using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Collections.Specialized;

namespace Web.Core {

	public abstract class Config<T> : IDisposable where T : Config<T> {

		private static T _instance = null;

		public static T instance {
			get {
				if(_instance == null) throw new FLocalException("not initialized");
				return _instance;
			}
		}

		private NameValueCollection data;

		public string AppInfo {
			get {
				return data["AppInfo"];
			}
		}

		protected Config(NameValueCollection data) {
			this.data = data;
		}

		protected static void doInit(Func<T> configCreator) {
			if(_instance != null) throw new FLocalException("already initialized");
			lock(typeof(Config<T>)) {
				if(_instance != null) throw new FLocalException("already initialized");
				_instance = configCreator();
			}
		}

		protected static void doReInit(Func<T> configCreator) {
			lock(typeof(Config<T>)) {
				_instance = configCreator();
			}
		}

		public static bool isInitialized {
			get {
				return _instance != null;
			}
		}

		public virtual void Dispose() {
		}

		protected static bool parseBool(string value) {
			switch(value.ToLower().Trim()) {
				case "1":
				case "true":
				case "on":
				case "enabled":
				case "yes":
					return true;
				case "0":
				case "false":
				case "off":
				case "disabled":
				case "no":
					return false;
				default:
					throw new CriticalException("Cannot parse '" + value + "'");
			}
		}

	}
}