using UnityEngine;
using UnityEngine.InputSystem;
using System.Collections.Generic;

public class SelectionManager : MonoBehaviour
{
    [Header("Selection Settings")]
    public LayerMask selectableLayerMask = -1;
    public Material ghostMaterial;

    private Villager selectedVillager;
    private GameObject selectedObject;
    private Camera playerCamera;

    // Drag and Drop
    private bool isDragging = false;
    private GameObject dragGhost;
    private Vector3 dragStartPosition;

    // Box Selection
    private bool isBoxSelecting = false;
    private Vector2 boxSelectionStart;

    public Villager SelectedVillager => selectedVillager;
    public GameObject SelectedObject => selectedObject;

    // Event for selection changes
    public delegate void SelectionChangedHandler();
    public static event SelectionChangedHandler OnSelectionChanged;

    void Start()
    {
        playerCamera = Camera.main;
        if (playerCamera == null)
            playerCamera = FindObjectOfType<Camera>();
    }

    void Update()
    {
        HandleInput();
        HandleDragAndDrop();
    }

    void HandleInput()
    {
        // Left click - selection or box selection start
        var mouse = Mouse.current;
        if (mouse.leftButton.wasPressedThisFrame)
        {
            // Start potential box selection
            boxSelectionStart = mouse.position.ReadValue();
            isBoxSelecting = false; // Not yet, wait for drag
        }

        // Check if dragging for box selection (only when no villager is selected)
        if (mouse.leftButton.isPressed && !isDragging && selectedVillager == null)
        {
            Vector2 currentMousePos = mouse.position.ReadValue();
            float dragDistance = Vector2.Distance(boxSelectionStart, currentMousePos);

            // Start box selection if dragged more than 10 pixels
            if (dragDistance > 10f && !isBoxSelecting)
            {
                isBoxSelecting = true;
                Debug.Log("Started box selection");
            }
        }        // Complete box selection on release
        if (mouse.leftButton.wasReleasedThisFrame)
        {
            if (isBoxSelecting)
            {
                CompleteBoxSelection();
                isBoxSelecting = false;
            }
            else if (!isDragging)
            {
                // Single click selection (only if not dragging)
                HandleSelection();
            }
        }

        // Right click - cancel/deselect
        if (mouse.rightButton.wasPressedThisFrame)
        {
            CancelCurrentAction();
        }
    }

    void HandleSelection()
    {
        if (Mouse.current == null || playerCamera == null) return;

        Ray ray = playerCamera.ScreenPointToRay(Mouse.current.position.ReadValue());
        RaycastHit hit;

        if (Physics.Raycast(ray, out hit, Mathf.Infinity, selectableLayerMask))
        {
            GameObject hitObject = hit.collider.gameObject;

            // Check if we hit a villager
            Villager villager = hitObject.GetComponent<Villager>();
            if (villager != null)
            {
                SelectVillager(villager);
                return;
            }

            // Check for other selectable objects
            ISelectable selectable = hitObject.GetComponent<ISelectable>();
            if (selectable != null)
            {
                SelectObject(hitObject);
                return;
            }

            // If we hit something else, check parent objects
            Transform parent = hitObject.transform.parent;
            while (parent != null)
            {
                villager = parent.GetComponent<Villager>();
                if (villager != null)
                {
                    SelectVillager(villager);
                    return;
                }

                selectable = parent.GetComponent<ISelectable>();
                if (selectable != null)
                {
                    SelectObject(parent.gameObject);
                    return;
                }

                parent = parent.parent;
            }
        }

        // If we didn't hit anything selectable, deselect
        DeselectAll();
    }

    void HandleDragAndDrop()
    {
        if (Mouse.current == null) return;

        var mouse = Mouse.current;

        // Don't start dragging if box selecting
        if (isBoxSelecting) return;

        // Start dragging
        if (selectedVillager != null && mouse.leftButton.wasPressedThisFrame && !isDragging)
        {
            StartDrag();
        }

