//
//  MarkupContainerElement.cs - the abstract base class from which MarkupElements which can contain other MarkupElements derive
//
//  Author:
//       Michael Becker <alcexhim@gmail.com>
//
//  Copyright (c) 2011-2020 Mike Becker's Software
//
//  This program is free software: you can redistribute it and/or modify
//  it under the terms of the GNU General Public License as published by
//  the Free Software Foundation, either version 3 of the License, or
//  (at your option) any later version.
//
//  This program is distributed in the hope that it will be useful,
//  but WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//  GNU General Public License for more details.
//
//  You should have received a copy of the GNU General Public License
//  along with this program.  If not, see <http://www.gnu.org/licenses/>.

using System;

namespace UniversalEditor.ObjectModels.Markup
{
	/// <summary>
	/// The abstract base class from which <see cref="MarkupElement" />s which can contain other <see cref="MarkupElement" />s derive.
	/// </summary>
	public abstract class MarkupContainerElement : MarkupElement, IMarkupElementContainer
	{
		/// <summary>
		/// Gets a collection of <see cref="MarkupElement" /> instances representing the elements contained within this <see cref="MarkupContainerElement" />.
		/// </summary>
		/// <value>The elements contained within this <see cref="MarkupContainerElement" />.</value>
		public MarkupElement.MarkupElementCollection Elements { get; } = null;

		public MarkupContainerElement()
		{
			this.Elements = new MarkupElement.MarkupElementCollection(this);
		}
		public MarkupElement FindElement(params string[] fullNames)
		{
			MarkupElement result;
			if (fullNames.Length == 0)
			{
				result = null;
			}
			else
			{
				MarkupElement e = this.Elements[fullNames[0]];
				for (int i = 1; i < fullNames.Length; i++)
				{
					if (e != null && e is MarkupContainerElement)
					{
						e = (e as MarkupContainerElement).Elements[fullNames[i]];
					}
				}
				result = e;
			}
			return result;
		}
		public MarkupTagElement CreateElement(params string[] elementNames)
		{
			MarkupTagElement basetag = null;
			MarkupTagElement tag = null;
			for (int i = elementNames.Length - 1; i > -1; i--)
			{
				if (tag == null)
				{
					tag = new MarkupTagElement();
					tag.FullName = elementNames[i];
					basetag = tag;
					this.Elements.Add(tag);
				}
				else
				{
					MarkupTagElement newtag = new MarkupTagElement();
					newtag.FullName = elementNames[i];
					tag.Elements.Add(newtag);
					tag = newtag;
				}
			}
			return basetag;
		}

		private string _XMLSchema = null;
		public string XMLSchema
		{
			get
			{
				if (_XMLSchema != null)
					return _XMLSchema;

				if (this.Namespace == null)
					return null;

				for (int i = 0; i < this.ParentObjectModel.Elements.Count; i++)
				{
					MarkupTagElement tagTopLevel = (this.ParentObjectModel.Elements[i] as MarkupTagElement);
					if (tagTopLevel == null)
						continue;

					MarkupAttribute att = tagTopLevel.Attributes["xmlns:" + this.Namespace];
					if (att != null)
						return att.Value;
				}

				return null;
			}
			set
			{
				if (this.ParentObjectModel == null)
				{
					_XMLSchema = value;
					return;
				}

				for (int i = 0; i < this.ParentObjectModel.Elements.Count; i++)
				{
					MarkupTagElement tagTopLevel = (this.ParentObjectModel.Elements[i] as MarkupTagElement);
					if (tagTopLevel == null)
						continue;

					foreach (MarkupAttribute att in tagTopLevel.Attributes)
					{
						if (att.Namespace == "xmlns")
						{
							if (att.Value == value)
							{
								Namespace = att.Name;
								break;
							}
						}
					}
				}
			}
		}

		protected override void UpdateParentObjectModel()
		{
			base.UpdateParentObjectModel();
			this.Elements.ParentObjectModel = this.ParentObjectModel;
			for (int i = 0; i < this.Elements.Count; i++)
			{
				this.Elements[i].ParentObjectModel = this.ParentObjectModel;
			}
		}

		protected string FindSchemaTagPrefix(string schema)
		{
			for (int i = 0; i < this.ParentObjectModel.Elements.Count; i++)
			{
				MarkupTagElement tagTopLevel = (this.ParentObjectModel.Elements[i] as MarkupTagElement);
				if (tagTopLevel != null)
				{
					for (int j = 0; j < tagTopLevel.Attributes.Count; j++)
					{
						if (tagTopLevel.Attributes[j].Name.Equals("xmlns") && tagTopLevel.Attributes[j].Value.Equals(schema))
						{
							return String.Empty;
						}
						else if (tagTopLevel.Attributes[j].Namespace != null && tagTopLevel.Attributes[j].Namespace.Equals("xmlns") && tagTopLevel.Attributes[j].Value.Equals(schema))
						{
							return tagTopLevel.Attributes[j].Name;
						}
					}
				}
			}
			return null;
		}

		public MarkupElement FindElementUsingSchema(string schema, string name)
		{
			string tagPrefix = FindSchemaTagPrefix(schema);

			if (tagPrefix == null)
			{
				Console.WriteLine("ue: MarkupObjectModel: tag prefix for schema '" + schema + "' not found");
				return null;
			}

			string fullName = null;
			if (String.IsNullOrEmpty(tagPrefix))
			{
				fullName = name;
			}
			else
			{
				fullName = tagPrefix + ":" + name;
			}
			return FindElement(fullName);
		}

		public override void Combine(MarkupElement el)
		{
			MarkupTagElement tag = (el as MarkupTagElement);
			if (tag == null) throw new InvalidOperationException("Cannot combine MarkupTagElement with " + el.GetType().Name);

			foreach (MarkupElement el1 in tag.Elements)
			{
				string id = null;
				MarkupTagElement tag1 = (el1 as MarkupTagElement);
				if (tag1 != null)
				{
					MarkupAttribute attID = tag1.Attributes["ID"];
					if (attID != null) id = attID.Value;
				}

				if (Elements.Contains(el1.FullName, id, (el1 is MarkupTagElement ? (el1 as MarkupTagElement).Attributes : null)))
				{
					Elements[el1.FullName].Combine(el1);
				}
				else
				{
					Elements.Add(el1);
				}
			}
		}
	}
}