package main

import (
	"context"
	"errors"
	"fmt"
	"io"
	"log"
	"os"
	"strings"
	"sync"
	"time"

	"github.com/spf13/cobra"
	"golang.org/x/sync/semaphore"

	"source.monogon.dev/go/clitable"
	"source.monogon.dev/metropolis/cli/metroctl/core"
	clicontext "source.monogon.dev/metropolis/cli/pkg/context"
	"source.monogon.dev/metropolis/node/core/identity"
	"source.monogon.dev/version"

	apb "source.monogon.dev/metropolis/proto/api"
)

var nodeCmd = &cobra.Command{
	Short: "Updates and queries node information.",
	Use:   "node",
}

var nodeDescribeCmd = &cobra.Command{
	Short:   "Describes cluster nodes.",
	Use:     "describe [node-id] [--filter] [--output] [--format]",
	Example: "metroctl node describe metropolis-c556e31c3fa2bf0a36e9ccb9fd5d6056",
	Run: func(cmd *cobra.Command, args []string) {
		ctx := clicontext.WithInterrupt(context.Background())
		cc := dialAuthenticated(ctx)
		mgmt := apb.NewManagementClient(cc)

		nodes, err := core.GetNodes(ctx, mgmt, flags.filter)
		if err != nil {
			log.Fatalf("While calling Management.GetNodes: %v", err)
		}

		printNodes(nodes, args, nil)
	},
	Args: cobra.ArbitraryArgs,
}

var nodeListCmd = &cobra.Command{
	Short:   "Lists cluster nodes.",
	Use:     "list [node-id] [--filter] [--output] [--format]",
	Example: "metroctl node list --filter node.status.external_address==\"10.8.0.2\"",
	Run: func(cmd *cobra.Command, args []string) {
		ctx := clicontext.WithInterrupt(context.Background())
		cc := dialAuthenticated(ctx)
		mgmt := apb.NewManagementClient(cc)

		nodes, err := core.GetNodes(ctx, mgmt, flags.filter)
		if err != nil {
			log.Fatalf("While calling Management.GetNodes: %v", err)
		}

		printNodes(nodes, args, map[string]bool{"node id": true})
	},
	Args: cobra.ArbitraryArgs,
}

var nodeUpdateCmd = &cobra.Command{
	Short:   "Updates the operating system of a cluster node.",
	Use:     "update [NodeIDs]",
	Example: "metroctl node update --bundle-url https://example.com/bundle.zip --activation-mode reboot metropolis-25fa5f5e9349381d4a5e9e59de0215e3",
	RunE: func(cmd *cobra.Command, args []string) error {
		bundleUrl, err := cmd.Flags().GetString("bundle-url")
		if err != nil {
			return err
		}

		if len(bundleUrl) == 0 {
			return fmt.Errorf("flag bundle-url is required")
		}

		activationMode, err := cmd.Flags().GetString("activation-mode")
		if err != nil {
			return err
		}

		var am apb.ActivationMode
		switch strings.ToLower(activationMode) {
		case "none":
			am = apb.ActivationMode_ACTIVATION_NONE
		case "reboot":
			am = apb.ActivationMode_ACTIVATION_REBOOT
		case "kexec":
			am = apb.ActivationMode_ACTIVATION_KEXEC
		default:
			return fmt.Errorf("invalid value for flag activation-mode")
		}

		maxUnavailable, err := cmd.Flags().GetUint64("max-unavailable")
		if err != nil {
			return err
		}
		if maxUnavailable == 0 {
			return errors.New("unable to update notes with max-unavailable set to zero")
		}
		unavailableSemaphore := semaphore.NewWeighted(int64(maxUnavailable))

		ctx := clicontext.WithInterrupt(context.Background())

		cacert, err := core.GetClusterCAWithTOFU(ctx, connectOptions())
		if err != nil {
			return fmt.Errorf("could not get CA certificate: %w", err)
		}

		mgmt := apb.NewManagementClient(dialAuthenticated(ctx))

		nodes, err := core.GetNodes(ctx, mgmt, "")
		if err != nil {
			return fmt.Errorf("while calling Management.GetNodes: %v", err)
		}
		// Narrow down the output set to supplied node IDs, if any.
		qids := make(map[string]bool)
		if len(args) != 0 && args[0] != "all" {
			for _, a := range args {
				qids[a] = true
			}
		}

		updateReq := &apb.UpdateNodeRequest{
			BundleUrl:      bundleUrl,
			ActivationMode: am,
		}

		var wg sync.WaitGroup

		for _, n := range nodes {
			// Filter the information we want client-side.
			if len(qids) != 0 {
				nid := identity.NodeID(n.Pubkey)
				if _, e := qids[nid]; !e {
					continue
				}
			}

			if err := unavailableSemaphore.Acquire(ctx, 1); err != nil {
				return err
			}
			wg.Add(1)

