// Copyright (c) 2004, 2016, Oracle and/or its affiliates. All rights reserved.
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License, version 2.0, as
// published by the Free Software Foundation.
//
// This program is also distributed with certain software (including
// but not limited to OpenSSL) that is licensed under separate terms,
// as designated in a particular file or component or in included license
// documentation.  The authors of MySQL hereby grant you an
// additional permission to link the program and your derivative works
// with the separately licensed software that they have included with
// MySQL.
//
// Without limiting anything contained in the foregoing, this file,
// which is part of MySQL Connector/NET, is also subject to the
// Universal FOSS Exception, version 1.0, a copy of which can be found at
// http://oss.oracle.com/licenses/universal-foss-exception.
//
// 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, version 2.0, for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software Foundation, Inc.,
// 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA

using System;
using System.Collections;
using System.Text;

namespace MySql.Data.Common
{
    internal class ContextString
    {
        readonly bool _escapeBackslash;

        // Create a private ctor so the compiler doesn't give us a default one
        public ContextString(string contextMarkers, bool escapeBackslash)
        {
            this.ContextMarkers = contextMarkers;
            this._escapeBackslash = escapeBackslash;
        }

        public string ContextMarkers { get; set; }

        public int IndexOf(string src, string target)
        {
            return this.IndexOf(src, target, 0);
        }

        public int IndexOf(string src, string target, int startIndex)
        {
            int index = src.IndexOf(target, startIndex);
            while (index != -1)
            {
                if (!this.IndexInQuotes(src, index, startIndex))
                {
                    break;
                }

                index = src.IndexOf(target, index + 1);
            }

            return index;
        }

        private bool IndexInQuotes(string src, int index, int startIndex)
        {
            char contextMarker = Char.MinValue;
            bool escaped = false;

            for (int i = startIndex; i < index; i++)
            {
                char c = src[i];

                int contextIndex = this.ContextMarkers.IndexOf(c);

                // if we have found the closing marker for our open marker, then close the context
                if (contextIndex > -1 && contextMarker == this.ContextMarkers[contextIndex] && !escaped)
                {
                    contextMarker = Char.MinValue;
                }

                // if we have found a context marker and we are not in a context yet, then start one
                else if (contextMarker == Char.MinValue && contextIndex > -1 && !escaped)
                {
                    contextMarker = c;
                }
                else if (c == '\\' && this._escapeBackslash)
                {
                    escaped = !escaped;
                }
            }

            return contextMarker != Char.MinValue || escaped;
        }

        public int IndexOf(string src, char target)
        {
            char contextMarker = Char.MinValue;
            bool escaped = false;
            int pos = 0;

            foreach (char c in src)
            {
                int contextIndex = this.ContextMarkers.IndexOf(c);

                // if we have found the closing marker for our open marker, then close the context
                if (contextIndex > -1 && contextMarker == this.ContextMarkers[contextIndex] && !escaped)
                {
                    contextMarker = Char.MinValue;
                }

                // if we have found a context marker and we are not in a context yet, then start one
                else if (contextMarker == Char.MinValue && contextIndex > -1 && !escaped)
                {
                    contextMarker = c;
                }
                else if (contextMarker == Char.MinValue && c == target)
                {
                    return pos;
                }
                else if (c == '\\' && this._escapeBackslash)
                {
                    escaped = !escaped;
                }

                pos++;
            }

            return -1;
        }

        public string[] Split(string src, string delimiters)
        {
            ArrayList parts = new ArrayList();
            StringBuilder sb = new StringBuilder();
            bool escaped = false;

            char contextMarker = Char.MinValue;

            foreach (char c in src)
            {
                if (delimiters.IndexOf(c) != -1 && !escaped)
                {
                    if (contextMarker != Char.MinValue)
                    {
                        sb.Append(c);
                    }
                    else
                    {
                        if (sb.Length <= 0)
                        {
                            continue;
                        }

                        parts.Add(sb.ToString());
                        sb.Remove(0, sb.Length);
                    }
                }
                else if (c == '\\' && this._escapeBackslash)
                {
                    escaped = !escaped;
                }
                else
                {
                    int contextIndex = this.ContextMarkers.IndexOf(c);
                    if (!escaped && contextIndex != -1)
                    {
                        // if we have found the closing marker for our open 
                        // marker, then close the context
                        if ((contextIndex % 2) == 1)
                        {
                            if (contextMarker == this.ContextMarkers[contextIndex - 1])
                            {
                                contextMarker = Char.MinValue;
                            }
                        }
                        else
                        {
                            // if the opening and closing context markers are 
                            // the same then we will always find the opening
                            // marker.
                            if (contextMarker == this.ContextMarkers[contextIndex + 1])
                            {
                                contextMarker = Char.MinValue;
                            }
                            else if (contextMarker == Char.MinValue)
                            {
                                contextMarker = c;
                            }
                        }
                    }

                    sb.Append(c);
                }
            }

            if (sb.Length > 0)
            {
                parts.Add(sb.ToString());
            }

            return (string[])parts.ToArray(typeof(string));
        }
    }
}