// 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 (
	"context"
	"testing"
	"time"

	"net/http"
	"net/http/httptest"
	"net/url"

	"github.com/go-kit/kit/log"
	"github.com/prometheus/common/model"
	"github.com/prometheus/prometheus/discovery/targetgroup"
	"github.com/prometheus/prometheus/util/testutil"
)

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

	if err != nil {
		t.Errorf("Unexpected error when initializing 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"},
		ServiceTags: []string{"http"},
	}
	consulDiscovery, err := NewDiscovery(conf, nil)

	if err != nil {
		t.Errorf("Unexpected error when initializing 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 TestConfiguredServiceWithTags(t *testing.T) {
	type testcase struct {
		// What we've configured to watch.
		conf *SDConfig
		// The service we're checking if we should watch or not.
		serviceName string
		serviceTags []string
		shouldWatch bool
	}

	cases := []testcase{
		{
			conf: &SDConfig{
				Services:    []string{"configuredServiceName"},
				ServiceTags: []string{"http", "v1"},
			},
			serviceName: "configuredServiceName",
			serviceTags: []string{""},
			shouldWatch: false,
		},
		{
			conf: &SDConfig{
				Services:    []string{"configuredServiceName"},
				ServiceTags: []string{"http", "v1"},
			},
			serviceName: "configuredServiceName",
			serviceTags: []string{"http", "v1"},
			shouldWatch: true,
		},
		{
			conf: &SDConfig{
				Services:    []string{"configuredServiceName"},
				ServiceTags: []string{"http", "v1"},
			},
			serviceName: "nonConfiguredServiceName",
			serviceTags: []string{""},
			shouldWatch: false,
		},
		{
			conf: &SDConfig{
				Services:    []string{"configuredServiceName"},
				ServiceTags: []string{"http", "v1"},
			},
			serviceName: "nonConfiguredServiceName",
			serviceTags: []string{"http, v1"},
			shouldWatch: false,
		},
		{
			conf: &SDConfig{
				Services:    []string{"configuredServiceName"},
				ServiceTags: []string{"http", "v1"},
			},
			serviceName: "configuredServiceName",
			serviceTags: []string{"http", "v1", "foo"},
			shouldWatch: true,
		},
		{
			conf: &SDConfig{
				Services:    []string{"configuredServiceName"},
				ServiceTags: []string{"http", "v1", "foo"},
			},
			serviceName: "configuredServiceName",
			serviceTags: []string{"http", "v1", "foo"},
			shouldWatch: true,
		},
		{
			conf: &SDConfig{
				Services:    []string{"configuredServiceName"},
				ServiceTags: []string{"http", "v1"},
			},
			serviceName: "configuredServiceName",
			serviceTags: []string{"http", "v1", "v1"},
			shouldWatch: true,
		},
	}

	for _, tc := range cases {
		consulDiscovery, err := NewDiscovery(tc.conf, nil)

		if err != nil {
			t.Errorf("Unexpected error when initializing discovery %v", err)
		}
		ret := consulDiscovery.shouldWatch(tc.serviceName, tc.serviceTags)
		if ret != tc.shouldWatch {
			t.Errorf("Expected should watch? %t, got %t. Watched service and tags: %s %+v, input was %s %+v", tc.shouldWatch, ret, tc.conf.Services, tc.conf.ServiceTags, tc.serviceName, tc.serviceTags)
		}

	}
}

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

	if err != nil {
		t.Errorf("Unexpected error when initializing 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",
"TaggedAddresses": {"lan":"192.168.10.10","wan":"10.0.10.10"},
"NodeMeta": {"rack_name": "2304"},
"ServiceID": "test",
"ServiceName": "test",
"ServiceMeta": {"version":"1.0.0","environment":"stagging"},
"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("Unhandled consul call: %s", r.URL)
		}
		w.Header().Add("X-Consul-Index", "1")
		w.Write([]byte(response))
	}))
	stuburl, err := url.Parse(stub.URL)
	testutil.Ok(t, err)

	config := &SDConfig{
		Server:          stuburl.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)
	testutil.Ok(t, err)
	return d
}

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

// 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.ServiceTags = []string{"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()
}

func TestGetDatacenterShouldReturnError(t *testing.T) {
	for _, tc := range []struct {
		handler    func(http.ResponseWriter, *http.Request)
		errMessage string
	}{
		{
			// Define a handler that will return status 500.
			handler: func(w http.ResponseWriter, r *http.Request) {
				w.WriteHeader(500)
			},
			errMessage: "Unexpected response code: 500 ()",
		},
		{
			// Define a handler that will return incorrect response.
			handler: func(w http.ResponseWriter, r *http.Request) {
				w.Write([]byte(`{"Config": {"Not-Datacenter": "test-dc"}}`))
			},
			errMessage: "invalid value '<nil>' for Config.Datacenter",
		},
	} {
		stub := httptest.NewServer(http.HandlerFunc(tc.handler))
		stuburl, err := url.Parse(stub.URL)
		testutil.Ok(t, err)

		config := &SDConfig{
			Server:          stuburl.Host,
			Token:           "fake-token",
			RefreshInterval: model.Duration(1 * time.Second),
		}
		defer stub.Close()
		d := newDiscovery(t, config)

		// Should be empty if not initialized.
		testutil.Equals(t, "", d.clientDatacenter)

		err = d.getDatacenter()

		// An error should be returned.
		testutil.Equals(t, tc.errMessage, err.Error())
		// Should still be empty.
		testutil.Equals(t, "", d.clientDatacenter)
	}
}
