/*
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 canary

import (
	"context"
	"fmt"
	"strings"

	corev1 "k8s.io/api/core/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/client-go/util/retry"

	flaggerv1 "github.com/fluxcd/flagger/pkg/apis/flagger/v1beta1"
	clientset "github.com/fluxcd/flagger/pkg/client/clientset/versioned"
)

func syncCanaryStatus(flaggerClient clientset.Interface, cd *flaggerv1.Canary, status flaggerv1.CanaryStatus, canaryResource interface{}, setAll func(cdCopy *flaggerv1.Canary)) error {
	hash := computeHash(canaryResource)

	firstTry := true
	name, ns := cd.GetName(), cd.GetNamespace()
	err := retry.RetryOnConflict(retry.DefaultBackoff, func() (err error) {
		if !firstTry {
			cd, err = flaggerClient.FlaggerV1beta1().Canaries(ns).Get(context.TODO(), name, metav1.GetOptions{})
			if err != nil {
				return fmt.Errorf("canary %s.%s get query failed: %w", name, ns, err)
			}
		}

		cdCopy := cd.DeepCopy()
		cdCopy.Status.Phase = status.Phase
		cdCopy.Status.CanaryWeight = status.CanaryWeight
		cdCopy.Status.FailedChecks = status.FailedChecks
		cdCopy.Status.Iterations = status.Iterations
		cdCopy.Status.LastAppliedSpec = hash
		cdCopy.Status.LastTransitionTime = metav1.Now()
		setAll(cdCopy)

		if ok, conditions := MakeStatusConditions(cd, status.Phase); ok {
			cdCopy.Status.Conditions = conditions
		}

		err = updateStatusWithUpgrade(flaggerClient, cdCopy)
		firstTry = false
		return
	})

	if err != nil {
		return fmt.Errorf("failed after retries: %w", err)
	}
	return nil
}

func setStatusFailedChecks(flaggerClient clientset.Interface, cd *flaggerv1.Canary, val int) error {
	firstTry := true
	name, ns := cd.GetName(), cd.GetNamespace()
	err := retry.RetryOnConflict(retry.DefaultBackoff, func() (err error) {
		if !firstTry {
			cd, err = flaggerClient.FlaggerV1beta1().Canaries(ns).Get(context.TODO(), name, metav1.GetOptions{})
			if err != nil {
				return fmt.Errorf("canary %s.%s get query failed: %w", name, ns, err)
			}
		}
		cdCopy := cd.DeepCopy()
		cdCopy.Status.FailedChecks = val
		cdCopy.Status.LastTransitionTime = metav1.Now()

		err = updateStatusWithUpgrade(flaggerClient, cdCopy)
		firstTry = false
		return
	})
	if err != nil {
		return fmt.Errorf("failed after retries: %w", err)
	}
	return nil
}

func setStatusWeight(flaggerClient clientset.Interface, cd *flaggerv1.Canary, val int) error {
	firstTry := true
	name, ns := cd.GetName(), cd.GetNamespace()
	err := retry.RetryOnConflict(retry.DefaultBackoff, func() (err error) {
		if !firstTry {
			cd, err = flaggerClient.FlaggerV1beta1().Canaries(ns).Get(context.TODO(), name, metav1.GetOptions{})
			if err != nil {
				return fmt.Errorf("canary %s.%s get query failed: %w", name, ns, err)
			}
		}
		cdCopy := cd.DeepCopy()
		cdCopy.Status.CanaryWeight = val
		cdCopy.Status.LastTransitionTime = metav1.Now()

		err = updateStatusWithUpgrade(flaggerClient, cdCopy)
		firstTry = false
		return
	})
	if err != nil {
		return fmt.Errorf("failed after retries: %w", err)
	}
	return nil
}

func setStatusIterations(flaggerClient clientset.Interface, cd *flaggerv1.Canary, val int) error {
	firstTry := true
	name, ns := cd.GetName(), cd.GetNamespace()
	err := retry.RetryOnConflict(retry.DefaultBackoff, func() (err error) {
		if !firstTry {
			cd, err = flaggerClient.FlaggerV1beta1().Canaries(ns).Get(context.TODO(), name, metav1.GetOptions{})
			if err != nil {
				return fmt.Errorf("canary %s.%s get query failed: %w", name, ns, err)
			}
		}

		cdCopy := cd.DeepCopy()
		cdCopy.Status.Iterations = val
		cdCopy.Status.LastTransitionTime = metav1.Now()

		err = updateStatusWithUpgrade(flaggerClient, cdCopy)
		firstTry = false
		return
	})

	if err != nil {
		return fmt.Errorf("failed after retries: %w", err)
	}
	return nil
}

func setStatusPhase(flaggerClient clientset.Interface, cd *flaggerv1.Canary, phase flaggerv1.CanaryPhase) error {
	firstTry := true
	name, ns := cd.GetName(), cd.GetNamespace()
	err := retry.RetryOnConflict(retry.DefaultBackoff, func() (err error) {
		if !firstTry {
			cd, err = flaggerClient.FlaggerV1beta1().Canaries(ns).Get(context.TODO(), name, metav1.GetOptions{})
			if err != nil {
				return fmt.Errorf("canary %s.%s get query failed: %w", name, ns, err)
			}
		}

		cdCopy := cd.DeepCopy()
		cdCopy.Status.Phase = phase
		cdCopy.Status.LastTransitionTime = metav1.Now()

		if phase != flaggerv1.CanaryPhaseProgressing && phase != flaggerv1.CanaryPhaseWaiting {
			cdCopy.Status.CanaryWeight = 0
			cdCopy.Status.Iterations = 0
		}

