package command

import (
	"fmt"
	"os"
	"strings"

	"github.com/hashicorp/go-multierror"
	"github.com/hashicorp/nomad/api"
	"github.com/hashicorp/nomad/command/agent"
	"github.com/hashicorp/nomad/helper/pointer"
	"github.com/posener/complete"
)

type JobValidateCommand struct {
	Meta
	JobGetter
}

func (c *JobValidateCommand) Help() string {
	helpText := `
Usage: nomad job validate [options] <path>
Alias: nomad validate

  Checks if a given HCL job file has a valid specification. This can be used to
  check for any syntax errors or validation problems with a job.

  If the supplied path is "-", the jobfile is read from stdin. Otherwise
  it is read from the file at the supplied path or downloaded and
  read from URL specified.

  The run command will set the vault_token of the job based on the following
  precedence, going from highest to lowest: the -vault-token flag, the
  $VAULT_TOKEN environment variable and finally the value in the job file.

  When ACLs are enabled, this command requires a token with the 'read-job'
  capability for the job's namespace.

General Options:

  ` + generalOptionsUsage(usageOptsDefault) + `

Validate Options:

  -json
    Parses the job file as JSON. If the outer object has a Job field, such as
    from "nomad job inspect" or "nomad run -output", the value of the field is
    used as the job.

  -hcl1
    Parses the job file as HCLv1. Takes precedence over "-hcl2-strict".

  -hcl2-strict
    Whether an error should be produced from the HCL2 parser where a variable
    has been supplied which is not defined within the root variables. Defaults
    to true, but ignored if "-hcl1" is also defined.

  -vault-token
    Used to validate if the user submitting the job has permission to run the job
    according to its Vault policies. A Vault token must be supplied if the vault
    stanza allow_unauthenticated is disabled in the Nomad server configuration.
    If the -vault-token flag is set, the passed Vault token is added to the jobspec
    before sending to the Nomad servers. This allows passing the Vault token
    without storing it in the job file. This overrides the token found in the
    $VAULT_TOKEN environment variable and the vault_token field in the job file.
    This token is cleared from the job after validating and cannot be used within
    the job executing environment. Use the vault stanza when templating in a job
    with a Vault token.

  -vault-namespace
    If set, the passed Vault namespace is stored in the job before sending to the
    Nomad servers.

  -var 'key=value'
    Variable for template, can be used multiple times.

  -var-file=path
    Path to HCL2 file containing user variables.
`
	return strings.TrimSpace(helpText)
}

func (c *JobValidateCommand) Synopsis() string {
	return "Checks if a given job specification is valid"
}

func (c *JobValidateCommand) AutocompleteFlags() complete.Flags {
	return complete.Flags{
		"-hcl1":            complete.PredictNothing,
		"-hcl2-strict":     complete.PredictNothing,
		"-vault-token":     complete.PredictAnything,
		"-vault-namespace": complete.PredictAnything,
		"-var":             complete.PredictAnything,
		"-var-file":        complete.PredictFiles("*.var"),
	}
}

func (c *JobValidateCommand) AutocompleteArgs() complete.Predictor {
	return complete.PredictOr(
		complete.PredictFiles("*.nomad"),
		complete.PredictFiles("*.hcl"),
		complete.PredictFiles("*.json"),
	)
}

func (c *JobValidateCommand) Name() string { return "job validate" }

func (c *JobValidateCommand) Run(args []string) int {
	var vaultToken, vaultNamespace string

	flagSet := c.Meta.FlagSet(c.Name(), FlagSetClient)
	flagSet.Usage = func() { c.Ui.Output(c.Help()) }
	flagSet.BoolVar(&c.JobGetter.JSON, "json", false, "")
	flagSet.BoolVar(&c.JobGetter.HCL1, "hcl1", false, "")
	flagSet.BoolVar(&c.JobGetter.Strict, "hcl2-strict", true, "")
	flagSet.StringVar(&vaultToken, "vault-token", "", "")
	flagSet.StringVar(&vaultNamespace, "vault-namespace", "", "")
	flagSet.Var(&c.JobGetter.Vars, "var", "")
	flagSet.Var(&c.JobGetter.VarFiles, "var-file", "")

