#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.Globalization;
using System.Text;

namespace Google.ProtocolBuffers
{
    /// <summary>
    /// Helpers for converting names to pascal case etc.
    /// </summary>
    public class NameHelpers
    {
        public static string UnderscoresToPascalCase(string input)
        {
            return UnderscoresToPascalOrCamelCase(input, true);
        }

        public static string UnderscoresToCamelCase(string input)
        {
            return UnderscoresToPascalOrCamelCase(input, false);
        }

        /// <summary>
        /// Converts a string to Pascal or Camel case. The first letter is capitalized or
        /// lower-cased depending on <paramref name="pascal"/> is true. 
        /// After the first letter, any punctuation is removed but triggers capitalization
        /// of the next letter. Digits are preserved but trigger capitalization of the next
        /// letter.
        /// All capitalisation is done in the invariant culture. 
        /// </summary>
        private static string UnderscoresToPascalOrCamelCase(string input, bool pascal)
        {
            StringBuilder result = new StringBuilder();
            bool capitaliseNext = pascal;
            for (int i = 0; i < input.Length; i++)
            {
                char c = input[i];
                if ('a' <= c && c <= 'z')
                {
                    if (capitaliseNext)
                    {
                        result.Append(char.ToUpper(c, CultureInfo.InvariantCulture));
                    }
                    else
                    {
                        result.Append(c);
                    }
                    capitaliseNext = false;
                }
                else if ('A' <= c && c <= 'Z')
                {
                    if (i == 0 && !pascal)
                    {
                        // Force first letter to lower-case unless explicitly told to
                        // capitalize it.
                        result.Append(char.ToLower(c, CultureInfo.InvariantCulture));
                    }
                    else
                    {
                        // Capital letters after the first are left as-is.
                        result.Append(c);
                    }
                    capitaliseNext = false;
                }
                else if ('0' <= c && c <= '9')
                {
                    result.Append(c);
                    capitaliseNext = true;
                }
                else
                {
                    capitaliseNext = true;
                }
            }
            return result.ToString();
        }

        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;
        }
    }
}