#region MigraDoc - Creating Documents on the Fly
//
// Authors:
//   Stefan Lange
//   Klaus Potzesny
//   David Stephensen
//
// Copyright (c) 2001-2017 empira Software GmbH, Cologne Area (Germany)
//
// http://www.pdfsharp.com
// http://www.migradoc.com
// http://sourceforge.net/projects/pdfsharp
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 
// DEALINGS IN THE SOFTWARE.
#endregion

using System;
using System.Diagnostics;
using System.Globalization;
using System.IO;
using System.Text;
using MigraDoc.DocumentObjectModel.publics;

namespace MigraDoc.DocumentObjectModel
{
    /// <summary>
    /// Object to be passed to the Serialize function of a DocumentObject to convert
    /// it into DDL.
    /// </summary>
    public sealed class Serializer
    {
        /// <summary>
        /// A Serializer object for converting MDDOM into DDL.
        /// </summary>
        /// <param name="textWriter">A TextWriter to write DDL in.</param>
        /// <param name="indent">Indent of a new block. Default is 2.</param>
        /// <param name="initialIndent">Initial indent to start with.</param>
        public Serializer(TextWriter textWriter, int indent, int initialIndent)
        {
            if (textWriter == null)
                throw new ArgumentNullException("textWriter");

            _textWriter = textWriter;
            _indent = indent;
            _writeIndent = initialIndent;
            if (textWriter is StreamWriter)
                WriteStamp();
        }

        /// <summary>
        /// Initializes a new instance of the Serializer class with the specified TextWriter.
        /// </summary>
        public Serializer(TextWriter textWriter) : this(textWriter, 2, 0) { }

        /// <summary>
        /// Initializes a new instance of the Serializer class with the specified TextWriter and indentation.
        /// </summary>
        public Serializer(TextWriter textWriter, int indent) : this(textWriter, indent, 0) { }

        readonly TextWriter _textWriter;

        /// <summary>
        /// Gets or sets the indentation for a new indentation level.
        /// </summary>
        public int Indent
        {
            get { return _indent; }
            set { _indent = value; }
        }
        int _indent = 2;

        /// <summary>
        /// Gets or sets the initial indentation which precede every line.
        /// </summary>
        public int InitialIndent
        {
            get { return _writeIndent; }
            set { _writeIndent = value; }
        }
        int _writeIndent;

        /// <summary>
        /// Increases indent of DDL code.
        /// </summary>
        void IncreaseIndent()
        {
            _writeIndent += _indent;
        }

        /// <summary>
        /// Decreases indent of DDL code.
        /// </summary>
        void DecreaseIndent()
        {
            _writeIndent -= _indent;
        }

        /// <summary>
        /// Writes the header for a DDL file containing copyright and creation time information.
        /// </summary>
        public void WriteStamp()
        {
            if (_fWriteStamp)
            {
                WriteComment("Created by empira MigraDoc Document Object Model");
                WriteComment(String.Format("generated file created {0:d} at {0:t}", DateTime.Now));
            }
        }

        /// <summary>
        /// Appends a string indented without line feed.
        /// </summary>
        public void Write(string str)
        {
            string wrappedStr = DoWordWrap(str);
            if (wrappedStr.Length < str.Length && wrappedStr != "")
            {
                WriteLineToStream(wrappedStr);
                Write(str.Substring(wrappedStr.Length));
            }
            else
                WriteToStream(str);
            CommitText();
        }

        /// <summary>
        /// Writes a string indented with line feed.
        /// </summary>
        public void WriteLine(string str)
        {
            string wrappedStr = DoWordWrap(str);
            if (wrappedStr.Length < str.Length)
            {
                WriteLineToStream(wrappedStr);
                WriteLine(str.Substring(wrappedStr.Length));
            }
            else
                WriteLineToStream(wrappedStr);
            CommitText();
        }

