using ReactiveUI;
using Splat;
using System;
using System.Diagnostics;
using System.Linq;
using Microsoft.Extensions.DependencyInjection;

namespace AuroraDesk.Views;

/// <summary>
/// 视图定位器，用于将 ViewModel 映射到对应的 View
/// 支持依赖注入创建 View 实例
/// </summary>
public class ViewLocator : IViewLocator
{
    /// <summary>
    /// 根据 ViewModel 类型解析对应的 View
    /// </summary>
    public IViewFor? ResolveView<T>(T? viewModel, string? contract = null)
    {
        if (viewModel == null)
        {
            Debug.WriteLine("[ViewLocator] ViewModel is null");
            return null;
        }

        var viewModelType = viewModel.GetType();
        Debug.WriteLine($"[ViewLocator] Resolving View for ViewModel: {viewModelType.FullName}");
        
        // 将 ViewModel 名称转换为 View 名称
        var viewModelName = viewModelType.Name; // 只获取类名
        
        // 处理多种命名模式
        var viewName = viewModelName
            .Replace("PageViewModel", "PageView")
            .Replace("ViewModel", "View");
        
        Debug.WriteLine($"[ViewLocator] Looking for View: {viewName}");
        Debug.WriteLine($"[ViewLocator] ViewModel Namespace: {viewModelType.Namespace}");
        
        // 获取与 ViewModel 在同一命名空间下的 View
        var assembly = viewModelType.Assembly;
        var targetNamespace = viewModelType.Namespace?.Replace(".ViewModels", ".Views");
        Debug.WriteLine($"[ViewLocator] Target namespace: {targetNamespace}");
        
        var viewType = assembly.GetTypes()
            .FirstOrDefault(t => t.Name == viewName && t.Namespace == targetNamespace);

        if (viewType == null)
        {
            Debug.WriteLine($"[ViewLocator] View not found: {viewName} in {targetNamespace}");
            return null;
        }

        Debug.WriteLine($"[ViewLocator] Found View: {viewType.FullName}");
        
        IViewFor? view = null;
        
        // 尝试从依赖注入容器获取 View 实例
        try
        {
            var serviceProvider = Locator.Current.GetService<IServiceProvider>();
            if (serviceProvider != null)
            {
                view = serviceProvider.GetService(viewType) as IViewFor;
                if (view != null)
                {
                    Debug.WriteLine($"[ViewLocator] Created View from DI: {view.GetType().FullName}");
                }
            }
        }
        catch (Exception ex)
        {
            Debug.WriteLine($"[ViewLocator] Failed to get View from DI: {ex.Message}");
        }
        
        // 如果 DI 中没有，使用 Activator 创建
        if (view == null)
        {
            try
            {
                view = Activator.CreateInstance(viewType) as IViewFor;
                if (view != null)
                {
                    Debug.WriteLine($"[ViewLocator] Created View with Activator: {view.GetType().FullName}");
                }
            }
            catch (Exception ex)
            {
                Debug.WriteLine($"[ViewLocator] Failed to create View with Activator: {ex.Message}");
            }
        }
        
        if (view == null)
        {
            Debug.WriteLine("[ViewLocator] Failed to create View instance");
        }
        
        return view;
    }
}