat.Enemies;
using BumpCombat.Spawning;
using NUnit.Framework;
using UnityEngine;

namespace BumpCombat.Tests
{
    public sealed class FiniteArenaGeometryTests
    {
        [TearDown]
        public void Cleanup()
        {
            ArenaBounds[] bounds = Object.FindObjectsByType<ArenaBounds>(
                FindObjectsSortMode.None);
            for (int i = 0; i < bounds.Length; i++)
            {
                Object.DestroyImmediate(bounds[i].gameObject);
            }

            SpawnDirector[] directors = Object.FindObjectsByType<SpawnDirector>(
                FindObjectsSortMode.None);
            for (int i = 0; i < directors.Length; i++)
            {
                if (directors[i] != null)
                {
                    Object.DestroyImmediate(directors[i].gameObject);
                }
            }

            ArenaBounds.Instance?.gameObject.SetActive(false);
        }

        [Test]
        public void DefaultGeometry_UsesFullFloorWithSmallSharedActorClearance()
        {
            GameObject root = CreateBounds();
            ArenaBounds bounds = root.GetComponent<ArenaBounds>();

            Assert.That(bounds.BackgroundHalfExtents.x, Is.EqualTo(15f).Within(0.0001f));
            Assert.That(bounds.BackgroundHalfExtents.y, Is.EqualTo(8.4375f).Within(0.0001f));
            Assert.That(bounds.PlayableHalfExtents, Is.EqualTo(bounds.BackgroundHalfExtents));
            Assert.That(bounds.PlayerPadding, Is.EqualTo(new Vector2(0.5f, 0.625f)));
            Assert.That(bounds.PlayerClampHalfExtents.x, Is.EqualTo(14.5f).Within(0.0001f));
            Assert.That(bounds.PlayerClampHalfExtents.y, Is.EqualTo(7.8125f).Within(0.0001f));
            Assert.That(bounds.SharedActorClampHalfExtents, Is.EqualTo(bounds.PlayerClampHalfExtents));
            Assert.That(bounds.CameraCenterHalfExtents.x, Is.EqualTo(5f).Within(0.0001f));
            Assert.That(bounds.CameraCenterHalfExtents.y, Is.EqualTo(2.8125f).Within(0.0001f));
        }

        [Test]
        public void ClampsPlayerEnemyAndCameraInsideFiniteMap()
        {
            GameObject root = CreateBounds();
            ArenaBounds bounds = root.GetComponent<ArenaBounds>();

            Vector2 playerPosition = bounds.ClampPlayerPosition(new Vector2(99f, -99f));
            Assert.That(playerPosition.x, Is.EqualTo(14.5f).Within(0.0001f));
            Assert.That(playerPosition.y, Is.EqualTo(-7.8125f).Within(0.0001f));
            Vector2 enemyPosition = bounds.ClampEnemyPosition(new Vector2(-99f, 99f));
            Assert.That(enemyPosition.x, Is.EqualTo(-14.5f).Within(0.0001f));
            Assert.That(enemyPosition.y, Is.EqualTo(7.8125f).Within(0.0001f));
            Assert.That(
                bounds.ClampEnemyPosition(new Vector2(99f, -99f)),
                Is.EqualTo(bounds.ClampPlayerPosition(new Vector2(99f, -99f))));
            Vector2 cameraPosition = bounds.ClampCameraCenter(new Vector2(99f, -99f));
            Assert.That(cameraPosition.x, Is.EqualTo(5f).Within(0.0001f));
            Assert.That(cameraPosition.y, Is.EqualTo(-2.8125f).Within(0.0001f));

            GameObject cameraObject = new("Arena Bounds Camera Test");
            Camera camera = cameraObject.AddComponent<Camera>();
            camera.orthographic = true;
            camera.orthographicSize = 5.625f;
            camera.aspect = 16f / 9f;
            Vector2 cameraCenter = bounds.ClampCameraCenter(
                new Vector2(99f, 99f),
                bounds.GetCameraVisibleHalfExtents(camera));
            camera.transform.position = cameraCenter;
            Bounds visibleBounds = bounds.GetCameraVisibleBounds(camera);
            Assert.That(visibleBounds.min.x, Is.GreaterThanOrEqualTo(-15f));
            Assert.That(visibleBounds.max.x, Is.EqualTo(15f).Within(0.0001f));
            Assert.That(visibleBounds.min.y, Is.GreaterThanOrEqualTo(-8.4375f));
            Assert.That(visibleBounds.max.y, Is.EqualTo(8.4375f).Within(0.0001f));

