// 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;
using System.Text;
using Rauchy.Regionerate.Domain.Entities;

namespace Rauchy.Regionerate.Shared.Components.Rendering
{
    /// <summary>
    /// Renders <see cref="Region"/> objects into strings.
    /// </summary>
    public abstract class RegionRenderer : ICodeRenderer<Region>
    {
        #region Fields (2) 

        private readonly CodeLayout.Configuration _configuration;
        private const string TabAmountCannotBeLessThanZero = "Tab amount cannot be less than zero";

        #endregion Fields 

        #region Constructors (1) 

        protected RegionRenderer( CodeLayout.Configuration configuration )
        {
            if ( configuration.RenderingOptions.TabAmount < 0 )
            {
                throw new ArgumentOutOfRangeException( TabAmountCannotBeLessThanZero );
            }

            _configuration = configuration;
        }

        #endregion Constructors 

        #region Properties (1) 

        protected CodeLayout.Configuration Configuration
        {
            get
            {
                return _configuration;
            }
        }

        #endregion Properties 

        #region Methods (6) 

        // Public Methods (2) 

        // [rgn] Public Methods (2)
        public static RegionRenderer CreateNew( RegionStyle style, CodeLayout.Configuration configuration )
        {
            switch ( style )
            {
                case RegionStyle.Visible:
                    return new VisibleRegionRenderer( configuration );
                case RegionStyle.Comment:
                    return new CommentRegionRenderer( configuration );
                case RegionStyle.Invisible:
                    return new InvisibleRegionRenderer( configuration );
                default:
                    throw new NotSupportedException();
            }
        }

        /// <summary>
        /// Creates a string representation for the provided <see cref="Region"/>.
        /// </summary>
        /// <exception cref="ArgumentNullException">
        /// Thrown when <c>region</c> is <c>null</c>.
        /// </exception>
        public virtual string Render( Region region )
        {
            if ( region == null )
            {
                throw new ArgumentNullException( "region" );
            }

            StringBuilder stringBuilder = new StringBuilder();

            stringBuilder.Append( RenderHeader( region ) );

            // Pad first child.
            if ( region.Children.Count > 0 )
            {
                for ( int i = 0; i < region.PadFirstChild; i++ )
                {
                    stringBuilder.AppendLine();
                }
            }

            // Append children
            foreach ( Code child in region.Children )
            {
                string childText = RenderingCentral.Render( child, _configuration );
                stringBuilder.Append( childText );
            }

            // Pad last child.
            if ( region.Children.Count > 0 )
            {
                for ( int i = 0; i < region.PadLastChild; i++ )
                {
                    stringBuilder.AppendLine();
                }
            }

            stringBuilder.Append( RenderFooter( region ) );

            return stringBuilder.ToString();
        }

        // Protected Methods (3) 

        // [rgn] Protected Methods (3)
        /// <remarks>
        /// Build the footer portion which is shared to all rendering styles. 
        /// Consists the symbol and region title.
        /// </remarks>
        /// <param name="region"></param>
        /// <returns></returns>
        protected virtual string RenderFooter( Region region )
        {
            return _configuration.Symbol.Embed( region.Title );
        }

        /// <remarks>
        /// Build the header portion which is shared to all rendering styles. 
        /// Consists of the symbol, region title and children count. (if required)
        /// </remarks>
        /// <param name="region"></param>
        /// <returns></returns>
        protected virtual string RenderHeader( Region region )
        {
            string text = region.Title;
            if ( _configuration.RenderingOptions.ShowCount )
            {
                text += string.Format( " ({0})", CountRecognizedCode( region ) );
            }

            return _configuration.Symbol.Embed( text );
        }

        protected string RenderHeader( Region region, string prefix, string title )
        {
            StringBuilder header = new StringBuilder();

            header.Append( TextUtilities.GetTabString( _configuration.RenderingOptions ) );
            // Tabifies the region header.
            header.Append( prefix );
            header.Append( title );
            header.AppendLine();

            return header.ToString();
        }

        // Private Methods (1) 

        // [rgn] Private Methods (1)
        /// <summary>
        /// Counts the functional code instances inside a <see cref="Region"/>. (recursive)
        /// </summary>
        /// <param name="region">The region to count.</param>
        /// <returns>
        /// The amount of <see cref="FunctionalCode"/> objects inside the <see cref="Region"/> and 
        /// its inner <see cref="Region"/> instances.
        /// </returns>
        private static int CountRecognizedCode( Region region )
        {
            int count = 0;
            foreach ( Code code in region.Children )
            {
                if ( code is FunctionalCode )
                {
                    count++;
                }

                if ( code is Region )
                {
                    count += CountRecognizedCode( code as Region );
                }
            }

            return count;
        }

        #endregion Methods 
    }
}