package command

import (
	"fmt"
	"io/ioutil"
	"os"
	"strings"

	"github.com/posener/complete"
)

const (
	// DefaultHclVolumeInitName is the default name we use when initializing
	// the example volume file in HCL format
	DefaultHclVolumeInitName = "volume.hcl"

	// DefaultHclVolumeInitName is the default name we use when initializing
	// the example volume file in JSON format
	DefaultJsonVolumeInitName = "volume.json"
)

// VolumeInitCommand generates a new volume spec that you can customize to
// your liking, like vagrant init
type VolumeInitCommand struct {
	Meta
}

func (c *VolumeInitCommand) Help() string {
	helpText := `
Usage: nomad volume init

  Creates an example volume specification file that can be used as a starting
  point to customize further.

Init Options:

  -json
    Create an example JSON volume specification.
`
	return strings.TrimSpace(helpText)
}

func (c *VolumeInitCommand) Synopsis() string {
	return "Create an example volume specification file"
}

func (c *VolumeInitCommand) AutocompleteFlags() complete.Flags {
	return complete.Flags{
		"-json": complete.PredictNothing,
	}
}

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

func (c *VolumeInitCommand) Name() string { return "volume init" }

func (c *VolumeInitCommand) Run(args []string) int {
	var jsonOutput bool
	flags := c.Meta.FlagSet(c.Name(), FlagSetClient)
	flags.Usage = func() { c.Ui.Output(c.Help()) }
	flags.BoolVar(&jsonOutput, "json", false, "")

	if err := flags.Parse(args); err != nil {
		return 1
	}

	// Check that we get no arguments
	args = flags.Args()
	if l := len(args); l != 0 {
		c.Ui.Error("This command takes no arguments")
		c.Ui.Error(commandErrorText(c))
		return 1
	}

	fileName := DefaultHclVolumeInitName
	fileContent := defaultHclVolumeSpec
	if jsonOutput {
		fileName = DefaultJsonVolumeInitName
		fileContent = defaultJsonVolumeSpec
	}

	// Check if the file already exists
	_, err := os.Stat(fileName)
	if err != nil && !os.IsNotExist(err) {
		c.Ui.Error(fmt.Sprintf("Failed to stat %q: %v", fileName, err))
		return 1
	}
	if !os.IsNotExist(err) {
		c.Ui.Error(fmt.Sprintf("Volume specification %q already exists", fileName))
		return 1
	}

	// Write out the example
	err = ioutil.WriteFile(fileName, []byte(fileContent), 0660)
	if err != nil {
		c.Ui.Error(fmt.Sprintf("Failed to write %q: %v", fileName, err))
		return 1
	}

	// Success
	c.Ui.Output(fmt.Sprintf("Example volume specification written to %s", fileName))
	return 0
}

var defaultHclVolumeSpec = strings.TrimSpace(`
id              = "ebs_prod_db1"
name            = "database"
type            = "csi"
external_id     = "vol-23452345"
access_mode     = "single-node-writer"
attachment_mode = "file-system"

mount_options {
  fs_type     = "ext4"
  mount_flags = ["ro"]
}
secrets {
  example_secret = "xyzzy"
}
parameters {
  skuname = "Premium_LRS"
}
context {
  endpoint = "http://192.168.1.101:9425"
}
`)

var defaultJsonVolumeSpec = strings.TrimSpace(`
{
  "id": "ebs_prod_db1",
  "name": "database",
  "type": "csi",
  "external_id": "vol-23452345",
  "access_mode": "single-node-writer",
  "attachment_mode": "file-system",
  "mount_options": {
    "fs_type": "ext4",
    "mount_flags": [
      "ro"
    ]
  },
  "secrets": {
    "example_secret": "xyzzy"
  },
  "parameters": {
    "skuname": "Premium_LRS"
  },
  "context": {
    "endpoint": "http://192.168.1.101:9425"
  }
}
`)