package command

import (
	"context"
	"fmt"
	"log"
	"strings"

	"github.com/hashicorp/terraform/command/clistate"
	"github.com/hashicorp/terraform/state"
)

// UntaintCommand is a cli.Command implementation that manually untaints
// a resource, marking it as primary and ready for service.
type UntaintCommand struct {
	Meta
}

func (c *UntaintCommand) Run(args []string) int {
	args = c.Meta.process(args, false)

	var allowMissing bool
	var module string
	cmdFlags := c.Meta.flagSet("untaint")
	cmdFlags.BoolVar(&allowMissing, "allow-missing", false, "module")
	cmdFlags.StringVar(&module, "module", "", "module")
	cmdFlags.StringVar(&c.Meta.statePath, "state", DefaultStateFilename, "path")
	cmdFlags.StringVar(&c.Meta.stateOutPath, "state-out", "", "path")
	cmdFlags.StringVar(&c.Meta.backupPath, "backup", "", "path")
	cmdFlags.BoolVar(&c.Meta.stateLock, "lock", true, "lock state")
	cmdFlags.DurationVar(&c.Meta.stateLockTimeout, "lock-timeout", 0, "lock timeout")
	cmdFlags.Usage = func() { c.Ui.Error(c.Help()) }
	if err := cmdFlags.Parse(args); err != nil {
		return 1
	}

	// Require the one argument for the resource to untaint
	args = cmdFlags.Args()
	if len(args) != 1 {
		c.Ui.Error("The untaint command expects exactly one argument.")
		cmdFlags.Usage()
		return 1
	}

	name := args[0]
	if module == "" {
		module = "root"
	} else {
		module = "root." + module
	}

	// Load the backend
	b, err := c.Backend(nil)
	if err != nil {
		c.Ui.Error(fmt.Sprintf("Failed to load backend: %s", err))
		return 1
	}

	// Get the state
	env := c.Env()
	st, err := b.State(env)
	if err != nil {
		c.Ui.Error(fmt.Sprintf("Failed to load state: %s", err))
		return 1
	}
	if err := st.RefreshState(); err != nil {
		c.Ui.Error(fmt.Sprintf("Failed to load state: %s", err))
		return 1
	}

	if c.stateLock {
		lockCtx, cancel := context.WithTimeout(context.Background(), c.stateLockTimeout)
		defer cancel()

		lockInfo := state.NewLockInfo()
		lockInfo.Operation = "untaint"
		lockID, err := clistate.Lock(lockCtx, st, lockInfo, c.Ui, c.Colorize())
		if err != nil {
			c.Ui.Error(fmt.Sprintf("Error locking state: %s", err))
			return 1
		}

		defer clistate.Unlock(st, lockID, c.Ui, c.Colorize())
	}

	// Get the actual state structure
	s := st.State()
	if s.Empty() {
		if allowMissing {
			return c.allowMissingExit(name, module)
		}

		c.Ui.Error(fmt.Sprintf(
			"The state is empty. The most common reason for this is that\n" +
				"an invalid state file path was given or Terraform has never\n " +
				"been run for this infrastructure. Infrastructure must exist\n" +
				"for it to be untainted."))
		return 1
	}

	// Get the proper module holding the resource we want to untaint
	modPath := strings.Split(module, ".")
	mod := s.ModuleByPath(modPath)
	if mod == nil {
		if allowMissing {
			return c.allowMissingExit(name, module)
		}

		c.Ui.Error(fmt.Sprintf(
			"The module %s could not be found. There is nothing to untaint.",
			module))
		return 1
	}

	// If there are no resources in this module, it is an error
	if len(mod.Resources) == 0 {
		if allowMissing {
			return c.allowMissingExit(name, module)
		}

		c.Ui.Error(fmt.Sprintf(
			"The module %s has no resources. There is nothing to untaint.",
			module))
		return 1
	}

	// Get the resource we're looking for
	rs, ok := mod.Resources[name]
	if !ok {
		if allowMissing {
			return c.allowMissingExit(name, module)
		}

		c.Ui.Error(fmt.Sprintf(
			"The resource %s couldn't be found in the module %s.",
			name,
			module))
		return 1
	}

	// Untaint the resource
	rs.Untaint()

	log.Printf("[INFO] Writing state output to: %s", c.Meta.StateOutPath())
	if err := st.WriteState(s); err != nil {
		c.Ui.Error(fmt.Sprintf("Error writing state file: %s", err))
		return 1
	}
	if err := st.PersistState(); err != nil {
		c.Ui.Error(fmt.Sprintf("Error writing state file: %s", err))
		return 1
	}

	c.Ui.Output(fmt.Sprintf(
		"The resource %s in the module %s has been successfully untainted!",
		name, module))
	return 0
}

func (c *UntaintCommand) Help() string {
	helpText := `
Usage: terraform untaint [options] name

  Manually unmark a resource as tainted, restoring it as the primary
  instance in the state.  This reverses either a manual 'terraform taint'
  or the result of provisioners failing on a resource.

  This will not modify your infrastructure. This command changes your
  state to unmark a resource as tainted.  This command can be undone by
  reverting the state backup file that is created, or by running
  'terraform taint' on the resource.

Options:

  -allow-missing      If specified, the command will succeed (exit code 0)
                      even if the resource is missing.

  -backup=path        Path to backup the existing state file before
                      modifying. Defaults to the "-state-out" path with
                      ".backup" extension. Set to "-" to disable backup.

  -lock=true          Lock the state file when locking is supported.

  -lock-timeout=0s    Duration to retry a state lock.

  -module=path        The module path where the resource lives. By
                      default this will be root. Child modules can be specified
                      by names. Ex. "consul" or "consul.vpc" (nested modules).

  -no-color           If specified, output won't contain any color.

  -state=path         Path to read and save state (unless state-out
                      is specified). Defaults to "terraform.tfstate".

  -state-out=path     Path to write updated state file. By default, the
                      "-state" path will be used.

`
	return strings.TrimSpace(helpText)
}

func (c *UntaintCommand) Synopsis() string {
	return "Manually unmark a resource as tainted"
}

func (c *UntaintCommand) allowMissingExit(name, module string) int {
	c.Ui.Output(fmt.Sprintf(
		"The resource %s in the module %s was not found, but\n"+
			"-allow-missing is set, so we're exiting successfully.",
		name, module))
	return 0
}