		// on promotion set primary spec hash
		if phase == flaggerv1.CanaryPhaseInitialized || phase == flaggerv1.CanaryPhaseSucceeded {
			cdCopy.Status.LastPromotedSpec = cd.Status.LastAppliedSpec
		}

		if ok, conditions := MakeStatusConditions(cdCopy, phase); ok {
			cdCopy.Status.Conditions = conditions
		}

		err = updateStatusWithUpgrade(flaggerClient, cdCopy)
		firstTry = false
		return
	})
	if err != nil {
		return fmt.Errorf("failed after retries: %w", err)
	}
	return nil
}

// getStatusCondition returns a condition based on type
func getStatusCondition(status flaggerv1.CanaryStatus, conditionType flaggerv1.CanaryConditionType) *flaggerv1.CanaryCondition {
	for i := range status.Conditions {
		c := status.Conditions[i]
		if c.Type == conditionType {
			return &c
		}
	}
	return nil
}

// MakeStatusCondition updates the canary status conditions based on canary phase
func MakeStatusConditions(cd *flaggerv1.Canary,
	phase flaggerv1.CanaryPhase) (bool, []flaggerv1.CanaryCondition) {
	currentCondition := getStatusCondition(cd.Status, flaggerv1.PromotedType)

	message := fmt.Sprintf("New %s detected, starting initialization.", cd.Spec.TargetRef.Kind)
	status := corev1.ConditionUnknown
	switch phase {
	case flaggerv1.CanaryPhaseInitializing:
		status = corev1.ConditionUnknown
		message = fmt.Sprintf("New %s detected, starting initialization.", cd.Spec.TargetRef.Kind)
	case flaggerv1.CanaryPhaseInitialized:
		status = corev1.ConditionTrue
		message = fmt.Sprintf("%s initialization completed.", cd.Spec.TargetRef.Kind)
	case flaggerv1.CanaryPhaseWaiting:
		status = corev1.ConditionUnknown
		message = "Waiting for approval."
	case flaggerv1.CanaryPhaseWaitingPromotion:
		status = corev1.ConditionUnknown
		message = "Waiting for approval."
	case flaggerv1.CanaryPhaseProgressing:
		status = corev1.ConditionUnknown
		message = "New revision detected, progressing canary analysis."
	case flaggerv1.CanaryPhasePromoting:
		status = corev1.ConditionUnknown
		message = "Canary analysis completed, starting primary rolling update."
	case flaggerv1.CanaryPhaseFinalising:
		status = corev1.ConditionUnknown
		message = "Canary analysis completed, routing all traffic to primary."
	case flaggerv1.CanaryPhaseSucceeded:
		status = corev1.ConditionTrue
		message = "Canary analysis completed successfully, promotion finished."
	case flaggerv1.CanaryPhaseFailed:
		status = corev1.ConditionFalse
		message = fmt.Sprintf("Canary analysis failed, %s scaled to zero.", cd.Spec.TargetRef.Kind)
	}

	newCondition := &flaggerv1.CanaryCondition{
		Type:               flaggerv1.PromotedType,
		Status:             status,
		LastUpdateTime:     metav1.Now(),
		LastTransitionTime: metav1.Now(),
		Message:            message,
		Reason:             string(phase),
	}

	if currentCondition != nil &&
		currentCondition.Status == newCondition.Status &&
		currentCondition.Reason == newCondition.Reason {
		return false, nil
	}

	if currentCondition != nil && currentCondition.Status == newCondition.Status {
		newCondition.LastTransitionTime = currentCondition.LastTransitionTime
	}

	return true, []flaggerv1.CanaryCondition{*newCondition}
}

// updateStatusWithUpgrade tries to update the status sub-resource
// if the status update fails with:
// Canary.flagger.app is invalid: apiVersion: Invalid value: flagger.app/v1alpha3: must be flagger.app/v1beta1
// then the canary object will be updated to the latest API version
func updateStatusWithUpgrade(flaggerClient clientset.Interface, cd *flaggerv1.Canary) error {
	_, err := flaggerClient.FlaggerV1beta1().Canaries(cd.Namespace).UpdateStatus(context.TODO(), cd, metav1.UpdateOptions{})
	if err != nil && strings.Contains(err.Error(), "flagger.app/v1alpha") {
		// upgrade alpha resource
		if _, updateErr := flaggerClient.FlaggerV1beta1().Canaries(cd.Namespace).Update(context.TODO(), cd, metav1.UpdateOptions{}); updateErr != nil {
			return fmt.Errorf("updating canary %s.%s from v1alpha to v1beta failed: %w", cd.Name, cd.Namespace, updateErr)
		}
		// retry status update
		_, err = flaggerClient.FlaggerV1beta1().Canaries(cd.Namespace).UpdateStatus(context.TODO(), cd, metav1.UpdateOptions{})
	}

	if err != nil {
		return fmt.Errorf("updating canary %s.%s status failed: %w", cd.Name, cd.Namespace, err)
	}
	return err
}