/*

Licensed under the GNU AFFERO GENERAL PUBLIC LICENSE Version 3 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    https://www.gnu.org/licenses/agpl-3.0.html

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 status

import (
	"sort"

	corev1 "k8s.io/api/core/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
)

// ConditionType encodes information on the condition
// +kubebuilder:object:generate=true
type ConditionType string

const (
	ConditionNone       ConditionType = ""
	ConditionPlanning   ConditionType = "Planning"
	ConditionRunning    ConditionType = "Running"
	ConditionCreating   ConditionType = "Creating"
	ConditionInstalling ConditionType = "Installing"
	ConditionUpgrading  ConditionType = "Upgrading"
	ConditionComplete   ConditionType = "Complete"
	ConditionFailed     ConditionType = "Failed"
)

// A ConditionReason represents the reason a resource is in a condition.
type ConditionReason string

// Reasons a resource is or is not ready.
const (
	ReasonAvailable   ConditionReason = "Resource is available for use"
	ReasonUnavailable ConditionReason = "Resource is not available for use"
	ReasonCreating    ConditionReason = "Resource is being created"
	ReasonDeleting    ConditionReason = "Resource is being deleted"
)

// Reasons a resource is or is not synced.
const (
	ReasonReconcileSuccess ConditionReason = "Successfully reconciled resource"
	ReasonReconcileError   ConditionReason = "Encountered an error during resource reconciliation"
)

// Condition types.
const (
	// TypeReady resources are believed to be ready to handle work.
	TypeReady ConditionType = "Ready"

	// TypeSynced resources are believed to be in sync with the
	// Kubernetes resources that manage their lifecycle.
	TypeSynced ConditionType = "Synced"

//	TypeProgressing ConditionType = "Progressing"
//	TypeNotReady    ConditionType = "NotReady"
)

// Creating returns a condition that indicates the resource is currently
// being created.
func Creating() Condition {
	return Condition{
		Type:               TypeReady,
		Status:             corev1.ConditionFalse,
		LastTransitionTime: metav1.Now(),
		Reason:             ReasonCreating,
	}
}

/* // Creating returns a condition that indicates the resource is currently
// being created.
func Progressing() Condition {
	return Condition{
		Type:               TypeProgressing,
		Status:             corev1.ConditionFalse,
		LastTransitionTime: metav1.Now(),
		Reason:             ReasonProgressing,
	}
} */

// Deleting returns a condition that indicates the resource is currently
// being deleted.
func Deleting() Condition {
	return Condition{
		Type:               TypeReady,
		Status:             corev1.ConditionFalse,
		LastTransitionTime: metav1.Now(),
		Reason:             ReasonDeleting,
	}
}

// Available returns a condition that indicates the resource is
// currently observed to be available for use.
func Available() Condition {
	return Condition{
		Type:               TypeReady,
		Status:             corev1.ConditionTrue,
		LastTransitionTime: metav1.Now(),
		Reason:             ReasonAvailable,
	}
}

// Unavailable returns a condition that indicates the resource is not
// currently available for use. Unavailable should be set only when Crossplane
// expects the resource to be available but knows it is not, for example
// because its API reports it is unhealthy.
func Unavailable() Condition {
	return Condition{
		Type:               TypeReady,
		Status:             corev1.ConditionFalse,
		LastTransitionTime: metav1.Now(),
		Reason:             ReasonUnavailable,
	}
}

// ReconcileSuccess returns a condition indicating that Crossplane successfully
// completed the most recent reconciliation of the resource.
func ReconcileSuccess() Condition {
	return Condition{
		Type:               TypeSynced,
		Status:             corev1.ConditionTrue,
		LastTransitionTime: metav1.Now(),
		Reason:             ReasonReconcileSuccess,
	}
}