        /// <summary>
        /// Returns the part of the string str that fits into the line (up to 80 chars).
        /// If Wordwrap is impossible it returns the input-string str itself.
        /// </summary>
        string DoWordWrap(string str)
        {
            if (str.Length + _writeIndent < LineBreakBeyond)
                return str;

            int idxCRLF = str.IndexOf("\x0D\x0A", StringComparison.Ordinal);
            if (idxCRLF > 0 && idxCRLF + _writeIndent <= LineBreakBeyond)
                return str.Substring(0, idxCRLF + 1);

            int splitIndexBlank = str.Substring(0, LineBreakBeyond - _writeIndent).LastIndexOf(" ", StringComparison.Ordinal);
            int splitIndexCRLF = str.Substring(0, LineBreakBeyond - _writeIndent).LastIndexOf("\x0D\x0A", StringComparison.Ordinal);
            int splitIndex = Math.Max(splitIndexBlank, splitIndexCRLF);
            if (splitIndex == -1)
                splitIndex = Math.Min(str.IndexOf(" ", LineBreakBeyond - _writeIndent + 1, StringComparison.Ordinal),
                                             str.IndexOf("\x0D\x0A", LineBreakBeyond - _writeIndent + 1, StringComparison.Ordinal));
            return splitIndex > 0 ? str.Substring(0, splitIndex) : str;

        }

        /// <summary>
        /// Writes an empty line.
        /// </summary>
        public void WriteLine()
        {
            WriteLine(String.Empty);
        }

        /// <summary>
        /// Write a line without committing (without marking the text as serialized).
        /// </summary>
        public void WriteLineNoCommit(string str)
        {
            WriteLineToStream(str);
        }

        /// <summary>
        /// Write a line without committing (without marking the text as serialized).
        /// </summary>
        public void WriteLineNoCommit()
        {
            WriteLineNoCommit(String.Empty);
        }

        /// <summary>
        /// Writes a text as comment and automatically word-wraps it.
        /// </summary>
        public void WriteComment(string comment)
        {
            if (String.IsNullOrEmpty(comment))
                return;

            // if string contains CR/LF, split up recursively
            int crlf = comment.IndexOf("\x0D\x0A", StringComparison.Ordinal);
            if (crlf != -1)
            {
                WriteComment(comment.Substring(0, crlf));
                WriteComment(comment.Substring(crlf + 2));
                return;
            }
            CloseUpLine();
            int len;
            int chopBeyond = LineBreakBeyond - _indent - "// ".Length;
            while ((len = comment.Length) > 0)
            {
                string wrt;
                if (len <= chopBeyond)
                {
                    wrt = "// " + comment;
                    comment = String.Empty;
                }
                else
                {
                    int idxChop;
                    if ((idxChop = comment.LastIndexOf(' ', chopBeyond)) == -1 &&
                        (idxChop = comment.IndexOf(' ', chopBeyond)) == -1)
                    {
                        wrt = "// " + comment;
                        comment = String.Empty;
                    }
                    else
                    {
                        wrt = "// " + comment.Substring(0, idxChop);
                        comment = comment.Substring(idxChop + 1);
                    }
                }
                WriteLineToStream(wrt);
                CommitText();
            }
        }

        /// <summary>
        /// Writes a line break if the current position is not at the beginning
        /// of a new line.
        /// </summary>
        public void CloseUpLine()
        {
            if (_linePos > 0)
                WriteLine();
        }

        /// <summary>
        /// Effectively writes text to the stream. The text is automatically indented and
        /// word-wrapped. A given text gets never word-wrapped to keep comments or string
        /// literals unbroken.
        /// </summary>
        void WriteToStream(string text, bool fLineBreak, bool fAutoIndent)
        {
            // if string contains CR/LF, split up recursively
            int crlf = text.IndexOf("\x0D\x0A", StringComparison.Ordinal);
            if (crlf != -1)
            {
                WriteToStream(text.Substring(0, crlf), true, fAutoIndent);
                WriteToStream(text.Substring(crlf + 2), fLineBreak, fAutoIndent);
                return;
            }

