namespace MAF1.Utils;

/// <summary>
/// 从模型回复里抽出 JSON 对象。模型常包 ```json ... ```，或在前后加说明文字。
/// </summary>
public static class JsonText
{
    public static string UnwrapObject(string text)
    {
        string trimmed = text.Trim();
        if (trimmed.StartsWith("```", StringComparison.Ordinal))
        {
            int firstNewLine = trimmed.IndexOf('\n');
            int lastFence = trimmed.LastIndexOf("```", StringComparison.Ordinal);
            if (firstNewLine >= 0 && lastFence > firstNewLine)
            {
                trimmed = trimmed[(firstNewLine + 1)..lastFence].Trim();
            }
        }

        int objectStart = trimmed.IndexOf('{');
        int objectEnd = trimmed.LastIndexOf('}');
        if (objectStart >= 0 && objectEnd > objectStart)
        {
            return trimmed[objectStart..(objectEnd + 1)];
        }

        return trimmed;
    }
}