/*
* Copyright 2020 Intel Corporation, Inc
*
* 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 module

import (
	"crypto/rand"
	"crypto/rsa"
	"crypto/x509"
	"crypto/x509/pkix"
	"encoding/base64"
	"encoding/json"
	"encoding/pem"
	"fmt"
	"strings"

	"github.com/onap/multicloud-k8s/src/orchestrator/pkg/appcontext"
	"github.com/onap/multicloud-k8s/src/orchestrator/pkg/appcontext/subresources"
	"github.com/onap/multicloud-k8s/src/orchestrator/pkg/grpc/installappclient"
	"github.com/onap/multicloud-k8s/src/orchestrator/pkg/infra/db"
	log "github.com/onap/multicloud-k8s/src/orchestrator/pkg/infra/logutils"
	"github.com/onap/multicloud-k8s/src/orchestrator/pkg/module/controller"
	pkgerrors "github.com/pkg/errors"
	"gopkg.in/yaml.v2"
	certificatesv1beta1 "k8s.io/api/certificates/v1beta1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
)

// rsyncName denotes the name of the rsync controller
const rsyncName = "rsync"

type Resource struct {
	ApiVersion    string         `yaml:"apiVersion"`
	Kind          string         `yaml:"kind"`
	MetaData      MetaDatas      `yaml:"metadata"`
	Specification Specs          `yaml:"spec,omitempty"`
	Rules         []RoleRules    `yaml:"rules,omitempty"`
	Subjects      []RoleSubjects `yaml:"subjects,omitempty"`
	RoleRefs      RoleRef        `yaml:"roleRef,omitempty"`
}

type MetaDatas struct {
	Name      string `yaml:"name"`
	Namespace string `yaml:"namespace,omitempty"`
}

type Specs struct {
	Request string   `yaml:"request,omitempty"`
	Usages  []string `yaml:"usages,omitempty"`
	// TODO: validate quota keys
	// //Hard           logicalcloud.QSpec    `yaml:"hard,omitempty"`
	// Hard QSpec `yaml:"hard,omitempty"`
	Hard map[string]string `yaml:"hard,omitempty"`
}

type RoleRules struct {
	ApiGroups []string `yaml:"apiGroups"`
	Resources []string `yaml:"resources"`
	Verbs     []string `yaml:"verbs"`
}

type RoleSubjects struct {
	Kind     string `yaml:"kind"`
	Name     string `yaml:"name"`
	ApiGroup string `yaml:"apiGroup"`
}

type RoleRef struct {
	Kind     string `yaml:"kind"`
	Name     string `yaml:"name"`
	ApiGroup string `yaml:"apiGroup"`
}

func cleanupCompositeApp(context appcontext.AppContext, err error, reason string, details []string) error {
	cleanuperr := context.DeleteCompositeApp()
	newerr := pkgerrors.Wrap(err, reason)
	if cleanuperr != nil {
		log.Warn("Error cleaning AppContext, ", log.Fields{
			"Related details": details,
		})
		// this would be useful: https://godoc.org/go.uber.org/multierr
		return pkgerrors.Wrap(err, "After previous error, cleaning the AppContext also failed.")
	}
	return newerr
}

func createNamespace(logicalcloud LogicalCloud) (string, string, error) {

	name := logicalcloud.Specification.NameSpace

	namespace := Resource{
		ApiVersion: "v1",
		Kind:       "Namespace",
		MetaData: MetaDatas{
			Name: name,
		},
	}

	nsData, err := yaml.Marshal(&namespace)
	if err != nil {
		return "", "", err
	}

	return string(nsData), strings.Join([]string{name, "+Namespace"}, ""), nil
}

func createRole(logicalcloud LogicalCloud) (string, string, error) {

	userPermissions := logicalcloud.Specification.User.UserPermissions[0]
	name := strings.Join([]string{logicalcloud.MetaData.LogicalCloudName, "-role"}, "")

	role := Resource{
		ApiVersion: "rbac.authorization.k8s.io/v1beta1",
		Kind:       "Role",
		MetaData: MetaDatas{
			Name:      name,
			Namespace: logicalcloud.Specification.NameSpace,
		},
		Rules: []RoleRules{RoleRules{
			ApiGroups: userPermissions.APIGroups,
			Resources: userPermissions.Resources,
			Verbs:     userPermissions.Verbs,
		},
		},
	}

