using System.CommandLine;
using System.Diagnostics;
using System.Text.Json;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Hosting;

namespace ThingHK;

/// <summary>
/// ThingHK 入口。
///
/// 子命令：
///   serve  (默认) 启动 HTTP 服务，暴露 /status /snapshot /stream /config
///   scan           阶段一的覆盖矩阵测试（保留以便复测）
///
/// 默认（无参数）等价于 serve --port 8730 --basic。
/// </summary>
internal static class Program
{
    private const int DefaultPort = 8730;
    private const int DefaultFastMs = 1000;
    private const int DefaultSlowMs = 5000;

    public static async Task<int> Main(string[] args)
    {
        // 无参数 → 默认 serve（最常见用法）
        if (args.Length == 0)
        {
            return await ServeAsync(DefaultPort, basic: true, DefaultFastMs, DefaultSlowMs);
        }

        // serve 子命令
        var serveCmd = new Command("serve", "启动 HTTP 服务");
        var portOpt = new Option<int>("--port", () => DefaultPort, "监听端口");
        var basicOpt = new Option<bool>("--basic", "仅启用核心四类硬件，降低冷启动耗时");
        var fullOpt = new Option<bool>("--full", "启用全部硬件（含主板/控制器/网络等）");
        var fastOpt = new Option<int>("--fast-ms", () => DefaultFastMs, "快通道采样间隔（毫秒）");
        var slowOpt = new Option<int>("--slow-ms", () => DefaultSlowMs, "慢通道采样间隔（毫秒）");
        serveCmd.AddOption(portOpt);
        serveCmd.AddOption(basicOpt);
        serveCmd.AddOption(fullOpt);
        serveCmd.AddOption(fastOpt);
        serveCmd.AddOption(slowOpt);
        serveCmd.SetHandler((port, basic, full, fast, slow) =>
            ServeAsync(port, basic || !full, fast, slow),
            portOpt, basicOpt, fullOpt, fastOpt, slowOpt);

        // scan 子命令（阶段一覆盖矩阵测试，保留）
        var scanCmd = new Command("scan", "扫描一次并输出覆盖矩阵（阶段一验证用）");
        var scanJsonOpt = new Option<bool>("--json", "JSON 输出");
        var scanBasicOpt = new Option<bool>("--basic", "仅核心四类硬件");
        scanCmd.AddOption(scanJsonOpt);
        scanCmd.AddOption(scanBasicOpt);
        scanCmd.SetHandler((json, basic) => ScanAsync(json, basic), scanJsonOpt, scanBasicOpt);

        var root = new RootCommand("ThingHardwareKernel - Thing 硬件监控内核");
        root.Add(serveCmd);
        root.Add(scanCmd);
        // 兼容阶段一的旧用法：ThingHK.exe --json --basic
        root.SetHandler(() => ServeAsync(DefaultPort, basic: true, DefaultFastMs, DefaultSlowMs));

        return await root.InvokeAsync(args);
    }

    private static async Task<int> ServeAsync(int port, bool basic, int fastMs, int slowMs)
    {
        Console.Error.WriteLine($"[ThingHK] serve 模式: port={port} basic={basic} fast={fastMs}ms slow={slowMs}ms");

        using var kernel = new KernelHost();
        await kernel.StartAsync(basic, fastMs, slowMs);

        var builder = WebApplication.CreateBuilder();
        builder.WebHost.UseUrls($"http://127.0.0.1:{port}/");

        // 抑制 Kestrel 默认日志噪音
        builder.Logging.ClearProviders();
        builder.Logging.AddProvider(new StderrLoggerProvider());

        var app = builder.Build();
        app.MapThingHKEndpoints(kernel);

        // Ctrl+C 优雅关闭
        var cts = new CancellationTokenSource();
        Console.CancelKeyPress += (_, e) => { e.Cancel = true; cts.Cancel(); };
        AppDomain.CurrentDomain.ProcessExit += (_, _) => cts.Cancel();

        Console.Error.WriteLine($"[ThingHK] HTTP 服务监听: http://127.0.0.1:{port}/");
        Console.Error.WriteLine("[ThingHK] 路由: GET / GET /status GET /snapshot GET /stream POST /config");

        try
        {
            await app.RunAsync(cts.Token);
        }
        catch (TaskCanceledException) { /* 正常关闭 */ }
        Console.Error.WriteLine("[ThingHK] 已退出");
        return 0;
    }

    /// <summary>
    /// 阶段一覆盖矩阵测试入口（保留）。
    /// </summary>
    private static async Task<int> ScanAsync(bool json, bool basic)
    {
        Console.Error.WriteLine($"[ThingHK] scan 模式: json={json} basic={basic}");
        using var hw = new HardwareManager(basic);

        // 第二轮 Update：部分传感器首轮才初始化
        hw.UpdateAll();
        var snap = hw.BuildSnapshot();

        if (json)
        {
            // 阶段一 Report 字段已合并进 SensorSnapshot，复用 ColdStartMs
            Console.WriteLine(JsonSerializer.Serialize(snap, ThingHKJsonContext.Default.SensorSnapshot));
        }
        else
        {
            PrintText(snap, hw.ColdStartMs, hw.IsAdmin);
        }
        await Task.CompletedTask;
        return snap.Groups.Count == 0 ? 3 : 0;
    }

    private static void PrintText(SensorSnapshot r, double coldStartMs, bool isAdmin)
    {
        Console.WriteLine("==== ThingHK 覆盖矩阵 ====");
        Console.WriteLine($"管理员: {isAdmin} | 冷启动: {coldStartMs:F1} ms | .NET: {Environment.Version}");
        Console.WriteLine($"硬件分组数: {r.Groups.Count}");
        int total = 0, readable = 0;
        foreach (var g in r.Groups)
        {
            Console.WriteLine();
            Console.WriteLine($"[{g.Name}]  ({g.Sensors.Count} 个传感器)");
            foreach (var s in g.Sensors)
            {
                total++;
                string val = s.Value.HasValue ? $"{s.Value.Value:F2}{(string.IsNullOrEmpty(s.Unit) ? "" : " " + s.Unit)}" : "N/A";
                if (s.Value.HasValue) readable++;
                Console.WriteLine($"  - {s.Name,-32} {s.Type,-14} {val}");
            }
        }
        Console.WriteLine();
        Console.WriteLine($"==== 汇总: {readable}/{total} 个传感器有值 ====");
    }
}

/// <summary>
/// 把 ASP.NET Core 日志重定向到 stderr，避免污染 stdout（stdout 留给 /snapshot 等 JSON 响应）。
/// </summary>
internal sealed class StderrLoggerProvider : ILoggerProvider
{
    public ILogger CreateLogger(string categoryName) => new StderrLogger();
    public void Dispose() { }

    private sealed class StderrLogger : ILogger
    {
        public IDisposable BeginScope<TState>(TState state) where TState : notnull => NullScope.Instance;
        public bool IsEnabled(LogLevel logLevel) => logLevel >= LogLevel.Warning;
        public void Log<TState>(LogLevel level, EventId id, TState state, Exception? ex, Func<TState, Exception?, string> formatter)
        {
            if (!IsEnabled(level)) return;
            Console.Error.WriteLine($"[kestrel] {formatter(state, ex)}");
        }
    }

    private sealed class NullScope : IDisposable
    {
        public static NullScope Instance { get; } = new();
        public void Dispose() { }
    }
}