using Serilog;

namespace YZWater.Core.Services;

/// <summary>
/// 数据库备份服务
/// </summary>
public static class BackupService
{
    private static readonly string BackupDir = "Backups";

    /// <summary>
    /// 创建数据库备份
    /// </summary>
    public static async Task<(bool Success, string Path)> BackupAsync()
    {
        try
        {
            Directory.CreateDirectory(BackupDir);

            var timestamp = DateTime.Now.ToString("yyyyMMdd_HHmmss");
            var backupPath = Path.Combine(BackupDir, $"yzwater_backup_{timestamp}.db");

            // SQLite 备份：复制数据库文件
            var sourcePath = "yzwater.db";
            if (!File.Exists(sourcePath))
            {
                Log.Warning("数据库文件不存在: {Path}", sourcePath);
                return (false, string.Empty);
            }

            // 使用 SqlSugar 的备份功能
            var db = DatabaseService.Db;
            await Task.Run(() =>
            {
                File.Copy(sourcePath, backupPath, true);
            });

            Log.Information("数据库备份成功: {Path}", backupPath);
            AuditService.Log("系统", "Backup", $"数据库备份: {backupPath}");
            return (true, backupPath);
        }
        catch (Exception ex)
        {
            Log.Error(ex, "数据库备份失败");
            return (false, string.Empty);
        }
    }

    /// <summary>
    /// 恢复数据库
    /// </summary>
    public static async Task<bool> RestoreAsync(string backupPath)
    {
        try
        {
            if (!File.Exists(backupPath))
            {
                Log.Warning("备份文件不存在: {Path}", backupPath);
                return false;
            }

            var targetPath = "yzwater.db";

            // 先备份当前数据库
            var preRestoreBackup = Path.Combine(BackupDir, $"yzwater_pre_restore_{DateTime.Now:yyyyMMdd_HHmmss}.db");
            if (File.Exists(targetPath))
            {
                File.Copy(targetPath, preRestoreBackup, true);
            }

            await Task.Run(() =>
            {
                File.Copy(backupPath, targetPath, true);
            });

            Log.Information("数据库恢复成功，恢复前备份: {Path}", preRestoreBackup);
            AuditService.Log("系统", "Restore", $"数据库恢复: {backupPath}，恢复前备份: {preRestoreBackup}");
            return true;
        }
        catch (Exception ex)
        {
            Log.Error(ex, "数据库恢复失败");
            return false;
        }
    }

    /// <summary>
    /// 获取备份列表
    /// </summary>
    public static List<(string Path, DateTime Time, long Size)> GetBackups()
    {
        if (!Directory.Exists(BackupDir))
            return new List<(string, DateTime, long)>();

        return Directory.GetFiles(BackupDir, "*.db")
            .Select(f => new FileInfo(f))
            .OrderByDescending(f => f.CreationTime)
            .Select(f => (f.FullName, f.CreationTime, f.Length))
            .ToList();
    }

    /// <summary>
    /// 清理旧备份（保留最近 N 个）
    /// </summary>
    public static int CleanupOldBackups(int keepCount = 10)
    {
        if (!Directory.Exists(BackupDir))
            return 0;

        var backups = Directory.GetFiles(BackupDir, "*.db")
            .Select(f => new FileInfo(f))
            .OrderByDescending(f => f.CreationTime)
            .Skip(keepCount)
            .ToList();

        foreach (var backup in backups)
        {
            try
            {
                backup.Delete();
                Log.Debug("已删除旧备份: {Path}", backup.FullName);
            }
            catch (Exception ex)
            {
                Log.Warning(ex, "删除旧备份失败: {Path}", backup.FullName);
            }
        }

        if (backups.Count > 0)
            Log.Information("已清理 {Count} 个旧备份", backups.Count);

        return backups.Count;
    }
}