package command

import (
	"context"
	"fmt"
	"io"
	"os"
	"strings"

	"github.com/hashicorp/vault/api"
	"github.com/mitchellh/cli"
	"github.com/posener/complete"
)

var (
	_ cli.Command             = (*KVPatchCommand)(nil)
	_ cli.CommandAutocomplete = (*KVPatchCommand)(nil)
)

type KVPatchCommand struct {
	*BaseCommand

	flagCAS    int
	flagMethod string
	testStdin  io.Reader // for tests
}

func (c *KVPatchCommand) Synopsis() string {
	return "Sets or updates data in the KV store without overwriting"
}

func (c *KVPatchCommand) Help() string {
	helpText := `
Usage: vault kv patch [options] KEY [DATA]

  *NOTE*: This is only supported for KV v2 engine mounts.

  Writes the data to the given path in the key-value store. The data can be of
  any type.

      $ vault kv patch secret/foo bar=baz

  The data can also be consumed from a file on disk by prefixing with the "@"
  symbol. For example:

      $ vault kv patch secret/foo @data.json

  Or it can be read from stdin using the "-" symbol:

      $ echo "abcd1234" | vault kv patch secret/foo bar=-

  To perform a Check-And-Set operation, specify the -cas flag with the
  appropriate version number corresponding to the key you want to perform
  the CAS operation on:

      $ vault kv patch -cas=1 secret/foo bar=baz

  By default, this operation will attempt an HTTP PATCH operation. If your
  policy does not allow that, it will fall back to a read/local update/write approach.
  If you wish to specify which method this command should use, you may do so
  with the -method flag. When -method=patch is specified, only an HTTP PATCH
  operation will be tried. If it fails, the entire command will fail.

      $ vault kv patch -method=patch secret/foo bar=baz

  When -method=rw is specified, only a read/local update/write approach will be tried.
  This was the default behavior previous to Vault 1.9.

      $ vault kv patch -method=rw secret/foo bar=baz

  Additional flags and more advanced use cases are detailed below.

` + c.Flags().Help()
	return strings.TrimSpace(helpText)
}

func (c *KVPatchCommand) Flags() *FlagSets {
	set := c.flagSet(FlagSetHTTP | FlagSetOutputField | FlagSetOutputFormat)

	// Patch specific options
	f := set.NewFlagSet("Common Options")

	f.IntVar(&IntVar{
		Name:    "cas",
		Target:  &c.flagCAS,
		Default: 0,
		Usage: `Specifies to use a Check-And-Set operation. If set to 0 or not
		set, the patch will be allowed. If the index is non-zero the patch will
		only be allowed if the key’s current version matches the version
		specified in the cas parameter.`,
	})

	f.StringVar(&StringVar{
		Name:   "method",
		Target: &c.flagMethod,
		Usage: `Specifies which method of patching to use. If set to "patch", then
		an HTTP PATCH request will be issued. If set to "rw", then a read will be
		performed, then a local update, followed by a remote update.`,
	})

	return set
}

func (c *KVPatchCommand) AutocompleteArgs() complete.Predictor {
	return nil
}

func (c *KVPatchCommand) AutocompleteFlags() complete.Flags {
	return c.Flags().Completions()
}

func (c *KVPatchCommand) Run(args []string) int {
	f := c.Flags()

	if err := f.Parse(args); err != nil {
		c.UI.Error(err.Error())
		return 1
	}

	args = f.Args()
	// Pull our fake stdin if needed
	stdin := (io.Reader)(os.Stdin)
	if c.testStdin != nil {
		stdin = c.testStdin
	}

	switch {
	case len(args) < 1:
		c.UI.Error(fmt.Sprintf("Not enough arguments (expected >1, got %d)", len(args)))
		return 1
	case len(args) == 1:
		c.UI.Error("Must supply data")
		return 1
	}

	var err error
	path := sanitizePath(args[0])

	client, err := c.Client()
	if err != nil {
		c.UI.Error(err.Error())
		return 2
	}

	newData, err := parseArgsData(stdin, args[1:])
	if err != nil {
		c.UI.Error(fmt.Sprintf("Failed to parse K=V data: %s", err))
		return 1
	}

	mountPath, v2, err := isKVv2(path, client)
	if err != nil {
		c.UI.Error(err.Error())
		return 2
	}

	if !v2 {
		c.UI.Error("K/V engine mount must be version 2 for patch support")
		return 2
	}

	path = addPrefixToKVPath(path, mountPath, "data")
	if err != nil {
		c.UI.Error(err.Error())
		return 2
	}

