using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using JD.Kernel.StaticHelpers;

namespace JD.Kernel.Structs
{
    /// <summary>
    /// A simple file location.
    /// </summary>
    [Serializable]
    public struct FileLocation
    {
        #region Constants

        /// <summary>
        /// String that is used in canonical strings when the fileName is empty.
        /// </summary>
        internal const string UnknownFileName = "<Unknown FileName>";

        #endregion

        #region Variables

        private string m_fileName;
        private int m_lineNumber;
        private int m_columnNumber;
        private int m_endLineNumber;
        private int m_endColumnNumber;
        private AdditionalInfo m_additionalInfo;

        #endregion

        #region Constructor

        /// <summary>
        /// Constructor.
        /// </summary>
        /// <param name="fileName"></param>
        public FileLocation(string fileName)
            : this(fileName, 0, 0)
        {
        }

        /// <summary>
        /// Constructor.
        /// </summary>
        /// <param name="fileName"></param>
        /// <param name="additionalInfo"></param>
        public FileLocation(string fileName, object additionalInfo)
            : this(fileName, 0, 0)
        {
            AddInfo(additionalInfo);
        }

        /// <summary>
        /// Constructor.
        /// </summary>
        /// <param name="fileName"></param>
        /// <param name="line"></param>
        /// <param name="column"></param>
        public FileLocation(string fileName, int line, int column)
            : this(fileName, line, column, line, column)
        {
        }

        /// <summary>
        /// Constructor.
        /// </summary>
        /// <param name="fileName"></param>
        /// <param name="line"></param>
        /// <param name="column"></param>
        /// <param name="endLine"></param>
        /// <param name="endColumn"></param>
        public FileLocation(string fileName, int line, int column, int endLine, int endColumn)
        {
            m_fileName = fileName;
            m_lineNumber = line;
            m_columnNumber = column;
            m_endLineNumber = endLine;
            m_endColumnNumber = endColumn;
            m_additionalInfo = null;
        }
        
        /// <summary>
        /// Copy constructor.
        /// </summary>
        /// <param name="src"></param>
        public FileLocation(FileLocation src)
        {
            m_fileName = src.m_fileName;
            m_lineNumber = src.m_lineNumber;
            m_columnNumber = src.m_columnNumber;
            m_endLineNumber = src.m_endLineNumber;
            m_endColumnNumber = src.m_endColumnNumber;
            m_additionalInfo = src.m_additionalInfo;
        }

        #endregion

        #region Properties

        /// <summary>
        /// Default, empty, file location
        /// </summary>
        public static FileLocation Empty
        {
            get
            {
                return new FileLocation(string.Empty);
            }
        }

        /// <summary>
        /// FileName.
        /// </summary>
        public string FileName
        {
            get { return m_fileName; }
            set { m_fileName = value; }
        }

        /// <summary>
        /// Line number.
        /// </summary>
        public int LineNumber
        {
            get { return m_lineNumber; }
            set 
            { 
                m_lineNumber = value;
                if (EndLineNumber == 0)
                {
                    EndLineNumber = value;
                }
            }
        }

        /// <summary>
        /// Column number.
        /// </summary>
        public int ColumnNumber
        {
            get { return m_columnNumber; }
            set 
            { 
                m_columnNumber = value;
                if (EndColumnNumber == 0)
                {
                    EndColumnNumber = value;
                }
            }
        }

        /// <summary>
        /// End line number.
        /// </summary>
        public int EndLineNumber
        {
            get { return m_endLineNumber; }
            set { m_endLineNumber = value; }
        }

        /// <summary>
        /// End column number.
        /// </summary>
        public int EndColumnNumber
        {
            get { return m_endColumnNumber; }
            set { m_endColumnNumber = value; }
        }
        
        public bool IsEmpty
        {
            get { return string.IsNullOrEmpty(m_fileName); }
        }

        public string AdditionalInfoDisplayString
        {
            get { return string.Join(", ", EnumerateAdditionalInfo()); }
        }
        
        #endregion

        #region Methods

        #region Additional Info

        /// <summary>
        /// Retrieves additional info about this file location. <see cref="AddInfo"/>.
        /// </summary>
        /// <returns>The first info found of the given type, or null if no info is found of that type.</returns>
        public TInfo GetInfo<TInfo>()
        {
            return EnumerateAdditionalInfo().OfType<TInfo>().FirstOrDefault();
        }

        /// <summary>
        /// Adds additional info that can be interpreted by views to provide more context to a file location.
        /// </summary>
        /// <remarks>
        /// The info must be serializable.
        /// </remarks>
        /// <example>An actual item in a file, the position of the camera, etc...</example>
        /// <param name="info"></param>
        public void AddInfo(object info)
        {
            var newInfo = new AdditionalInfo(m_additionalInfo, info);
            m_additionalInfo = newInfo;
        }
        
        private IEnumerable<object> EnumerateAdditionalInfo()
        {
            for (var node = m_additionalInfo; node != null; node = node.Next)
            {
                yield return node.Info;
            }
        }

        #endregion
        
        /// <summary>
        /// Overriden.
        /// </summary>
        /// <returns></returns>
        public override string ToString()
        {
            StringBuilder builder = new StringBuilder();
            if (!string.IsNullOrEmpty(FileName) || LineNumber != 0)
            {
                builder.AppendFormat("{0}", string.IsNullOrEmpty(FileName) ? UnknownFileName : FileName);
                if (LineNumber != 0)
                {
                    if (ColumnNumber == 0)
                    {
                        if (EndLineNumber == LineNumber)
                        {
                            builder.AppendFormat("({0})", LineNumber);
                        }
                        else
                        {
                            builder.AppendFormat("({0}-{1})", LineNumber, EndLineNumber);
                        }
                    }
                    else if (EndLineNumber == LineNumber)
                    {
                        if (EndColumnNumber == ColumnNumber)
                        {
                            builder.AppendFormat("({0},{1})", LineNumber, ColumnNumber);
                        }
                        else
                        {
                            builder.AppendFormat("({0},{1}-{2})", LineNumber, ColumnNumber, EndColumnNumber);
                        }
                    }
                    else if (EndColumnNumber == ColumnNumber)
                    {
                        builder.AppendFormat("({0}-{1},{2})", LineNumber, EndLineNumber, ColumnNumber);
                    }
                    else
                    {
                        builder.AppendFormat("({0},{1},{2},{3})", LineNumber, ColumnNumber, EndLineNumber, EndColumnNumber);
                    }
                }
            }

            return builder.ToString();
        }

        #endregion

        #region Inner Types

        [Serializable]
        private class AdditionalInfo
        {
            public readonly AdditionalInfo Next;
            public readonly object Info;

            public AdditionalInfo(AdditionalInfo next, object info)
            {
                Throw.IfNull(info, "info");

                Next = next;
                Info = info;
            }
        }

        #endregion
    }
}