package mutator

import (
	"context"
	"strings"
	"unicode"

	"github.com/databricks/cli/bundle"
	"github.com/databricks/cli/bundle/config"
)

type populateCurrentUser struct{}

// PopulateCurrentUser sets the `current_user` property on the workspace.
func PopulateCurrentUser() bundle.Mutator {
	return &populateCurrentUser{}
}

func (m *populateCurrentUser) Name() string {
	return "PopulateCurrentUser"
}

func (m *populateCurrentUser) Apply(ctx context.Context, b *bundle.Bundle) error {
	w := b.WorkspaceClient()
	me, err := w.CurrentUser.Me(ctx)
	if err != nil {
		return err
	}

	b.Config.Workspace.CurrentUser = &config.User{
		ShortName: getShortUserName(me.UserName),
		User:      me,
	}
	return nil
}

// Get a short-form username, based on the user's primary email address.
// We leave the full range of unicode letters in tact, but remove all "special" characters,
// including dots, which are not supported in e.g. experiment names.
func getShortUserName(emailAddress string) string {
	r := []rune(strings.Split(emailAddress, "@")[0])
	for i := 0; i < len(r); i++ {
		if !unicode.IsLetter(r[i]) {
			r[i] = '_'
		}
	}
	return string(r)
}