	roleData, err := yaml.Marshal(&role)
	if err != nil {
		return "", "", err
	}

	return string(roleData), strings.Join([]string{name, "+Role"}, ""), nil
}

func createRoleBinding(logicalcloud LogicalCloud) (string, string, error) {

	name := strings.Join([]string{logicalcloud.MetaData.LogicalCloudName, "-roleBinding"}, "")

	roleBinding := Resource{
		ApiVersion: "rbac.authorization.k8s.io/v1beta1",
		Kind:       "RoleBinding",
		MetaData: MetaDatas{
			Name:      name,
			Namespace: logicalcloud.Specification.NameSpace,
		},
		Subjects: []RoleSubjects{RoleSubjects{
			Kind:     "User",
			Name:     logicalcloud.Specification.User.UserName,
			ApiGroup: "",
		},
		},

		RoleRefs: RoleRef{
			Kind:     "Role",
			Name:     strings.Join([]string{logicalcloud.MetaData.LogicalCloudName, "-role"}, ""),
			ApiGroup: "",
		},
	}

	rBData, err := yaml.Marshal(&roleBinding)
	if err != nil {
		return "", "", err
	}

	return string(rBData), strings.Join([]string{name, "+RoleBinding"}, ""), nil
}

func createQuota(quota []Quota, namespace string) (string, string, error) {

	lcQuota := quota[0]
	name := lcQuota.MetaData.QuotaName

	q := Resource{
		ApiVersion: "v1",
		Kind:       "ResourceQuota",
		MetaData: MetaDatas{
			Name:      name,
			Namespace: namespace,
		},
		Specification: Specs{
			Hard: lcQuota.Specification,
		},
	}

	qData, err := yaml.Marshal(&q)
	if err != nil {
		return "", "", err
	}

	return string(qData), strings.Join([]string{name, "+ResourceQuota"}, ""), nil
}

func createUserCSR(logicalcloud LogicalCloud) (string, string, string, error) {

	KEYSIZE := 4096
	userName := logicalcloud.Specification.User.UserName
	name := strings.Join([]string{logicalcloud.MetaData.LogicalCloudName, "-user-csr"}, "")

	key, err := rsa.GenerateKey(rand.Reader, KEYSIZE)
	if err != nil {
		return "", "", "", err
	}

	csrTemplate := x509.CertificateRequest{Subject: pkix.Name{CommonName: userName}}

	csrCert, err := x509.CreateCertificateRequest(rand.Reader, &csrTemplate, key)
	if err != nil {
		return "", "", "", err
	}

	//Encode csr
	csr := pem.EncodeToMemory(&pem.Block{
		Type:  "CERTIFICATE REQUEST",
		Bytes: csrCert,
	})

	csrObj := Resource{
		ApiVersion: "certificates.k8s.io/v1beta1",
		Kind:       "CertificateSigningRequest",
		MetaData: MetaDatas{
			Name: name,
		},
		Specification: Specs{
			Request: base64.StdEncoding.EncodeToString(csr),
			Usages:  []string{"digital signature", "key encipherment"},
		},
	}

	csrData, err := yaml.Marshal(&csrObj)
	if err != nil {
		return "", "", "", err
	}

	keyData := base64.StdEncoding.EncodeToString(pem.EncodeToMemory(
		&pem.Block{
			Type:  "RSA PRIVATE KEY",
			Bytes: x509.MarshalPKCS1PrivateKey(key),
		},
	))
	if err != nil {
		return "", "", "", err
	}

	return string(csrData), string(keyData), strings.Join([]string{name, "+CertificateSigningRequest"}, ""), nil
}

func createApprovalSubresource(logicalcloud LogicalCloud) (string, error) {
	subresource := subresources.ApprovalSubresource{
		Message:        "Approved for Logical Cloud authentication",
		Reason:         "LogicalCloud",
		Type:           string(certificatesv1beta1.CertificateApproved),
		LastUpdateTime: metav1.Now().Format("2006-01-02T15:04:05Z"),
	}
	csrData, err := json.Marshal(subresource)
	return string(csrData), err
}

