Refactor: Move login out of models (#16199)

`models` does far too much. In particular it handles all `UserSignin`.

It shouldn't be responsible for calling LDAP, SMTP or PAM for signing in.

Therefore we should move this code out of `models`.

This code has to depend on `models` - therefore it belongs in `services`.

There is a package in `services` called `auth` and clearly this functionality belongs in there.

Plan:

- [x] Change `auth.Auth` to `auth.Method` - as they represent methods of authentication.
- [x] Move `models.UserSignIn` into `auth`
- [x] Move `models.ExternalUserLogin`
- [x] Move most of the `LoginVia*` methods to `auth` or subpackages
- [x] Move Resynchronize functionality to `auth`
  - Involved some restructuring of `models/ssh_key.go` to reduce the size of this massive file and simplify its files.
- [x] Move the rest of the LDAP functionality in to the ldap subpackage
- [x] Re-factor the login sources to express an interfaces `auth.Source`?
  - I've done this through some smaller interfaces Authenticator and Synchronizable - which would allow us to extend things in future
- [x] Now LDAP is out of models - need to think about modules/auth/ldap and I think all of that functionality might just be moveable
- [x] Similarly a lot Oauth2 functionality need not be in models too and should be moved to services/auth/source/oauth2
  - [x] modules/auth/oauth2/oauth2.go uses xorm... This is naughty - probably need to move this into models.
  - [x] models/oauth2.go - mostly should be in modules/auth/oauth2 or services/auth/source/oauth2 
- [x] More simplifications of login_source.go may need to be done
- Allow wiring in of notify registration -  *this can now easily be done - but I think we should do it in another PR*  - see #16178 
- More refactors...?
  - OpenID should probably become an auth Method but I think that can be left for another PR
  - Methods should also probably be cleaned up  - again another PR I think.
  - SSPI still needs more refactors.* Rename auth.Auth auth.Method
* Restructure ssh_key.go

- move functions from models/user.go that relate to ssh_key to ssh_key
- split ssh_key.go to try create clearer function domains for allow for
future refactors here.

Signed-off-by: Andrew Thornton <art27@cantab.net>

cmd/admin_auth_ldap.go

@@ -9,7 +9,7 @@ import (
 	"strings"
 
 	"code.gitea.io/gitea/models"
-	"code.gitea.io/gitea/modules/auth/ldap"
+	"code.gitea.io/gitea/services/auth/source/ldap"
 
 	"github.com/urfave/cli"
 )
@@ -172,7 +172,7 @@ func parseLoginSource(c *cli.Context, loginSource *models.LoginSource) {
 		loginSource.Name = c.String("name")
 	}
 	if c.IsSet("not-active") {
-		loginSource.IsActived = !c.Bool("not-active")
+		loginSource.IsActive = !c.Bool("not-active")
 	}
 	if c.IsSet("synchronize-users") {
 		loginSource.IsSyncEnabled = c.Bool("synchronize-users")
@@ -180,70 +180,70 @@ func parseLoginSource(c *cli.Context, loginSource *models.LoginSource) {
 }
 
