// Copyright 2015 The Prometheus 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 consul

import (
	"testing"

	"github.com/stretchr/testify/require"
	"net/http"
	"net/http/httptest"
	"net/url"

	"context"
	"github.com/go-kit/kit/log"
	"github.com/prometheus/common/model"
	"github.com/prometheus/prometheus/discovery/targetgroup"
	"time"
)

func TestConfiguredService(t *testing.T) {
	conf := &SDConfig{
		Services: []string{"configuredServiceName"}}
	consulDiscovery, err := NewDiscovery(conf, nil)

	if err != nil {
		t.Errorf("Unexpected error when initialising discovery %v", err)
	}
	if !consulDiscovery.shouldWatch("configuredServiceName", []string{""}) {
		t.Errorf("Expected service %s to be watched", "configuredServiceName")
	}
	if consulDiscovery.shouldWatch("nonConfiguredServiceName", []string{""}) {
		t.Errorf("Expected service %s to not be watched", "nonConfiguredServiceName")
	}
}

func TestConfiguredServiceWithTag(t *testing.T) {
	conf := &SDConfig{
		Services:   []string{"configuredServiceName"},
		ServiceTag: "http",
	}
	consulDiscovery, err := NewDiscovery(conf, nil)

	if err != nil {
		t.Errorf("Unexpected error when initialising discovery %v", err)
	}
	if consulDiscovery.shouldWatch("configuredServiceName", []string{""}) {
		t.Errorf("Expected service %s to not be watched without tag", "configuredServiceName")
	}
	if !consulDiscovery.shouldWatch("configuredServiceName", []string{"http"}) {
		t.Errorf("Expected service %s to be watched with tag %s", "configuredServiceName", "http")
	}
	if consulDiscovery.shouldWatch("nonConfiguredServiceName", []string{""}) {
		t.Errorf("Expected service %s to not be watched without tag", "nonConfiguredServiceName")
	}
	if consulDiscovery.shouldWatch("nonConfiguredServiceName", []string{"http"}) {
		t.Errorf("Expected service %s to not be watched with tag %s", "nonConfiguredServiceName", "http")
	}
}

func TestNonConfiguredService(t *testing.T) {
	conf := &SDConfig{}
	consulDiscovery, err := NewDiscovery(conf, nil)

	if err != nil {
		t.Errorf("Unexpected error when initialising discovery %v", err)
	}
	if !consulDiscovery.shouldWatch("nonConfiguredServiceName", []string{""}) {
		t.Errorf("Expected service %s to be watched", "nonConfiguredServiceName")
	}
}

const (
	AgentAnswer       = `{"Config": {"Datacenter": "test-dc"}}`
	ServiceTestAnswer = `[{
"ID": "b78c2e48-5ef3-1814-31b8-0d880f50471e",
"Node": "node1",
"Address": "1.1.1.1",
"Datacenter": "test-dc",
"NodeMeta": {"rack_name": "2304"},
"ServiceID": "test",
"ServiceName": "test",
"ServiceTags": ["tag1"],
"ServicePort": 3341,
"CreateIndex": 1,
"ModifyIndex": 1
}]`
	ServicesTestAnswer = `{"test": ["tag1"], "other": ["tag2"]}`
)

func newServer(t *testing.T) (*httptest.Server, *SDConfig) {
	// github.com/hashicorp/consul/testutil/ would be nice but it needs a local consul binary.
	stub := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		response := ""
		switch r.URL.String() {
		case "/v1/agent/self":
			response = AgentAnswer
		case "/v1/catalog/service/test?node-meta=rack_name%3A2304&stale=&tag=tag1&wait=30000ms":
			response = ServiceTestAnswer
		case "/v1/catalog/service/test?wait=30000ms":
			response = ServiceTestAnswer
		case "/v1/catalog/service/other?wait=30000ms":
			response = `[]`
		case "/v1/catalog/services?node-meta=rack_name%3A2304&stale=&wait=30000ms":
			response = ServicesTestAnswer
		case "/v1/catalog/services?wait=30000ms":
			response = ServicesTestAnswer
		case "/v1/catalog/services?index=1&node-meta=rack_name%3A2304&stale=&wait=30000ms":
			time.Sleep(5 * time.Second)
			response = ServicesTestAnswer
		case "/v1/catalog/services?index=1&wait=30000ms":
			time.Sleep(5 * time.Second)
			response = ServicesTestAnswer
		default:
			t.Errorf("Unhandeld consul call: %s", r.URL)
		}
		w.Header().Add("X-Consul-Index", "1")
		w.Write([]byte(response))
	}))
	url, err := url.Parse(stub.URL)
	require.NoError(t, err)

	config := &SDConfig{
		Server:          url.Host,
		Token:           "fake-token",
		RefreshInterval: model.Duration(1 * time.Second),
	}
	return stub, config
}

func newDiscovery(t *testing.T, config *SDConfig) *Discovery {
	logger := log.NewNopLogger()
	d, err := NewDiscovery(config, logger)
	require.NoError(t, err)
	return d
}

func checkOneTarget(t *testing.T, tg []*targetgroup.Group) {
	require.Equal(t, 1, len(tg))
	target := tg[0]
	require.Equal(t, "test-dc", string(target.Labels["__meta_consul_dc"]))
	require.Equal(t, target.Source, string(target.Labels["__meta_consul_service"]))
	if target.Source == "test" {
		// test service should have one node.
		require.NotEmpty(t, target.Targets)
	}
}

// Watch all the services in the catalog.
func TestAllServices(t *testing.T) {
	stub, config := newServer(t)
	defer stub.Close()

	d := newDiscovery(t, config)

	ctx, cancel := context.WithCancel(context.Background())
	ch := make(chan []*targetgroup.Group)
	go d.Run(ctx, ch)
	checkOneTarget(t, <-ch)
	checkOneTarget(t, <-ch)
	cancel()
}

// Watch only the test service.
func TestOneService(t *testing.T) {
	stub, config := newServer(t)
	defer stub.Close()

	config.Services = []string{"test"}
	d := newDiscovery(t, config)

	ctx, cancel := context.WithCancel(context.Background())
	ch := make(chan []*targetgroup.Group)
	go d.Run(ctx, ch)
	checkOneTarget(t, <-ch)
	cancel()
}

// Watch the test service with a specific tag and node-meta.
func TestAllOptions(t *testing.T) {
	stub, config := newServer(t)
	defer stub.Close()

	config.Services = []string{"test"}
	config.NodeMeta = map[string]string{"rack_name": "2304"}
	config.ServiceTag = "tag1"
	config.AllowStale = true
	config.Token = "fake-token"

	d := newDiscovery(t, config)

	ctx, cancel := context.WithCancel(context.Background())
	ch := make(chan []*targetgroup.Group)
	go d.Run(ctx, ch)
	checkOneTarget(t, <-ch)
	cancel()
}