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

/// <summary>
/// 新营地建造Demo
/// </summary>
public class NewCampBuildDemo : MonoBehaviour
{
    /// <summary>
    /// 状态
    /// </summary>
    private enum E_State
    {
        None,
        /// <summary>
        /// 拖动状态
        /// </summary>
        Drag,
        /// <summary>
        /// 停止状态
        /// </summary>
        Stop,
    }

    /// <summary>
    /// 网格系统
    /// </summary>
    [SerializeField]
    private TerrainGridSystem gridSystem;
    /// <summary>
    /// 测试建筑
    /// </summary>
    [SerializeField]
    private Transform tsGo;

    /// <summary>
    /// 格子状态字典
    /// </summary>
    private Dictionary<Vector2Int, E_GridState> dicGridState;
    /// <summary>
    /// 记录所有格子字典
    /// </summary>
    private Dictionary<Vector2Int, Cell> dicAllGrid;
    /// <summary>
    /// 格子拖动状态编辑
    /// </summary>
    private HashSet<Cell> setGridDragEdit;
    /// <summary>
    /// 测试建筑物
    /// </summary>
    private Building building;
    /// <summary>
    /// 射线检测点列表
    /// </summary>
    private RaycastHit[] hits;
    /// <summary>
    /// 当前状态
    /// </summary>
    private E_State state;

    private void Awake()
    {
        setGridDragEdit = new HashSet<Cell>();
        dicAllGrid = new Dictionary<Vector2Int, Cell>();
        dicGridState = new Dictionary<Vector2Int, E_GridState>();
        foreach (Cell cell in gridSystem.cells)
        {
            Vector2Int vector2Int = new(cell.row, cell.column);
            dicAllGrid[vector2Int] = cell;
            dicGridState[vector2Int] = E_GridState.Empty;
        }

        building = new Building(tsGo.gameObject, Vector2Int.zero, Vector2Int.up);
        gridSystem.allowHighlightWhileDragging = true;
        hits = new RaycastHit[1];
        state = E_State.None;
    }

    private void Update()
    {
        UpdateInput();

        if (state == E_State.Drag)
        {
            ClearDragCell(); // 还原拖动的格子

            Vector2 mousePos = Mouse.current.position.ReadValue();
            // 发射射线
            Ray ray = Camera.main.ScreenPointToRay(mousePos);
            int hitNum = Physics.RaycastNonAlloc(ray.origin, ray.direction, hits);
            if (hitNum > 0)
            {
                RaycastHit firstHit = hits[0];
                Cell centerCell = gridSystem.CellGetAtPosition(firstHit.point, true); // 中心点
                if (null != centerCell)
                {
                    foreach (Vector2Int offset in building.GridOffsets)
                    {
                        Vector2Int newPos = new Vector2Int(centerCell.row, centerCell.column) + offset;
                        if (dicAllGrid.TryGetValue(newPos, out Cell cell))
                        {
                            setGridDragEdit.Add(cell);
                            gridSystem.CellSetColor(cell, Color.green); // 绿色
                            Vector3 pos = gridSystem.CellGetPosition(cell);
                            if (Vector2Int.zero == offset)
                                tsGo.position = new Vector3(pos.x, tsGo.position.y, pos.z);
                        }
                    }
                }
            }
        }

        if (state == E_State.Drag && Input.GetMouseButtonDown(0))
        {
            Build();
        }
    }

    private void UpdateInput()
    {
        if (Input.GetKeyDown(KeyCode.Alpha1))
        {
            gridSystem.showCells = false;
            gridSystem.showTerritories = false;
            gridSystem.showTerritoriesInteriorBorders = false;
            gridSystem.HideAll();
        }

        if (Input.GetKeyDown(KeyCode.Alpha2))
        {
            gridSystem.showCells = true;
            gridSystem.showTerritories = true;
            gridSystem.showTerritoriesInteriorBorders = true;
            gridSystem.ShowAll();
        }

        if (Input.GetKeyDown(KeyCode.Alpha3))
        {
            state = E_State.Drag;
            Debug.Log("进入拖动状态");
        }

        if (Input.GetKeyDown(KeyCode.Alpha4))
        {
            state = E_State.None;
            Debug.Log("进入普通状态");
        }
    }

