#region Copyright notice and license



// Protocol Buffers - Google's data interchange format

// Copyright 2008 Google Inc.  All rights reserved.

// http://github.com/jskeet/dotnet-protobufs/

// Original C++/Java/Python code:

// http://code.google.com/p/protobuf/

//

// Redistribution and use in source and binary forms, with or without

// modification, are permitted provided that the following conditions are

// met:

//

//     * Redistributions of source code must retain the above copyright

// notice, this list of conditions and the following disclaimer.

//     * Redistributions in binary form must reproduce the above

// copyright notice, this list of conditions and the following disclaimer

// in the documentation and/or other materials provided with the

// distribution.

//     * Neither the name of Google Inc. nor the names of its

// contributors may be used to endorse or promote products derived from

// this software without specific prior written permission.

//

// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.



#endregion



using System;

using System.Text.RegularExpressions;



namespace Google.ProtocolBuffers

{

    /// <summary>

    /// Helpers for converting names to pascal case etc.

    /// </summary>

    public class NameHelpers

    {

        /// <summary>

        /// All characters that are not alpha-numeric

        /// </summary>

        private static readonly Regex NonAlphaNumericCharacters = new Regex(@"[^a-zA-Z0-9]+");



        /// <summary>

        /// Matches lower-case character that follow either an underscore, or a number

        /// </summary>

        private static readonly Regex UnderscoreOrNumberWithLowerCase = new Regex(@"[0-9_][a-z]");



        /// <summary>

        /// Removes non alpha numeric characters while capitalizing letters that follow

        /// a number or underscore.  The first letter is always upper case.

        /// </summary>

        public static string UnderscoresToPascalCase(string input)

        {

            string name = UnderscoresToUpperCase(input);



            // Pascal case always begins with upper-case letter

            if (Char.IsLower(name[0]))

            {

                char[] chars = name.ToCharArray();

                chars[0] = char.ToUpper(chars[0]);

                return new string(chars);

            }

            return name;

        }



        /// <summary>

        /// Removes non alpha numeric characters while capitalizing letters that follow

        /// a number or underscore.  The first letter is always lower case.

        /// </summary>

        public static string UnderscoresToCamelCase(string input)

        {

            string name = UnderscoresToUpperCase(input);



            // Camel case always begins with lower-case letter

            if (Char.IsUpper(name[0]))

            {

                char[] chars = name.ToCharArray();

                chars[0] = char.ToLower(chars[0]);

                return new string(chars);

            }

            return name;

        }



        /// <summary>

        /// Capitalizes any characters following an '_' or a number '0' - '9' and removes

        /// all non alpha-numeric characters.  If the resulting string begins with a number

        /// an '_' will be prefixed.  

        /// </summary>

        private static string UnderscoresToUpperCase(string input)

        {

            string name = UnderscoreOrNumberWithLowerCase.Replace(input, x => x.Value.ToUpper());

            name = NonAlphaNumericCharacters.Replace(name, String.Empty);



            if (name.Length == 0)

            {

                throw new ArgumentException(String.Format("The field name '{0}' is invalid.", input));

            }



            // Fields can not start with a number

            if (Char.IsNumber(name[0]))

            {

                name = '_' + name;

            }



            return name;

        }



        internal static string StripProto(string text)

        {

            if (!StripSuffix(ref text, ".protodevel"))

            {

                StripSuffix(ref text, ".proto");

            }

            return text;

        }



        /// <summary>

        /// Attempts to strip a suffix from a string, returning whether

        /// or not the suffix was actually present.

        /// </summary>

        public static bool StripSuffix(ref string text, string suffix)

        {

            if (text.EndsWith(suffix))

            {

                text = text.Substring(0, text.Length - suffix.Length);

                return true;

            }

            return false;

        }

    }

}