/*
queryDBAndSetRsyncInfo queries the MCO db to find the record the sync controller
and then sets the RsyncInfo global variable.
*/
func queryDBAndSetRsyncInfo() (installappclient.RsyncInfo, error) {
	client := controller.NewControllerClient()
	vals, _ := client.GetControllers()
	for _, v := range vals {
		if v.Metadata.Name == rsyncName {
			log.Info("Initializing RPC connection to resource synchronizer", log.Fields{
				"Controller": v.Metadata.Name,
			})
			rsyncInfo := installappclient.NewRsyncInfo(v.Metadata.Name, v.Spec.Host, v.Spec.Port)
			return rsyncInfo, nil
		}
	}
	return installappclient.RsyncInfo{}, pkgerrors.Errorf("queryRsyncInfoInMCODB Failed - Could not get find rsync by name : %v", rsyncName)
}

/*
callRsyncInstall method shall take in the app context id and invoke the rsync service via grpc
*/
func callRsyncInstall(contextid interface{}) error {
	rsyncInfo, err := queryDBAndSetRsyncInfo()
	log.Info("Calling the Rsync ", log.Fields{
		"RsyncName": rsyncInfo.RsyncName,
	})
	if err != nil {
		return err
	}

	appContextID := fmt.Sprintf("%v", contextid)
	err = installappclient.InvokeInstallApp(appContextID)
	if err != nil {
		return err
	}
	return nil
}

/*
callRsyncUninstall method shall take in the app context id and invoke the rsync service via grpc
*/
func callRsyncUninstall(contextid interface{}) error {
	rsyncInfo, err := queryDBAndSetRsyncInfo()
	log.Info("Calling the Rsync ", log.Fields{
		"RsyncName": rsyncInfo.RsyncName,
	})
	if err != nil {
		return err
	}

	appContextID := fmt.Sprintf("%v", contextid)
	err = installappclient.InvokeUninstallApp(appContextID)
	if err != nil {
		return err
	}
	return nil
}

// Apply prepares all yaml resources to be given to the clusters via rsync,
// then creates an appcontext with such resources and asks rsync to apply the logical cloud
func Apply(project string, logicalcloud LogicalCloud, clusterList []Cluster,
	quotaList []Quota) error {

	APP := "logical-cloud"
	logicalCloudName := logicalcloud.MetaData.LogicalCloudName

	lcclient := NewLogicalCloudClient()
	lckey := LogicalCloudKey{
		LogicalCloudName: logicalcloud.MetaData.LogicalCloudName,
		Project:          project,
	}

	// Check if there was a previous context for this logical cloud
	ac, cid, err := lcclient.GetLogicalCloudContext(project, logicalCloudName)
	if cid != "" {
		// Make sure rsync status for this logical cloud is Terminated,
		// otherwise we can't re-apply logical cloud yet
		acStatus, _ := getAppContextStatus(ac)
		switch acStatus.Status {
		case appcontext.AppContextStatusEnum.Terminated:
			// We now know Logical Cloud has terminated, so let's update the entry before we process the apply
			err = db.DBconn.RemoveTag(lcclient.storeName, lckey, lcclient.tagContext)
			if err != nil {
				return pkgerrors.Wrap(err, "Error removing lccontext tag from Logical Cloud")
			}
			// And fully delete the old AppContext
			err := ac.DeleteCompositeApp()
			if err != nil {
				return pkgerrors.Wrap(err, "Error deleting AppContext CompositeApp Logical Cloud")
			}
		case appcontext.AppContextStatusEnum.Terminating:
			return pkgerrors.New("The Logical Cloud can't be re-applied yet, it is being terminated.")
		case appcontext.AppContextStatusEnum.Instantiated:
			return pkgerrors.New("The Logical Cloud is already applied.")
		default:
			return pkgerrors.New("The Logical Cloud can't be applied at this point.")
		}
	}

