using System.Reflection;
using Serilog;

namespace YZWater.Core.Services;

/// <summary>
/// 在线升级服务（借鉴 AutoFMA UpdateService，委托注入模式）
///
/// 设计原则：
///   1. Core 层只负责版本管理和更新触发，不依赖具体 UI 框架
///   2. 实际的更新检查/下载/安装逻辑由 UI 层通过 SetTriggerAction 注入
///   3. config.json 配置 Update.Enabled / CheckOnStartup / CheckIntervalHours
///
/// Avalonia 无 AutoUpdater.NET 官方支持，UI 层可接入 Squirrel 或自研下载器后注入。
/// </summary>
public static class UpdateService
{
    private static DateTime? _lastCheckTime;
    private static Action? _triggerAction;
    private static System.Threading.Timer? _checkTimer;

    /// <summary>
    /// 更新配置
    /// </summary>
    public class UpdateConfig
    {
        /// <summary>是否启用在线更新</summary>
        public bool Enabled { get; set; }

        /// <summary>更新清单地址（appcast URL）</summary>
        public string AppcastUrl { get; set; } = string.Empty;

        /// <summary>启动时是否检查更新</summary>
        public bool CheckOnStartup { get; set; } = true;

        /// <summary>检查间隔（小时，默认 24）</summary>
        public int CheckIntervalHours { get; set; } = 24;
    }

    /// <summary>
    /// 当前程序版本（Major.Minor.Build）
    /// </summary>
    public static string GetCurrentVersion()
    {
        var version = Assembly.GetEntryAssembly()?.GetName().Version;
        return version != null ? $"{version.Major}.{version.Minor}.{version.Build}" : "0.0.0";
    }

    /// <summary>上次检查时间</summary>
    public static DateTime? LastCheckTime => _lastCheckTime;

    /// <summary>更新触发器是否已注入</summary>
    public static bool IsTriggerRegistered => _triggerAction != null;

    /// <summary>
    /// 注入实际更新触发逻辑（由 UI 层调用，如 Squirrel 下载安装流程）
    /// </summary>
    public static void SetTriggerAction(Action triggerAction)
    {
        _triggerAction = triggerAction;
        Log.Information("在线更新触发器已注入");
    }

    /// <summary>
    /// 触发在线更新
    /// </summary>
    public static bool TriggerUpdate()
    {
        if (_triggerAction == null)
        {
            Log.Warning("更新触发器未注入，无法执行在线更新");
            return false;
        }

        Log.Information("触发在线更新，当前版本: {Version}", GetCurrentVersion());
        _lastCheckTime = DateTime.Now;
        try
        {
            _triggerAction();
            return true;
        }
        catch (Exception ex)
        {
            Log.Error(ex, "触发在线更新失败");
            return false;
        }
    }

    /// <summary>
    /// 启动定期检查（启动时检查一次 + 按 CheckIntervalHours 定时）
    /// </summary>
    public static void StartPeriodicCheck(Action onCheckDue)
    {
        var config = ConfigService.GetConfig()?.Update;
        if (config is not { Enabled: true })
        {
            Log.Debug("在线更新未启用，跳过定期检查");
            return;
        }

        var interval = TimeSpan.FromHours(Math.Max(1, config.CheckIntervalHours));

        // 启动时检查一次
        if (config.CheckOnStartup)
        {
            Task.Run(() =>
            {
                try
                {
                    _lastCheckTime = DateTime.Now;
                    onCheckDue();
                }
                catch (Exception ex)
                {
                    Log.Error(ex, "启动时检查更新失败");
                }
            });
        }

        // 定时检查
        _checkTimer ??= new System.Threading.Timer(_ =>
        {
            try
            {
                _lastCheckTime = DateTime.Now;
                onCheckDue();
            }
            catch (Exception ex)
            {
                Log.Error(ex, "定时检查更新失败");
            }
        }, null, interval, interval);

        Log.Information("在线更新定期检查已启动，间隔 {Hours} 小时", config.CheckIntervalHours);
    }

    /// <summary>
    /// 停止定期检查
    /// </summary>
    public static void StopPeriodicCheck()
    {
        _checkTimer?.Dispose();
        _checkTimer = null;
    }
}