    /// <summary>
    /// 清除拖动的格子
    /// </summary>
    private void ClearDragCell()
    {
        foreach (Cell cell in setGridDragEdit)
        {
            if (dicGridState.TryGetValue(new Vector2Int(cell.row, cell.column), out E_GridState cellState))
                SetCellState(cell, cellState);
        }

        setGridDragEdit.Clear();
    }

    /// <summary>
    /// 校验是否可以放置
    /// </summary>
    /// <returns></returns>
    private bool CheckBuild(Cell centerCell, Vector2Int[] offsets, out List<Cell> listCell)
    {
        listCell = new List<Cell>();

        if (null == centerCell)
            return false;

        foreach (Vector2Int offset in offsets)
        {
            Vector2Int newPos = new Vector2Int(centerCell.row, centerCell.column) + offset;
            if (!dicGridState.TryGetValue(newPos, out E_GridState gridState))
                return false;

            if (E_GridState.Using == gridState)
                return false;

            if(dicAllGrid.TryGetValue(newPos,out Cell cell))
                listCell.Add(cell);
        }

        return true;
    }

    /// <summary>
    /// 建造
    /// </summary>
    private void Build()
    {
        // 左键按下
        Vector2 mousePos = Mouse.current.position.ReadValue();
        // 发射射线
        Ray ray = Camera.main.ScreenPointToRay(mousePos);
        int hitNum = Physics.RaycastNonAlloc(ray.origin, ray.direction, hits);
        if (hitNum <= 0)
            return;

        RaycastHit firstHit = hits[0];
        Cell centerCell = gridSystem.CellGetAtPosition(firstHit.point, true); // 中心点
        if (!CheckBuild(centerCell, building.GridOffsets, out List<Cell> listCell))
        {
            Debug.LogError("该位置不能放置");
            return;
        }

        foreach (Cell cell in listCell)
        {
            SetCellState(cell, E_GridState.Using);
        }

        setGridDragEdit.Clear();

        state = E_State.None;
    }

    /// <summary>
    /// 设置格子状态
    /// </summary>
    private void SetCellState(Cell cell, E_GridState gridState)
    {
        dicGridState[new Vector2Int(cell.row, cell.column)] = gridState;
        switch (gridState)
        {
            case E_GridState.Empty:
                {
                    gridSystem.CellSetColor(cell, new Color(0f, 0f, 0f, 0f)); // 透明
                }
                break;
            case E_GridState.Drag:
                {
                    gridSystem.CellSetColor(cell, Color.green); // 绿色
                }
                break;
            case E_GridState.DragNot:
                {
                    gridSystem.CellSetColor(cell, Color.red); // 红色
                }
                break;
            case E_GridState.Using:
                {
                    gridSystem.CellSetColor(cell, Color.blue); // 蓝色
                }
                break;
        }
    }
}

/// <summary>
/// 建筑物
/// </summary>
public class Building
{
    /// <summary>
    /// 格子偏移
    /// </summary>
    public Vector2Int[] GridOffsets;
    public GameObject Go;
    /// <summary>
    /// 格子索引
    /// </summary>
    public int CellIndex = -1;

    public Building(GameObject go, params Vector2Int[] gridOffsets)
    {
        GridOffsets = gridOffsets;
        Go = go;
    }
}

/// <summary>
/// 格子状态
/// </summary>
public enum E_GridState
{
    /// <summary>
    /// 空
    /// </summary>
    Empty,
    /// <summary>
    /// 拖动可用
    /// </summary>
    Drag,
    /// <summary>
    /// 拖动不可用
    /// </summary>
    DragNot,
    /// <summary>
    /// 已经使用
    /// </summary>
    Using,
}