        // Update drag
        if (isDragging)
        {
            UpdateDrag();
        }

        // End dragging
        if (isDragging && mouse.leftButton.wasReleasedThisFrame)
        {
            EndDrag();
        }
    }

    void StartDrag()
    {
        isDragging = true;
        dragStartPosition = selectedVillager.transform.position;

        // Create ghost object
        CreateDragGhost();
    }

    void UpdateDrag()
    {
        if (dragGhost != null)
        {
            // Move ghost to mouse position
            Ray ray = playerCamera.ScreenPointToRay(Mouse.current.position.ReadValue());
            if (Physics.Raycast(ray, out RaycastHit hit))
            {
                dragGhost.transform.position = hit.point + Vector3.up * 0.1f;
            }
        }
    }

    void EndDrag()
    {
        isDragging = false;

        if (dragGhost != null)
        {
            Vector3 dropPosition = dragGhost.transform.position;

            // Check what we're dropping on
            Ray ray = playerCamera.ScreenPointToRay(Mouse.current.position.ReadValue());
            if (Physics.Raycast(ray, out RaycastHit hit))
            {
                HandleDrop(hit.collider.gameObject, dropPosition);
            }

            DestroyDragGhost();
        }
    }

    void CreateDragGhost()
    {
        if (selectedVillager != null)
        {
            dragGhost = Instantiate(selectedVillager.gameObject);

            // Make it a ghost (semi-transparent, no collisions)
            Collider ghostCollider = dragGhost.GetComponent<Collider>();
            if (ghostCollider != null)
                ghostCollider.enabled = false;

            // Remove any scripts that might interfere
            Villager ghostVillager = dragGhost.GetComponent<Villager>();
            if (ghostVillager != null)
                Destroy(ghostVillager);

            // Apply ghost material
            Renderer ghostRenderer = dragGhost.GetComponent<Renderer>();
            if (ghostRenderer != null && ghostMaterial != null)
            {
                ghostRenderer.material = ghostMaterial;
            }
            else if (ghostRenderer != null)
            {
                Color ghostColor = ghostRenderer.material.color;
                ghostColor.a = 0.5f;
                ghostRenderer.material.color = ghostColor;
            }
        }
    }

    void DestroyDragGhost()
    {
        if (dragGhost != null)
        {
            Destroy(dragGhost);
            dragGhost = null;
        }
    }

    void HandleDrop(GameObject dropTarget, Vector3 dropPosition)
    {
        if (selectedVillager == null) return;

        VillagerManager villagerManager = GameManager.Instance.villagerManager;

        // Determine what to do based on drop target
        string targetTag = dropTarget.tag;

        JobType newJob = targetTag switch
        {
            "Tree" => JobType.Woodcutter,
            "Stone" => JobType.Stonecutter,
            "Farm" => JobType.Farmer,
            "TownHall" => JobType.None, // Unemployed - return to town hall
            _ => selectedVillager.currentJob // Keep current job if dropped on something else
        };

        // Special check for Builder job - requires workshop
        if (newJob == JobType.Builder)
        {
            GameObject[] workshops = GameObject.FindGameObjectsWithTag("BuildingWorkshop");
            if (workshops == null || workshops.Length == 0)
            {
                Debug.LogWarning("⚠️ Cannot assign Builder job - No Builder's Workshop found! Build one first.");
                return;
            }
        }

        if (newJob != selectedVillager.currentJob || (newJob != JobType.None && selectedVillager.targetWorkplace != dropTarget))
        {
            // Assign job and specific workplace
            villagerManager.AssignVillagerToSpecificWorkplace(selectedVillager, newJob, dropTarget);
            Debug.Log($"Assigned {selectedVillager.villagerName} to {newJob} at specific {dropTarget.name}");
        }
    }
    public void SelectVillager(Villager villager)
    {
        // Deselect previous
        DeselectAll();

        selectedVillager = villager;
        selectedObject = villager.gameObject;

        villager.SetSelected(true);

