using System ;
using System.Text ;
using System.IO ;
using System.Runtime.Serialization.Json ;
using System.Xml ;
using System.Xml.Linq ;
using System.Xml.XPath ;

// --------------------------------------------------------------------

public class JsonConfig
{
    private XElement mRootElem ;

    public JsonConfig( string caption, string fname )
    {
        // load the JSON config
        string data ;
        if ( File.Exists( fname ) ) {
            Program.logTraceMsg( String.Format( "Loading {0}: {1}", caption, Path.GetFullPath(fname) ) ) ;
            data = File.ReadAllText( fname ) ;
        } else
            data ="{}" ;
        var jsonReader = JsonReaderWriterFactory.CreateJsonReader(
             Encoding.UTF8.GetBytes( data ),
             new XmlDictionaryReaderQuotas()
        ) ;
        mRootElem = XElement.Load( jsonReader ) ;
    }

    public string getStringVal( string xpath, string defaultVal="" )
    {
        // return the specified value
        var elem = mRootElem.XPathSelectElement( xpath ) ;
        if ( elem == null )
            return defaultVal ;
        return elem.Value ;
    }

    public int getIntVal( string xpath, int defaultVal=0 )
    {
        // return the specified value
        try {
            return Int32.Parse( getStringVal( xpath ) ) ;
        } catch( System.FormatException ) {
            return defaultVal ;
        }
    }
}