Add ability to reorder playlist items

utils/strings.go

@@ -25,3 +25,16 @@ func StringInSlice(a string, list []string) bool {
 	}
 	return false
 }
+
+func InsertString(array []string, value string, index int) []string {
+	return append(array[:index], append([]string{value}, array[index:]...)...)
+}
+
+func RemoveString(array []string, index int) []string {
+	return append(array[:index], array[index+1:]...)
+}
+
+func MoveString(array []string, srcIndex int, dstIndex int) []string {
+	value := array[srcIndex]
+	return InsertString(RemoveString(array, srcIndex), value, dstIndex)
+}

utils/strings_test.go

@@ -48,4 +48,16 @@ var _ = Describe("Strings", func() {
 			Expect(StringInSlice("bbb", []string{"bbb", "aaa", "ccc"})).To(BeTrue())
 		})
 	})
+
+	Describe("MoveString", func() {
+		It("moves item to end of slice", func() {
+			Expect(MoveString([]string{"1", "2", "3"}, 0, 2)).To(ConsistOf("2", "3", "1"))
+		})
+		It("moves item to beginning of slice", func() {
+			Expect(MoveString([]string{"1", "2", "3"}, 2, 0)).To(ConsistOf("3", "1", "2"))
+		})
+		It("keeps item in same position if srcIndex == dstIndex", func() {
+			Expect(MoveString([]string{"1", "2", "3"}, 1, 1)).To(ConsistOf("1", "2", "3"))
+		})
+	})
 })