using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using static Terminal.Gui.ConfigurationManager;

#nullable enable

namespace Terminal.Gui {

	/// <summary>
	/// Defines a configuration settings scope. Classes that inherit from this abstract class can be used to define
	/// scopes for configuration settings. Each scope is a JSON object that contains a set of configuration settings.
	/// </summary>
	public class Scope<T> : Dictionary<string, ConfigProperty> { //, IScope<Scope<T>> {
		/// <summary>
		/// Crates a new instance.
		/// </summary>
		public Scope () : base (StringComparer.InvariantCultureIgnoreCase)
		{
			foreach (var p in GetScopeProperties ()) {
				Add (p.Key, new ConfigProperty () { PropertyInfo = p.Value.PropertyInfo, PropertyValue = null });
			}
		}

		private IEnumerable<KeyValuePair<string, ConfigProperty>> GetScopeProperties ()
		{
			return ConfigurationManager._allConfigProperties!.Where (cp =>
				(cp.Value.PropertyInfo?.GetCustomAttribute (typeof (SerializableConfigurationProperty))
				as SerializableConfigurationProperty)?.Scope == GetType ());
		}

		/// <summary>
		/// Updates this instance from the specified source scope.
		/// </summary>
		/// <param name="source"></param>
		/// <returns>The updated scope (this).</returns>
		public Scope<T>? Update (Scope<T> source)
		{
			foreach (var prop in source) {
				if (ContainsKey (prop.Key))
					this [prop.Key].PropertyValue = this [prop.Key].UpdateValueFrom (prop.Value.PropertyValue!);
				else {
					this [prop.Key].PropertyValue = prop.Value.PropertyValue;
				}
			}
			return this;
		}

		/// <summary>
		/// Retrieves the values of the properties of this scope from their corresponding static properties.
		/// </summary>
		public void RetrieveValues ()
		{
			foreach (var p in this.Where (cp => cp.Value.PropertyInfo != null)) {
				p.Value.RetrieveValue ();
			}
		}

		/// <summary>
		/// Applies the values of the properties of this scope to their corresponding static properties.
		/// </summary>
		/// <returns></returns>
		internal virtual bool Apply ()
		{
			bool set = false;
			foreach (var p in this.Where (t => t.Value != null && t.Value.PropertyValue != null)) {
				if (p.Value.Apply ()) {
					set = true;
				}
			}
			return set;
		}
	}
}