namespace Admin.NET.Plugin.AiDOP.DataPlatform;

/// <summary>
/// source_system 只表示真实来源系统。写入通道记在 written_by，不再把 AIDOP 同时当成来源和写入方。
/// </summary>
public static class MdpSourceIdentity
{
    public const string DbSync = "DB_SYNC";
    public const string ApiInbound = "API_INBOUND";
    public const string PlatformForm = "PLATFORM_FORM";
    public const string Seed = "SEED";
    public const string LegacyUnverified = "LEGACY_UNVERIFIED";
    public const string Native = "AIDOP_NATIVE";

    /// <summary>
    /// 先按原始表名查登记表，再用贴源行自带的 source_system。两处都没有时留空，不写成 AIDOP。
    /// </summary>
    public static string Resolve(string tableExpr, string systemExpr) =>
        $"COALESCE((SELECT r.source_system FROM mdp_source_table_registry r WHERE r.source_table = {tableExpr} LIMIT 1), NULLIF({systemExpr},''), '')";

    /// <summary>QAD 驼峰表名 → 165；T8 拼音前缀 → T8。对不上的返回 null，调用方不得猜测。</summary>
    public static string? ClassifySourceTable(string? name)
    {
        if (string.IsNullOrWhiteSpace(name)) return null;
        var table = name.Trim();
        if (table.StartsWith("ic_", StringComparison.Ordinal)
            || table.StartsWith("kc_", StringComparison.Ordinal)
            || table.StartsWith("cj_", StringComparison.Ordinal)
            || table.StartsWith("sys_pe", StringComparison.Ordinal))
            return "T8";
        if (char.IsUpper(table[0]) && table.Skip(1).Any(char.IsUpper) && !table.Contains('_'))
            return "DOPDEMORQ_SQLSERVER";
        return null;
    }
}