            int len = text.Length;
            if (len > 0)
            {
                if (_linePos > 0)
                {
                    // does not work
                    // if (IsBlankRequired(this .lastChar, _text[0]))
                    //   _text = "·" + _text;
                }
                else
                {
                    if (fAutoIndent)
                    {
                        text = Indentation + text;
                        len += _writeIndent;
                    }
                }
                _textWriter.Write(text);
                _linePos += len;
                // wordwrap required?
                if (_linePos > LineBreakBeyond)
                {
                    fLineBreak = true;
                    //this .textWriter.Write("//¶");  // for debugging only
                }
                else
                    _lastChar = text[len - 1];
            }

            if (fLineBreak)
            {
                _textWriter.WriteLine(String.Empty);  // what a line break is may depend on encoding
                _linePos = 0;
                _lastChar = '\x0A';
            }
        }

        /// <summary>
        /// Write the text into the stream without breaking it and adds an indentation to it.
        /// </summary>
        void WriteToStream(string text)
        {
            WriteToStream(text, false, true);
        }

        /// <summary>
        /// Write a line to the stream.
        /// </summary>
        void WriteLineToStream(string text)
        {
            WriteToStream(text, true, true);
        }

        ///// <summary>
        ///// Mighty function to figure out if a blank is required as separator.
        ///// // Does not work without context...
        ///// </summary>
        //bool IsBlankRequired(char left, char right)
        //{
        //    if (left == ' ' || right == ' ')
        //        return false;

        //    // 1st try
        //    bool leftLetterOrDigit = Char.IsLetterOrDigit(left);
        //    bool rightLetterOrDigit = Char.IsLetterOrDigit(right);

        //    if (leftLetterOrDigit && rightLetterOrDigit)
        //        return true;

        //    return false;
        //}

        /// <summary>
        /// Start attribute part.
        /// </summary>
        public int BeginAttributes()
        {
            int pos = Position;
            WriteLineNoCommit("[");
            IncreaseIndent();
            BeginBlock();
            return pos;
        }

        /// <summary>
        /// Start attribute part.
        /// </summary>
        public int BeginAttributes(string str)
        {
            int pos = Position;
            WriteLineNoCommit(str);
            WriteLineNoCommit("[");
            IncreaseIndent();
            BeginBlock();
            return pos;
        }

        /// <summary>
        /// End attribute part.
        /// </summary>
        public bool EndAttributes()
        {
            DecreaseIndent();
            WriteLineNoCommit("]");
            return EndBlock();
        }

        /// <summary>
        /// End attribute part.
        /// </summary>
        public bool EndAttributes(int pos)
        {
            bool commit = EndAttributes();
            if (!commit)
                Position = pos;
            return commit;
        }

        /// <summary>
        /// Write attribute of type Unit, Color, int, float, double, bool, string or enum.
        /// </summary>
        public void WriteSimpleAttribute(string valueName, object value)
        {
            INullableValue ival = value as INullableValue;
            if (ival != null)
                value = ival.GetValue();

            Type type = value.GetType();

            if (type == typeof(Unit))
            {
                string strUnit = value.ToString();
                if (((Unit)value).Type == UnitType.Point)
                    WriteLine(valueName + " = " + strUnit);
                else
                    WriteLine(valueName + " = \"" + strUnit + "\"");
            }
            else if (type == typeof(float))
            {
                WriteLine(valueName + " = " + ((float)value).ToString(CultureInfo.InvariantCulture));
            }
            else if (type == typeof(double))
            {
                WriteLine(valueName + " = " + ((double)value).ToString(CultureInfo.InvariantCulture));
            }
            else if (type == typeof(bool))
            {
                WriteLine(valueName + " = " + value.ToString().ToLower());
            }
            else if (type == typeof(string))
            {
                StringBuilder sb = new StringBuilder(value.ToString());
                sb.Replace("\\", "\\\\");
                sb.Replace("\"", "\\\"");
                WriteLine(valueName + " = \"" + sb + "\"");
            }
#if !NETFX_CORE
            else if (type == typeof(int) || type.BaseType == typeof(Enum) || type == typeof(Color))
#else
            else if (type == typeof(int) || type.GetTypeInfo().BaseType == typeof(Enum) || type == typeof(Color))
#endif
            {
                WriteLine(valueName + " = " + value);
            }
            else
            {
                string message = String.Format("Type '{0}' of value '{1}' not supported", type, valueName);
                Debug.Assert(false, message);
            }
        }

