using System;
using System.Text;
using System.Runtime.InteropServices;
using System.Collections.Specialized;

namespace TBF.Tools
{
	/// <summary>
	/// The class use the WinApi GetPrivateProfileSectionNames,
	/// GetPrivateProfileSection, GetPrivateProfileString, WritePrivateProfileString
	/// and present easy methods to work from a NET point of view.
	/// Usage:
	///		IniUtil ini = new IniUtil(@"C:\program files (x86)\myapp\myapp.ini");
	///		string country = ini.GetValue("Carrier","Country","NoCountry");
	/// </summary>
	public class IniUtil
	{
		[DllImport("kernel32.dll")]
		private static extern int GetPrivateProfileSectionNames(byte[] lpszReturnBuffer, int nSize, string lpFileName);
		[DllImport("kernel32.dll")]
		private static extern int GetPrivateProfileSection(string lpAppName, byte[] lpReturnedString, int nSize, string lpFileName);
		[DllImport("kernel32.dll")]
		private static extern int GetPrivateProfileString(string lpApplicationName, string lpKeyName, string lpDefault, byte[] lpReturnedString, int nSize, string lpFileName);
		[DllImport("kernel32.dll")]
		private static extern bool WritePrivateProfileString(string lpApplicationName, string lpKeyName, string lpString, string lpFileName);

		private const int VALUE_BUFFER = 511;
		private const int SECTION_BUFFER = (1024 * 16);
		private string m_sIniFile;

		/// <summary>
		/// .ctor with INI file name
		/// </summary>
		/// <param name="fileName">Fullpath to the INI file</param>
		public IniUtil(string fileName)
		{
			m_sIniFile = fileName;
		}

		/// <summary>
		/// Set the value for a specific key in a section
		/// </summary>
		/// <param name="section">Section containing the key to write to</param>
		/// <param name="key">Key to insert/update</param>
		/// <param name="keyvalue">Value for the key</param>
		/// <returns>True if OK</returns>
		public bool SetValue(string section, string key, string keyvalue)
		{
			return WritePrivateProfileString(section, key, keyvalue, m_sIniFile);
		}

		/// <summary>
		/// Gets the value of the specidied key in the specified section, 
		/// If the key doesn't exists returns the default value
		/// </summary>
		/// <param name="section">Section containing the key to read from</param>
		/// <param name="key">Required key</param>
		/// <param name="ifMissing">Value to return in case the key is missing</param>
		/// <returns>string value of the key or missing value</returns>
		public string GetValue(string section, string key, string ifMissing)
		{
			byte[] by = new byte[VALUE_BUFFER];
			int n = GetPrivateProfileString(section, key, ifMissing, by, VALUE_BUFFER, m_sIniFile);
			string s = Encoding.ASCII.GetString(by);
			return s.Substring(0, n);
		}

		/// <summary>
		/// Returns the NameValueCollection for every key in the section
		/// </summary>
		/// <param name="section">Section name</param>
		/// <returns>NameValueCollection with nake=Key and value=value</returns>
		public NameValueCollection GetSectionKeysvalues(string section)
		{
			NameValueCollection n = new NameValueCollection();
			if(section.Length > 0)
			{
				byte[] by = new byte[SECTION_BUFFER];
				int x = GetPrivateProfileSection(section, by, SECTION_BUFFER, m_sIniFile);
				if(x > 0) x--;
				string keysvalues = Encoding.ASCII.GetString(by, 0, x);
				string[] temp = keysvalues.Split('\0');
				foreach(string s in temp)
				{
					string[] t = s.Split('=');
					n.Add(t[0], t[1]);
				}
			}
			return n;
		}

		/// <summary>
		/// Get the names of all sections in .INI
		/// </summary>
		/// <returns>string array with all the key names</returns>
		public string[] GetSectionNames()
		{
			byte[] by = new byte[SECTION_BUFFER];
			int x = GetPrivateProfileSectionNames(by, SECTION_BUFFER, m_sIniFile);
			if(x > 0) x--;
			string keys = Encoding.ASCII.GetString(by, 0, x);
			return keys.Split('\0');
		}
	}
}