// Copyright (c) HashiCorp, Inc.
// SPDX-License-Identifier: MPL-2.0

package command

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

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

type OperatorRaftStateCommand struct {
	Meta
}

func (c *OperatorRaftStateCommand) Help() string {
	helpText := `
Usage: nomad operator raft state <path to nomad data dir>

  Display the server state obtained by replaying raft log entries persisted in
  the Nomad data directory in JSON format.

  This command requires file system permissions to access the data directory on
  disk. The Nomad server locks access to the data directory, so this command
  cannot be run on a data directory that is being used by a running Nomad server.

  This is a low-level debugging tool and not subject to Nomad's usual backward
  compatibility guarantees.

Options:

  -last-index=<last_index>
    Set the last log index to be applied, to drop spurious log entries not
    properly committed. If passed last_index is zero or negative, it's perceived
    as an offset from the last index seen in raft.
`
	return strings.TrimSpace(helpText)
}

func (c *OperatorRaftStateCommand) AutocompleteFlags() complete.Flags {
	return complete.Flags{
		"-last-index": complete.PredictNothing,
	}
}

func (c *OperatorRaftStateCommand) AutocompleteArgs() complete.Predictor {
	return complete.PredictFiles("*")
}

func (c *OperatorRaftStateCommand) Synopsis() string {
	return "Display raft server state"
}

func (c *OperatorRaftStateCommand) Name() string { return "operator raft state" }

func (c *OperatorRaftStateCommand) Run(args []string) int {
	var fLastIdx int64

	flags := c.Meta.FlagSet(c.Name(), 0)
	flags.Usage = func() { fmt.Println(c.Help()) }
	flags.Int64Var(&fLastIdx, "last-index", 0, "")

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

	if len(args) != 1 {
		c.Ui.Error("This command takes one argument: <path>")
		c.Ui.Error(commandErrorText(c))

		return 1
	}

	// Find raft.db folder
	raftPath, err := raftutil.FindRaftDir(args[0])
	if err != nil {
		c.Ui.Error(err.Error())
		return 1
	}

	fsm, err := raftutil.NewFSM(raftPath)
	if err != nil {
		c.Ui.Error(err.Error())
		return 1
	}
	defer fsm.Close()

	_, _, err = fsm.ApplyAll()
	if err != nil {
		c.Ui.Error(err.Error())
		return 1
	}

	state := fsm.StateAsMap()
	enc := json.NewEncoder(os.Stdout)
	enc.SetIndent("", "  ")
	if err := enc.Encode(state); err != nil {
		c.Ui.Error(fmt.Sprintf("failed to encode output: %v", err))
		return 1
	}

	return 0
}