// Copyright (c) 2007 Omer Rauchwerger (a.k.a rauchy) (omer@rauchy.net)
// All rights reserved.
//
// This file is part of Regionerate.
// 
// 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.Collections.Generic;
using System.Xml;
using Rauchy.Regionerate.Shared.Components.Rendering;

namespace Rauchy.Regionerate.Shared.Components
{
    /// <summary>
    /// Provides quick access to opeartions on <see cref="CodeLayout"/> objects.
    /// </summary>
    public class CodeLayoutOperations
    {
        #region Fields (2) 

        private readonly CodeLayout _codeLayout;
        private readonly XmlNamespaceManager _namespaceManager;

        #endregion Fields 

        #region Constructors (1) 

        /// <summary>
        /// Initializes a new instance of the <see cref="CodeLayoutOperations"/> class.
        /// </summary>
        /// <param name="codeLayout">The code layout.</param>
        public CodeLayoutOperations( CodeLayout codeLayout )
        {
            _codeLayout = codeLayout;

            _namespaceManager = new XmlNamespaceManager( _codeLayout.NameTable );
            string codeLayoutNamespaceUri = string.Concat( Templates.BaseNamespaceUri, Templates.CodeLayoutSchemaName );
            _namespaceManager.AddNamespace( "cl", codeLayoutNamespaceUri );
        }

        #endregion Constructors 

        #region Methods (7) 

        // Public Methods (2) 

        // [rgn] Public Methods (2)
        public CodeLayout.Configuration GetConfiguration()
        {
            XmlNode configurationNode = _codeLayout.SelectSingleNode( "./cl:CodeLayout/cl:Configuration",
                                                                      _namespaceManager );

            // Read the symbol and rendering options.
            Symbol symbol = ReadSymbolValue();
            bool showCount = ReadShowCountValue();
            int tabAmount = ReadTabAmountValue();
            bool useTabs = ReadUseTabsValue();
            int spaceAmount = ReadSpaceAmountValue();

            // Create the Configuration object.
            CodeLayout.RenderingOptions renderingOptions = new CodeLayout.RenderingOptions(showCount, tabAmount, useTabs, spaceAmount);
            CodeLayout.UnpackOptions unpackOptions = ReadUnpackOptions();
            CodeLayout.Configuration configuration = new CodeLayout.Configuration( symbol, renderingOptions,
                                                                                   unpackOptions );

            return configuration;
        }

        /// <summary>
        /// Gets the symbol declared in the provided <see cref="CodeLayout"/>.
        /// </summary>
        public string GetSymbol()
        {
            return _codeLayout.SelectSingleNode( "./cl:CodeLayout/@Symbol", _namespaceManager ).Value;
        }

        // Private Methods (7) 

        // [rgn] Private Methods (7)
        private bool ReadShowCountValue()
        {
            XmlNode showCountNode = SelectSingleNode( "./cl:CodeLayout/cl:Configuration/cl:Rendering/@ShowCount" );
            return bool.Parse( showCountNode.Value );
        }

        private Symbol ReadSymbolValue()
        {
            XmlNode symbolNode = SelectSingleNode( "./cl:CodeLayout/cl:Configuration/cl:Symbol" );
            Symbol symbol = Symbol.Parse( symbolNode );
            return symbol;
        }

        private int ReadTabAmountValue()
        {
            XmlNode tabAmountNode = SelectSingleNode( "./cl:CodeLayout/cl:Configuration/cl:Rendering/@Tabs" );
            return int.Parse( tabAmountNode.Value );
        }

        private bool ReadUseTabsValue()
        {
           XmlNode useTabsNode = SelectSingleNode("./cl:CodeLayout/cl:Configuration/cl:Rendering/@UseTabs");
           return bool.Parse(useTabsNode.Value);
        }

        private int ReadSpaceAmountValue()
        {
           XmlNode spaceAmountNode = SelectSingleNode("./cl:CodeLayout/cl:Configuration/cl:Rendering/@Spaces");
           return int.Parse(spaceAmountNode.Value);
        }

        private CodeLayout.UnpackOptions ReadUnpackOptions()
        {
            IList<string> regionPatterns = new List<string>();
            foreach ( XmlNode node in
                _codeLayout.SelectNodes( "./cl:CodeLayout/cl:Configuration/cl:Unpack/cl:Regions", _namespaceManager ) )
            {
                string regionPattern = node.Attributes[ "ThatMatch" ].Value;
                regionPatterns.Add( regionPattern );
            }

            CodeLayout.UnpackOptions unpackOptions = new CodeLayout.UnpackOptions( regionPatterns );
            return unpackOptions;
        }

        /// <summary>
        /// Runs an XPath query on the <see cref="CodeLayout"/>.
        /// </summary>
        /// <returns></returns>
        private XmlNode SelectSingleNode( string query )
        {
            return _codeLayout.SelectSingleNode( query, _namespaceManager );
        }

        #endregion Methods 
    }
}