			go func(n *apb.Node) {
				defer wg.Done()
				cc := dialAuthenticatedNode(ctx, n.Id, n.Status.ExternalAddress, cacert)
				nodeMgmt := apb.NewNodeManagementClient(cc)
				log.Printf("sending update request to: %s (%s)", n.Id, n.Status.ExternalAddress)
				start := time.Now()
				_, err := nodeMgmt.UpdateNode(ctx, updateReq)
				if err != nil {
					log.Printf("update request to node %s failed: %v", n.Id, err)
					// A failed UpdateNode does not mean that the node is now unavailable as it
					// hasn't started activating yet.
					unavailableSemaphore.Release(1)
				}
				// Wait for the internal activation sleep plus the heartbeat
				// to make sure the node has missed one heartbeat (or is
				// back up already).
				time.Sleep((5 + 10) * time.Second)
				for {
					select {
					case <-time.After(10 * time.Second):
						nodes, err := core.GetNodes(ctx, mgmt, fmt.Sprintf("node.id == %q", n.Id))
						if err != nil {
							log.Printf("while getting node status for %s: %v", n.Id, err)
							continue
						}
						if len(nodes) == 0 {
							log.Printf("node status for %s returned no node", n.Id)
							continue
						}
						if len(nodes) > 1 {
							log.Printf("node status for %s returned too many nodes (%d)", n.Id, len(nodes))
							continue
						}
						s := nodes[0]
						if s.Health == apb.Node_HEALTHY {
							if s.Status != nil && s.Status.Version != nil {
								log.Printf("node %s updated in %v to version %s", s.Id, time.Since(start), version.Semver(s.Status.Version))
							} else {
								log.Printf("node %s updated in %v to unknown version", s.Id, time.Since(start))
							}
							unavailableSemaphore.Release(1)
							return
						}
					case <-ctx.Done():
						log.Printf("update to node %s incomplete", n.Id)
						return
					}
				}
			}(n)
		}

		// Wait for all update processes to finish
		wg.Wait()

		return nil
	},
	Args: cobra.MinimumNArgs(1),
}

var nodeDeleteCmd = &cobra.Command{
	Short:   "Deletes a node from the cluster.",
	Use:     "delete [NodeID] [--bypass-has-roles] [--bypass-not-decommissioned]",
	Example: "metroctl node delete metropolis-25fa5f5e9349381d4a5e9e59de0215e3",
	RunE: func(cmd *cobra.Command, args []string) error {
		bypassHasRoles, err := cmd.Flags().GetBool("bypass-has-roles")
		if err != nil {
			return err
		}

		bypassNotDecommissioned, err := cmd.Flags().GetBool("bypass-not-decommissioned")
		if err != nil {
			return err
		}

		ctx := clicontext.WithInterrupt(context.Background())
		mgmt := apb.NewManagementClient(dialAuthenticated(ctx))

		nodes, err := core.GetNodes(ctx, mgmt, fmt.Sprintf("node.id==%q", args[0]))
		if err != nil {
			return fmt.Errorf("while calling Management.GetNodes: %v", err)
		}

		if len(nodes) == 0 {
			return fmt.Errorf("could not find node with id: %s", args[0])
		}

		if len(nodes) != 1 {
			return fmt.Errorf("expected one node, got %d", len(nodes))
		}

		n := nodes[0]
		log.Printf("deleting node: %s (%s)", n.Id, n.Status.ExternalAddress)

		req := &apb.DeleteNodeRequest{
			Node: &apb.DeleteNodeRequest_Id{
				Id: n.Id,
			},
		}

		if bypassHasRoles {
			req.SafetyBypassHasRoles = &apb.DeleteNodeRequest_SafetyBypassHasRoles{}
		}

		if bypassNotDecommissioned {
			req.SafetyBypassNotDecommissioned = &apb.DeleteNodeRequest_SafetyBypassNotDecommissioned{}
		}

		_, err = mgmt.DeleteNode(ctx, req)
		return err
	},
	Args: cobra.ExactArgs(1),
}

func init() {
	nodeUpdateCmd.Flags().String("bundle-url", "", "The URL to the new version")
	nodeUpdateCmd.Flags().String("activation-mode", "reboot", "How the update should be activated (kexec, reboot, none)")
	nodeUpdateCmd.Flags().Uint64("max-unavailable", 1, "Maximum nodes which can be unavailable during the update process")

	nodeDeleteCmd.Flags().Bool("bypass-has-roles", false, "Allows to bypass the HasRoles check")
	nodeDeleteCmd.Flags().Bool("bypass-not-decommissioned", false, "Allows to bypass the NotDecommissioned check")

	nodeCmd.AddCommand(nodeDescribeCmd)
	nodeCmd.AddCommand(nodeListCmd)
	nodeCmd.AddCommand(nodeUpdateCmd)
	nodeCmd.AddCommand(nodeDeleteCmd)
	rootCmd.AddCommand(nodeCmd)
}

func printNodes(nodes []*apb.Node, args []string, onlyColumns map[string]bool) {
	o := io.WriteCloser(os.Stdout)
	if flags.output != "" {
		of, err := os.Create(flags.output)
		if err != nil {
			log.Fatalf("Couldn't create the output file at %s: %v", flags.output, err)
		}
		o = of
	}

	// Narrow down the output set to supplied node IDs, if any.
	qids := make(map[string]bool)
	if len(args) != 0 && args[0] != "all" {
		for _, a := range args {
			qids[a] = true
		}
	}

	var t clitable.Table
	for _, n := range nodes {
		// Filter the information we want client-side.
		if len(qids) != 0 {
			nid := identity.NodeID(n.Pubkey)
			if _, e := qids[nid]; !e {
				continue
			}
		}
		t.Add(nodeEntry(n))
	}

	t.Print(o, onlyColumns)
}