using System;
using System.IO;
using System.Text;

namespace SetAssemblyVersion
{
    /// <summary>
    /// A small utility to stamp the version of our .net API assemblies
    /// 
    /// Original source: http://www.codeproject.com/Articles/31236/How-To-Update-Assembly-Version-Number-Automaticall
    /// </summary>
    class AssemblyInfoUtil
    {
        private static int incParamNum = 0;

        private static string fileName = "";

        private static string versionStr = null;

        private static bool isVB = false;

        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        [STAThread]
        static void Main(string[] args)
        {
            for (int i = 0; i < args.Length; i++)
            {
                if (args[i].StartsWith("-inc:"))
                {
                    string s = args[i].Substring("-inc:".Length);
                    incParamNum = int.Parse(s);
                }
                else if (args[i].StartsWith("-set:"))
                {
                    versionStr = args[i].Substring("-set:".Length);
                }
                else
                    fileName = args[i];
            }

            if (Path.GetExtension(fileName).ToLower() == ".vb")
                isVB = true;

            if (fileName == "")
            {
                System.Console.WriteLine("Usage: AssemblyInfoUtil <path to AssemblyInfo.cs or AssemblyInfo.vb file> [options]");
                System.Console.WriteLine("Options: ");
                System.Console.WriteLine("  -set:<new version number> - set new version number (in NN.NN.NN.NN format)");
                System.Console.WriteLine("  -inc:<parameter index>  - increases the parameter with specified index (can be from 1 to 4)");
                return;
            }

            if (!File.Exists(fileName))
            {
                System.Console.WriteLine("Error: Can not find file \"" + fileName + "\"");
                return;
            }

            System.Console.Write("Processing \"" + fileName + "\"...");
            StreamReader reader = new StreamReader(fileName);
            StreamWriter writer = new StreamWriter(fileName + ".out");
            String line;

            while ((line = reader.ReadLine()) != null)
            {
                line = ProcessLine(line);
                writer.WriteLine(line);
            }
            reader.Close();
            writer.Close();

            File.Delete(fileName);
            File.Move(fileName + ".out", fileName);
            System.Console.WriteLine("Done!");
        }

        private static string ProcessLine(string line)
        {
            if (isVB)
            {
                line = ProcessLinePart(line, "<Assembly: AssemblyVersion(\"");
                line = ProcessLinePart(line, "<Assembly: AssemblyFileVersion(\"");
                line = ProcessLinePart(line, "<Assembly: AssemblyInformationalVersion(\"");
            }
            else
            {
                line = ProcessLinePart(line, "[assembly: AssemblyVersion(\"");
                line = ProcessLinePart(line, "[assembly: AssemblyFileVersion(\"");
                line = ProcessLinePart(line, "[assembly: AssemblyInformationalVersion(\"");
            }
            return line;
        }

        private static string ProcessLinePart(string line, string part)
        {
            int spos = line.IndexOf(part);
            if (spos >= 0)
            {
                spos += part.Length;
                int epos = line.IndexOf('"', spos);
                string oldVersion = line.Substring(spos, epos - spos);
                string newVersion = "";
                bool performChange = false;

                if (incParamNum > 0)
                {
                    string[] nums = oldVersion.Split('.');
                    if (nums.Length >= incParamNum && nums[incParamNum - 1] != "*")
                    {
                        Int64 val = Int64.Parse(nums[incParamNum - 1]);
                        val++;
                        nums[incParamNum - 1] = val.ToString();
                        newVersion = nums[0];
                        for (int i = 1; i < nums.Length; i++)
                        {
                            newVersion += "." + nums[i];
                        }
                        performChange = true;
                    }
                }

                else if (versionStr != null)
                {
                    newVersion = versionStr;
                    performChange = true;
                }

                if (performChange)
                {
                    StringBuilder str = new StringBuilder(line);
                    str.Remove(spos, epos - spos);
                    str.Insert(spos, newVersion);
                    line = str.ToString();
                }
            }
            return line;
        }
    }
}