feat: add basic structure of idp templates (#5053)

add basic structure and implement first providers for IDP templates to be able to manage and use them in the future

internal/idp/providers/oidc/session.go

@@ -0,0 +1,99 @@
+package oidc
+
+import (
+	"context"
+	"errors"
+
+	"github.com/zitadel/oidc/v2/pkg/client/rp"
+	"github.com/zitadel/oidc/v2/pkg/oidc"
+	"golang.org/x/text/language"
+
+	"github.com/zitadel/zitadel/internal/idp"
+)
+
+var ErrCodeMissing = errors.New("no auth code provided")
+
+var _ idp.Session = (*Session)(nil)
+
+// Session is the [idp.Session] implementation for the OIDC provider.
+type Session struct {
+	Provider *Provider
+	AuthURL  string
+	Code     string
+	Tokens   *oidc.Tokens
+}
+
+// GetAuthURL implements the [idp.Session] interface.
+func (s *Session) GetAuthURL() string {
+	return s.AuthURL
+}
+
+// FetchUser implements the [idp.Session] interface.
+// It will execute an OIDC code exchange if needed to retrieve the tokens,
+// call the userinfo endpoint and map the received information into an [idp.User].
+func (s *Session) FetchUser(ctx context.Context) (user idp.User, err error) {
+	if s.Tokens == nil {
+		if err = s.authorize(ctx); err != nil {
+			return nil, err
+		}
+	}
+	info, err := rp.Userinfo(
+		s.Tokens.AccessToken,
+		s.Tokens.TokenType,
+		s.Tokens.IDTokenClaims.GetSubject(),
+		s.Provider.RelyingParty,
+	)
+	if err != nil {
+		return nil, err
+	}
+	u := s.Provider.userInfoMapper(info)
+	return u, nil
+}
+
+func (s *Session) authorize(ctx context.Context) (err error) {
+	if s.Code == "" {
+		return ErrCodeMissing
+	}
+	s.Tokens, err = rp.CodeExchange(ctx, s.Code, s.Provider.RelyingParty)
+	return err
+}
+
+func NewUser(info oidc.UserInfo) *User {
+	return &User{UserInfo: info}
+}
+
+type User struct {
+	oidc.UserInfo
+}
+
+func (u *User) GetID() string {
+	return u.GetSubject()
+}
+
+func (u *User) GetFirstName() string {
+	return u.GetGivenName()
+}
+
+func (u *User) GetLastName() string {
+	return u.GetFamilyName()
+}
+
+func (u *User) GetDisplayName() string {
+	return u.GetName()
+}
+
+func (u *User) GetPhone() string {
+	return u.GetPhoneNumber()
+}
+
+func (u *User) IsPhoneVerified() bool {
+	return u.IsPhoneNumberVerified()
+}
+
+func (u *User) GetPreferredLanguage() language.Tag {
+	return u.GetLocale()
+}
+
+func (u *User) GetAvatarURL() string {
+	return u.GetPicture()
+}