Assign new tasks on the fly

The old logic assigned a task when the user finished the
demo, logged in, or finished an annotation. This was not
optimal as it could lead to race conditions where some
datasets were annotated unnecessarily. With this change
we select the dataset to annotate at the exact moment the
user wants to do another one.

1 files changed, 16 insertions, 15 deletions

diff --git a/app/auth/routes.py b/app/auth/routes.py
index fa792c2..0556233 100644
--- a/app/auth/routes.py
+++ b/app/auth/routes.py
@@ -30,8 +30,7 @@ from app.auth.email import (
     send_password_reset_email,
     send_email_confirmation_email,
 )
-from app.models import User, Task
-from app.utils.tasks import generate_user_task
+from app.models import User, Task, Annotation
 
 
 LEGAL = markdown.markdown(
@@ -92,6 +91,21 @@ def login():
         current_user.last_active = datetime.datetime.utcnow()
         db.session.commit()
 
+        # remove any assigned unfinished datasets, as these may no longer be
+        # needed
+        user_tasks = Task.query.filter_by(
+            annotator_id=current_user.id, done=False
+        ).all()
+        for task in user_tasks:
+            anns = Annotation.query.filter_by(task_id=task.id).all()
+            if len(anns) > 0:
+                flash(
+                    "Internal error, unfinished tasks has annotations!",
+                    "error",
+                )
+            db.session.delete(task)
+            db.session.commit()
+
         # redirect if not confirmed yet
         if not user.is_confirmed:
             return redirect(url_for("auth.not_confirmed"))
@@ -105,19 +119,6 @@ def login():
         if not user.is_introduced:
             return redirect(url_for("main.index"))
 
-        # assign task if no remaining and not at maximum.
-        remaining = Task.query.filter_by(
-            annotator_id=user.id, done=False
-        ).all()
-        if remaining:
-            return redirect(next_page)
-
-        task = generate_user_task(user)
-        if task is None:
-            return redirect(next_page)
-
-        db.session.add(task)
-        db.session.commit()
         return redirect(next_page)
     return render_template("auth/login.html", title="Sign In", form=form)