using Unity.Netcode;
using UnityEngine;
using UnityEngine.InputSystem;
using UnityEngine.EventSystems;

namespace Northbound
{
    public class BuildingPlacement : NetworkBehaviour
    {
        [Header("Settings")]
        public LayerMask groundLayer;
        public float maxPlacementDistance = 100f;

        [Header("Preview Materials")]
        public Material validMaterial;
        public Material invalidMaterial;

        [Header("Current Selection")]
        public int selectedBuildingIndex = 0;

        [Header("Debug Visualization")]
        public bool showGridBounds = true;

        private bool isBuildModeActive = false;
        private GameObject previewObject;
        private int currentRotation = 0; // 0-3
        private Material[] originalMaterials;
        private Renderer[] previewRenderers;
        private PlayerInputActions _inputActions;

        public override void OnNetworkSpawn()
        {
            if (!IsOwner) return;

            _inputActions = new PlayerInputActions();
            _inputActions.Player.ToggleBuildMode.performed += OnToggleBuildMode;
            _inputActions.Player.Rotate.performed += OnRotate;
            _inputActions.Player.Build.performed += OnBuild;
            _inputActions.Enable();

            // Create default materials if not assigned
            if (validMaterial == null)
            {
                validMaterial = CreateGhostMaterial(new Color(0, 1, 0, 0.5f));
            }

            if (invalidMaterial == null)
            {
                invalidMaterial = CreateGhostMaterial(new Color(1, 0, 0, 0.5f));
            }
        }

        private Material CreateGhostMaterial(Color color)
        {
            // Try to find appropriate shader for current render pipeline
            Shader shader = Shader.Find("Universal Render Pipeline/Lit");
            if (shader == null)
                shader = Shader.Find("Standard");
            if (shader == null)
                shader = Shader.Find("Diffuse");

            Material mat = new Material(shader);

            // Set base color
            if (mat.HasProperty("_BaseColor"))
                mat.SetColor("_BaseColor", color); // URP
            else if (mat.HasProperty("_Color"))
                mat.SetColor("_Color", color); // Standard

            // Enable transparency
            if (mat.HasProperty("_Surface"))
            {
                // URP Transparency
                mat.SetFloat("_Surface", 1); // Transparent
                mat.SetFloat("_Blend", 0); // Alpha
                mat.SetFloat("_AlphaClip", 0);
                mat.SetFloat("_SrcBlend", (int)UnityEngine.Rendering.BlendMode.SrcAlpha);
                mat.SetFloat("_DstBlend", (int)UnityEngine.Rendering.BlendMode.OneMinusSrcAlpha);
                mat.SetFloat("_ZWrite", 0);
                mat.renderQueue = 3000;
                mat.EnableKeyword("_SURFACE_TYPE_TRANSPARENT");
                mat.EnableKeyword("_ALPHAPREMULTIPLY_ON");
            }
            else
            {
                // Standard RP Transparency
                mat.SetFloat("_Mode", 3); // Transparent mode
                mat.SetInt("_SrcBlend", (int)UnityEngine.Rendering.BlendMode.SrcAlpha);
                mat.SetInt("_DstBlend", (int)UnityEngine.Rendering.BlendMode.OneMinusSrcAlpha);
                mat.SetInt("_ZWrite", 0);
                mat.DisableKeyword("_ALPHATEST_ON");
                mat.EnableKeyword("_ALPHABLEND_ON");
                mat.DisableKeyword("_ALPHAPREMULTIPLY_ON");
                mat.renderQueue = 3000;
            }

            return mat;
        }

        public override void OnNetworkDespawn()
        {
            if (IsOwner && _inputActions != null)
            {
                _inputActions.Player.ToggleBuildMode.performed -= OnToggleBuildMode;
                _inputActions.Player.Rotate.performed -= OnRotate;
                _inputActions.Player.Build.performed -= OnBuild;
                _inputActions.Disable();
                _inputActions.Dispose();
            }
        }

        private void Update()
        {
            if (!IsOwner) return;

            if (isBuildModeActive)
            {
                UpdatePreviewPosition();
            }
        }

        private void OnToggleBuildMode(InputAction.CallbackContext context)
        {
            isBuildModeActive = !isBuildModeActive;

            if (isBuildModeActive)
            {
                // UI 표시
                if (BuildingQuickslotUI.Instance != null)
                {
                    BuildingQuickslotUI.Instance.ShowQuickslot(this);
                }

                CreatePreview();
            }
            else
            {
                // UI 숨김
                if (BuildingQuickslotUI.Instance != null)
                {
                    BuildingQuickslotUI.Instance.HideQuickslot();
                }

                DestroyPreview();
            }

            Debug.Log($"[BuildingPlacement] 건설 모드 {(isBuildModeActive ? "활성화" : "비활성화")}");
        }

        /// <summary>
        /// UI에서 건물 선택 시 호출
        /// </summary>
        public void SetSelectedBuilding(int index)
        {
            if (index < 0 || BuildingManager.Instance == null || 
                index >= BuildingManager.Instance.availableBuildings.Count)
            {
                Debug.LogWarning($"[BuildingPlacement] 유효하지 않은 건물 인덱스: {index}");
                return;
            }

            selectedBuildingIndex = index;
            currentRotation = 0; // 회전 초기화

            // 프리뷰 다시 생성
            if (isBuildModeActive)
            {
                DestroyPreview();
                CreatePreview();
            }