	// Get resources to be added
	namespace, namespaceName, err := createNamespace(logicalcloud)
	if err != nil {
		return pkgerrors.Wrap(err, "Error Creating Namespace YAML for logical cloud")
	}

	role, roleName, err := createRole(logicalcloud)
	if err != nil {
		return pkgerrors.Wrap(err, "Error Creating Role YAML for logical cloud")
	}

	roleBinding, roleBindingName, err := createRoleBinding(logicalcloud)
	if err != nil {
		return pkgerrors.Wrap(err, "Error Creating RoleBinding YAML for logical cloud")
	}

	quota, quotaName, err := createQuota(quotaList, logicalcloud.Specification.NameSpace)
	if err != nil {
		return pkgerrors.Wrap(err, "Error Creating Quota YAML for logical cloud")
	}

	csr, key, csrName, err := createUserCSR(logicalcloud)
	if err != nil {
		return pkgerrors.Wrap(err, "Error Creating User CSR and Key for logical cloud")
	}

	approval, err := createApprovalSubresource(logicalcloud)

	// From this point on, we are dealing with a new context (not "ac" from above)
	context := appcontext.AppContext{}
	ctxVal, err := context.InitAppContext()
	if err != nil {
		return pkgerrors.Wrap(err, "Error creating AppContext")
	}

	handle, err := context.CreateCompositeApp()
	if err != nil {
		return pkgerrors.Wrap(err, "Error creating AppContext CompositeApp")
	}

	appHandle, err := context.AddApp(handle, APP)
	if err != nil {
		return cleanupCompositeApp(context, err, "Error adding App to AppContext", []string{logicalCloudName, ctxVal.(string)})
	}

	// Iterate through cluster list and add all the clusters
	for _, cluster := range clusterList {
		clusterName := strings.Join([]string{cluster.Specification.ClusterProvider, "+", cluster.Specification.ClusterName}, "")
		clusterHandle, err := context.AddCluster(appHandle, clusterName)
		// pre-build array to pass to cleanupCompositeApp() [for performance]
		details := []string{logicalCloudName, clusterName, ctxVal.(string)}

		if err != nil {
			return cleanupCompositeApp(context, err, "Error adding Cluster to AppContext", details)
		}

		// Add namespace resource to each cluster
		_, err = context.AddResource(clusterHandle, namespaceName, namespace)
		if err != nil {
			return cleanupCompositeApp(context, err, "Error adding Namespace Resource to AppContext", details)
		}

		// Add csr resource to each cluster
		csrHandle, err := context.AddResource(clusterHandle, csrName, csr)
		if err != nil {
			return cleanupCompositeApp(context, err, "Error adding CSR Resource to AppContext", details)
		}

		// Add csr approval as a subresource of csr:
		_, err = context.AddLevelValue(csrHandle, "subresource/approval", approval)
		if err != nil {
			return cleanupCompositeApp(context, err, "Error approving CSR via AppContext", details)
		}

		// Add private key to MongoDB
		err = db.DBconn.Insert("orchestrator", lckey, nil, "privatekey", key)
		if err != nil {
			return cleanupCompositeApp(context, err, "Error adding private key to DB", details)
		}

		// Add Role resource to each cluster
		_, err = context.AddResource(clusterHandle, roleName, role)
		if err != nil {
			return cleanupCompositeApp(context, err, "Error adding role Resource to AppContext", details)
		}

		// Add RoleBinding resource to each cluster
		_, err = context.AddResource(clusterHandle, roleBindingName, roleBinding)
		if err != nil {
			return cleanupCompositeApp(context, err, "Error adding roleBinding Resource to AppContext", details)
		}

		// Add quota resource to each cluster
		_, err = context.AddResource(clusterHandle, quotaName, quota)
		if err != nil {
			return cleanupCompositeApp(context, err, "Error adding quota Resource to AppContext", details)
		}

		// Add Subresource Order and Subresource Dependency
		subresOrder, err := json.Marshal(map[string][]string{"subresorder": []string{"approval"}})
		if err != nil {
			return pkgerrors.Wrap(err, "Error creating subresource order JSON")
		}
		subresDependency, err := json.Marshal(map[string]map[string]string{"subresdependency": map[string]string{"approval": "go"}})

