using System.IO.Compression;
using System.Text;

namespace Admin.NET.Plugin.AiDOP.DataPlatform.FileImport;

public static class MdpFileImportSecurity
{
    public const long MaxBytes = 20 * 1024 * 1024;
    public const int MaxRows = 50000;
    public const int MaxColumns = 80;
    public const int MaxCellChars = 2000;

    public static void EnsureXlsx(string fileName, long length, Stream stream)
    {
        if (length <= 0)
            throw new InvalidOperationException("空文件");
        if (length > MaxBytes)
            throw new InvalidOperationException("文件超过 20MB");
        var ext = Path.GetExtension(fileName);
        if (!string.Equals(ext, ".xlsx", StringComparison.OrdinalIgnoreCase))
            throw new InvalidOperationException("仅支持 .xlsx");
        if (fileName.EndsWith(".xlsm", StringComparison.OrdinalIgnoreCase) || fileName.Contains(".."))
            throw new InvalidOperationException("不允许宏文件或路径穿越");

        Span<byte> header = stackalloc byte[4];
        var read = stream.Read(header);
        if (stream.CanSeek) stream.Position = 0;
        if (read < 4 || header[0] != (byte)'P' || header[1] != (byte)'K')
            throw new InvalidOperationException("不是合法 xlsx（ZIP）文件");

        if (stream.CanSeek)
        {
            using var zip = new ZipArchive(stream, ZipArchiveMode.Read, leaveOpen: true, Encoding.UTF8);
            if (zip.Entries.Any(e => e.FullName.Contains("vbaProject", StringComparison.OrdinalIgnoreCase)
                                     || e.FullName.Contains("externalLink", StringComparison.OrdinalIgnoreCase)))
                throw new InvalidOperationException("拒绝含宏或外部链接的工作簿");
            stream.Position = 0;
        }
    }

    public static void EnsureCell(string? value)
    {
        if (value != null && value.Length > MaxCellChars)
            throw new InvalidOperationException($"单元格超过 {MaxCellChars} 字符");
        if (value != null && value.StartsWith('='))
            throw new InvalidOperationException("不允许公式单元格");
    }

    public static void StripClientTenant(IDictionary<string, object?> row)
    {
        var keys = row.Keys.Where(k => k.Equals("tenant_id", StringComparison.OrdinalIgnoreCase)
                                       || k.Equals("TenantId", StringComparison.OrdinalIgnoreCase)).ToList();
        foreach (var k in keys)
            row.Remove(k);
    }
}