package command

import (
	"fmt"
	"strings"
	"time"

	"github.com/hashicorp/terraform/command/arguments"
	"github.com/hashicorp/terraform/command/clistate"
	"github.com/hashicorp/terraform/command/views"
	"github.com/hashicorp/terraform/tfdiags"
	"github.com/mitchellh/cli"
	"github.com/posener/complete"
)

type WorkspaceDeleteCommand struct {
	Meta
	LegacyName bool
}

func (c *WorkspaceDeleteCommand) Run(args []string) int {
	args = c.Meta.process(args)
	envCommandShowWarning(c.Ui, c.LegacyName)

	var force bool
	var stateLock bool
	var stateLockTimeout time.Duration
	cmdFlags := c.Meta.defaultFlagSet("workspace delete")
	cmdFlags.BoolVar(&force, "force", false, "force removal of a non-empty workspace")
	cmdFlags.BoolVar(&stateLock, "lock", true, "lock state")
	cmdFlags.DurationVar(&stateLockTimeout, "lock-timeout", 0, "lock timeout")
	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
	}

	args = cmdFlags.Args()
	if len(args) != 1 {
		c.Ui.Error("Expected a single argument: NAME.\n")
		return cli.RunResultHelp
	}

	configPath, err := ModulePath(args[1:])
	if err != nil {
		c.Ui.Error(err.Error())
		return 1
	}

	var diags tfdiags.Diagnostics

	backendConfig, backendDiags := c.loadBackendConfig(configPath)
	diags = diags.Append(backendDiags)
	if diags.HasErrors() {
		c.showDiagnostics(diags)
		return 1
	}

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

	// This command will not write state
	c.ignoreRemoteBackendVersionConflict(b)

	workspaces, err := b.Workspaces()
	if err != nil {
		c.Ui.Error(err.Error())
		return 1
	}

	workspace := args[0]
	exists := false
	for _, ws := range workspaces {
		if workspace == ws {
			exists = true
			break
		}
	}

	if !exists {
		c.Ui.Error(fmt.Sprintf(strings.TrimSpace(envDoesNotExist), workspace))
		return 1
	}

	currentWorkspace, err := c.Workspace()
	if err != nil {
		c.Ui.Error(fmt.Sprintf("Error selecting workspace: %s", err))
		return 1
	}
	if workspace == currentWorkspace {
		c.Ui.Error(fmt.Sprintf(strings.TrimSpace(envDelCurrent), workspace))
		return 1
	}

	// we need the actual state to see if it's empty
	stateMgr, err := b.StateMgr(workspace)
	if err != nil {
		c.Ui.Error(err.Error())
		return 1
	}

	var stateLocker clistate.Locker
	if stateLock {
		stateLocker = clistate.NewLocker(c.stateLockTimeout, views.NewStateLocker(arguments.ViewHuman, c.View))
		if diags := stateLocker.Lock(stateMgr, "state-replace-provider"); diags.HasErrors() {
			c.showDiagnostics(diags)
			return 1
		}
	} else {
		stateLocker = clistate.NewNoopLocker()
	}

	if err := stateMgr.RefreshState(); err != nil {
		// We need to release the lock before exit
		stateLocker.Unlock()
		c.Ui.Error(err.Error())
		return 1
	}

	hasResources := stateMgr.State().HasResources()

	if hasResources && !force {
		// We need to release the lock before exit
		stateLocker.Unlock()
		c.Ui.Error(fmt.Sprintf(strings.TrimSpace(envNotEmpty), workspace))
		return 1
	}

	// We need to release the lock just before deleting the state, in case
	// the backend can't remove the resource while holding the lock. This
	// is currently true for Windows local files.
	//
	// TODO: While there is little safety in locking while deleting the
	// state, it might be nice to be able to coordinate processes around
	// state deletion, i.e. in a CI environment. Adding Delete() as a
	// required method of States would allow the removal of the resource to
	// be delegated from the Backend to the State itself.
	stateLocker.Unlock()

	err = b.DeleteWorkspace(workspace)
	if err != nil {
		c.Ui.Error(err.Error())
		return 1
	}

	c.Ui.Output(
		c.Colorize().Color(
			fmt.Sprintf(envDeleted, workspace),
		),
	)

	if hasResources {
		c.Ui.Output(
			c.Colorize().Color(
				fmt.Sprintf(envWarnNotEmpty, workspace),
			),
		)
	}

	return 0
}

func (c *WorkspaceDeleteCommand) AutocompleteArgs() complete.Predictor {
	return completePredictSequence{
		complete.PredictNothing, // the "select" subcommand itself (already matched)
		c.completePredictWorkspaceName(),
		complete.PredictDirs(""),
	}
}

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

func (c *WorkspaceDeleteCommand) Help() string {
	helpText := `
Usage: terraform [global options] workspace delete [OPTIONS] NAME

  Delete a Terraform workspace


Options:

  -force             Remove even a non-empty workspace.

  -lock=false        Don't hold a state lock during the operation. This is
                     dangerous if others might concurrently run commands
                     against the same workspace.

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

`
	return strings.TrimSpace(helpText)
}

func (c *WorkspaceDeleteCommand) Synopsis() string {
	return "Delete a workspace"
}