 // parseLdapConfig assigns values on config according to command line flags.
-func parseLdapConfig(c *cli.Context, config *models.LDAPConfig) error {
+func parseLdapConfig(c *cli.Context, config *ldap.Source) error {
 	if c.IsSet("name") {
-		config.Source.Name = c.String("name")
+		config.Name = c.String("name")
 	}
 	if c.IsSet("host") {
-		config.Source.Host = c.String("host")
+		config.Host = c.String("host")
 	}
 	if c.IsSet("port") {
-		config.Source.Port = c.Int("port")
+		config.Port = c.Int("port")
 	}
 	if c.IsSet("security-protocol") {
 		p, ok := findLdapSecurityProtocolByName(c.String("security-protocol"))
 		if !ok {
 			return fmt.Errorf("Unknown security protocol name: %s", c.String("security-protocol"))
 		}
-		config.Source.SecurityProtocol = p
+		config.SecurityProtocol = p
 	}
 	if c.IsSet("skip-tls-verify") {
-		config.Source.SkipVerify = c.Bool("skip-tls-verify")
+		config.SkipVerify = c.Bool("skip-tls-verify")
 	}
 	if c.IsSet("bind-dn") {
-		config.Source.BindDN = c.String("bind-dn")
+		config.BindDN = c.String("bind-dn")
 	}
 	if c.IsSet("user-dn") {
-		config.Source.UserDN = c.String("user-dn")
+		config.UserDN = c.String("user-dn")
 	}
 	if c.IsSet("bind-password") {
-		config.Source.BindPassword = c.String("bind-password")
+		config.BindPassword = c.String("bind-password")
 	}
 	if c.IsSet("user-search-base") {
-		config.Source.UserBase = c.String("user-search-base")
+		config.UserBase = c.String("user-search-base")
 	}
 	if c.IsSet("username-attribute") {
-		config.Source.AttributeUsername = c.String("username-attribute")
+		config.AttributeUsername = c.String("username-attribute")
 	}
 	if c.IsSet("firstname-attribute") {
-		config.Source.AttributeName = c.String("firstname-attribute")
+		config.AttributeName = c.String("firstname-attribute")
 	}
 	if c.IsSet("surname-attribute") {
-		config.Source.AttributeSurname = c.String("surname-attribute")
+		config.AttributeSurname = c.String("surname-attribute")
 	}
 	if c.IsSet("email-attribute") {
-		config.Source.AttributeMail = c.String("email-attribute")
+		config.AttributeMail = c.String("email-attribute")
 	}
 	if c.IsSet("attributes-in-bind") {
-		config.Source.AttributesInBind = c.Bool("attributes-in-bind")
+		config.AttributesInBind = c.Bool("attributes-in-bind")
 	}
 	if c.IsSet("public-ssh-key-attribute") {
-		config.Source.AttributeSSHPublicKey = c.String("public-ssh-key-attribute")
+		config.AttributeSSHPublicKey = c.String("public-ssh-key-attribute")
 	}
 	if c.IsSet("page-size") {
-		config.Source.SearchPageSize = uint32(c.Uint("page-size"))
+		config.SearchPageSize = uint32(c.Uint("page-size"))
 	}
 	if c.IsSet("user-filter") {
-		config.Source.Filter = c.String("user-filter")
+		config.Filter = c.String("user-filter")
 	}
 	if c.IsSet("admin-filter") {
-		config.Source.AdminFilter = c.String("admin-filter")
+		config.AdminFilter = c.String("admin-filter")
 	}
 	if c.IsSet("restricted-filter") {
-		config.Source.RestrictedFilter = c.String("restricted-filter")
+		config.RestrictedFilter = c.String("restricted-filter")
 	}
 	if c.IsSet("allow-deactivate-all") {
-		config.Source.AllowDeactivateAll = c.Bool("allow-deactivate-all")
+		config.AllowDeactivateAll = c.Bool("allow-deactivate-all")
 	}
 	return nil
 }
@@ -251,7 +251,7 @@ func parseLdapConfig(c *cli.Context, config *models.LDAPConfig) error {
 // findLdapSecurityProtocolByName finds security protocol by its name ignoring case.
 // It returns the value of the security protocol and if it was found.
 func findLdapSecurityProtocolByName(name string) (ldap.SecurityProtocol, bool) {
-	for i, n := range models.SecurityProtocolNames {
+	for i, n := range ldap.SecurityProtocolNames {
 		if strings.EqualFold(name, n) {
 			return i, true
 		}
@@ -289,17 +289,15 @@ func (a *authService) addLdapBindDn(c *cli.Context) error {
 	}
 
 	loginSource := &models.LoginSource{
-		Type:      models.LoginLDAP,
-		IsActived: true, // active by default
-		Cfg: &models.LDAPConfig{
-			Source: &ldap.Source{
-				Enabled: true, // always true
-			},
+		Type:     models.LoginLDAP,
+		IsActive: true, // active by default
+		Cfg: &ldap.Source{
+			Enabled: true, // always true
 		},
 	}
 
 	parseLoginSource(c, loginSource)
-	if err := parseLdapConfig(c, loginSource.LDAP()); err != nil {
+	if err := parseLdapConfig(c, loginSource.Cfg.(*ldap.Source)); err != nil {
 		return err
 	}
 
@@ -318,7 +316,7 @@ func (a *authService) updateLdapBindDn(c *cli.Context) error {
 	}
 
 	parseLoginSource(c, loginSource)
-	if err := parseLdapConfig(c, loginSource.LDAP()); err != nil {
+	if err := parseLdapConfig(c, loginSource.Cfg.(*ldap.Source)); err != nil {
 		return err
 	}
 
@@ -336,17 +334,15 @@ func (a *authService) addLdapSimpleAuth(c *cli.Context) error {
 	}
 
 	loginSource := &models.LoginSource{
-		Type:      models.LoginDLDAP,
-		IsActived: true, // active by default
-		Cfg: &models.LDAPConfig{
-			Source: &ldap.Source{
-				Enabled: true, // always true
-			},
+		Type:     models.LoginDLDAP,
+		IsActive: true, // active by default
+		Cfg: &ldap.Source{
+			Enabled: true, // always true
 		},
 	}
 
 	parseLoginSource(c, loginSource)
-	if err := parseLdapConfig(c, loginSource.LDAP()); err != nil {
+	if err := parseLdapConfig(c, loginSource.Cfg.(*ldap.Source)); err != nil {
 		return err
 	}
 
@@ -365,7 +361,7 @@ func (a *authService) updateLdapSimpleAuth(c *cli.Context) error {
 	}
 
 	parseLoginSource(c, loginSource)
-	if err := parseLdapConfig(c, loginSource.LDAP()); err != nil {
+	if err := parseLdapConfig(c, loginSource.Cfg.(*ldap.Source)); err != nil {
 		return err
 	}