package command

import (
	"context"
	"fmt"
	"strings"

	"github.com/hashicorp/terraform/addrs"
	"github.com/hashicorp/terraform/command/clistate"
	"github.com/hashicorp/terraform/states"
	"github.com/hashicorp/terraform/tfdiags"
)

// 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)
	var allowMissing bool
	cmdFlags := c.Meta.ignoreRemoteVersionFlagSet("untaint")
	cmdFlags.BoolVar(&allowMissing, "allow-missing", false, "allow missing")
	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.StringVar(&c.Meta.statePath, "state", "", "path")
	cmdFlags.StringVar(&c.Meta.stateOutPath, "state-out", "", "path")
	cmdFlags.Usage = func() { c.Ui.Error(c.Help()) }
	if err := cmdFlags.Parse(args); err != nil {
		c.Ui.Error(fmt.Sprintf("Error parsing command-line flags: %s\n", err.Error()))
		return 1
	}

	var diags tfdiags.Diagnostics

	// 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
	}

	addr, addrDiags := addrs.ParseAbsResourceInstanceStr(args[0])
	diags = diags.Append(addrDiags)
	if addrDiags.HasErrors() {
		c.showDiagnostics(diags)
		return 1
	}

	// Load the backend
	b, backendDiags := c.Backend(nil)
	diags = diags.Append(backendDiags)
	if backendDiags.HasErrors() {
		c.showDiagnostics(diags)
		return 1
	}

	// Determine the workspace name
	workspace, err := c.Workspace()
	if err != nil {
		c.Ui.Error(fmt.Sprintf("Error selecting workspace: %s", err))
		return 1
	}

	// Check remote Terraform version is compatible
	remoteVersionDiags := c.remoteBackendVersionCheck(b, workspace)
	diags = diags.Append(remoteVersionDiags)
	c.showDiagnostics(diags)
	if diags.HasErrors() {
		return 1
	}

	// Get the state
	stateMgr, err := b.StateMgr(workspace)
	if err != nil {
		c.Ui.Error(fmt.Sprintf("Failed to load state: %s", err))
		return 1
	}

	if c.stateLock {
		stateLocker := clistate.NewLocker(context.Background(), c.stateLockTimeout, c.Ui, c.Colorize())
		if err := stateLocker.Lock(stateMgr, "untaint"); err != nil {
			c.Ui.Error(fmt.Sprintf("Error locking state: %s", err))
			return 1
		}
		defer stateLocker.Unlock(nil)
	}

	if err := stateMgr.RefreshState(); err != nil {
		c.Ui.Error(fmt.Sprintf("Failed to load state: %s", err))
		return 1
	}

	// Get the actual state structure
	state := stateMgr.State()
	if state.Empty() {
		if allowMissing {
			return c.allowMissingExit(addr)
		}

		diags = diags.Append(tfdiags.Sourceless(
			tfdiags.Error,
			"No such resource instance",
			"The state currently contains no resource instances whatsoever. This may occur if the configuration has never been applied or if it has recently been destroyed.",
		))
		c.showDiagnostics(diags)
		return 1
	}

	ss := state.SyncWrapper()

	// Get the resource and instance we're going to taint
	rs := ss.Resource(addr.ContainingResource())
	is := ss.ResourceInstance(addr)
	if is == nil {
		if allowMissing {
			return c.allowMissingExit(addr)
		}

		diags = diags.Append(tfdiags.Sourceless(
			tfdiags.Error,
			"No such resource instance",
			fmt.Sprintf("There is no resource instance in the state with the address %s. If the resource configuration has just been added, you must run \"terraform apply\" once to create the corresponding instance(s) before they can be tainted.", addr),
		))
		c.showDiagnostics(diags)
		return 1
	}

	obj := is.Current
	if obj == nil {
		if len(is.Deposed) != 0 {
			diags = diags.Append(tfdiags.Sourceless(
				tfdiags.Error,
				"No such resource instance",
				fmt.Sprintf("Resource instance %s is currently part-way through a create_before_destroy replacement action. Run \"terraform apply\" to complete its replacement before tainting it.", addr),
			))
		} else {
			// Don't know why we're here, but we'll produce a generic error message anyway.
			diags = diags.Append(tfdiags.Sourceless(
				tfdiags.Error,
				"No such resource instance",
				fmt.Sprintf("Resource instance %s does not currently have a remote object associated with it, so it cannot be tainted.", addr),
			))
		}
		c.showDiagnostics(diags)
		return 1
	}

	if obj.Status != states.ObjectTainted {
		diags = diags.Append(tfdiags.Sourceless(
			tfdiags.Error,
			"Resource instance is not tainted",
			fmt.Sprintf("Resource instance %s is not currently tainted, and so it cannot be untainted.", addr),
		))
		c.showDiagnostics(diags)
		return 1
	}
	obj.Status = states.ObjectReady
	ss.SetResourceInstanceCurrent(addr, obj, rs.ProviderConfig)

	if err := stateMgr.WriteState(state); err != nil {
		c.Ui.Error(fmt.Sprintf("Error writing state file: %s", err))
		return 1
	}
	if err := stateMgr.PersistState(); err != nil {
		c.Ui.Error(fmt.Sprintf("Error writing state file: %s", err))
		return 1
	}

	c.Ui.Output(fmt.Sprintf("Resource instance %s has been successfully untainted.", addr))
	return 0
}

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

  Terraform uses the term "tainted" to describe a resource instance
  which may not be fully functional, either because its creation
  partially failed or because you've manually marked it as such using
  the "terraform taint" command.

  This command removes that state from a resource instance, causing
  Terraform to see it as fully-functional and not in need of
  replacement.

  This will not modify your infrastructure directly. It only avoids
  Terraform planning to replace a tainted instance in a future operation.

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.

  -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.

  -ignore-remote-version  Continue even if remote and local Terraform versions
                          differ. This may result in an unusable workspace, and
                          should be used with extreme caution.

`
	return strings.TrimSpace(helpText)
}

func (c *UntaintCommand) Synopsis() string {
	return "Remove the 'tainted' state from a resource instance"
}

func (c *UntaintCommand) allowMissingExit(name addrs.AbsResourceInstance) int {
	c.showDiagnostics(tfdiags.Sourceless(
		tfdiags.Warning,
		"No such resource instance",
		fmt.Sprintf("Resource instance %s was not found, but this is not an error because -allow-missing was set.", name),
	))
	return 0
}