		// Add Resource Order and Resource Dependency
		resOrder, err := json.Marshal(map[string][]string{"resorder": []string{namespaceName, quotaName, csrName, roleName, roleBindingName}})
		if err != nil {
			return pkgerrors.Wrap(err, "Error creating resource order JSON")
		}
		resDependency, err := json.Marshal(map[string]map[string]string{"resdependency": map[string]string{namespaceName: "go",
			quotaName: strings.Join([]string{"wait on ", namespaceName}, ""), csrName: strings.Join([]string{"wait on ", quotaName}, ""),
			roleName: strings.Join([]string{"wait on ", csrName}, ""), roleBindingName: strings.Join([]string{"wait on ", roleName}, "")}})

		// Add App Order and App Dependency
		appOrder, err := json.Marshal(map[string][]string{"apporder": []string{APP}})
		if err != nil {
			return pkgerrors.Wrap(err, "Error creating resource order JSON")
		}
		appDependency, err := json.Marshal(map[string]map[string]string{"appdependency": map[string]string{APP: "go"}})
		if err != nil {
			return pkgerrors.Wrap(err, "Error creating resource dependency JSON")
		}

		// Add Resource-level Order and Dependency
		_, err = context.AddInstruction(clusterHandle, "resource", "order", string(resOrder))
		if err != nil {
			return cleanupCompositeApp(context, err, "Error adding instruction order to AppContext", details)
		}
		_, err = context.AddInstruction(clusterHandle, "resource", "dependency", string(resDependency))
		if err != nil {
			return cleanupCompositeApp(context, err, "Error adding instruction dependency to AppContext", details)
		}
		_, err = context.AddInstruction(csrHandle, "subresource", "order", string(subresOrder))
		if err != nil {
			return cleanupCompositeApp(context, err, "Error adding instruction order to AppContext", details)
		}
		_, err = context.AddInstruction(csrHandle, "subresource", "dependency", string(subresDependency))
		if err != nil {
			return cleanupCompositeApp(context, err, "Error adding instruction dependency to AppContext", details)
		}

		// Add App-level Order and Dependency
		_, err = context.AddInstruction(handle, "app", "order", string(appOrder))
		if err != nil {
			return cleanupCompositeApp(context, err, "Error adding app-level order to AppContext", details)
		}
		_, err = context.AddInstruction(handle, "app", "dependency", string(appDependency))
		if err != nil {
			return cleanupCompositeApp(context, err, "Error adding app-level dependency to AppContext", details)
		}
	}
	// save the context in the logicalcloud db record
	err = db.DBconn.Insert("orchestrator", lckey, nil, "lccontext", ctxVal)
	if err != nil {
		return cleanupCompositeApp(context, err, "Error adding AppContext to DB", []string{logicalCloudName, ctxVal.(string)})
	}

	// call resource synchronizer to instantiate the CRs in the cluster
	err = callRsyncInstall(ctxVal)
	if err != nil {
		return err
	}

	return nil

}

// Terminate asks rsync to terminate the logical cloud, then waits in the background until
// rsync claims the logical cloud is terminated, and then deletes the appcontext
func Terminate(project string, logicalcloud LogicalCloud, clusterList []Cluster,
	quotaList []Quota) error {

	logicalCloudName := logicalcloud.MetaData.LogicalCloudName

	lcclient := NewLogicalCloudClient()

	ac, cid, err := lcclient.GetLogicalCloudContext(project, logicalCloudName)
	if err != nil {
		return pkgerrors.Wrapf(err, "Logical Cloud doesn't seem applied: %v", logicalCloudName)
	}

	// Check if there was a previous context for this logical cloud
	if cid != "" {
		// Make sure rsync status for this logical cloud is Terminated,
		// otherwise we can't re-apply logical cloud yet
		acStatus, _ := getAppContextStatus(ac)
		switch acStatus.Status {
		case appcontext.AppContextStatusEnum.Terminated:
			return pkgerrors.New("The Logical Cloud has already been terminated: " + logicalCloudName)
		case appcontext.AppContextStatusEnum.Terminating:
			return pkgerrors.New("The Logical Cloud is already being terminated: " + logicalCloudName)
		case appcontext.AppContextStatusEnum.Instantiated:
			// call resource synchronizer to delete the CRs from every cluster of the logical cloud
			err = callRsyncUninstall(cid)
			return err
		default:
			return pkgerrors.New("The Logical Cloud can't be deleted at this point: " + logicalCloudName)
		}
	}
	return pkgerrors.New("Logical Cloud is not applied: " + logicalCloudName)
}