package command

import (
	"bytes"
	"context"
	"fmt"
	"os"
	"sort"
	"strings"

	"github.com/hashicorp/go-getter"
	"github.com/hashicorp/terraform/backend"
	"github.com/hashicorp/terraform/config"
	"github.com/hashicorp/terraform/config/module"
	"github.com/hashicorp/terraform/terraform"
)

// ApplyCommand is a Command implementation that applies a Terraform
// configuration and actually builds or changes infrastructure.
type ApplyCommand struct {
	Meta

	// If true, then this apply command will become the "destroy"
	// command. It is just like apply but only processes a destroy.
	Destroy bool

	// When this channel is closed, the apply will be cancelled.
	ShutdownCh <-chan struct{}
}

func (c *ApplyCommand) Run(args []string) int {
	var destroyForce, refresh bool
	args = c.Meta.process(args, true)

	cmdName := "apply"
	if c.Destroy {
		cmdName = "destroy"
	}

	cmdFlags := c.Meta.flagSet(cmdName)
	if c.Destroy {
		cmdFlags.BoolVar(&destroyForce, "force", false, "force")
	}
	cmdFlags.BoolVar(&refresh, "refresh", true, "refresh")
	cmdFlags.IntVar(
		&c.Meta.parallelism, "parallelism", DefaultParallelism, "parallelism")
	cmdFlags.StringVar(&c.Meta.statePath, "state", "", "path")
	cmdFlags.StringVar(&c.Meta.stateOutPath, "state-out", "", "path")
	cmdFlags.StringVar(&c.Meta.backupPath, "backup", "", "path")
	cmdFlags.Usage = func() { c.Ui.Error(c.Help()) }
	if err := cmdFlags.Parse(args); err != nil {
		return 1
	}

	// Get the args. The "maybeInit" flag tracks whether we may need to
	// initialize the configuration from a remote path. This is true as long
	// as we have an argument.
	args = cmdFlags.Args()
	maybeInit := len(args) == 1
	configPath, err := ModulePath(args)
	if err != nil {
		c.Ui.Error(err.Error())
		return 1
	}

	if !c.Destroy && maybeInit {
		// We need the pwd for the getter operation below
		pwd, err := os.Getwd()
		if err != nil {
			c.Ui.Error(fmt.Sprintf("Error getting pwd: %s", err))
			return 1
		}

		// Do a detect to determine if we need to do an init + apply.
		if detected, err := getter.Detect(configPath, pwd, getter.Detectors); err != nil {
			c.Ui.Error(fmt.Sprintf(
				"Invalid path: %s", err))
			return 1
		} else if !strings.HasPrefix(detected, "file") {
			// If this isn't a file URL then we're doing an init +
			// apply.
			var init InitCommand
			init.Meta = c.Meta
			if code := init.Run([]string{detected}); code != 0 {
				return code
			}

			// Change the config path to be the cwd
			configPath = pwd
		}
	}

	// Check if the path is a plan
	plan, err := c.Plan(configPath)
	if err != nil {
		c.Ui.Error(err.Error())
		return 1
	}
	if c.Destroy && plan != nil {
		c.Ui.Error(fmt.Sprintf(
			"Destroy can't be called with a plan file."))
		return 1
	}
	if plan != nil {
		// Reset the config path for backend loading
		configPath = ""
	}

	// Load the module if we don't have one yet (not running from plan)
	var mod *module.Tree
	if plan == nil {
		mod, err = c.Module(configPath)
		if err != nil {
			c.Ui.Error(fmt.Sprintf("Failed to load root config module: %s", err))
			return 1
		}
	}

	/*
		terraform.SetDebugInfo(DefaultDataDir)

		// Check for the legacy graph
		if experiment.Enabled(experiment.X_legacyGraph) {
			c.Ui.Output(c.Colorize().Color(
				"[reset][bold][yellow]" +
					"Legacy graph enabled! This will use the graph from Terraform 0.7.x\n" +
					"to execute this operation. This will be removed in the future so\n" +
					"please report any issues causing you to use this to the Terraform\n" +
					"project.\n\n"))
		}
	*/

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

	// If we're not forcing and we're destroying, verify with the
	// user at this point.
	if !destroyForce && c.Destroy {
		// Default destroy message
		desc := "Terraform will delete all your managed infrastructure.\n" +
			"There is no undo. Only 'yes' will be accepted to confirm."

		// If targets are specified, list those to user
		if c.Meta.targets != nil {
			var descBuffer bytes.Buffer
			descBuffer.WriteString("Terraform will delete the following infrastructure:\n")
			for _, target := range c.Meta.targets {
				descBuffer.WriteString("\t")
				descBuffer.WriteString(target)
				descBuffer.WriteString("\n")
			}
			descBuffer.WriteString("There is no undo. Only 'yes' will be accepted to confirm")
			desc = descBuffer.String()
		}

		v, err := c.UIInput().Input(&terraform.InputOpts{
			Id:          "destroy",
			Query:       "Do you really want to destroy?",
			Description: desc,
		})
		if err != nil {
			c.Ui.Error(fmt.Sprintf("Error asking for confirmation: %s", err))
			return 1
		}
		if v != "yes" {
			c.Ui.Output("Destroy cancelled.")
			return 1
		}
	}

	// Build the operation
	opReq := c.Operation()
	opReq.Destroy = c.Destroy
	opReq.Module = mod
	opReq.Plan = plan
	opReq.PlanRefresh = refresh
	opReq.Type = backend.OperationTypeApply

	// Perform the operation
	ctx, ctxCancel := context.WithCancel(context.Background())
	defer ctxCancel()
	op, err := b.Operation(ctx, opReq)
	if err != nil {
		c.Ui.Error(fmt.Sprintf("Error starting operation: %s", err))
		return 1
	}

	// Wait for the operation to complete or an interrupt to occur
	select {
	case <-c.ShutdownCh:
		// Cancel our context so we can start gracefully exiting
		ctxCancel()

		// Notify the user
		c.Ui.Output("Interrupt received. Gracefully shutting down...")

