// Package link defines services capable of linking keys to users.

package link

import (

"fmt"

"net/url"

"regexp"

"github.com/pkg/errors"

)

// Service describes a user service.

type Service interface {

// Identifier of the service, e.g. "github", "twitter".

ID() string

// Normalize the service user name.

// For example, on Twitter, "@username" becomes "username" or "Gabriel"

// becomes "gabriel".

NormalizeName(name string) string

// ValidateName validates the service user name.

ValidateName(name string) error

// NormalizeURLString normalizes an url string.

NormalizeURLString(name string, urs string) (string, error)

// ValidateURLString validates the URL string and returns where to find the

// signed statement.

// For example, on reddit ".json" is appended.

ValidateURLString(name string, urs string) (string, error)

// CheckContent returns data with statement.

// For Twitter, Github there is no check since the user owns the URL location.

// For Reddit, we need to verify the listing, author and subreddit and return only the listing text.

CheckContent(name string, b []byte) ([]byte, error)

}

// NewService returns a service by name.

func NewService(service string) (Service, error) {

switch service {

case Twitter.ID():

return Twitter, nil

case Github.ID():

return Github, nil

case Reddit.ID():

return Reddit, nil

case HTTPS.ID():

return HTTPS, nil

default:

return nil, errors.Errorf("invalid service %s", service)

}

}

var regAlphaNumericWithDash = regexp.MustCompile(`^[a-z0-9-]+$`)

var regAlphaNumericWithUnderscore = regexp.MustCompile(`^[a-z0-9_]+$`)

var regAlphaNumericWithDashUnderscore = regexp.MustCompile(`^[a-z0-9-_]+$`)

func isAlphaNumericWithDash(s string) bool {

return regAlphaNumericWithDash.MatchString(s)

}

func isAlphaNumericWithUnderscore(s string) bool {

return regAlphaNumericWithUnderscore.MatchString(s)

}

func isAlphaNumericWithDashUnderscore(s string) bool {

return regAlphaNumericWithDashUnderscore.MatchString(s)

}

func basicURLString(urs string) (string, error) {

ur, err := url.Parse(urs)

if err != nil {

return "", err

}

return fmt.Sprintf("%s://%s%s", ur.Scheme, ur.Host, ur.Path), nil

}