        Debug.Log($"SelectionManager: Selected villager: {villager.villagerName}");
        Debug.Log($"SelectionManager: OnVillagerSelected event triggered");

        // Notify UI of selection change
        OnSelectionChanged?.Invoke();
    }

    public void SelectObject(GameObject obj)
    {
        // Deselect previous
        DeselectAll();

        selectedObject = obj;

        ISelectable selectable = obj.GetComponent<ISelectable>();
        selectable?.OnSelected();

        Debug.Log($"Selected object: {obj.name}");

        // Notify UI of selection change
        OnSelectionChanged?.Invoke();
    }

    public void DeselectAll()
    {
        if (selectedVillager != null)
        {
            selectedVillager.SetSelected(false);
            selectedVillager = null;
        }

        if (selectedObject != null)
        {
            ISelectable selectable = selectedObject.GetComponent<ISelectable>();
            selectable?.OnDeselected();
            selectedObject = null;
        }

        // Cancel any ongoing drag
        if (isDragging)
        {
            isDragging = false;
            DestroyDragGhost();
        }

        Debug.Log("SelectionManager: Deselected all");

        // Notify UI of selection change
        OnSelectionChanged?.Invoke();
    }

    void OnGUI()
    {
        if (isBoxSelecting && Mouse.current != null)
        {
            Vector2 mouseStart = boxSelectionStart;
            Vector2 mouseEnd = Mouse.current.position.ReadValue();

            // Convert to GUI coordinates (Y is flipped)
            mouseStart.y = Screen.height - mouseStart.y;
            mouseEnd.y = Screen.height - mouseEnd.y;

            Rect selectionRect = new Rect(
                Mathf.Min(mouseStart.x, mouseEnd.x),
                Mathf.Min(mouseStart.y, mouseEnd.y),
                Mathf.Abs(mouseStart.x - mouseEnd.x),
                Mathf.Abs(mouseStart.y - mouseEnd.y)
            );

            // Draw selection box
            GUI.color = new Color(0.8f, 0.8f, 0.95f, 0.25f);
            GUI.DrawTexture(selectionRect, Texture2D.whiteTexture);
            GUI.color = new Color(0.8f, 0.8f, 0.95f, 1f);
            GUI.Box(selectionRect, "");
        }
    }

    void CompleteBoxSelection()
    {
        Vector2 mouseStart = boxSelectionStart;
        Vector2 mouseEnd = Mouse.current.position.ReadValue();

        // Create screen space rectangle
        Rect selectionRect = new Rect(
            Mathf.Min(mouseStart.x, mouseEnd.x),
            Mathf.Min(mouseStart.y, mouseEnd.y),
            Mathf.Abs(mouseStart.x - mouseEnd.x),
            Mathf.Abs(mouseStart.y - mouseEnd.y)
        );

        // Find all villagers
        Villager[] allVillagers = FindObjectsOfType<Villager>();
        Villager firstVillager = null;

        foreach (Villager villager in allVillagers)
        {
            Vector3 screenPos = playerCamera.WorldToScreenPoint(villager.transform.position);

            // Check if villager is in selection box and in front of camera
            if (screenPos.z > 0 && selectionRect.Contains(new Vector2(screenPos.x, screenPos.y)))
            {
                if (firstVillager == null)
                {
                    firstVillager = villager;
                }
            }
        }

        // Select the first villager found
        if (firstVillager != null)
        {
            SelectVillager(firstVillager);
            Debug.Log($"Box selection completed: selected {firstVillager.villagerName}");
        }
        else
        {
            Debug.Log("Box selection completed: no villagers found");
        }
    }

    void CancelCurrentAction()
    {
        if (isDragging)
        {
            isDragging = false;
            DestroyDragGhost();
        }
        else if (isBoxSelecting)
        {
            isBoxSelecting = false;
        }
        else
        {
            DeselectAll();
        }

        Debug.Log("Cancelled current action");
    }
}

// Interface for selectable objects
public interface ISelectable
{
    void OnSelected();
    void OnDeselected();
}