/*
 * File.Reader.cs
 * 
 * Copyright © 2009
 * Diversified Technical Systems, Inc.
 * All Rights Reserved
 */

using DTS.Common.Utilities;
using DTS.Common.Utilities.DotNetProgrammingConstructs;
using System.Collections.Generic;

namespace DTS.Serialization
{
    // *** see File.cs ***
    public abstract partial class File
    {   ///
        /// <summary>
        /// A class for reading files of this type.  There can be several reader types in a
        /// File-based class -- one for each "type" that the reader target is to be read/converted
        /// into.
        /// </summary>
        /// 
        /// <typeparam name="T">
        /// The file type that this reader belongs to.
        /// </typeparam>
        ///
        public abstract class Reader<T> : Exceptional, IReader
            where T : File
        {   ///
            /// <summary>
            /// Constructor for the DTS.Export.File.Reader class.  Note that access restrictions require that
            /// readers be constructed by the hosting DTS.Export.File class only.  Use a File-level property or
            /// factory function to create/pass reader objects to outside parties.
            /// </summary>
            /// 
            /// <param name="fileType">
            /// The associated DTS.Serialization.File-based class.
            /// </param>
            ///
            protected Reader(T fileType)
            {
                try
                {
                    FileType = fileType;
                    ChFileCompare = new ChannelFilenameComparer(fileType);
                }

                catch (System.Exception ex)
                {
                    throw new Exception("encountered problem constructing " + GetType().FullName, ex);
                }
            }

            /// <summary>
            /// Get the <see cref="DTS.Serialization.File"/>-type associated with this reader.
            /// </summary>
            protected T FileType
            {
                get => _FileType.Value;
                private set => _FileType.Value = value;
            }
            private readonly Property<T> _FileType
                = new Property<T>(
                    typeof(Reader<T>).Namespace + ".File.Reader.FileType",
                    null,
                    false
                );

            /// <summary>
            /// Channel Filename comparer used by some file types.
            /// </summary>
            protected ChannelFilenameComparer ChFileCompare
            {
                get => _ChFileCompare.Value;
                private set => _ChFileCompare.Value = value;
            }
            private readonly Property<ChannelFilenameComparer> _ChFileCompare
                = new Property<ChannelFilenameComparer>(
                    typeof(ChannelFilenameComparer).Namespace + ".File.Reader.ChFileCompare",
                    null,
                    false
                );

            protected class ChannelFilenameComparer : IComparer<string>
            {
                public File file { get; private set; }
                public int Compare(string left, string right)
                {
                    return file.GetChannelNumberFromChannelFileName(left) != file.GetChannelNumberFromChannelFileName(right) ?
                                file.GetChannelNumberFromChannelFileName(left) - file.GetChannelNumberFromChannelFileName(right) :
                                string.Compare(left, right); // 19044 only dual-cal sensors will have repeat channel numbers (nonlinear then linear),
                                                             //  so do a straight compare to put nonlinear .chn before linear .lin.chn
                                                             //  if a non-SLICE or TDAS file type uses this, will be a regular string compare as GetChannelNumber... returns -1 always
                }
                public ChannelFilenameComparer(T fileType)
                {
                    if (fileType is File f)
                    {
                        file = f;
                    }
                }
            }
        }
    }
}