// Copyright 2019 Yunion
//
// 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 runtime

import (
	"time"

	runtimeapi "k8s.io/cri-api/pkg/apis/runtime/v1"
)

// Runtime interface defines the interfaces that should be implemented
// by a container runtime.
// Thread safety is required from implementations of this interface.
type Runtime interface {
	// Type returns the type of the container runtime.
	Type() string

	// GetPods returns a list of containers grouped by pods. The boolean parameter
	// specifies whether the runtime returns all containers including those already
	// exited and dead containers (used for garbage collection).
	GetPods(all bool) ([]*Pod, error)

	// GetPodStatus retrieves the status of the pod, including the
	// information of all containers in the pod that are visible in Runtime.
	GetPodStatus(uid, name, namespace string) (*PodStatus, error)
}

// Pod is a group of containers.
type Pod struct {
	// The ID of the pod, which can be used to retrieve a particular pod
	// from the pod list returned by GetPods().
	Id    string
	CRIId string
	// The name and namespace of the pod, which is readable by human.
	Name      string
	Namespace string
	// List of containers that belongs to the pod. It may contain only
	// running containers, or mixed with dead ones (when GetPods(true)).
	Containers []*Container
	// List of sandboxes associated with this pod. The sandboxes are converted
	// to Container temporarily to avoid substantial changes to other
	// components. This is only populated by kuberuntime.
	Sandboxes []*Container
}

// ContainerID is a type that identifies a container.
type ContainerID struct {
	// The type of the container runtime. e.g. 'docker'.
	Type string
	// The identification of the container, this is comsumable by
	// the underlying container runtime. (Note that the container
	// runtime interface still takes the whole struct as input).
	ID string
}

// State represents the state of a container
type State string

const (
	// ContainerStateCreated indicates a container that has been created (e.g. with docker create) but not started.
	ContainerStateCreated State = "created"
	// ContainerStateRunning indicates a currently running container.
	ContainerStateRunning State = "running"
	// ContainerStateExited indicates a container that ran and completed ("stopped" in other contexts, although a created container is technically also "stopped").
	ContainerStateExited State = "exited"
	// ContainerStateUnknown encompasses all the states that we currently don't care about (like restarting, paused, dead).
	ContainerStateUnknown State = "unknown"
)

// Container provides the runtime information for a container, such as ID, hash,
// state of the container.
type Container struct {
	// The ID of the container, used by the container runtime to identify
	// a container.
	ID ContainerID
	// The name of the container, which should be the same as specified by
	// v1.Container.
	Name string
	// The image name of the container, this also includes the tag of the image,
	// the expected form is "NAME:TAG".
	Image string
	// The id of the image used by the container.
	ImageID string
	// State is the state of the container.
	State State
}

// Pods represents the list of pods
type Pods []*Pod

// FindPodByID finds and returns a pod in the pod list by UID. It will return an empty pod
// if not found.
func (p Pods) FindPodByID(podUID string) Pod {
	for i := range p {
		if p[i].Id == podUID {
			return *p[i]
		}
	}
	return Pod{}
}

// FindPodByFullName finds and returns a pod in the pod list by the full name.
// It will return an empty pod if not found.
func (p Pods) FindPodByFullName(podFullName string) Pod {
	for i := range p {
		if BuildPodFullName(p[i].Name, p[i].Namespace) == podFullName {
			return *p[i]
		}
	}
	return Pod{}
}

// FindPod combines FindPodByID and FindPodByFullName, it finds and returns a pod in the
// pod list either by the full name or the pod ID. It will return an empty pod
// if not found.
func (p Pods) FindPod(podFullName string, podUID string) Pod {
	if len(podFullName) > 0 {
		return p.FindPodByFullName(podFullName)
	}
	return p.FindPodByID(podUID)
}

// FindContainerByName returns a container in the pod with the given name.
// When there are multiple containers with the same name, the first match will
// be returned.
func (p *Pod) FindContainerByName(containerName string) *Container {
	for _, c := range p.Containers {
		if c.Name == containerName {
			return c
		}
	}
	return nil
}

// FindContainerByID returns a container in the pod with the given ContainerID.
func (p *Pod) FindContainerByID(id ContainerID) *Container {
	for _, c := range p.Containers {
		if c.ID == id {
			return c
		}
	}
	return nil
}

// FindSandboxByID returns a sandbox in the pod with the given ContainerID.
func (p *Pod) FindSandboxByID(id ContainerID) *Container {
	for _, c := range p.Sandboxes {
		if c.ID == id {
			return c
		}
	}
	return nil
}

// BuildPodFullName builds the pod full name from pod name and namespace.
func BuildPodFullName(name, namespace string) string {
	return name + "_" + namespace
}

type PodStatus struct {
	ID                string
	Name              string
	Namespace         string
	IPs               []string
	ContainerStatuses []*Status
	SandboxStatuses   []*runtimeapi.PodSandboxStatus
}

func (ps PodStatus) GetContainerStatus(ctrId string) *Status {
	for i := range ps.ContainerStatuses {
		cs := ps.ContainerStatuses[i]
		if cs.ID.ID == ctrId {
			return cs
		}
	}
	return nil
}

// Status represents the status of a container.
type Status struct {
	// ID of the container.
	ID ContainerID
	// Name of the container.
	Name string
	// ID of the sandbox to which this container belongs.
	PodSandboxID string
	// Status of the container.
	State State
	// Creation time of the container.
	CreatedAt time.Time
	// Start time of the container.
	StartedAt time.Time
	// Finish time of the container.
	FinishedAt time.Time
	// Exit code of the container.
	ExitCode int
	// Name of the image, this also includes the tag of the image,
	// the expected form is "NAME:TAG".
	Image string
	// ID of the image.
	ImageID string
	// Hash of the container, used for comparison.
	Hash uint64
	// Number of times that the container has been restarted.
	RestartCount int
	// A string explains why container is in such a status.
	Reason string
	// Message written by the container before exiting (stored in
	// TerminationMessagePath).
	Message string
}