auth: Add `/register-user` endpoint

* gn3/app.py: register top-level error handlers. reorganise oauth2 blueprint.
* gn3/auth/__init__.py: reorganise oaut2 blueprint.
* gn3/auth/authentication/oauth2/views.py: reorganise oauth2 blueprint.
* gn3/auth/authorisation/exceptions.py -> gn3/auth/authorisation/errors.py
* gn3/auth/authorisation/groups.py: rename file/module
* gn3/auth/authorisation/resources.py: rename file/module
* gn3/auth/authorisation/views.py: Add `/register-user` endpoint
* gn3/auth/blueprint.py: reorganise oauth2 blueprint.
* gn3/errors.py: register top-level error handlers.

4 files changed, 63 insertions, 6 deletions

diff --git a/gn3/auth/authorisation/exceptions.py b/gn3/auth/authorisation/errors.py
index 16fc9bb..fa2d6b7 100644
--- a/gn3/auth/authorisation/exceptions.py
+++ b/gn3/auth/authorisation/errors.py
@@ -6,3 +6,6 @@ class AuthorisationError(Exception):
 
     All exceptions in this package should inherit from this class.
     """
+
+class UserRegistrationError(AuthorisationError):
+    """Raised whenever a user registration fails"""
diff --git a/gn3/auth/authorisation/groups.py b/gn3/auth/authorisation/groups.py
index cb32f00..ff4dc80 100644
--- a/gn3/auth/authorisation/groups.py
+++ b/gn3/auth/authorisation/groups.py
@@ -12,7 +12,7 @@ from gn3.auth.authentication.checks import authenticated_p
 from .checks import authorised_p
 from .privileges import Privilege
 from .roles import Role, create_role
-from .exceptions import AuthorisationError
+from .errors import AuthorisationError
 
 class Group(NamedTuple):
     """Class representing a group."""
diff --git a/gn3/auth/authorisation/resources.py b/gn3/auth/authorisation/resources.py
index 0a91930..bc6ba44 100644
--- a/gn3/auth/authorisation/resources.py
+++ b/gn3/auth/authorisation/resources.py
@@ -6,7 +6,7 @@ from gn3.auth import db
 from gn3.auth.authentication.users import User
 
 from .checks import authorised_p
-from .exceptions import AuthorisationError
+from .errors import AuthorisationError
 from .groups import Group, user_group, is_group_leader, authenticated_user_group
 
 class MissingGroupError(AuthorisationError):
diff --git a/gn3/auth/authorisation/views.py b/gn3/auth/authorisation/views.py
index 3e9d9b9..73d39d2 100644
--- a/gn3/auth/authorisation/views.py
+++ b/gn3/auth/authorisation/views.py
@@ -1,13 +1,17 @@
 """Endpoints for the authorisation stuff."""
-from flask import jsonify, current_app
+from typing import Tuple, Optional
+from flask import request, jsonify, current_app
 
 from gn3.auth import db
+from gn3.auth.blueprint import oauth2
+
 from .groups import user_group
+from .errors import UserRegistrationError
 from .roles import user_roles as _user_roles
-from ..authentication.oauth2.views import oauth2
 from ..authentication.oauth2.resource_server import require_oauth
+from ..authentication.oauth2.models.oauth2token import token_by_access_token
 
-@oauth2.route("/user")
+@oauth2.route("/user", methods=["GET"])
 @require_oauth("profile")
 def user_details():
     """Return user's details."""
@@ -23,10 +27,60 @@ def user_details():
             "group": group.maybe(False, lambda grp: grp)
         })
 
-@oauth2.route("/user-roles")
+@oauth2.route("/user-roles", methods=["GET"])
 @require_oauth
 def user_roles():
     """Return the non-resource roles assigned to the user."""
     with require_oauth.acquire("role") as token:
         with db.connection(current_app.config["AUTH_DB"]) as conn:
             return jsonify(_user_roles(conn, token.user))
+
+def __email_valid__(email: str) -> Tuple[bool, Optional[str]]:
+    """Validate the email address."""
+    if email == "":
+        return False, "Empty email address"
+
+    ## Check that the address is a valid email address
+
+    ## Success
+    return True, None
+
+def __password_valid__(password, confirm_password) -> Tuple[bool, Optional[str]]:
+    if password == "" or confirm_password == "":
+        return False, "Empty password value"
+
+    if password != confirm_password:
+        return False, "Mismatched password values"
+
+    return True, None
+
+def __assert_not_logged_in__(conn: db.DbConnection):
+    bearer = request.headers.get('Authorization')
+    if bearer:
+        token = token_by_access_token(conn, bearer.split(None)[1]).maybe(# type: ignore[misc]
+            False, lambda tok: tok)
+        if token:
+            raise UserRegistrationError(
+                "Cannot register user while authenticated")
+
+@oauth2.route("/register-user", methods=["POST"])
+def register_user():
+    """Register a user."""
+    with db.connection(current_app.config["AUTH_DB"]) as conn:
+        __assert_not_logged_in__(conn)
+
+        form = request.form
+        errors = tuple(
+                error[1] for error in
+            [__email_valid__(form.get("email", "")),
+             __password_valid__(form.get("password", ""),
+                                form.get("confirm_password", ""))]
+            if error[0])
+        if len(errors) > 0:
+            raise UserRegistrationError(*errors)
+        # Provide default privileges
+        return jsonify(
+            {
+                "error": "not_implemented",
+                "error_description": "Feature not implemented"
+             }), 500