		// Still get the result, since there is still one
		select {
		case <-c.ShutdownCh:
			c.Ui.Error(
				"Two interrupts received. Exiting immediately. Note that data\n" +
					"loss may have occurred.")
			return 1
		case <-op.Done():
		}
	case <-op.Done():
		if err := op.Err; err != nil {
			c.Ui.Error(err.Error())
			return 1
		}
	}

	if !c.Destroy {
		// Get the right module that we used. If we ran a plan, then use
		// that module.
		if plan != nil {
			mod = plan.Module
		}

		if outputs := outputsAsString(op.State, terraform.RootModulePath, mod.Config().Outputs, true); outputs != "" {
			c.Ui.Output(c.Colorize().Color(outputs))
		}
	}

	return 0
}

func (c *ApplyCommand) Help() string {
	if c.Destroy {
		return c.helpDestroy()
	}

	return c.helpApply()
}

func (c *ApplyCommand) Synopsis() string {
	if c.Destroy {
		return "Destroy Terraform-managed infrastructure"
	}

	return "Builds or changes infrastructure"
}

func (c *ApplyCommand) helpApply() string {
	helpText := `
Usage: terraform apply [options] [DIR-OR-PLAN]

  Builds or changes infrastructure according to Terraform configuration
  files in DIR.

  By default, apply scans the current directory for the configuration
  and applies the changes appropriately. However, a path to another
  configuration or an execution plan can be provided. Execution plans can be
  used to only execute a pre-determined set of actions.

  DIR can also be a SOURCE as given to the "init" command. In this case,
  apply behaves as though "init" was called followed by "apply". This only
  works for sources that aren't files, and only if the current working
  directory is empty of Terraform files. This is a shortcut for getting
  started.

Options:

  -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.

  -input=true            Ask for input for variables if not directly set.

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

  -parallelism=n         Limit the number of concurrent operations.
                         Defaults to 10.

  -refresh=true          Update state prior to checking for differences. This
                         has no effect if a plan file is given to apply.

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

  -state-out=path        Path to write state to that is different than
                         "-state". This can be used to preserve the old
                         state.

  -target=resource       Resource to target. Operation will be limited to this
                         resource and its dependencies. This flag can be used
                         multiple times.

  -var 'foo=bar'         Set a variable in the Terraform configuration. This
                         flag can be set multiple times.

  -var-file=foo          Set variables in the Terraform configuration from
                         a file. If "terraform.tfvars" is present, it will be
                         automatically loaded if this flag is not specified.


`
	return strings.TrimSpace(helpText)
}

func (c *ApplyCommand) helpDestroy() string {
	helpText := `
Usage: terraform destroy [options] [DIR]

  Destroy Terraform-managed infrastructure.

Options:

  -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.

  -force                 Don't ask for input for destroy confirmation.

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

  -parallelism=n         Limit the number of concurrent operations.
                         Defaults to 10.

  -refresh=true          Update state prior to checking for differences. This
                         has no effect if a plan file is given to apply.

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

  -state-out=path        Path to write state to that is different than
                         "-state". This can be used to preserve the old
                         state.

  -target=resource       Resource to target. Operation will be limited to this
                         resource and its dependencies. This flag can be used
                         multiple times.

  -var 'foo=bar'         Set a variable in the Terraform configuration. This
                         flag can be set multiple times.

  -var-file=foo          Set variables in the Terraform configuration from
                         a file. If "terraform.tfvars" is present, it will be
                         automatically loaded if this flag is not specified.


`
	return strings.TrimSpace(helpText)
}

func outputsAsString(state *terraform.State, modPath []string, schema []*config.Output, includeHeader bool) string {
	if state == nil {
		return ""
	}

	ms := state.ModuleByPath(modPath)
	if ms == nil {
		return ""
	}

	outputs := ms.Outputs
	outputBuf := new(bytes.Buffer)
	if len(outputs) > 0 {
		schemaMap := make(map[string]*config.Output)
		if schema != nil {
			for _, s := range schema {
				schemaMap[s.Name] = s
			}
		}

		if includeHeader {
			outputBuf.WriteString("[reset][bold][green]\nOutputs:\n\n")
		}

		// Output the outputs in alphabetical order
		keyLen := 0
		ks := make([]string, 0, len(outputs))
		for key, _ := range outputs {
			ks = append(ks, key)
			if len(key) > keyLen {
				keyLen = len(key)
			}
		}
		sort.Strings(ks)

		for _, k := range ks {
			schema, ok := schemaMap[k]
			if ok && schema.Sensitive {
				outputBuf.WriteString(fmt.Sprintf("%s = <sensitive>\n", k))
				continue
			}

			v := outputs[k]
			switch typedV := v.Value.(type) {
			case string:
				outputBuf.WriteString(fmt.Sprintf("%s = %s\n", k, typedV))
			case []interface{}:
				outputBuf.WriteString(formatListOutput("", k, typedV))
				outputBuf.WriteString("\n")
			case map[string]interface{}:
				outputBuf.WriteString(formatMapOutput("", k, typedV))
				outputBuf.WriteString("\n")
			}
		}
	}

	return strings.TrimSpace(outputBuf.String())
}