// Copyright (c) HashiCorp, Inc.
// SPDX-License-Identifier: BUSL-1.1

package command

import (
	"fmt"
	"io"
	"os"
	"strings"
	"time"

	"github.com/hashicorp/nomad/api"
	"github.com/hashicorp/nomad/helper/raftutil"
	"github.com/posener/complete"
)

type OperatorSnapshotSaveCommand struct {
	Meta
}

func (c *OperatorSnapshotSaveCommand) Help() string {
	helpText := `
Usage: nomad operator snapshot save [options] <file>

  Retrieves an atomic, point-in-time snapshot of the state of the Nomad servers
  which includes jobs, nodes, allocations, periodic jobs, and ACLs.

  If ACLs are enabled, a management token must be supplied in order to perform
  snapshot operations.

  To create a snapshot from the leader server and save it to "backup.snap":

    $ nomad operator snapshot save backup.snap

  To create a potentially stale snapshot from any available server (useful if no
  leader is available):

    $ nomad operator snapshot save -stale backup.snap

  This is useful for situations where a cluster is in a degraded state and no
  leader is available. To target a specific server for a snapshot, you can run
  the 'nomad operator snapshot save' command on that specific server.


General Options:

  ` + generalOptionsUsage(usageOptsDefault|usageOptsNoNamespace) + `

Snapshot Save Options:

  -redact
    The -redact option will locally edit the snapshot to remove any cleartext key
    material from the root keyring. Only the AEAD keyring provider has cleartext
    key material in Raft. Note that this operation requires loading the snapshot
    into memory locally.

  -stale
    The -stale option defaults to "false" which means the leader provides the
    result. If the cluster is in an outage state without a leader, you may need
    to set -stale to "true" to get the configuration from a non-leader server.
`
	return strings.TrimSpace(helpText)
}

func (c *OperatorSnapshotSaveCommand) AutocompleteFlags() complete.Flags {
	return mergeAutocompleteFlags(c.Meta.AutocompleteFlags(FlagSetClient),
		complete.Flags{
			"-stale": complete.PredictAnything,
		})
}

func (c *OperatorSnapshotSaveCommand) AutocompleteArgs() complete.Predictor {
	return complete.PredictNothing
}

func (c *OperatorSnapshotSaveCommand) Synopsis() string {
	return "Saves snapshot of Nomad server state"
}

func (c *OperatorSnapshotSaveCommand) Name() string { return "operator snapshot save" }

func (c *OperatorSnapshotSaveCommand) Run(args []string) int {
	var stale, redact bool

	flags := c.Meta.FlagSet(c.Name(), FlagSetClient)
	flags.Usage = func() { c.Ui.Output(c.Help()) }

	flags.BoolVar(&stale, "stale", false, "")
	flags.BoolVar(&redact, "redact", false, "")

	if err := flags.Parse(args); err != nil {
		c.Ui.Error(fmt.Sprintf("Failed to parse args: %v", err))
		return 1
	}

	// Check for misuse
	// Check that we either got no filename or exactly one.
	args = flags.Args()
	if len(args) > 1 {
		c.Ui.Error("This command takes either no arguments or one: <filename>")
		c.Ui.Error(commandErrorText(c))
		return 1
	}

	now := time.Now()
	filename := fmt.Sprintf("nomad-state-%04d%02d%0d-%d.snap", now.Year(), now.Month(), now.Day(), now.Unix())

	if len(args) == 1 {
		filename = args[0]
	}

	if _, err := os.Lstat(filename); err == nil {
		c.Ui.Error(fmt.Sprintf("Destination file already exists: %q", filename))
		c.Ui.Error(commandErrorText(c))
		return 1
	} else if !os.IsNotExist(err) {
		c.Ui.Error(fmt.Sprintf("Unexpected failure checking %q: %v", filename, err))
		return 1
	}

	// Set up a client.
	client, err := c.Meta.Client()
	if err != nil {
		c.Ui.Error(fmt.Sprintf("Error initializing client: %s", err))
		return 1
	}

	tmpFile, err := os.Create(filename + ".tmp")
	if err != nil {
		c.Ui.Error(fmt.Sprintf("Failed to create file: %v", err))
		return 1
	}

	// Fetch the current configuration.
	q := &api.QueryOptions{
		AllowStale: stale,
	}
	snapIn, err := client.Operator().Snapshot(q)
	if err != nil {
		c.Ui.Error(fmt.Sprintf("Failed to get snapshot file: %v", err))
		return 1
	}

	defer snapIn.Close()

	_, err = io.Copy(tmpFile, snapIn)
	if err != nil {
		c.Ui.Error(fmt.Sprintf("Failed to download snapshot file: %v", err))
		return 1
	}

	if redact {
		c.Ui.Info("Redacting key material from snapshot")
		err := raftutil.RedactSnapshot(tmpFile)
		if err != nil {
			c.Ui.Error(fmt.Sprintf("Could not redact snapshot: %v", err))
			return 1
		}
	}

	err = os.Rename(tmpFile.Name(), filename)
	if err != nil {
		c.Ui.Error(fmt.Sprintf("Failed to finalize snapshot file: %v", err))
		return 1
	}

	c.Ui.Output(fmt.Sprintf("State file written to %v", filename))
	return 0
}