	// Check the method and behave accordingly
	var secret *api.Secret
	var code int

	switch c.flagMethod {
	case "rw":
		secret, code = c.readThenWrite(client, path, newData)
	case "patch":
		secret, code = c.mergePatch(client, path, newData, false)
	case "":
		secret, code = c.mergePatch(client, path, newData, true)
	default:
		c.UI.Error(fmt.Sprintf("Unsupported method provided to -method flag: %s", c.flagMethod))
		return 2
	}

	if code != 0 {
		return code
	}

	return OutputSecret(c.UI, secret)
}

func (c *KVPatchCommand) readThenWrite(client *api.Client, path string, newData map[string]interface{}) (*api.Secret, int) {
	// First, do a read.
	// Note that we don't want to see curl output for the read request.
	curOutputCurl := client.OutputCurlString()
	client.SetOutputCurlString(false)
	secret, err := kvReadRequest(client, path, nil)
	client.SetOutputCurlString(curOutputCurl)
	if err != nil {
		c.UI.Error(fmt.Sprintf("Error doing pre-read at %s: %s", path, err))
		return nil, 2
	}

	// Make sure a value already exists
	if secret == nil || secret.Data == nil {
		c.UI.Error(fmt.Sprintf("No value found at %s", path))
		return nil, 2
	}

	// Verify metadata found
	rawMeta, ok := secret.Data["metadata"]
	if !ok || rawMeta == nil {
		c.UI.Error(fmt.Sprintf("No metadata found at %s; patch only works on existing data", path))
		return nil, 2
	}
	meta, ok := rawMeta.(map[string]interface{})
	if !ok {
		c.UI.Error(fmt.Sprintf("Metadata found at %s is not the expected type (JSON object)", path))
		return nil, 2
	}
	if meta == nil {
		c.UI.Error(fmt.Sprintf("No metadata found at %s; patch only works on existing data", path))
		return nil, 2
	}

	// Verify old data found
	rawData, ok := secret.Data["data"]
	if !ok || rawData == nil {
		c.UI.Error(fmt.Sprintf("No data found at %s; patch only works on existing data", path))
		return nil, 2
	}
	data, ok := rawData.(map[string]interface{})
	if !ok {
		c.UI.Error(fmt.Sprintf("Data found at %s is not the expected type (JSON object)", path))
		return nil, 2
	}
	if data == nil {
		c.UI.Error(fmt.Sprintf("No data found at %s; patch only works on existing data", path))
		return nil, 2
	}

	// Copy new data over
	for k, v := range newData {
		data[k] = v
	}

	secret, err = client.Logical().Write(path, map[string]interface{}{
		"data": data,
		"options": map[string]interface{}{
			"cas": meta["version"],
		},
	})
	if err != nil {
		c.UI.Error(fmt.Sprintf("Error writing data to %s: %s", path, err))
		return nil, 2
	}

	if secret == nil {
		// Don't output anything unless using the "table" format
		if Format(c.UI) == "table" {
			c.UI.Info(fmt.Sprintf("Success! Data written to: %s", path))
		}
		return nil, 0
	}

	if c.flagField != "" {
		return nil, PrintRawField(c.UI, secret, c.flagField)
	}

	return secret, 0
}

func (c *KVPatchCommand) mergePatch(client *api.Client, path string, newData map[string]interface{}, rwFallback bool) (*api.Secret, int) {
	data := map[string]interface{}{
		"data":    newData,
		"options": map[string]interface{}{},
	}

	if c.flagCAS > 0 {
		data["options"].(map[string]interface{})["cas"] = c.flagCAS
	}

	secret, err := client.Logical().JSONMergePatch(context.Background(), path, data)
	if err != nil {
		// If it's a 405, that probably means the server is running a pre-1.9
		// Vault version that doesn't support the HTTP PATCH method.
		// Fall back to the old way of doing it if the user didn't specify a -method.
		// If they did, and it was "patch", then just error.
		if re, ok := err.(*api.ResponseError); ok && re.StatusCode == 405 && rwFallback {
			return c.readThenWrite(client, path, newData)
		}
		// If it's a 403, that probably means they don't have the patch capability in their policy. Fall back to
		// the old way of doing it if the user didn't specify a -method. If they did, and it was "patch", then just error.
		if re, ok := err.(*api.ResponseError); ok && re.StatusCode == 403 && rwFallback {
			c.UI.Warn(fmt.Sprintf("Data was written to %s but we recommend that you add the \"patch\" capability to your ACL policy in order to use HTTP PATCH in the future.", path))
			return c.readThenWrite(client, path, newData)
		}

		c.UI.Error(fmt.Sprintf("Error writing data to %s: %s", path, err))
		return nil, 2
	}

	if secret == nil {
		// Don't output anything unless using the "table" format
		if Format(c.UI) == "table" {
			c.UI.Info(fmt.Sprintf("Success! Data written to: %s", path))
		}
		return nil, 0
	}

	if c.flagField != "" {
		return nil, PrintRawField(c.UI, secret, c.flagField)
	}

	return secret, 0
}