1 files changed, 184 insertions, 0 deletions
diff --git a/MediaBrowser.Api/SimilarItemsHelper.cs b/MediaBrowser.Api/SimilarItemsHelper.cs
new file mode 100644
index 000000000..e64ccb11d
--- /dev/null
+++ b/MediaBrowser.Api/SimilarItemsHelper.cs
@@ -0,0 +1,184 @@
+using MediaBrowser.Controller.Dto;
+using MediaBrowser.Controller.Entities;
+using MediaBrowser.Controller.Entities.Audio;
+using MediaBrowser.Controller.Library;
+using MediaBrowser.Controller.Persistence;
+using MediaBrowser.Model.Entities;
+using MediaBrowser.Model.Logging;
+using MediaBrowser.Model.Querying;
+using ServiceStack.ServiceHost;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace MediaBrowser.Api
+{
+    /// <summary>
+    /// Class BaseGetSimilarItems
+    /// </summary>
+    public class BaseGetSimilarItems : IReturn<ItemsResult>
+    {
+        /// <summary>
+        /// Gets or sets the user id.
+        /// </summary>
+        /// <value>The user id.</value>
+        [ApiMember(Name = "UserId", Description = "Optional. Filter by user id, and attach user data", IsRequired = false, DataType = "string", ParameterType = "query", Verb = "GET")]
+        public Guid? UserId { get; set; }
+
+        /// <summary>
+        /// Gets or sets the id.
+        /// </summary>
+        /// <value>The id.</value>
+        [ApiMember(Name = "Id", Description = "Item Id", IsRequired = true, DataType = "string", ParameterType = "path", Verb = "GET")]
+        public string Id { get; set; }
+
+        /// <summary>
+        /// The maximum number of items to return
+        /// </summary>
+        /// <value>The limit.</value>
+        [ApiMember(Name = "Limit", Description = "Optional. The maximum number of records to return", IsRequired = false, DataType = "int", ParameterType = "query", Verb = "GET")]
+        public int? Limit { get; set; }
+    }
+
+    /// <summary>
+    /// Class SimilarItemsHelper
+    /// </summary>
+    public static class SimilarItemsHelper
+    {
+        /// <summary>
+        /// Gets the similar items.
+        /// </summary>
+        /// <param name="userManager">The user manager.</param>
+        /// <param name="libraryManager">The library manager.</param>
+        /// <param name="userDataRepository">The user data repository.</param>
+        /// <param name="logger">The logger.</param>
+        /// <param name="request">The request.</param>
+        /// <param name="includeInSearch">The include in search.</param>
+        /// <param name="getSimilarityScore">The get similarity score.</param>
+        /// <returns>ItemsResult.</returns>
+        internal static ItemsResult GetSimilarItems(IUserManager userManager, ILibraryManager libraryManager, IUserDataRepository userDataRepository, ILogger logger, BaseGetSimilarItems request, Func<BaseItem, bool> includeInSearch, Func<BaseItem, BaseItem, int> getSimilarityScore)
+        {
+            var user = request.UserId.HasValue ? userManager.GetUserById(request.UserId.Value) : null;
+
+            var item = string.IsNullOrEmpty(request.Id) ?
+                (request.UserId.HasValue ? user.RootFolder :
+                (Folder)libraryManager.RootFolder) : DtoBuilder.GetItemByClientId(request.Id, userManager, libraryManager, request.UserId);
+
+            // Get everything
+            var fields = Enum.GetNames(typeof(ItemFields)).Select(i => (ItemFields)Enum.Parse(typeof(ItemFields), i, true)).ToList();
+
+            var dtoBuilder = new DtoBuilder(logger, libraryManager, userDataRepository);
+
+            var inputItems = user == null
+                                 ? libraryManager.RootFolder.RecursiveChildren
+                                 : user.RootFolder.GetRecursiveChildren(user);
+
+            var items = GetSimilaritems(item, inputItems, includeInSearch, getSimilarityScore).ToArray();
+
+            var result = new ItemsResult
+            {
+                Items = items.Take(request.Limit ?? items.Length).Select(i => dtoBuilder.GetBaseItemDto(i, fields, user)).Select(t => t.Result).ToArray(),
+
+                TotalRecordCount = items.Length
+            };
+
+            return result;
+        }
+
+        /// <summary>
+        /// Gets the similaritems.
