using System;
using System.IO;
using System.Xml;

namespace SomeNamespace
{
    static class SettingsProvider
    {
        private const string CONFIG_FILE = "config.xml";
        private static XmlDocument _xmlDoc = null;


        private static string ConfigPath
        {
            get { return Program.ApplicationFolder + @"\" + CONFIG_FILE; }
        }


        public static void Save(string key, string value)
        {
            XmlNode node = _xmlDoc.SelectSingleNode("./config/" + key);

            if (node != null)
            {
                node.InnerText = value;
                Save();
            }
            else
            {
                // XML node doesnt exist thus create a new one
                Get(key, value);
            }
        }

        /// <summary>
        /// Gets a value of the settings. If the setting does not exist, defaultValue is returned.
        /// </summary>
        public static string Get(string key, string defaultValue)
        {
            if (_xmlDoc == null)
            {
                _xmlDoc = new XmlDocument();

                // Load config.xml
                string fullPath = SettingsProvider.ConfigPath;

                if (!File.Exists(fullPath))
                {
                    // Xml declaration
                    XmlDeclaration declaration = _xmlDoc.CreateXmlDeclaration("1.0", null, null);
                    _xmlDoc.AppendChild(declaration);

                    // Root node <config>
                    XmlElement rootNode = _xmlDoc.CreateElement("config");
                    _xmlDoc.AppendChild(rootNode);

                    Save();
                }
                else
                {
                    _xmlDoc.Load(fullPath);
                }
            }

            XmlNode node = _xmlDoc.SelectSingleNode("./config/" + key);

            if (node != null)
            {
                return node.InnerText;
            }
            else
            {
                // Add default value
                XmlElement newSetting = _xmlDoc.CreateElement(key);
                newSetting.InnerText = defaultValue;
                _xmlDoc.ChildNodes[1].AppendChild(newSetting);

                Save();

                return defaultValue;
            }
        }

        public static void Save()
        {
            if (_xmlDoc != null)
            {
                _xmlDoc.Save(SettingsProvider.ConfigPath);
            }
        }
    }
}