using System;
using System.IO;
using System.Text;
using System.Xml.Serialization;

namespace DeviceTest
{
    /// <summary>
    /// Class to be serialized to an XML file...
    /// </summary>
	[XmlRootAttribute("DeviceTest")]
    public class LocalSettings
    {
		public string ParentClassName;
		public string ParentName;
		public string ParentSettings;

		public string ComponentClassName;
		public string ComponentName;
		public string ParentComponentName;
		public string ComponentSettings;

        public LocalSettings()
        {
        }

        /// <summary>
        /// Load public fields of this class from the XML file.
        /// </summary>
		/// <returns>LocalSettings object or null when Load() fails</returns>
		public static LocalSettings Load(string fileName)
        {
            try
            {
				using (TextReader reader = new StreamReader(fileName))
                {
                    LocalSettings ls = (new XmlSerializer(typeof(LocalSettings))).Deserialize(reader) as LocalSettings;
                    // Copy the settings just in case De-serialize() completes OK
					return ls;
                }
            }
            catch (Exception e)
            {
                string msg = e.Message;
				return null;
            }
        }

        /// <summary>
        /// Save public fields of this class to the XML file.
        /// </summary>
        public void Save()
        {
            try
            {
				using (TextWriter writer = new StreamWriter(Program.LocalSettingsFileName))
                {
                    (new XmlSerializer(typeof(LocalSettings))).Serialize(writer, this);
                }
            }
            catch (Exception e)
            {
                string msg = e.Message;
            }
        }

		/// <summary>
		/// Updates history stored in a string array by a new latest string.
		/// </summary>
		/// <param name="lastStrValue">Last entered string</param>
		/// <returns>true = updated and saved</returns>
		public bool UpdateHistory(string lastStrValue, ref string[] history)
		{
			const int MaxHistoryLen = 10;

			if (string.IsNullOrEmpty(lastStrValue)) return false;

			int currentHistoryLength = (history != null) ? history.Length : 0;

			int match = -1;
			for (int i = 0; i < currentHistoryLength; i++)
			{
				if (history[i] == lastStrValue)
				{
					match = i;
					break;
				}
			}

			if (match >= 0 || currentHistoryLength >= MaxHistoryLen)
			{
				/// History does not have to be extended (because of a match) or should not be extended (because of the lenght)
				if (match < 0) match = currentHistoryLength - 1;

				for (int j = match; j > 0; j--)
				{
					history[j] = history[j - 1];
				}
				history[0] = lastStrValue;
			}
			else
			{
				/// History will be extended, new item inserted at the beginning
				string[] newHistory = new string[currentHistoryLength + 1];
				newHistory[0] = lastStrValue;
				for (int j = 1; j <= currentHistoryLength; j++)
				{
					newHistory[j] = history[j - 1];
				}
				history = newHistory;
			}
			Save();
			return true;
		}
    }
}