// ReconcileError returns a condition indicating that Crossplane encountered an
// error while reconciling the resource. This could mean Crossplane was
// unable to update the resource to reflect its desired state, or that
// Crossplane was unable to determine the current actual state of the resource.
func ReconcileError(err error) Condition {
	return Condition{
		Type:               TypeSynced,
		Status:             corev1.ConditionFalse,
		LastTransitionTime: metav1.Now(),
		Reason:             ReasonReconcileError,
		Message:            err.Error(),
	}
}

// Condition describes the state of an object at a certain point.
// +kubebuilder:object:generate=true
type Condition struct {
	// Type of condition.
	Type ConditionType `json:"type" protobuf:"bytes,1,opt,name=type,casttype=StatefulSetConditionType"`
	// Status of the condition, one of True, False, Unknown.
	Status corev1.ConditionStatus `json:"status" protobuf:"bytes,2,opt,name=status,casttype=k8s.io/api/core/v1.ConditionStatus"`
	// The reason for the condition's last transition.
	Reason ConditionReason `json:"reason,omitempty" protobuf:"bytes,4,opt,name=reason"`
	// A human readable message indicating details about the transition.
	Message string `json:"message,omitempty" protobuf:"bytes,5,opt,name=message"`
	// Last time the condition was probed
	//	LastUpdateTime metav1.Time `json:"lastUpdateTime,omitempty" protobuf:"bytes,3,opt,name=lastProbeTime"`
	// Last time the condition transitioned from one status to another.
	LastTransitionTime metav1.Time `json:"lastTransitionTime,omitempty" protobuf:"bytes,3,opt,name=lastTransitionTime"`
}

// Equal returns true if the condition is identical to the supplied condition,
// ignoring the LastTransitionTime.
func (c Condition) Equal(other Condition) bool {
	return c.Type == other.Type &&
		c.Status == other.Status &&
		c.Reason == other.Reason &&
		c.Message == other.Message
}

// WithMessage returns a condition by adding the provided message to existing
// condition.
func (c Condition) WithMessage(msg string) Condition {
	c.Message = msg
	return c
}

// NewConditionedStatus returns a stat with the supplied conditions set.
func NewConditionedStatus(c ...Condition) *ApplicationStatus {
	s := &ApplicationStatus{}
	s.SetConditions(c...)
	return s
}

// GetCondition returns the condition for the given ConditionType if exists,
// otherwise returns nil
func (s *ApplicationStatus) GetCondition(ct ConditionType) Condition {
	for _, c := range s.Conditions {
		if c.Type == ct {
			return c
		}
	}

	return Condition{Type: ct, Status: corev1.ConditionUnknown}
}

// SetConditions sets the supplied conditions, replacing any existing conditions
// of the same type. This is a no-op if all supplied conditions are identical,
// ignoring the last transition time, to those already set.
func (s *ApplicationStatus) SetConditions(c ...Condition) {
	for _, new := range c {
		exists := false
		for i, existing := range s.Conditions {
			if existing.Type != new.Type {
				continue
			}

			if existing.Equal(new) {
				exists = true
				continue
			}

			s.Conditions[i] = new
			exists = true
		}
		if !exists {
			s.Conditions = append(s.Conditions, new)
		}
	}
}

// Equal returns true if the status is identical to the supplied status,
// ignoring the LastTransitionTimes and order of statuses.
func (s *ApplicationStatus) Equal(other *ApplicationStatus) bool {
	if s == nil || other == nil {
		return s == nil && other == nil
	}

	if len(other.Conditions) != len(s.Conditions) {
		return false
	}

	sc := make([]Condition, len(s.Conditions))
	copy(sc, s.Conditions)

	oc := make([]Condition, len(other.Conditions))
	copy(oc, other.Conditions)

	// We should not have more than one condition of each type.
	sort.Slice(sc, func(i, j int) bool { return sc[i].Type < sc[j].Type })
	sort.Slice(oc, func(i, j int) bool { return oc[i].Type < oc[j].Type })

	for i := range sc {
		if !sc[i].Equal(oc[i]) {
			return false
		}
	}

	return true
}