            Debug.Log($"[BuildingPlacement] 건물 선택됨: {BuildingManager.Instance.availableBuildings[index].buildingName}");
        }

        private void CreatePreview()
        {
            if (BuildingManager.Instance == null)
            {
                Debug.LogWarning("[BuildingPlacement] BuildingManager가 없습니다.");
                return;
            }

            if (selectedBuildingIndex < 0 || selectedBuildingIndex >= BuildingManager.Instance.availableBuildings.Count)
            {
                Debug.LogWarning($"[BuildingPlacement] 유효하지 않은 건물 인덱스: {selectedBuildingIndex}");
                return;
            }

            BuildingData data = BuildingManager.Instance.availableBuildings[selectedBuildingIndex];
            if (data == null || data.prefab == null)
            {
                Debug.LogWarning("[BuildingPlacement] BuildingData 또는 Prefab이 없습니다.");
                return;
            }

            // 완성 건물 프리팹으로 프리뷰 생성 (사용자가 완성 모습을 볼 수 있도록)
            previewObject = Instantiate(data.prefab);
            
            // Remove NetworkObject component from preview
            NetworkObject netObj = previewObject.GetComponent<NetworkObject>();
            if (netObj != null)
            {
                Destroy(netObj);
            }

            // Remove Building component from preview
            Building building = previewObject.GetComponent<Building>();
            if (building != null)
            {
                Destroy(building);
            }

            // Apply ghost materials
            previewRenderers = previewObject.GetComponentsInChildren<Renderer>();
            foreach (var renderer in previewRenderers)
            {
                Material[] mats = new Material[renderer.materials.Length];
                for (int i = 0; i < mats.Length; i++)
                {
                    mats[i] = validMaterial;
                }
                renderer.materials = mats;
            }

            // Disable colliders in preview
            foreach (var collider in previewObject.GetComponentsInChildren<Collider>())
            {
                collider.enabled = false;
            }

            Debug.Log($"[BuildingPlacement] 프리뷰 생성됨: {data.buildingName}");
        }

        private void DestroyPreview()
        {
            if (previewObject != null)
            {
                Destroy(previewObject);
                previewObject = null;
            }
        }

        private void UpdatePreviewPosition()
        {
            if (previewObject == null || BuildingManager.Instance == null)
                return;

            Ray ray = Camera.main.ScreenPointToRay(Mouse.current.position.ReadValue());
            
            if (Physics.Raycast(ray, out RaycastHit hit, maxPlacementDistance, groundLayer))
            {
                BuildingData data = BuildingManager.Instance.availableBuildings[selectedBuildingIndex];
                
                // Check if placement is valid
                bool isValid = BuildingManager.Instance.IsValidPlacement(data, hit.point, currentRotation, out Vector3 snappedPosition);

                // Update preview position (placementOffset 적용)
                previewObject.transform.position = snappedPosition + data.placementOffset;
                previewObject.transform.rotation = Quaternion.Euler(0, currentRotation * 90f, 0);

                // Update material based on validity
                Material targetMat = isValid ? validMaterial : invalidMaterial;
                foreach (var renderer in previewRenderers)
                {
                    Material[] mats = new Material[renderer.materials.Length];
                    for (int i = 0; i < mats.Length; i++)
                    {
                        mats[i] = targetMat;
                    }
                    renderer.materials = mats;
                }
            }
        }

        private void OnRotate(InputAction.CallbackContext context)
        {
            if (!isBuildModeActive) return;

            currentRotation = (currentRotation + 1) % 4;
        }

        private void OnBuild(InputAction.CallbackContext context)
        {
            if (!isBuildModeActive || previewObject == null) return;

            // UI 위에서 클릭한 경우 무시
            if (IsPointerOverUI())
            {
                Debug.Log("<color=cyan>[BuildingPlacement] UI 위에서 클릭함 - 건설 취소</color>");
                return;
            }

            // Get placement position
            Ray ray = Camera.main.ScreenPointToRay(Mouse.current.position.ReadValue());
            if (Physics.Raycast(ray, out RaycastHit hit, maxPlacementDistance, groundLayer))
            {
                BuildingData selectedData = BuildingManager.Instance.availableBuildings[selectedBuildingIndex];
                
                if (BuildingManager.Instance.IsValidPlacement(selectedData, hit.point, currentRotation, out Vector3 groundPosition))
                {
                    // 토대 배치 요청
                    BuildingManager.Instance.RequestPlaceFoundation(selectedBuildingIndex, groundPosition, currentRotation);
                    Debug.Log($"<color=cyan>[BuildingPlacement] 건설 시작: {selectedData.buildingName}</color>");
                }
                else
                {
                    Debug.Log("<color=yellow>[BuildingPlacement] 배치할 수 없는 위치입니다.</color>");
                }
            }
        }

        /// <summary>
        /// 마우스 포인터가 UI 위에 있는지 확인
        /// </summary>
        private bool IsPointerOverUI()
        {
            // EventSystem이 없으면 UI 체크 불가능
            if (EventSystem.current == null)
                return false;

            // New Input System을 사용하는 경우
            if (Mouse.current != null)
            {
                Vector2 mousePosition = Mouse.current.position.ReadValue();
                return EventSystem.current.IsPointerOverGameObject();
            }

            // Legacy Input System (폴백)
            return EventSystem.current.IsPointerOverGameObject();
        }

        /// <summary>
        /// 건설 모드 활성화 상태 확인
        /// </summary>
        public bool IsBuildModeActive()
        {
            return isBuildModeActive;
        }
    }
}