/*
Copyright The Helm 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 action

import (
	"regexp"
	"time"

	"github.com/pkg/errors"
	"k8s.io/apimachinery/pkg/api/meta"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/client-go/discovery"
	"k8s.io/client-go/rest"

	"helm.sh/helm/pkg/chartutil"
	"helm.sh/helm/pkg/kube"
	"helm.sh/helm/pkg/registry"
	"helm.sh/helm/pkg/release"
	"helm.sh/helm/pkg/storage"
)

// Timestamper is a function capable of producing a timestamp.Timestamper.
//
// By default, this is a time.Time function. This can be overridden for testing,
// though, so that timestamps are predictable.
var Timestamper = time.Now

var (
	// errMissingChart indicates that a chart was not provided.
	errMissingChart = errors.New("no chart provided")
	// errMissingRelease indicates that a release (name) was not provided.
	errMissingRelease = errors.New("no release provided")
	// errInvalidRevision indicates that an invalid release revision number was provided.
	errInvalidRevision = errors.New("invalid release revision")
	// errInvalidName indicates that an invalid release name was provided
	errInvalidName = errors.New("invalid release name, must match regex ^(([A-Za-z0-9][-A-Za-z0-9_.]*)?[A-Za-z0-9])+$ and the length must not longer than 53")
)

// ValidName is a regular expression for names.
//
// According to the Kubernetes help text, the regular expression it uses is:
//
//	(([A-Za-z0-9][-A-Za-z0-9_.]*)?[A-Za-z0-9])?
//
// We modified that. First, we added start and end delimiters. Second, we changed
// the final ? to + to require that the pattern match at least once. This modification
// prevents an empty string from matching.
var ValidName = regexp.MustCompile("^(([A-Za-z0-9][-A-Za-z0-9_.]*)?[A-Za-z0-9])+$")

// Configuration injects the dependencies that all actions share.
type Configuration struct {
	// RESTClientGetter is an interface that loads Kuberbetes clients.
	RESTClientGetter RESTClientGetter

	// Releases stores records of releases.
	Releases *storage.Storage

	// KubeClient is a Kubernetes API client.
	KubeClient kube.KubernetesClient

	// RegistryClient is a client for working with registries
	RegistryClient *registry.Client

	// Capabilities describes the capabilities of the Kubernetes cluster.
	Capabilities *chartutil.Capabilities

	Log func(string, ...interface{})
}

// capabilities builds a Capabilities from discovery information.
func (c *Configuration) getCapabilities() (*chartutil.Capabilities, error) {
	if c.Capabilities != nil {
		return c.Capabilities, nil
	}
	dc, err := c.RESTClientGetter.ToDiscoveryClient()
	if err != nil {
		return nil, errors.Wrap(err, "could not get Kubernetes discovery client")
	}
	kubeVersion, err := dc.ServerVersion()
	if err != nil {
		return nil, errors.Wrap(err, "could not get server version from Kubernetes")
	}
	apiVersions, err := GetVersionSet(dc)
	if err != nil {
		return nil, errors.Wrap(err, "could not get apiVersions from Kubernetes")
	}

	c.Capabilities = &chartutil.Capabilities{
		APIVersions: apiVersions,
		KubeVersion: chartutil.KubeVersion{
			Version: kubeVersion.GitVersion,
			Major:   kubeVersion.Major,
			Minor:   kubeVersion.Minor,
		},
	}
	return c.Capabilities, nil
}

// Now generates a timestamp
//
// If the configuration has a Timestamper on it, that will be used.
// Otherwise, this will use time.Now().
func (c *Configuration) Now() time.Time {
	return Timestamper()
}

func (c *Configuration) releaseContent(name string, version int) (*release.Release, error) {
	if err := validateReleaseName(name); err != nil {
		return nil, errors.Errorf("releaseContent: Release name is invalid: %s", name)
	}

	if version <= 0 {
		return c.Releases.Last(name)
	}

	return c.Releases.Get(name, version)
}

// GetVersionSet retrieves a set of available k8s API versions
func GetVersionSet(client discovery.ServerGroupsInterface) (chartutil.VersionSet, error) {
	groups, err := client.ServerGroups()
	if err != nil {
		return chartutil.DefaultVersionSet, err
	}

	// FIXME: The Kubernetes test fixture for cli appears to always return nil
	// for calls to Discovery().ServerGroups(). So in this case, we return
	// the default API list. This is also a safe value to return in any other
	// odd-ball case.
	if groups.Size() == 0 {
		return chartutil.DefaultVersionSet, nil
	}

	versions := metav1.ExtractGroupVersions(groups)
	return chartutil.VersionSet(versions), nil
}

// recordRelease with an update operation in case reuse has been set.
func (c *Configuration) recordRelease(r *release.Release) {
	if err := c.Releases.Update(r); err != nil {
		c.Log("warning: Failed to update release %s: %s", r.Name, err)
	}
}

type RESTClientGetter interface {
	ToRESTConfig() (*rest.Config, error)
	ToDiscoveryClient() (discovery.CachedDiscoveryInterface, error)
	ToRESTMapper() (meta.RESTMapper, error)
}