/*
Copyright 2017 The Kubernetes Authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package source

import (
	"testing"

	"github.com/kubernetes-incubator/external-dns/endpoint"
)

// Validates that multiSource is a Source
var _ Source = &multiSource{}

func TestMultiSource(t *testing.T) {
	t.Run("Endpoints", testMultiSourceEndpoints)
}

// testMultiSourceEndpoints tests merged endpoints from children are returned.
func testMultiSourceEndpoints(t *testing.T) {
	foo := &endpoint.Endpoint{DNSName: "foo", Target: "8.8.8.8"}
	bar := &endpoint.Endpoint{DNSName: "bar", Target: "8.8.4.4"}

	for _, tc := range []struct {
		title           string
		nestedEndpoints [][]*endpoint.Endpoint
		expected        []*endpoint.Endpoint
	}{
		{
			"no child sources return no endpoints",
			nil,
			[]*endpoint.Endpoint{},
		},
		{
			"single empty child source returns no endpoints",
			[][]*endpoint.Endpoint{{}},
			[]*endpoint.Endpoint{},
		},
		{
			"single non-empty child source returns child's endpoints",
			[][]*endpoint.Endpoint{{foo}},
			[]*endpoint.Endpoint{foo},
		},
		{
			"multiple non-empty child sources returns merged children's endpoints",
			[][]*endpoint.Endpoint{{foo}, {bar}},
			[]*endpoint.Endpoint{foo, bar},
		},
	} {
		t.Run(tc.title, func(t *testing.T) {
			// Prepare the nested mock sources
			sources := make([]Source, 0, len(tc.nestedEndpoints))

			for _, endpoints := range tc.nestedEndpoints {
				sources = append(sources, NewMockSource(endpoints))
			}

			// Create our object under test and get the endpoints.
			source := NewMultiSource(sources...)

			endpoints, err := source.Endpoints()
			if err != nil {
				t.Fatal(err)
			}

			// Validate returned endpoints against desired endpoints.
			validateEndpoints(t, endpoints, tc.expected)
		})
	}
}