package command

import (
	"fmt"
	"sort"
	"strings"

	"github.com/hashicorp/terraform/addrs"
	"github.com/hashicorp/terraform/states"
	"github.com/mitchellh/cli"
)

// StateRmCommand is a Command implementation that shows a single resource.
type StateRmCommand struct {
	StateMeta
}

func (c *StateRmCommand) Run(args []string) int {
	args, err := c.Meta.process(args, true)
	if err != nil {
		return 1
	}

	var dryRun bool
	cmdFlags := c.Meta.flagSet("state show")
	cmdFlags.BoolVar(&dryRun, "dry-run", false, "dry run")
	cmdFlags.StringVar(&c.backupPath, "backup", "-", "backup")
	cmdFlags.StringVar(&c.statePath, "state", "", "path")
	if err := cmdFlags.Parse(args); err != nil {
		return cli.RunResultHelp
	}
	args = cmdFlags.Args()

	if len(args) < 1 {
		c.Ui.Error("At least one address is required.\n")
		return cli.RunResultHelp
	}

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

	state := stateMgr.State()
	if state == nil {
		c.Ui.Error(fmt.Sprintf(errStateNotFound))
		return 1
	}

	// Filter what we are removing.
	results, err := c.filter(state, args)
	if err != nil {
		c.Ui.Error(fmt.Sprintf(errStateFilter, err))
		return cli.RunResultHelp
	}

	// If we have no results, exit early as we're not going to do anything.
	if len(results) == 0 {
		if dryRun {
			c.Ui.Output("Would have removed nothing.")
		} else {
			c.Ui.Output("No matching resources found.")
		}
		return 0
	}

	prefix := "Remove resource "
	if dryRun {
		prefix = "Would remove resource "
	}

	var isCount int
	ss := state.SyncWrapper()
	for _, result := range results {
		switch addr := result.Address.(type) {
		case addrs.ModuleInstance:
			var output []string
			for _, rs := range result.Value.(*states.Module).Resources {
				for k := range rs.Instances {
					isCount++
					output = append(output, prefix+rs.Addr.Absolute(addr).Instance(k).String())
				}
			}
			if len(output) > 0 {
				c.Ui.Output(strings.Join(sort.StringSlice(output), "\n"))
			}
			if !dryRun {
				ss.RemoveModule(addr)
			}

		case addrs.AbsResource:
			var output []string
			for k := range result.Value.(*states.Resource).Instances {
				isCount++
				output = append(output, prefix+addr.Instance(k).String())
			}
			if len(output) > 0 {
				c.Ui.Output(strings.Join(sort.StringSlice(output), "\n"))
			}
			if !dryRun {
				ss.RemoveResource(addr)
			}

		case addrs.AbsResourceInstance:
			isCount++
			c.Ui.Output(prefix + addr.String())
			if !dryRun {
				ss.ForgetResourceInstanceAll(addr)
				ss.RemoveResourceIfEmpty(addr.ContainingResource())
			}
		}
	}

	if dryRun {
		if isCount == 0 {
			c.Ui.Output("Would have removed nothing.")
		}
		return 0 // This is as far as we go in dry-run mode
	}

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

	if isCount == 0 {
		c.Ui.Output("No matching resources found.")
	} else {
		c.Ui.Output(fmt.Sprintf("Successfully removed %d resource(s).", isCount))
	}
	return 0
}

func (c *StateRmCommand) Help() string {
	helpText := `
Usage: terraform state rm [options] ADDRESS...

  Remove one or more items from the Terraform state.

  This command removes one or more resource instances from the Terraform state
  based on the addresses given. You can view and list the available instances
  with "terraform state list".

  This command creates a timestamped backup of the state on every invocation.
  This can't be disabled. Due to the destructive nature of this command,
  the backup is ensured by Terraform for safety reasons.

Options:

  -dry-run            If set, prints out what would've been removed but
                      doesn't actually remove anything.

  -backup=PATH        Path where Terraform should write the backup
                      state. This can't be disabled. If not set, Terraform
                      will write it to the same path as the statefile with
                      a backup extension.

  -state=PATH         Path to the source state file. Defaults to the configured
                      backend, or "terraform.tfstate"

`
	return strings.TrimSpace(helpText)
}

func (c *StateRmCommand) Synopsis() string {
	return "Remove instances from the state"
}

const errStateRm = `Error removing items from the state: %s

The state was not saved. No items were removed from the persisted
state. No backup was created since no modification occurred. Please
resolve the issue above and try again.`

const errStateRmPersist = `Error saving the state: %s

The state was not saved. No items were removed from the persisted
state. No backup was created since no modification occurred. Please
resolve the issue above and try again.`