using System.Collections.Generic;
using Logging;
using Map;
using UnityEngine;
using Utils;

/// <summary>
/// Program 类作为单例模式的核心管理器，负责维护和管理游戏或应用中的维度(Dimension)实例和焦点状态。
/// 它提供了维度注册、注销、获取以及焦点维度设置的功能。
/// </summary>
public class Program : Singleton<Program>
{
    /// <summary>
    /// 指示是否需要加载数据的标志，例如在游戏启动或场景切换时。
    /// </summary>
    public bool needLoad = true;

    /// <summary>
    /// 当前聚焦的实体对象，可能为空。
    /// </summary>
    public Entity.Entity focusedEntity = null;

    /// <summary>
    /// 当前活跃焦点的维度唯一标识符，可能为空。
    /// </summary>
    public string focuseDimensionId = null; 

    /// <summary>
    /// 当前聚焦的维度对象实例。当 <see cref="focuseDimensionId"/> 不为空时，此属性指向对应的维度实例。
    /// </summary>
    public Dimension FocusedDimension { get; private set; } 

    /// <summary>
    /// 维护所有已注册的维度实例的字典，键是维度的唯一标识符 (ID)。
    /// </summary>
    private readonly Dictionary<string, Dimension> _registeredDimensions = new Dictionary<string, Dimension>();

    /// <summary>
    /// 获取所有已注册的维度。返回一个只读字典副本，防止外部直接修改。
    /// </summary>
    public IReadOnlyDictionary<string, Dimension> RegisteredDimensions => _registeredDimensions;

    /// <summary>
    /// 注册一个维度实例到 Program。
    /// </summary>
    /// <param name="dimension">要注册的维度实例。</param>
    public void RegisterDimension(Dimension dimension)
    {
        if (dimension == null)
        {
            Debug.LogError("[Program] Attempted to register a null Dimension.");
            return;
        }
        string id = dimension.DimensionId;
        if (string.IsNullOrEmpty(id))
        {
            Debug.LogError($"[Program] Attempted to register a Dimension with an empty or null ID: {dimension.name}");
            return;
        }
        if (_registeredDimensions.ContainsKey(id))
        {
            Debug.LogWarning($"[Program] Dimension with ID '{id}' is already registered. Skipping duplicate registration for {dimension.name}.");
            return;
        }
        _registeredDimensions.Add(id, dimension);
        
        // 如果注册的维度是当前焦点维度，则更新 FocusedDimension 属性
        if (focuseDimensionId == id)
        {
            FocusedDimension = dimension;
        }
    }

    /// <summary>
    /// 从 Program 注销一个维度实例。
    /// </summary>
    /// <param name="dimension">要注销的维度实例。</param>
    public void UnregisterDimension(Dimension dimension)
    {
        if (dimension == null)
        {
            Debug.LogWarning("[Program] Attempted to unregister a null Dimension. Skipping.");
            return;
        }
        string id = dimension.DimensionId;
        if (_registeredDimensions.Remove(id))
        {
            // 如果注销的维度是当前焦点维度，则清除焦点
            if (focuseDimensionId == id)
            {
                focuseDimensionId = null;
                FocusedDimension = null;
            }
        }
        else
        {
            Debug.LogWarning($"[Program] Attempted to unregister Dimension '{id}' which was not found in the registered list.");
        }
    }

    /// <summary>
    /// 根据ID获取一个已注册的维度。
    /// </summary>
    /// <param name="dimensionId">维度的唯一标识符。</param>
    /// <returns>对应的Dimension实例，如果未找到则返回null。</returns>
    public Dimension GetDimension(string dimensionId)
    {
        _registeredDimensions.TryGetValue(dimensionId, out Dimension dimension);
        return dimension;
    }

    /// <summary>
    /// 设置当前聚焦的维度。
    /// </summary>
    /// <param name="dimensionId">要设置为焦点的维度的唯一标识符。如果传入null或空字符串，将清除当前焦点维度。</param>
    public void SetFocusedDimension(string dimensionId)
    {
        if (string.IsNullOrEmpty(dimensionId))
        {
            focuseDimensionId = null;
            FocusedDimension = null;
            return;
        }
        if (_registeredDimensions.TryGetValue(dimensionId, out Dimension newFocusedDimension))
        {
            focuseDimensionId = dimensionId;
            FocusedDimension = newFocusedDimension;
        }
        else
        {
            Debug.LogWarning($"[Program] Attempted to set focus to unregistered dimension ID: '{dimensionId}'. Focus not changed.");
        }
    }
}