using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Hosting;

namespace MAX.Plugins;

/// <summary>插件独立配置，不合并宿主或其他插件配置。</summary>
public sealed class PluginContext : IDisposable
{
    private int disposed;
    public string Id { get; }
    public string DirectoryPath { get; }
    public IHostEnvironment Environment { get; }
    public IConfigurationRoot Configuration { get; }

    public PluginContext(string id, string directoryPath, IHostEnvironment environment)
    {
        ArgumentException.ThrowIfNullOrWhiteSpace(id);
        ArgumentNullException.ThrowIfNull(environment);
        Id = id;
        DirectoryPath = Path.GetFullPath(directoryPath);
        Environment = environment;
        Configuration = new ConfigurationBuilder()
            .SetBasePath(DirectoryPath)
            .AddJsonFile("appsettings.json", optional: false, reloadOnChange: false)
            .AddJsonFile($"appsettings.{environment.EnvironmentName}.json", optional: true, reloadOnChange: false)
            .AddEnvironmentVariables($"Plugins__{id}__")
            .Build();
    }

    public string RequireConfiguration(string key) =>
        !string.IsNullOrWhiteSpace(Configuration[key]) ? Configuration[key]!
            : throw new InvalidOperationException($"插件 {Id} 缺少配置 {key}，请检查 {Path.Combine(DirectoryPath, "appsettings.json")}。");

    public void Dispose()
    {
        if (Interlocked.Exchange(ref disposed, 1) == 0)
            (Configuration as IDisposable)?.Dispose();
    }
}


/// <summary>按插件类型注入的上下文视图，配置及其生命周期由宿主的 PluginContext 统一管理。</summary>
public sealed class PluginContext<TPlugin>(PluginContext context) where TPlugin : IPlugin
{
	/// <summary>插件唯一标识。</summary>
	public string Id => context.Id;
	/// <summary>插件程序集和配置所在目录。</summary>
	public string DirectoryPath => context.DirectoryPath;
	/// <summary>当前宿主环境。</summary>
	public IHostEnvironment Environment => context.Environment;
	/// <summary>与插件入口共享的独立配置实例。</summary>
	public IConfigurationRoot Configuration => context.Configuration;

	/// <summary>读取必填配置，缺失时沿用插件上下文的错误说明。</summary>
	public string RequireConfiguration(string key) => context.RequireConfiguration(key);
}