// Copyright (c) 2020-2021 Tigera, Inc. All rights reserved.

// 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 migrate

import (
	"context"
	"encoding/json"
	"fmt"
	"strings"

	"github.com/docopt/docopt-go"
	"github.com/sirupsen/logrus"
	"golang.org/x/text/cases"
	"golang.org/x/text/language"
	"k8s.io/apimachinery/pkg/api/meta"
	v1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/runtime"

	apiv3 "github.com/projectcalico/api/pkg/apis/projectcalico/v3"

	"github.com/projectcalico/calico/calicoctl/calicoctl/commands/clientmgr"
	"github.com/projectcalico/calico/calicoctl/calicoctl/commands/common"
	"github.com/projectcalico/calico/calicoctl/calicoctl/commands/constants"
	"github.com/projectcalico/calico/calicoctl/calicoctl/util"
	"github.com/projectcalico/calico/libcalico-go/lib/apiconfig"
	libapiv3 "github.com/projectcalico/calico/libcalico-go/lib/apis/v3"
	"github.com/projectcalico/calico/libcalico-go/lib/backend/k8s/conversion"
)

var title = cases.Title(language.English)

// All of the resources we can retrieve via the v3 API.
// Any resources which have references to node names MUST come after
// nodes since the Kubernetes node names are not known until after nodes
// are processed.
var allV3Resources []string = []string{
	"ippools",
	"bgppeers",
	"globalnetworkpolicies",
	"globalnetworksets",
	"heps",
	"kubecontrollersconfigs",
	"networkpolicies",
	"networksets",
	"nodes",
	"bgpconfigs",
	"felixconfigs",
	"ipreservations",
	"bgpfilters",
}

var resourceDisplayMap map[string]string = map[string]string{
	"ipamBlocks":             "IPAMBlocks",
	"blockaffinities":        "BlockAffinities",
	"ipamhandles":            "IPAMHandles",
	"ipamconfigs":            "IPAMConfigurations",
	"ippools":                "IPPools",
	"bgpconfigs":             "BGPConfigurations",
	"bgppeers":               "BGPPeers",
	"clusterinfos":           "ClusterInformations",
	"felixconfigs":           "FelixConfigurations",
	"globalnetworkpolicies":  "GlobalNetworkPolicies",
	"globalnetworksets":      "GlobalNetworkSets",
	"heps":                   "HostEndpoints",
	"kubecontrollersconfigs": "KubeControllersConfigurations",
	"networkpolicies":        "NetworkPolicies",
	"networksets":            "Networksets",
	"nodes":                  "Nodes",
	"ipreservations":         "IPReservations",
	"bgpfilters":             "BGPFilters",
}

var namespacedResources map[string]struct{} = map[string]struct{}{
	"networkpolicies": {},
	"networksets":     {},
}

func Export(args []string) error {
	doc := `Usage:
  <BINARY_NAME> datastore migrate export [--config=<CONFIG>] [--allow-version-mismatch]

Options:
  -h --help                    Show this screen.
  -c --config=<CONFIG>         Path to the file containing connection
                               configuration in YAML or JSON format.
                               [default: ` + constants.DefaultConfigPath + `]
     --allow-version-mismatch  Allow client and cluster versions mismatch.

Description:
  Export the contents of the etcdv3 datastore.  Resources will be exported
  in yaml and json format. Save the results of this command to a file for
  later use with the import command.

  The following resources are exported:

<RESOURCE_LIST>

  The following resources are not exported:

    - WorkloadEndpoints
    - Profiles
`
	// Replace all instances of BINARY_NAME with the name of the binary.
	name, _ := util.NameAndDescription()
	doc = strings.ReplaceAll(doc, "<BINARY_NAME>", name)

	// Replace <RESOURCE_LIST> with the list of resources that will be exported.
	resourceList := ""
	for _, r := range allV3Resources {
		resourceList += fmt.Sprintf("    - %s\n", resourceDisplayMap[r])
	}
	doc = strings.Replace(doc, "<RESOURCE_LIST>", resourceList, 1)

	parsedArgs, err := docopt.ParseArgs(doc, args, "")
	if err != nil {
		return fmt.Errorf("Invalid option: 'calicoctl %s'. Use flag '--help' to read about a specific subcommand.", strings.Join(args, " "))
	}
	if len(parsedArgs) == 0 {
		return nil
	}

	err = common.CheckVersionMismatch(parsedArgs["--config"], parsedArgs["--allow-version-mismatch"])
	if err != nil {
		return err
	}

	cf := parsedArgs["--config"].(string)
	// Get the backend client.
	client, err := clientmgr.NewClient(cf)
	if err != nil {
		return err
	}

