using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Sitecore.Data.Items;
using Sitecore.Events;
using Sitecore.Layouts;
using Sitecore.Data.Fields;

namespace ParTech.Library.Events
{
    public class EnsureDataSourceIsGUID
    {
        public void OnItemSaving(object sender, EventArgs args)
        {
            Item item = Event.ExtractParameter(args, 0) as Item;
            if (item == null)
            {
                return;
            }

            LayoutField layoutField = new LayoutField(item.Fields[Sitecore.FieldIDs.LayoutField]);
            if (!layoutField.InnerField.HasValue)
            {
                return;
            }

            Item existingItem = item.Database.GetItem(item.ID, item.Language, item.Version);

            if (existingItem == null)
            {
                return;
            }

            LayoutField oldLayout = new LayoutField(existingItem.Fields[Sitecore.FieldIDs.LayoutField]);
            if (string.IsNullOrEmpty(layoutField.Value) || layoutField.Value == oldLayout.Value)
            {
                return;
            }

            LayoutDefinition layout = LayoutDefinition.Parse(layoutField.Value);

            for (int i = 0; i < layout.Devices.Count; i++)
            {
                DeviceDefinition device = layout.Devices[i] as DeviceDefinition;
                for (int j = 0; j < device.Renderings.Count; j++)
                {
                    RenderingDefinition rendering = device.Renderings[j] as RenderingDefinition;
                    if (!string.IsNullOrEmpty(rendering.Datasource) && rendering.Datasource.StartsWith("/"))
                    {
                        Item datasourceItem = item.Database.GetItem(rendering.Datasource);
                        if (datasourceItem == null)
                        {
                            Sitecore.Diagnostics.Log.Warn(string.Format("Could not find datasource item at path {0} while saving item {1}", rendering.Datasource, item.ID), this);
                            continue;
                        }
                        rendering.Datasource = datasourceItem.ID.ToString();
                    }
                }
            }

            layoutField.Value = layout.ToXml();
        }
    }
}