using System.Data.Common;
using System.Security.Cryptography;
using System.Text;

namespace Admin.NET.Plugin.AiDOP.Service.S8.Rules;

/// <summary>
/// S8-DYNAMIC-SQLSUGAR-SCOPE-FACTORY-1：S8 data_source endpoint 规范化与 hash 派生。
/// 纯字符串变换：
///   1) 用 DbConnectionStringBuilder 解析 raw endpoint 的 key/value（大小写无关）；
///   2) 按 OrdinalIgnoreCase 全部 key lower-case 化，避免不同输入 case 导致 hash 漂移；
///   3) 补齐缺失参数（已有 key 不覆盖），与主库 Database.json 池层参数对齐：
///        AllowPublicKeyRetrieval / Pooling / Minimum Pool Size / Maximum Pool Size /
///        Connection Timeout / Connection Idle Timeout / Connection LifeTime；
///   4) 按 key 字母序输出 normalized canonical connection string；
///   5) 对 normalized 做 SHA256 → 64 字符小写 hex EndpointHash。
/// 不访问数据库、不读写文件、不读 env、不输出连接串原文、不输出密码。
/// 输入为空或空白时抛 ArgumentException，message 不携带 endpoint 原文。
/// </summary>
internal static class S8DataSourceEndpointNormalizer
{
    public const string KeyAllowPublicKeyRetrieval = "allowpublickeyretrieval";
    public const string KeyPooling = "pooling";
    public const string KeyMinimumPoolSize = "minimum pool size";
    public const string KeyMaximumPoolSize = "maximum pool size";
    public const string KeyConnectionTimeout = "connection timeout";
    public const string KeyConnectionIdleTimeout = "connection idle timeout";
    public const string KeyConnectionLifeTime = "connection lifetime";

    private static readonly (string Key, string Value)[] _normalizeDefaults =
    {
        (KeyAllowPublicKeyRetrieval, "True"),
        (KeyPooling, "True"),
        (KeyMinimumPoolSize, "0"),
        (KeyMaximumPoolSize, "20"),
        (KeyConnectionTimeout, "10"),
        (KeyConnectionIdleTimeout, "180"),
        (KeyConnectionLifeTime, "300"),
    };

    public static S8DataSourceEndpointNormalizeResult Normalize(string rawEndpoint)
    {
        if (string.IsNullOrWhiteSpace(rawEndpoint))
            throw new ArgumentException("S8 data_source endpoint 不能为空或空白", nameof(rawEndpoint));

        var parsed = new DbConnectionStringBuilder { ConnectionString = rawEndpoint };

        // SortedDictionary(Ordinal) + 全部 key 小写化 → 相同语义 endpoint 落到相同 canonical 顺序，hash 稳定。
        var canonical = new SortedDictionary<string, string>(StringComparer.Ordinal);
        foreach (string key in parsed.Keys)
        {
            var canonicalKey = key.ToLowerInvariant();
            canonical[canonicalKey] = parsed[key]?.ToString() ?? string.Empty;
        }

        // 补齐缺失默认值；已有 key（如自定义 Maximum Pool Size）保留原值，不覆盖。
        foreach (var (defaultKey, defaultValue) in _normalizeDefaults)
        {
            if (!canonical.ContainsKey(defaultKey))
                canonical[defaultKey] = defaultValue;
        }

        // 用 DbConnectionStringBuilder 按 sorted key 顺序重组；其 ToString 自动处理 value quoting。
        var normalizedBuilder = new DbConnectionStringBuilder();
        foreach (var kv in canonical)
            normalizedBuilder[kv.Key] = kv.Value;
        var normalized = normalizedBuilder.ConnectionString;

        var bytes = SHA256.HashData(Encoding.UTF8.GetBytes(normalized));
        var hashHex = Convert.ToHexString(bytes).ToLowerInvariant();

        return new S8DataSourceEndpointNormalizeResult(normalized, hashHex);
    }
}

/// <summary>
/// S8 data_source endpoint 规范化结果。NormalizedConnectionString 用于建 SqlSugarScope；
/// EndpointHash 是 SHA256(normalized) 的 64 字符小写 hex，调用方可取前 N 位派生 ConfigId。
/// </summary>
public readonly record struct S8DataSourceEndpointNormalizeResult(string NormalizedConnectionString, string EndpointHash);