            cameraCenter = bounds.ClampCameraCenter(
                new Vector2(-99f, -99f),
                bounds.GetCameraVisibleHalfExtents(camera));
            camera.transform.position = cameraCenter;
            visibleBounds = bounds.GetCameraVisibleBounds(camera);
            Assert.That(visibleBounds.min.x, Is.EqualTo(-15f).Within(0.0001f));
            Assert.That(visibleBounds.max.x, Is.LessThanOrEqualTo(15f));
            Assert.That(visibleBounds.min.y, Is.EqualTo(-8.4375f).Within(0.0001f));
            Assert.That(visibleBounds.max.y, Is.LessThanOrEqualTo(8.4375f));
            Object.DestroyImmediate(cameraObject);
        }

        [Test]
        public void DeadZone_HoldsUntilTargetCrossesEachAxis()
        {
            Assert.That(
                ArenaCameraFollow.GetDeadZoneTargetCenter(
                    Vector2.zero,
                    new Vector2(0.5f, 0.3f),
                    new Vector2(0.5f, 0.3f)),
                Is.EqualTo(Vector2.zero));
            Vector2 movedCenter = ArenaCameraFollow.GetDeadZoneTargetCenter(
                Vector2.zero,
                new Vector2(0.7f, -0.5f),
                new Vector2(0.5f, 0.3f));
            Assert.That(movedCenter.x, Is.EqualTo(0.2f).Within(0.0001f));
            Assert.That(movedCenter.y, Is.EqualTo(-0.2f).Within(0.0001f));
        }

        [Test]
        public void SpawnPositionsStayReachableAndClearOfPlayer()
        {
            GameObject boundsObject = CreateBounds();
            ArenaBounds bounds = boundsObject.GetComponent<ArenaBounds>();
            GameObject directorObject = new("Spawn Director Test");
            SpawnDirector director = directorObject.AddComponent<SpawnDirector>();

            for (int i = 0; i < 64; i++)
            {
                Vector2 position = director.GetSpawnPositionForTests();
                Assert.That(bounds.IsInsideReachableArena(position, 0.25f), Is.True);
                Assert.That(position.magnitude, Is.GreaterThanOrEqualTo(4f));
            }
        }

        [Test]
        public void EnemyGroundAnchors_StayOnSharedPlayerBoundaryAfterEdgeAndCornerKnockback()
        {
            GameObject boundsObject = CreateBounds();
            ArenaBounds bounds = boundsObject.GetComponent<ArenaBounds>();
            EnemyController normalEnemy = CreateEnemy(
                new Vector2(0.72f, 0.72f),
                new Vector2(0.1f, -0.28f),
                1f);
            EnemyController eventEnemy = CreateEnemy(
                new Vector2(0.72f, 0.72f),
                new Vector2(-0.18f, -0.28f),
                1.25f);

            try
            {
                MethodInfo clampMethod = typeof(EnemyController).GetMethod(
                    "ClampEnemyPosition",
                    BindingFlags.Instance | BindingFlags.NonPublic);
                Assert.That(clampMethod, Is.Not.Null);

                EnemyController[] enemies = { normalEnemy, eventEnemy };
                for (int enemyIndex = 0; enemyIndex < enemies.Length; enemyIndex++)
                {
                    EnemyController enemy = enemies[enemyIndex];
                    Collider2D collider = enemy.GetComponent<Collider2D>();
                    Rigidbody2D body = enemy.GetComponent<Rigidbody2D>();
                    Vector2[] knockbackDestinations =
                    {
                        new(100f, 100f),
                        new(-100f, 100f),
                        new(100f, -100f),
                        new(-100f, -100f),
                    };

                    for (int i = 0; i < knockbackDestinations.Length; i++)
                    {
                        Vector2 clamped = (Vector2)clampMethod.Invoke(
                            enemy,
                            new object[] { knockbackDestinations[i] });
                        body.position = clamped;
                        Physics2D.SyncTransforms();

