package notifier

import (
	"context"
	"net/url"
	"testing"

	alertingImages "github.com/grafana/alerting/images"
	"github.com/grafana/alerting/receivers"
	alertingEmail "github.com/grafana/alerting/receivers/email/v1"
	alertingTemplates "github.com/grafana/alerting/templates"
	"github.com/prometheus/alertmanager/types"
	"github.com/prometheus/common/model"
	"github.com/stretchr/testify/require"

	"github.com/grafana/grafana/pkg/bus"
	"github.com/grafana/grafana/pkg/infra/log/logtest"
	"github.com/grafana/grafana/pkg/infra/tracing"
	"github.com/grafana/grafana/pkg/services/notifications"
	"github.com/grafana/grafana/pkg/setting"
)

// TestEmailNotifierIntegration tests channels.EmailNotifier in conjunction with Grafana notifications.EmailSender and two staged expansion of the alertingEmail body
func TestEmailNotifierIntegration(t *testing.T) {
	ns := createEmailSender(t)

	emailTmpl := alertingTemplates.ForTests(t)
	externalURL, err := url.Parse("http://localhost/base")
	require.NoError(t, err)
	emailTmpl.ExternalURL = externalURL

	cases := []struct {
		name        string
		alerts      []*types.Alert
		messageTmpl string
		subjectTmpl string
		expSubject  string
		expSnippets []string
	}{
		{
			name: "single alert with templated message",
			alerts: []*types.Alert{
				{
					Alert: model.Alert{
						Labels:      model.LabelSet{"alertname": "AlwaysFiring", "severity": "warning"},
						Annotations: model.LabelSet{"runbook_url": "http://fix.me", "__dashboardUid__": "abc", "__panelId__": "5"},
					},
				},
			},
			messageTmpl: `Hi, this is a custom template.
				{{ if gt (len .Alerts.Firing) 0 }}
					You have {{ len .Alerts.Firing }} alerts firing.
					{{ range .Alerts.Firing }} Firing: {{ .Labels.alertname }} at {{ .Labels.severity }} {{ end }}
				{{ end }}`,
			expSubject: "[FIRING:1]  (AlwaysFiring warning)",
			expSnippets: []string{
				"Hi, this is a custom template.",
				"You have 1 alerts firing.",
				"Firing: AlwaysFiring at warning",
			},
		},
		{
			name: "multiple alerts with templated message",
			alerts: []*types.Alert{
				{
					Alert: model.Alert{
						Labels:      model.LabelSet{"alertname": "FiringOne", "severity": "warning"},
						Annotations: model.LabelSet{"runbook_url": "http://fix.me", "__dashboardUid__": "abc", "__panelId__": "5"},
					},
				},
				{
					Alert: model.Alert{
						Labels:      model.LabelSet{"alertname": "FiringTwo", "severity": "critical"},
						Annotations: model.LabelSet{"runbook_url": "http://fix.me", "__dashboardUid__": "abc", "__panelId__": "5"},
					},
				},
			},
			messageTmpl: `Hi, this is a custom template.
				{{ if gt (len .Alerts.Firing) 0 }}
					You have {{ len .Alerts.Firing }} alerts firing.
					{{ range .Alerts.Firing }} Firing: {{ .Labels.alertname }} at {{ .Labels.severity }} {{ end }}
				{{ end }}`,
			expSubject: "[FIRING:2]  ",
			expSnippets: []string{
				"Hi, this is a custom template.",
				"You have 2 alerts firing.",
				"Firing: FiringOne at warning",
				"Firing: FiringTwo at critical",
			},
		},
		{
			name: "empty message with alerts uses default template content",
			alerts: []*types.Alert{
				{
					Alert: model.Alert{
						Labels:      model.LabelSet{"alertname": "FiringOne", "severity": "warning"},
						Annotations: model.LabelSet{"runbook_url": "http://fix.me", "__dashboardUid__": "abc", "__panelId__": "5"},
					},
				},
				{
					Alert: model.Alert{
						Labels:      model.LabelSet{"alertname": "FiringTwo", "severity": "critical"},
						Annotations: model.LabelSet{"runbook_url": "http://fix.me", "__dashboardUid__": "abc", "__panelId__": "5"},
					},
				},
			},
			messageTmpl: "",
			expSubject:  "[FIRING:2]  ",
			expSnippets: []string{
				"2 firing instances",
				"<strong>severity</strong>",
				"warning",
				"critical",
				"<strong>alertname</strong>",
				"FiringTwo",
				"FiringOne",
				"<a href=\"http://fix.me\"",
				"<a href=\"http://localhost/base/d/abc",
				"<a href=\"http://localhost/base/d/abc?viewPanel=5",
			},
		},
		{
			name: "message containing HTML gets HTMLencoded",
			alerts: []*types.Alert{
				{
					Alert: model.Alert{
						Labels:      model.LabelSet{"alertname": "AlwaysFiring", "severity": "warning"},
						Annotations: model.LabelSet{"runbook_url": "http://fix.me", "__dashboardUid__": "abc", "__panelId__": "5"},
					},
				},
			},
			messageTmpl: `<marquee>Hi, this is a custom template.</marquee>
				{{ if gt (len .Alerts.Firing) 0 }}
					<ol>
					{{range .Alerts.Firing }}<li>Firing: {{ .Labels.alertname }} at {{ .Labels.severity }} </li> {{ end }}
					</ol>
				{{ end }}`,
			expSubject: "[FIRING:1]  (AlwaysFiring warning)",
			expSnippets: []string{
				"&lt;marquee&gt;Hi, this is a custom template.&lt;/marquee&gt;",
				"&lt;li&gt;Firing: AlwaysFiring at warning &lt;/li&gt;",
			},
		},
		{
			name: "single alert with templated subject",
			alerts: []*types.Alert{
				{
					Alert: model.Alert{
						Labels:      model.LabelSet{"alertname": "AlwaysFiring", "severity": "warning"},
						Annotations: model.LabelSet{"runbook_url": "http://fix.me", "__dashboardUid__": "abc", "__panelId__": "5"},
					},
				},
			},
			subjectTmpl: `This notification is {{ .Status }}!`,
			expSubject:  "This notification is firing!",
			expSnippets: []string{},
		},
	}