+        /// </summary>
+        /// <param name="item">The item.</param>
+        /// <param name="inputItems">The input items.</param>
+        /// <param name="includeInSearch">The include in search.</param>
+        /// <param name="getSimilarityScore">The get similarity score.</param>
+        /// <returns>IEnumerable{BaseItem}.</returns>
+        private static IEnumerable<BaseItem> GetSimilaritems(BaseItem item, IEnumerable<BaseItem> inputItems, Func<BaseItem, bool> includeInSearch, Func<BaseItem, BaseItem, int> getSimilarityScore)
+        {
+            inputItems = inputItems.Where(includeInSearch);
+
+            // Avoid implicitly captured closure
+            var currentItem = item;
+
+            return inputItems.Where(i => i.Id != currentItem.Id)
+                .Select(i => new Tuple<BaseItem, int>(i, getSimilarityScore(item, i)))
+                .Where(i => i.Item2 > 0)
+                .OrderByDescending(i => i.Item2)
+                .ThenByDescending(i => i.Item1.CriticRating ?? 0)
+                .Select(i => i.Item1);
+        }
+
+        /// <summary>
+        /// Gets the similiarity score.
+        /// </summary>
+        /// <param name="item1">The item1.</param>
+        /// <param name="item2">The item2.</param>
+        /// <returns>System.Int32.</returns>
+        internal static int GetSimiliarityScore(BaseItem item1, BaseItem item2)
+        {
+            var points = 0;
+
+            if (!string.IsNullOrEmpty(item1.OfficialRating) && string.Equals(item1.OfficialRating, item2.OfficialRating, StringComparison.OrdinalIgnoreCase))
+            {
+                points += 1;
+            }
+
+            // Find common genres
+            points += item1.Genres.Where(i => item2.Genres.Contains(i, StringComparer.OrdinalIgnoreCase)).Sum(i => 5);
+
+            // Find common tags
+            points += item1.Tags.Where(i => item2.Tags.Contains(i, StringComparer.OrdinalIgnoreCase)).Sum(i => 5);
+
+            // Find common studios
+            points += item1.Studios.Where(i => item2.Studios.Contains(i, StringComparer.OrdinalIgnoreCase)).Sum(i => 3);
+
+            var item2PeopleNames = item2.People.Select(i => i.Name).ToList();
+
+            points += item1.People.Where(i => item2PeopleNames.Contains(i.Name, StringComparer.OrdinalIgnoreCase)).Sum(i =>
+            {
+                if (string.Equals(i.Name, PersonType.Director, StringComparison.OrdinalIgnoreCase))
+                {
+                    return 5;
+                }
+                if (string.Equals(i.Name, PersonType.Actor, StringComparison.OrdinalIgnoreCase))
+                {
+                    return 3;
+                }
+                if (string.Equals(i.Name, PersonType.Composer, StringComparison.OrdinalIgnoreCase))
+                {
+                    return 3;
+                }
+                if (string.Equals(i.Name, PersonType.GuestStar, StringComparison.OrdinalIgnoreCase))
+                {
+                    return 3;
+                }
+                if (string.Equals(i.Name, PersonType.Writer, StringComparison.OrdinalIgnoreCase))
+                {
+                    return 2;
+                }
+
+                return 1;
+            });
+
+            if (item1.ProductionYear.HasValue && item2.ProductionYear.HasValue)
+            {
+                var diff = Math.Abs(item1.ProductionYear.Value - item2.ProductionYear.Value);
+
+                // Add if they came out within the same decade
+                if (diff < 10)
+                {
+                    points += 3;
+                }
+
+                // And more if within five years
+                if (diff < 5)
+                {
+                    points += 3;
+                }
+            }
+
+            return points;
+        }
+
+    }
+}