refactor: repositories (#28)

* cleanup unnecessary mocks

* refactor document storage location

* remove unused function

* move ownership to document types to repo package

* move types and mappers to repo package

* refactor sets to own package

backend/pkgs/set/funcs.go

@@ -0,0 +1,101 @@
+package set
+
+// Diff returns the difference between two sets
+func Diff[T key](a, b Set[T]) Set[T] {
+	s := New[T]()
+	for k := range a.mp {
+		if !b.Contains(k) {
+			s.Insert(k)
+		}
+	}
+	return s
+}
+
+// Intersect returns the intersection between two sets
+func Intersect[T key](a, b Set[T]) Set[T] {
+	s := New[T]()
+	for k := range a.mp {
+		if b.Contains(k) {
+			s.Insert(k)
+		}
+	}
+	return s
+}
+
+// Union returns the union between two sets
+func Union[T key](a, b Set[T]) Set[T] {
+	s := New[T]()
+	for k := range a.mp {
+		s.Insert(k)
+	}
+	for k := range b.mp {
+		s.Insert(k)
+	}
+	return s
+}
+
+// Xor returns the symmetric difference between two sets
+func Xor[T key](a, b Set[T]) Set[T] {
+	s := New[T]()
+	for k := range a.mp {
+		if !b.Contains(k) {
+			s.Insert(k)
+		}
+	}
+	for k := range b.mp {
+		if !a.Contains(k) {
+			s.Insert(k)
+		}
+	}
+	return s
+}
+
+// Equal returns true if two sets are equal
+func Equal[T key](a, b Set[T]) bool {
+	if a.Len() != b.Len() {
+		return false
+	}
+	for k := range a.mp {
+		if !b.Contains(k) {
+			return false
+		}
+	}
+	return true
+}
+
+// Subset returns true if a is a subset of b
+func Subset[T key](a, b Set[T]) bool {
+	if a.Len() > b.Len() {
+		return false
+	}
+	for k := range a.mp {
+		if !b.Contains(k) {
+			return false
+		}
+	}
+	return true
+}
+
+// Superset returns true if a is a superset of b
+func Superset[T key](a, b Set[T]) bool {
+	if a.Len() < b.Len() {
+		return false
+	}
+	for k := range b.mp {
+		if !a.Contains(k) {
+			return false
+		}
+	}
+	return true
+}
+
+// Disjoint returns true if two sets are disjoint
+func Disjoint[T key](a, b Set[T]) bool {
+	for k := range a.mp {
+		if b.Contains(k) {
+			return false
+		}
+	}
+	return true
+
+}