	// Check that the datastore is locked.
	ctx := context.Background()
	locked, err := common.CheckLocked(ctx, client)
	if err != nil {
		return fmt.Errorf("Error while checking if datastore was locked: %s", err)
	} else if !locked {
		return fmt.Errorf("Datastore is not locked. Run the `calicoctl datastore migrate lock` command in order to begin migration.")
	}

	// Check that the datastore configured datastore is etcd
	cfg, err := clientmgr.LoadClientConfig(cf)
	if err != nil {
		logrus.Info("Error loading config")
		return err
	}

	if cfg.Spec.DatastoreType != apiconfig.EtcdV3 {
		return fmt.Errorf("Invalid datastore type: %s to export from for datastore migration. Datastore type must be etcdv3", cfg.Spec.DatastoreType)
	}

	rp := common.ResourcePrinterYAML{}
	etcdToKddNodeMap := make(map[string]string)
	// Loop through all the resource types to retrieve every resource available by the v3 API.
	for _, r := range allV3Resources {
		mockArgs := map[string]interface{}{
			"<KIND>":   r,
			"<NAME>":   []string{},
			"--config": cf,
			"--export": true,
			"--output": "yaml",
			"get":      true,
		}

		// Add options for pulling resources from all namespaces for namespaced resources.
		if r == "networksets" || r == "networkpolicies" {
			mockArgs["--all-namespaces"] = true
		}

		results := common.ExecuteConfigCommand(mockArgs, common.ActionGetOrList)
		if len(results.ResErrs) > 0 {
			var errStr string
			for i, err := range results.ResErrs {
				errStr += err.Error()
				if (i + 1) != len(results.ResErrs) {
					errStr += "\n"
				}
			}
			return fmt.Errorf("%s", errStr)
		}

		for i, resource := range results.Resources {
			// Remove relevant metadata because the --export flag does not remove it for lists.
			err := meta.EachListItem(resource, func(obj runtime.Object) error {
				rom := obj.(v1.ObjectMetaAccessor).GetObjectMeta()
				rom.SetUID("")
				rom.SetResourceVersion("")
				rom.SetCreationTimestamp(v1.Time{})
				rom.SetDeletionTimestamp(nil)
				rom.SetDeletionGracePeriodSeconds(nil)
				return nil
			})
			if err != nil {
				return fmt.Errorf("Unable to clean metadata for export for %s resource: %s", resourceDisplayMap[r], err)
			}

			// Skip exporting Kubernetes network policies.
			if r == "networkpolicies" {
				objs, err := meta.ExtractList(resource)
				if err != nil {
					return fmt.Errorf("Error extracting network policies for inspection before exporting: %s", err)
				}

				filtered := []runtime.Object{}
				for _, obj := range objs {
					metaObj, ok := obj.(v1.ObjectMetaAccessor)
					if !ok {
						return fmt.Errorf("Unable to convert Calico network policy for inspection")
					}
					if !strings.HasPrefix(metaObj.GetObjectMeta().GetName(), conversion.K8sNetworkPolicyNamePrefix) {
						filtered = append(filtered, obj)
					}
				}

				err = meta.SetList(resource, filtered)
				if err != nil {
					return fmt.Errorf("Unable to remove Kubernetes network policies for export: %s", err)
				}
				results.Resources[i] = resource
			}

			// Nodes need to also be modified to move the Orchestrator reference to the name field.
			if r == "nodes" {
				err := meta.EachListItem(resource, func(obj runtime.Object) error {
					node, ok := obj.(*libapiv3.Node)
					if !ok {
						return fmt.Errorf("Failed to convert resource to Node object for migration processing: %+v", obj)
					}

					var newNodeName string
					for _, orchRef := range node.Spec.OrchRefs {
						if orchRef.Orchestrator == "k8s" {
							newNodeName = orchRef.NodeName
						}
					}

					if newNodeName == "" {
						return fmt.Errorf("Node %s missing a 'k8s' orchestrator reference. Unable to export data unless every node has a 'k8s' orchestrator reference", node.GetObjectMeta().GetName())
					}

					etcdToKddNodeMap[node.GetObjectMeta().GetName()] = newNodeName
					node.GetObjectMeta().SetName(newNodeName)

					return nil
				})
				if err != nil {
					return fmt.Errorf("Unable to process metadata for export for Node resource: %s", err)
				}
			}

			// Felix configs may also need to be modified if node names do not match the Kubernetes node names.
			// Felix configs must come after nodes in the allV3Resources list since we populate the node mapping when nodes are exported.
			if r == "felixconfigs" {
				err := meta.EachListItem(resource, func(obj runtime.Object) error {
					felixConfig, ok := obj.(*apiv3.FelixConfiguration)
					if !ok {
						return fmt.Errorf("Failed to convert resource to FelixConfiguration object for migration processing: %+v", obj)
					}

					if strings.HasPrefix(felixConfig.GetObjectMeta().GetName(), "node.") {
						etcdNodeName := strings.TrimPrefix(felixConfig.GetObjectMeta().GetName(), "node.")
						if nodename, ok := etcdToKddNodeMap[etcdNodeName]; ok {
							felixConfig.GetObjectMeta().SetName(fmt.Sprintf("node.%s", nodename))
						}
					}