                        Vector2 safeHalfExtents = bounds.SharedActorClampHalfExtents;
                        Assert.That(body.position.x, Is.GreaterThanOrEqualTo(-safeHalfExtents.x - 0.0001f));
                        Assert.That(body.position.x, Is.LessThanOrEqualTo(safeHalfExtents.x + 0.0001f));
                        Assert.That(body.position.y, Is.GreaterThanOrEqualTo(-safeHalfExtents.y - 0.0001f));
                        Assert.That(body.position.y, Is.LessThanOrEqualTo(safeHalfExtents.y + 0.0001f));
                        Bounds colliderBounds = collider.bounds;
                        // The collider can overhang the ground-anchor edge by
                        // its art footprint; only the anchor defines movement.
                        Assert.That(colliderBounds.size.x, Is.GreaterThan(0f));
                        Assert.That(colliderBounds.size.y, Is.GreaterThan(0f));
                    }
                }
            }
            finally
            {
                Object.DestroyImmediate(normalEnemy.gameObject);
                Object.DestroyImmediate(eventEnemy.gameObject);
            }
        }

        [Test]
        public void EnemyGroundAnchor_PostPhysicsCorrectionRestoresSharedBoundary()
        {
            CreateBounds();
            EnemyController enemy = CreateEnemy(
                new Vector2(0.72f, 0.72f),
                new Vector2(-0.18f, -0.28f),
                1.25f);

            try
            {
                Rigidbody2D body = enemy.GetComponent<Rigidbody2D>();
                Collider2D collider = enemy.GetComponent<Collider2D>();
                body.position = new Vector2(100f, -100f);
                Physics2D.SyncTransforms();

                MethodInfo correctionMethod = typeof(EnemyController).GetMethod(
                    "KeepBodyInsideArena",
                    BindingFlags.Instance | BindingFlags.NonPublic);
                Assert.That(correctionMethod, Is.Not.Null);
                correctionMethod.Invoke(enemy, null);
                Physics2D.SyncTransforms();

                Bounds colliderBounds = collider.bounds;
                ArenaBounds bounds = ArenaBounds.Resolve();
                Vector2 safeHalfExtents = bounds.SharedActorClampHalfExtents;
                Assert.That(body.position.x, Is.GreaterThanOrEqualTo(-safeHalfExtents.x - 0.0001f));
                Assert.That(body.position.x, Is.LessThanOrEqualTo(safeHalfExtents.x + 0.0001f));
                Assert.That(body.position.y, Is.GreaterThanOrEqualTo(-safeHalfExtents.y - 0.0001f));
                Assert.That(body.position.y, Is.LessThanOrEqualTo(safeHalfExtents.y + 0.0001f));
                Assert.That(colliderBounds.size.x, Is.GreaterThan(0f));
            }
            finally
            {
                Object.DestroyImmediate(enemy.gameObject);
            }
        }

        private static EnemyController CreateEnemy(
            Vector2 colliderSize,
            Vector2 colliderOffset,
            float rootScale)
        {
            GameObject enemyObject = new("Boundary Test Enemy");
            Rigidbody2D body = enemyObject.AddComponent<Rigidbody2D>();
            body.bodyType = RigidbodyType2D.Kinematic;
            body.gravityScale = 0f;
            BoxCollider2D collider = enemyObject.AddComponent<BoxCollider2D>();
            collider.size = colliderSize;
            collider.offset = colliderOffset;
            enemyObject.AddComponent<SpriteRenderer>();
            enemyObject.transform.localScale = Vector3.one * rootScale;
            EnemyController enemy = enemyObject.AddComponent<EnemyController>();
            // Unity does not invoke runtime Awake in EditMode. Populate the
            // same private references that Awake would cache so this test
            // exercises the controller's real clamp path.
            SetPrivateField(enemy, "body", body);
            SetPrivateField(enemy, "bodyCollider", collider);
            Physics2D.SyncTransforms();
            return enemy;
        }

        private static void SetPrivateField<T>(
            object target,
            string fieldName,
            T value)
        {
            typeof(EnemyController)
                .GetField(fieldName, BindingFlags.Instance | BindingFlags.NonPublic)
                ?.SetValue(target, value);
        }

        private static GameObject CreateBounds()
        {
            GameObject root = new("Arena Bounds Test");
            root.AddComponent<ArenaBounds>();
            return root;
        }
    }
}