	if err := flagSet.Parse(args); err != nil {
		return 1
	}

	// Check that we got exactly one node
	args = flagSet.Args()
	if len(args) != 1 {
		c.Ui.Error("This command takes one argument: <path>")
		c.Ui.Error(commandErrorText(c))
		return 1
	}

	if c.JobGetter.HCL1 {
		c.JobGetter.Strict = false
	}

	if err := c.JobGetter.Validate(); err != nil {
		c.Ui.Error(fmt.Sprintf("Invalid job options: %s", err))
		return 1
	}

	// Get Job struct from Jobfile
	job, err := c.JobGetter.Get(args[0])
	if err != nil {
		c.Ui.Error(fmt.Sprintf("Error getting job struct: %s", err))
		return 1
	}

	// Get the HTTP client
	client, err := c.Meta.Client()
	if err != nil {
		c.Ui.Error(fmt.Sprintf("Error initializing client: %s", err))
		return 255
	}

	// Force the region to be that of the job.
	if r := job.Region; r != nil {
		client.SetRegion(*r)
	}

	// Parse the Vault token
	if vaultToken == "" {
		// Check the environment variable
		vaultToken = os.Getenv("VAULT_TOKEN")
	}

	if vaultToken != "" {
		job.VaultToken = pointer.Of(vaultToken)
	}

	if vaultNamespace != "" {
		job.VaultNamespace = pointer.Of(vaultNamespace)
	}

	// Check that the job is valid
	jr, _, err := client.Jobs().Validate(job, nil)
	if err != nil {
		jr, err = c.validateLocal(job)
	}
	if err != nil {
		c.Ui.Error(fmt.Sprintf("Error validating job: %s", err))
		return 1
	}

	if jr != nil && !jr.DriverConfigValidated {
		c.Ui.Output(
			c.Colorize().Color("[bold][yellow]Driver configuration not validated since connection to Nomad agent couldn't be established.[reset]\n"))
	}

	if jr != nil && jr.Error != "" {
		c.Ui.Error(
			c.Colorize().Color("[bold][red]Job validation errors:[reset]"))
		c.Ui.Error(jr.Error)
		return 1
	}

	// Print any warnings if there are any
	if jr.Warnings != "" {
		c.Ui.Output(
			c.Colorize().Color(fmt.Sprintf("[bold][yellow]Job Warnings:\n%s[reset]\n", jr.Warnings)))
	}

	// Done!
	c.Ui.Output(
		c.Colorize().Color("[bold][green]Job validation successful[reset]"))
	return 0
}

// validateLocal validates without talking to a Nomad agent
func (c *JobValidateCommand) validateLocal(aj *api.Job) (*api.JobValidateResponse, error) {
	var out api.JobValidateResponse

	job := agent.ApiJobToStructJob(aj)
	job.Canonicalize()

	if vErr := job.Validate(); vErr != nil {
		if merr, ok := vErr.(*multierror.Error); ok {
			for _, err := range merr.Errors {
				out.ValidationErrors = append(out.ValidationErrors, err.Error())
			}
			out.Error = merr.Error()
		} else {
			out.ValidationErrors = append(out.ValidationErrors, vErr.Error())
			out.Error = vErr.Error()
		}
	}

	out.Warnings = mergeMultierrorWarnings(job.Warnings())
	return &out, nil
}

func mergeMultierrorWarnings(errs ...error) string {
	if len(errs) == 0 {
		return ""
	}

	var mErr multierror.Error
	_ = multierror.Append(&mErr, errs...)

	mErr.ErrorFormat = warningsFormatter

	return mErr.Error()
}

func warningsFormatter(es []error) string {
	sb := strings.Builder{}
	sb.WriteString(fmt.Sprintf("%d warning(s):\n", len(es)))

	for i := range es {
		sb.WriteString(fmt.Sprintf("\n* %s", es[i]))
	}

	return sb.String()
}