CLI command for adding a student to a course

Also refactored CLI a little and made search for courses local
in to current semester.

owl.py

@@ -1521,6 +1521,34 @@ def cli_find_user(name):
     return users[0]
 
 
+def cli_find_semester(semester):
+    if semester is None:
+        db_query("SELECT * FROM owl_semesters ORDER BY rank DESC LIMIT 1")
+        semester_row = db.fetchone()
+        if not semester_row:
+            cli_die("No semester found")
+    else:
+        db_query("SELECT * FROM owl_semesters WHERE ident=%s", (semester,))
+        semester_row = db.fetchone()
+        if not semester_row:
+            cli_die("No such semester")
+    return semester_row
+
+
+def cli_find_course(ident):
+    semester_row = cli_find_semester(None)
+    db_query("""
+            SELECT c.*
+            FROM owl_courses c
+            WHERE ident=%s AND semid=%s
+        """, (ident, semester_row.semid))
+    course = db.fetchone()
+    if course:
+        return course
+    else:
+        cli_die(f'No course with identifier {course_ident} found')
+
+
 @app.cli.command("create-course")
 @click.argument("ident")
 @click.argument("name")
@@ -1531,21 +1559,11 @@ def cli_create_course(ident, name, teacher, token=None, semester=None):
     """Create a new course. TEACHER is the teacher's full name or email."""
 
     teacher_user = cli_find_user(teacher)
+    semester_row = cli_find_semester(semester)
 
     if not token:
         token = secrets.token_hex(6)
 
-    if semester is None:
-        db_query("SELECT * FROM owl_semesters ORDER BY rank DESC LIMIT 1")
-        semester_row = db.fetchone()
-        if not semester_row:
-            cli_die("No semester found")
-    else:
-        db_query("SELECT * FROM owl_semesters WHERE ident=%s", (semester,))
-        semester_row = db.fetchone()
-        if not semester_row:
-            cli_die("No such semester")
-
     db_query("""
             INSERT INTO owl_courses(ident, name, enroll_token, semid)
             VALUES (%s, %s, %s, %s)
@@ -1572,15 +1590,7 @@ def cli_add_teacher(course_ident, teacher):
     """Add a teacher to an existing course. TEACHER is the teacher's full name or e-mail."""
 
     teacher_user = cli_find_user(teacher)
-
-    db_query("""
-            SELECT *
-            FROM owl_courses
-            WHERE ident=%s
-        """, (course_ident,))
-    course = db.fetchone()
-    if not course:
-        cli_die(f'No course with identifier {course_ident} found')
+    course = cli_find_course(course_ident)
 
     db_query("""
             INSERT INTO owl_enroll(uid, cid, is_teacher)
@@ -1591,6 +1601,24 @@ def cli_add_teacher(course_ident, teacher):
     db_connection.commit()
 
 
+@app.cli.command("add-student")
+@click.argument("course_ident")
+@click.argument("student")
+def cli_add_teacher(course_ident, student):
+    """Add a student to an existing course. STUDENT is the teacher's full name or e-mail."""
+
+    student_user = cli_find_user(student)
+    course = cli_find_course(course_ident)
+
+    db_query("""
+            INSERT INTO owl_enroll(uid, cid, is_teacher)
+            VALUES (%s, %s, false)
+        """,
+        (student_user.uid, course.cid))
+
+    db_connection.commit()
+
+
 ### Sending notifications ###