					// Handling for possibly misconfigured iptables values from the v1 API.
					ConvertIptablesFields(felixConfig)

					return nil
				})
				if err != nil {
					return fmt.Errorf("Unable to process metadata for export for FelixConfiguration resource: %s", err)
				}
			}

			// BGP configs may also need to be modified if node names do not match the Kubernetes node names.
			// BGP configs must come after nodes in the allV3Resources list since we populate the node mapping when nodes are exported.
			if r == "bgpconfigs" {
				err := meta.EachListItem(resource, func(obj runtime.Object) error {
					bgpConfig, ok := obj.(*apiv3.BGPConfiguration)
					if !ok {
						return fmt.Errorf("Failed to convert resource to BGPConfiguration object for migration processing: %+v", obj)
					}

					if strings.HasPrefix(bgpConfig.GetObjectMeta().GetName(), "node.") {
						etcdNodeName := strings.TrimPrefix(bgpConfig.GetObjectMeta().GetName(), "node.")
						if nodename, ok := etcdToKddNodeMap[etcdNodeName]; ok {
							bgpConfig.GetObjectMeta().SetName(fmt.Sprintf("node.%s", nodename))
						}
					}

					return nil
				})
				if err != nil {
					return fmt.Errorf("Unable to process metadata for export for BGPConfiguration resource: %s", err)
				}
			}
		}

		err = rp.Print(results.Client, results.Resources)
		if err != nil {
			return err
		}

		// Add the yaml separator between resource types
		fmt.Print("---\n")
	}

	// Denote separation between the v3 resources and the cluster info resource which requires separate handling on import.
	fmt.Print("===\n")
	mockArgs := map[string]interface{}{
		"<KIND>":   "clusterinfos",
		"<NAME>":   "default",
		"--config": cf,
		"--export": false,
		"--output": "yaml",
		"get":      true,
	}
	results := common.ExecuteConfigCommand(mockArgs, common.ActionGetOrList)
	for _, resource := range results.Resources {
		clusterinfo, ok := resource.(*apiv3.ClusterInformation)
		if !ok {
			return fmt.Errorf("Failed to convert resource to ClusterInformation object: %+v", resource)
		}

		// Print the Cluster Info resource
		if output, err := json.MarshalIndent(clusterinfo, "", "  "); err != nil {
			return err
		} else {
			fmt.Printf("%s\n", string(output))
		}
	}

	if len(results.ResErrs) > 0 {
		var errStr string
		for i, err := range results.ResErrs {
			errStr += err.Error()
			if (i + 1) != len(results.ResErrs) {
				errStr += "\n"
			}
		}
		return fmt.Errorf("%s", errStr)
	}

	// Denote separation between resources stored in YAML and the JSON IPAM resources.
	// IPAM resources are stored in JSON since the objects are not supported by the v3 API
	// and are not meant to be used with other calicoctl commands except for import.
	fmt.Print("===\n")

	// Get the backend client.
	client, err = clientmgr.NewClient(cf)
	if err != nil {
		return err
	}

	// Use the v1 API in order to retrieve IPAM resources
	ipam := NewMigrateIPAM(client)
	ipam.SetNodeMap(etcdToKddNodeMap)
	err = ipam.PullFromDatastore()
	if err != nil {
		return err
	}

	// Print out the contents of IPAM
	output, err := json.MarshalIndent(ipam, "", "  ")
	if err != nil {
		return err
	} else {
		fmt.Printf("%s\n", string(output))
	}

	return nil
}

// ConvertIptablesFields ensures that all iptables fields are valid for the v3 API.
func ConvertIptablesFields(felixConfig *apiv3.FelixConfiguration) {
	if felixConfig.Spec.DefaultEndpointToHostAction != "" {
		felixConfig.Spec.DefaultEndpointToHostAction = title.String(strings.ToLower(felixConfig.Spec.DefaultEndpointToHostAction))
	}

	if felixConfig.Spec.IptablesFilterAllowAction != "" {
		felixConfig.Spec.IptablesFilterAllowAction = title.String(strings.ToLower(felixConfig.Spec.IptablesFilterAllowAction))
	}

	if felixConfig.Spec.IptablesMangleAllowAction != "" {
		felixConfig.Spec.IptablesMangleAllowAction = title.String(strings.ToLower(felixConfig.Spec.IptablesMangleAllowAction))
	}

	if felixConfig.Spec.IptablesFilterDenyAction != "" {
		felixConfig.Spec.IptablesFilterDenyAction = title.String(strings.ToLower(felixConfig.Spec.IptablesFilterDenyAction))
	}
}
