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

using Microsoft.SharePoint;

namespace FixContentType
{
    class Program
    {
        static void Usage()
        {
            Console.WriteLine("Usage:");
            Console.WriteLine("\tFixContentType.exe -url <Web url> -list <list title> -newct <new content type>");
            Console.WriteLine("Example:");
            Console.WriteLine("\tFixContentType.exe -url http://server_name/sites/site_name -list \"test list\" -newct \"Test Content Type\"");
        }

        static void Main(string[] args)
        {
            string sWeb = string.Empty;
            string sList = string.Empty;
            string sCT = string.Empty;

            // Parse command line parameters.
            for (int i = 0; i < args.Length; i++)
            {
                string sInput = args[i];
                switch (sInput.ToLower())
                {
                    case "-url":
                        sWeb = args[++i].ToString();
                        break;
                    case "-list":
                        sList = args[++i].ToString();
                        break;
                    case "-newct":
                        sCT = args[++i].ToString();
                        break;
                    default:
                        Console.WriteLine("Unrecognizable command switch: {0}", sInput);
                        Usage();
                        return;
                }
            }

            // All three parameters are required. Therefore, we must make sure that they are all there.
            if (sWeb == string.Empty ||
                sList == string.Empty ||
                sCT == string.Empty)
            {
                Console.WriteLine("Some swtiches or values are missing!");
                Usage();
                return;
            }

            // Make sure that the Web URL is valid.
            if (!Uri.IsWellFormedUriString(sWeb, UriKind.Absolute))
            {
                Console.WriteLine("The supplied web URL \"{0}\" is invalid", sWeb);
                Usage();
                return;
            }

            try
            {
                using (SPSite site = new SPSite(sWeb))
                {
                    using (SPWeb web = site.OpenWeb())
                    {
                        SPList list;

                        // The list may not exist. Therefore, you must check it.
                        try
                        {
                            list = web.Lists[sList];
                        }
                        catch (ArgumentException)
                        {
                            Console.WriteLine("Error getting list. The list \"{0}\" likely does not exist!", sList);
                            return;
                        }

                        // Make sure that "Allow Content type Management" is enabled in the list. If it is not enabled, enable it first.
                        if (!list.ContentTypesEnabled)
                        {
                            list.ContentTypesEnabled = true;
                            list.Update();
                        }

                        SPContentType contentType;

                        // Make sure that the content type does exist in the Web.
                        try
                        {
                            contentType = web.AvailableContentTypes[sCT];
                        }
                        catch (ArgumentException)
                        {
                            Console.WriteLine("Error getting content type. The content type \"{0}\" likely does not exist!", sCT);
                            return;
                        }

                        // The content type should also be added in the list. If it is not added, add it first.
                        bool typeAdded = true;
                        try
                        {
                            SPContentType testCT = list.ContentTypes[contentType.Id];
                        }
                        catch (ArgumentException)
                        {
                            typeAdded = false; 
                        }

                        if (!typeAdded)
                        {
                            list.ContentTypes.Add(contentType);
                        }

                        // Update 1000 items at one time for performance.
                        SPQuery oQuery = new SPQuery();
                        oQuery.Query = "<Query><OrderBy><FieldRef Name=\"ID\" /></OrderBy></Query>";
                        oQuery.RowLimit = 1000;

                        do {
                        
                            SPListItemCollection items = list.GetItems(oQuery);

                            for (int i = 0; i < items.Count;i++)
                            {
                                SPListItem item = items[i];
                                if (!contentType.Id.IsParentOf((SPContentTypeId) item[SPBuiltInFieldId.ContentTypeId]))
                                {
                                    Console.WriteLine("Updating list item at: {0}", item.Url);
                                    item[SPBuiltInFieldId.ContentTypeId] = contentType.Id;
                                    item.SystemUpdate(false);
                                }
                            }

                            oQuery.ListItemCollectionPosition=items.ListItemCollectionPosition;

                        } while (oQuery.ListItemCollectionPosition != null);
                    }
                }
            }
            catch (Exception ex)
            {
                Console.WriteLine("Error during updating content type: {0}", ex.Message);
            }

        }
    }
}