/*
Copyright 2020 The Flux 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 controller

import (
	"context"
	"fmt"
	"strings"

	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"

	corev1 "k8s.io/api/core/v1"

	flaggerv1 "github.com/fluxcd/flagger/pkg/apis/flagger/v1beta1"
	"github.com/fluxcd/flagger/pkg/notifier"
)

func (c *Controller) recordEventInfof(r *flaggerv1.Canary, template string, args ...interface{}) {
	c.logger.With("canary", fmt.Sprintf("%s.%s", r.Name, r.Namespace)).Infof(template, args...)
	c.eventRecorder.Event(r, corev1.EventTypeNormal, "Synced", fmt.Sprintf(template, args...))
	c.sendEventToWebhook(r, corev1.EventTypeNormal, template, args)
}

func (c *Controller) recordEventErrorf(r *flaggerv1.Canary, template string, args ...interface{}) {
	c.logger.With("canary", fmt.Sprintf("%s.%s", r.Name, r.Namespace)).Errorf(template, args...)
	c.eventRecorder.Event(r, corev1.EventTypeWarning, "Synced", fmt.Sprintf(template, args...))
	c.sendEventToWebhook(r, corev1.EventTypeWarning, template, args)
}

func (c *Controller) recordEventWarningf(r *flaggerv1.Canary, template string, args ...interface{}) {
	c.logger.With("canary", fmt.Sprintf("%s.%s", r.Name, r.Namespace)).Infof(template, args...)
	c.eventRecorder.Event(r, corev1.EventTypeWarning, "Synced", fmt.Sprintf(template, args...))
	c.sendEventToWebhook(r, corev1.EventTypeWarning, template, args)
}

func (c *Controller) sendEventToWebhook(r *flaggerv1.Canary, eventType, template string, args []interface{}) {
	webhookOverride := false
	for _, canaryWebhook := range r.GetAnalysis().Webhooks {
		if canaryWebhook.Type == flaggerv1.EventHook {
			webhookOverride = true
			err := CallEventWebhook(r, canaryWebhook, fmt.Sprintf(template, args...), eventType)
			if err != nil {
				c.logger.With("canary", fmt.Sprintf("%s.%s", r.Name, r.Namespace)).Errorf("error sending event to webhook: %s", err)
			}
		}
	}

	if c.eventWebhook != "" && !webhookOverride {
		hook := flaggerv1.CanaryWebhook{
			Name: "events",
			URL:  c.eventWebhook,
		}
		err := CallEventWebhook(r, hook, fmt.Sprintf(template, args...), eventType)
		if err != nil {
			c.logger.With("canary", fmt.Sprintf("%s.%s", r.Name, r.Namespace)).Errorf("error sending event to webhook: %s", err)
		}
	}
}

func (c *Controller) alert(canary *flaggerv1.Canary, message string, metadata bool, severity flaggerv1.AlertSeverity) {
	var fields []notifier.Field

	if c.clusterName != "" {
		fields = append(fields,
			notifier.Field{
				Name:  "Cluster",
				Value: c.clusterName,
			},
		)
	}

	if metadata {
		fields = append(fields, alertMetadata(canary)...)
	}

	// send alert with the global notifier
	if len(canary.GetAnalysis().Alerts) == 0 {
		err := c.notifier.Post(canary.Name, canary.Namespace, message, fields, string(severity))
		if err != nil {
			c.logger.With("canary", fmt.Sprintf("%s.%s", canary.Name, canary.Namespace)).
				Errorf("alert can't be sent: %v", err)
			return
		}
		return
	}

	// send canary alerts
	for _, alert := range canary.GetAnalysis().Alerts {
		// determine if alert should be sent based on severity level
		shouldAlert := false
		if alert.Severity == flaggerv1.SeverityInfo {
			shouldAlert = true
		} else {
			if severity == alert.Severity {
				shouldAlert = true
			}
			if severity == flaggerv1.SeverityError && alert.Severity == flaggerv1.SeverityWarn {
				shouldAlert = true
			}
		}
		if !shouldAlert {
			continue
		}

		// determine alert provider namespace
		providerNamespace := canary.GetNamespace()
		if alert.ProviderRef.Namespace != canary.Namespace && alert.ProviderRef.Namespace != "" {
			providerNamespace = alert.ProviderRef.Namespace
		}

