using System.Reflection;
using NewLife.Studio.Core;
using NewLife.Log;

namespace NewLife.Studio.App.Services;

/// <summary>模块加载器 — 扫描已加载 Assembly 中实现 IStudioModule 的类型</summary>
public class ModuleLoader
{
    private readonly List<ModuleInfo> _modules = [];
    private ModuleInfo? _activeModule;

    public IReadOnlyList<ModuleInfo> Modules => _modules.AsReadOnly();
    public ModuleInfo? ActiveModule => _activeModule;

    public event EventHandler<ModuleInfo>? ModuleActivated;

    /// <summary>扫描所有已加载的 Assembly 中实现 IStudioModule 的类型</summary>
    public void ScanModules()
    {
        _modules.Clear();

        foreach (var assembly in AppDomain.CurrentDomain.GetAssemblies())
        {
            foreach (var type in assembly.GetTypes())
            {
                if (type.IsAbstract || type.IsInterface)
                    continue;
                if (!typeof(IStudioModule).IsAssignableFrom(type))
                    continue;

                try
                {
                    if (Activator.CreateInstance(type) is IStudioModule module)
                    {
                        _modules.Add(new ModuleInfo
                        {
                            Id = module.Id,
                            DisplayName = module.DisplayName,
                            Icon = module.Icon,
                            Order = module.Order,
                            Module = module
                        });
                        XTrace.WriteLine($"ModuleLoader: Found module [{module.Id}] {module.DisplayName} in {type.FullName}");
                    }
                }
                catch (Exception ex)
                {
                    XTrace.WriteLine($"ModuleLoader: Failed to load module {type.FullName}: {ex.Message}");
                }
            }
        }

        _modules.Sort((a, b) => a.Order.CompareTo(b.Order));
        XTrace.WriteLine($"ModuleLoader: Loaded {_modules.Count} modules");
    }

    /// <summary>激活默认模块（第一个）</summary>
    public async Task ActivateDefaultAsync(CancellationToken ct = default)
    {
        if (_modules.Count > 0)
        {
            await ActivateModuleAsync(_modules[0], ct);
        }
    }

    /// <summary>切换到指定模块</summary>
    public async Task ActivateModuleAsync(ModuleInfo moduleInfo, CancellationToken ct = default)
    {
        if (_activeModule == moduleInfo)
            return;

        if (_activeModule != null)
        {
            await _activeModule.Module.OnDeactivateAsync(ct);
        }

        _activeModule = moduleInfo;
        await moduleInfo.Module.OnActivateAsync(ct);

        ModuleActivated?.Invoke(this, moduleInfo);
        XTrace.WriteLine($"ModuleLoader: Activated module [{moduleInfo.Id}]");
    }
}