// Copyright 2019 Prometheus Team
// 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 webhook

import (
	"bytes"
	"context"
	"fmt"
	"io"
	"net/http"
	"net/http/httptest"
	"os"
	"testing"
	"time"

	commoncfg "github.com/prometheus/common/config"
	"github.com/prometheus/common/model"
	"github.com/prometheus/common/promslog"
	"github.com/stretchr/testify/require"

	"github.com/prometheus/alertmanager/config"
	"github.com/prometheus/alertmanager/notify"
	"github.com/prometheus/alertmanager/notify/test"
	"github.com/prometheus/alertmanager/types"
)

func TestWebhookRetry(t *testing.T) {
	notifier, err := New(
		&config.WebhookConfig{
			URL:        config.SecretTemplateURL("http://example.com"),
			HTTPConfig: &commoncfg.HTTPClientConfig{},
		},
		test.CreateTmpl(t),
		promslog.NewNopLogger(),
	)
	if err != nil {
		require.NoError(t, err)
	}

	t.Run("test retry status code", func(t *testing.T) {
		for statusCode, expected := range test.RetryTests(test.DefaultRetryCodes()) {
			actual, _ := notifier.retrier.Check(statusCode, nil)
			require.Equal(t, expected, actual, "error on status %d", statusCode)
		}
	})

	t.Run("test retry error details", func(t *testing.T) {
		for _, tc := range []struct {
			status int
			body   io.Reader

			exp string
		}{
			{
				status: http.StatusBadRequest,
				body: bytes.NewBuffer([]byte(
					`{"status":"invalid event"}`,
				)),

				exp: fmt.Sprintf(`unexpected status code %d: {"status":"invalid event"}`, http.StatusBadRequest),
			},
			{
				status: http.StatusBadRequest,

				exp: fmt.Sprintf(`unexpected status code %d`, http.StatusBadRequest),
			},
		} {
			t.Run("", func(t *testing.T) {
				_, err = notifier.retrier.Check(tc.status, tc.body)
				require.Equal(t, tc.exp, err.Error())
			})
		}
	})
}

func TestWebhookTruncateAlerts(t *testing.T) {
	alerts := make([]*types.Alert, 10)

	truncatedAlerts, numTruncated := truncateAlerts(0, alerts)
	require.Len(t, truncatedAlerts, 10)
	require.EqualValues(t, 0, numTruncated)

	truncatedAlerts, numTruncated = truncateAlerts(4, alerts)
	require.Len(t, truncatedAlerts, 4)
	require.EqualValues(t, 6, numTruncated)

	truncatedAlerts, numTruncated = truncateAlerts(100, alerts)
	require.Len(t, truncatedAlerts, 10)
	require.EqualValues(t, 0, numTruncated)
}

func TestWebhookRedactedURL(t *testing.T) {
	ctx, u, fn := test.GetContextWithCancelingURL()
	defer fn()

	secret := "secret"
	notifier, err := New(
		&config.WebhookConfig{
			URL:        config.SecretTemplateURL(u.String()),
			HTTPConfig: &commoncfg.HTTPClientConfig{},
		},
		test.CreateTmpl(t),
		promslog.NewNopLogger(),
	)
	require.NoError(t, err)

	test.AssertNotifyLeaksNoSecret(ctx, t, notifier, secret)
}

func TestWebhookReadingURLFromFile(t *testing.T) {
	ctx, u, fn := test.GetContextWithCancelingURL()
	defer fn()

	f, err := os.CreateTemp(t.TempDir(), "webhook_url")
	require.NoError(t, err, "creating temp file failed")
	_, err = f.WriteString(u.String() + "\n")
	require.NoError(t, err, "writing to temp file failed")

	notifier, err := New(
		&config.WebhookConfig{
			URLFile:    f.Name(),
			HTTPConfig: &commoncfg.HTTPClientConfig{},
		},
		test.CreateTmpl(t),
		promslog.NewNopLogger(),
	)
	require.NoError(t, err)

	test.AssertNotifyLeaksNoSecret(ctx, t, notifier, u.String())
}

func TestWebhookURLTemplating(t *testing.T) {
	var calledURL string
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		calledURL = r.URL.Path
		w.WriteHeader(http.StatusOK)
	}))
	defer srv.Close()

	tests := []struct {
		name           string
		url            string
		groupLabels    model.LabelSet
		alertLabels    model.LabelSet
		expectError    bool
		expectedErrMsg string
		expectedPath   string
	}{
		{
			name:         "templating with alert labels",
			url:          srv.URL + "/{{ .GroupLabels.alertname }}/{{ .CommonLabels.severity }}",
			groupLabels:  model.LabelSet{"alertname": "TestAlert"},
			alertLabels:  model.LabelSet{"alertname": "TestAlert", "severity": "critical"},
			expectError:  false,
			expectedPath: "/TestAlert/critical",
		},
		{
			name:           "invalid template field",
			url:            srv.URL + "/{{ .InvalidField }}",
			groupLabels:    model.LabelSet{"alertname": "TestAlert"},
			alertLabels:    model.LabelSet{"alertname": "TestAlert"},
			expectError:    true,
			expectedErrMsg: "failed to template webhook URL",
		},
		{
			name:           "template renders to empty string",
			url:            "{{ if .CommonLabels.nonexistent }}http://example.com{{ end }}",
			groupLabels:    model.LabelSet{"alertname": "TestAlert"},
			alertLabels:    model.LabelSet{"alertname": "TestAlert"},
			expectError:    true,
			expectedErrMsg: "webhook URL is empty after templating",
		},
	}

	for _, tc := range tests {
		t.Run(tc.name, func(t *testing.T) {
			calledURL = "" // Reset for each test

			notifier, err := New(
				&config.WebhookConfig{
					URL:        config.SecretTemplateURL(tc.url),
					HTTPConfig: &commoncfg.HTTPClientConfig{},
				},
				test.CreateTmpl(t),
				promslog.NewNopLogger(),
			)
			require.NoError(t, err)

			ctx := context.Background()
			ctx = notify.WithGroupKey(ctx, "test-group")
			if tc.groupLabels != nil {
				ctx = notify.WithGroupLabels(ctx, tc.groupLabels)
			}

			alerts := []*types.Alert{
				{
					Alert: model.Alert{
						Labels:   tc.alertLabels,
						StartsAt: time.Now(),
						EndsAt:   time.Now().Add(time.Hour),
					},
				},
			}

			_, err = notifier.Notify(ctx, alerts...)

			if tc.expectError {
				require.Error(t, err)
				require.Contains(t, err.Error(), tc.expectedErrMsg)
			} else {
				require.NoError(t, err)
				require.Equal(t, tc.expectedPath, calledURL)
			}
		})
	}
}