		// find alert provider
		provider, err := c.flaggerInformers.AlertInformer.Lister().AlertProviders(providerNamespace).Get(alert.ProviderRef.Name)
		if err != nil {
			c.logger.With("canary", fmt.Sprintf("%s.%s", canary.Name, canary.Namespace)).
				Errorf("alert provider %s.%s error: %v", alert.ProviderRef.Name, providerNamespace, err)
			continue
		}

		// set hook URL address
		url := provider.Spec.Address

		// set the token which will be sent in the header
		// https://datatracker.ietf.org/doc/html/rfc6750
		token := ""

		// extract address from secret
		if provider.Spec.SecretRef != nil {
			secret, err := c.kubeClient.CoreV1().Secrets(providerNamespace).Get(context.TODO(), provider.Spec.SecretRef.Name, metav1.GetOptions{})
			if err != nil {
				c.logger.With("canary", fmt.Sprintf("%s.%s", canary.Name, canary.Namespace)).
					Errorf("alert provider %s.%s secretRef error: %v", alert.ProviderRef.Name, providerNamespace, err)
				continue
			}
			if address, ok := secret.Data["address"]; ok {
				url = string(address)
			} else {
				c.logger.With("canary", fmt.Sprintf("%s.%s", canary.Name, canary.Namespace)).
					Errorf("alert provider %s.%s secret does not contain an address", alert.ProviderRef.Name, providerNamespace)
				continue
			}

			if tokenFromSecret, ok := secret.Data["token"]; ok {
				token = string(tokenFromSecret)
			}
		}

		// set defaults
		username := "flagger"
		if provider.Spec.Username != "" {
			username = provider.Spec.Username
		}
		channel := "general"
		if provider.Spec.Channel != "" {
			channel = provider.Spec.Channel
		}
		proxy := ""
		if provider.Spec.Proxy != "" {
			proxy = provider.Spec.Proxy
		}

		// create notifier based on provider type
		f := notifier.NewFactory(url, token, proxy, username, channel)
		n, err := f.Notifier(provider.Spec.Type)
		if err != nil {
			c.logger.With("canary", fmt.Sprintf("%s.%s", canary.Name, canary.Namespace)).
				Errorf("alert provider %s.%s error: %v", alert.ProviderRef.Name, providerNamespace, err)
			continue
		}

		// send alert
		err = n.Post(canary.Name, canary.Namespace, message, fields, string(severity))
		if err != nil {
			c.logger.With("canary", fmt.Sprintf("%s.%s", canary.Name, canary.Namespace)).
				Errorf("alert provider %s.%s send error: %v", alert.ProviderRef.Name, providerNamespace, err)
		}

	}
}

func alertMetadata(canary *flaggerv1.Canary) []notifier.Field {
	var fields []notifier.Field

	fields = append(fields,
		notifier.Field{
			Name:  "Target",
			Value: fmt.Sprintf("%s/%s.%s", canary.Spec.TargetRef.Kind, canary.Spec.TargetRef.Name, canary.Namespace),
		},
		notifier.Field{
			Name:  "Failed checks threshold",
			Value: fmt.Sprintf("%v", canary.GetAnalysisThreshold()),
		},
		notifier.Field{
			Name:  "Progress deadline",
			Value: fmt.Sprintf("%vs", canary.GetProgressDeadlineSeconds()),
		},
	)

	strategy := canary.DeploymentStrategy()
	switch strategy {
	case flaggerv1.DeploymentStrategyABTesting:
		fields = append(fields, notifier.Field{
			Name:  "Traffic routing",
			Value: "A/B Testing",
		})
	case flaggerv1.DeploymentStrategyBlueGreen:
		fields = append(fields, notifier.Field{
			Name:  "Traffic routing",
			Value: "Blue/Green",
		})
	default:
		// Canary strategy
		if canary.GetAnalysis().StepWeight > 0 {
			fields = append(fields, notifier.Field{
				Name: "Traffic routing",
				Value: fmt.Sprintf("Weight step: %v max: %v",
					canary.GetAnalysis().StepWeight,
					canary.GetAnalysis().MaxWeight),
			})
		} else if len(canary.GetAnalysis().StepWeights) > 0 {
			fields = append(fields, notifier.Field{
				Name: "Traffic routing",
				Value: fmt.Sprintf("Weight steps: %s max: %v",
					strings.Trim(strings.Join(strings.Fields(fmt.Sprint(canary.GetAnalysis().StepWeights)), ","), "[]"),
					canary.GetAnalysis().MaxWeight),
			})
		}
	}
	return fields
}