1 files changed, 33 insertions, 5 deletions
diff --git a/src/main/scala/reading/models/Filter.scala b/src/main/scala/reading/models/Filter.scala
index d14ca63..7ec6340 100644
--- a/src/main/scala/reading/models/Filter.scala
+++ b/src/main/scala/reading/models/Filter.scala
@@ -5,6 +5,16 @@ trait Filter {
   def kind: FilterKind
   def nonFormattedName: String
   def name: String
+
+  override def equals(that: Any): Boolean =
+    that match {
+      case that: Filter =>
+        this.kind == that.kind && this.name == that.name
+      case _ =>
+        false
+    }
+
+  override def hashCode: Int = this.kind.hashCode + this.nonFormattedName.hashCode
 }
 
 object Filter {
@@ -23,15 +33,33 @@ object Filter {
     }
 
   def contains(filters: Seq[Filter], filter: Filter): Boolean =
-    filters.find(equals(_, filter)).nonEmpty
-
-  def equals(f1: Filter, f2: Filter): Boolean =
-    f1.kind == f2.kind && f1.name == f2.name
+    filters.find(_ == filter).nonEmpty
 
   def remove(fs: Seq[Filter], rf: Filter): Seq[Filter] =
     fs.filterNot { f =>
-      (equals(f, rf)
+      (f == rf
         || rf.kind == FilterKind.Grade && f.kind == FilterKind.Program
         || rf.kind == FilterKind.GroupedTheme && f.kind == FilterKind.Theme)
     }
+
+  val onBooks: Map[Filter, Seq[Book]] =
+    Seq(
+      Grade.values.map(Filter.apply(_)),
+      Program.values.map(Filter.apply(_)),
+      Theme.values.map(Filter.apply(_)),
+      GroupedTheme.values.map(Filter.apply(_)),
+      Genre.values.map(Filter.apply(_)),
+      Level.values.map(Filter.apply(_)),
+      Period.values.map(Filter.apply(_))
+    )
+      .flatten
+      .map(f => (f, Books().filter(f.filter)))
+      .toMap
+
+  def add(books: Seq[Book], filters: Seq[Filter]): Seq[Book] =
+    filters.foldLeft(books)(add)
+
+  def add(books: Seq[Book], filter: Filter): Seq[Book] =
+    books.intersect(onBooks.getOrElse(filter, Nil))
+
 }