	for _, c := range cases {
		t.Run(c.name, func(t *testing.T) {
			emailNotifier := createSut(t, c.messageTmpl, c.subjectTmpl, emailTmpl, ns)

			ok, err := emailNotifier.Notify(context.Background(), c.alerts...)
			require.NoError(t, err)
			require.True(t, ok)

			sentMsg := getSingleSentMessage(t, ns)

			require.NotNil(t, sentMsg)

			require.Equal(t, "\"Grafana Admin\" <from@address.com>", sentMsg.From)
			require.Equal(t, sentMsg.To[0], "someops@example.com")

			require.Equal(t, c.expSubject, sentMsg.Subject)

			require.Contains(t, sentMsg.Body, "text/html")
			html := sentMsg.Body["text/html"]
			require.NotNil(t, html)

			for _, s := range c.expSnippets {
				require.Contains(t, html, s)
			}
		})
	}
}

func createSut(t *testing.T, messageTmpl string, subjectTmpl string, emailTmpl *alertingTemplates.Template, ns receivers.EmailSender) *alertingEmail.Notifier {
	t.Helper()
	if subjectTmpl == "" {
		subjectTmpl = alertingTemplates.DefaultMessageTitleEmbed
	}
	return alertingEmail.New(alertingEmail.Config{
		SingleEmail: true,
		Addresses: []string{
			"someops@example.com",
			"somedev@example.com",
		},
		Message: messageTmpl,
		Subject: subjectTmpl,
	}, receivers.Metadata{}, emailTmpl, ns, &alertingImages.UnavailableProvider{}, &logtest.Fake{})
}

func getSingleSentMessage(t *testing.T, ns *emailSender) *notifications.Message {
	t.Helper()

	mailer := ns.ns.(*notifications.NotificationService).GetMailer().(*notifications.FakeMailer)
	require.Len(t, mailer.Sent, 1)
	sent := mailer.Sent[0]
	mailer.Sent = []*notifications.Message{}
	return sent
}

func createEmailSender(t *testing.T) *emailSender {
	t.Helper()

	tracer := tracing.InitializeTracerForTest()
	bus := bus.ProvideBus(tracer)

	cfg := setting.NewCfg()
	cfg.StaticRootPath = "../../../../public/"
	cfg.BuildVersion = "4.0.0"
	cfg.Smtp.Enabled = true
	cfg.Smtp.TemplatesPatterns = []string{"emails/*.html", "emails/*.txt"}
	cfg.Smtp.FromAddress = "from@address.com"
	cfg.Smtp.FromName = "Grafana Admin"
	cfg.Smtp.ContentTypes = []string{"text/html", "text/plain"}
	cfg.Smtp.Host = "localhost:1234"
	mailer := notifications.NewFakeMailer()

	ns, err := notifications.ProvideService(bus, cfg, mailer, nil)
	require.NoError(t, err)

	return &emailSender{ns: ns}
}