        /// <summary>
        /// Start content part.
        /// </summary>
        public int BeginContent()
        {
            int pos = Position;
            WriteLineNoCommit("{");
            IncreaseIndent();
            BeginBlock();
            return pos;
        }

        /// <summary>
        /// Start content part.
        /// </summary>
        public int BeginContent(string str)
        {
            int pos = Position;
            WriteLineNoCommit(str);
            WriteLineNoCommit("{");
            IncreaseIndent();
            BeginBlock();
            return pos;
        }

        /// <summary>
        /// End content part.
        /// </summary>
        public bool EndContent()
        {
            DecreaseIndent();
            WriteLineNoCommit("}");
            return EndBlock();
        }

        /// <summary>
        /// End content part.
        /// </summary>
        public bool EndContent(int pos)
        {
            bool commit = EndContent();
            if (!commit)
                Position = pos;
            return commit;
        }

        /// <summary>
        /// Starts a new nesting block.
        /// </summary>
        public int BeginBlock()
        {
            int pos = Position;
            if (_stackIdx + 1 >= _commitTextStack.Length)
                throw new ArgumentException("Block nesting level exhausted.");
            _stackIdx += 1;
            _commitTextStack[_stackIdx] = false;
            return pos;
        }

        /// <summary>
        /// Ends a nesting block.
        /// </summary>
        public bool EndBlock()
        {
            if (_stackIdx <= 0)
                throw new ArgumentException("Block nesting level underflow.");
            _stackIdx -= 1;
            if (_commitTextStack[_stackIdx + 1])
                _commitTextStack[_stackIdx] = _commitTextStack[_stackIdx + 1];
            return _commitTextStack[_stackIdx + 1];
        }

        /// <summary>
        /// Ends a nesting block.
        /// </summary>
        public bool EndBlock(int pos)
        {
            bool commit = EndBlock();
            if (!commit)
                Position = pos;
            return commit;
        }

        /// <summary>
        /// Gets or sets the position within the underlying stream.
        /// </summary>
        int Position
        {
            get
            {
                _textWriter.Flush();
                StreamWriter streamWriter = _textWriter as StreamWriter;
                if (streamWriter != null)
                    return (int)streamWriter.BaseStream.Position;

                StringWriter stringWriter = _textWriter as StringWriter;
                if (stringWriter != null)
                    return stringWriter.GetStringBuilder().Length;

                return 0;
            }
            set
            {
                _textWriter.Flush();
                StreamWriter streamWriter = _textWriter as StreamWriter;
                if (streamWriter != null)
                    streamWriter.BaseStream.SetLength(value);
                else
                {
                    StringWriter stringWriter = _textWriter as StringWriter;
                    if (stringWriter != null)
                        stringWriter.GetStringBuilder().Length = value;
                }
            }
        }

        /// <summary>
        /// Flushes the buffers of the underlying text writer.
        /// </summary>
        public void Flush()
        {
            _textWriter.Flush();
        }

        /// <summary>
        /// Returns an indent string of blanks.
        /// </summary>
        static string Ind(int indent)
        {
            return new String(' ', indent);
        }

        /// <summary>
        /// Gets an indent string of current indent.
        /// </summary>
        string Indentation
        {
            get { return Ind(_writeIndent); }
        }

        /// <summary>
        /// Marks the current block as 'committed'. That means the block contains
        /// serialized data.
        /// </summary>
        private void CommitText()
        {
            _commitTextStack[_stackIdx] = true;
        }
        int _stackIdx;
        readonly bool[] _commitTextStack = new bool[32];

        int _linePos;
        const int LineBreakBeyond = 200;
        char _lastChar;
        bool _fWriteStamp = false;
    }
}