feat: add model for messages (#117)

CHANGELOG.rst

@@ -13,6 +13,7 @@ Change Log
 
 Unreleased
 **********
+* Add LearningAssistantMessage model
 
 4.3.3 - 2024-10-15
 ******************

learning_assistant/migrations/0007_learningassistantmessage.py

@@ -0,0 +1,34 @@
+# Generated by Django 4.2.15 on 2024-10-22 12:17
+
+from django.conf import settings
+from django.db import migrations, models
+import django.db.models.deletion
+import django.utils.timezone
+import model_utils.fields
+import opaque_keys.edx.django.models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
+        ('learning_assistant', '0006_delete_courseprompt'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='LearningAssistantMessage',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('created', model_utils.fields.AutoCreatedField(default=django.utils.timezone.now, editable=False, verbose_name='created')),
+                ('modified', model_utils.fields.AutoLastModifiedField(default=django.utils.timezone.now, editable=False, verbose_name='modified')),
+                ('course_id', opaque_keys.edx.django.models.CourseKeyField(db_index=True, max_length=255)),
+                ('role', models.CharField(max_length=64)),
+                ('content', models.TextField()),
+                ('user', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to=settings.AUTH_USER_MODEL)),
+            ],
+            options={
+                'abstract': False,
+            },
+        ),
+    ]

learning_assistant/models.py

@@ -1,10 +1,13 @@
 """
 Database models for learning_assistant.
 """
+from django.contrib.auth import get_user_model
 from django.db import models
 from model_utils.models import TimeStampedModel
 from opaque_keys.edx.django.models import CourseKeyField
 
+USER_MODEL = get_user_model()
+
 
 class LearningAssistantCourseEnabled(TimeStampedModel):
     """
@@ -21,3 +24,18 @@ class LearningAssistantCourseEnabled(TimeStampedModel):
     course_id = CourseKeyField(max_length=255, db_index=True, unique=True)
 
     enabled = models.BooleanField()
+
+
+class LearningAssistantMessage(TimeStampedModel):
+    """
+    This model stores messages sent to and received from the learning assistant.
+
+    .. pii: content
+    .. pii_types: other
+    .. pii_retirement: third_party
+    """
+
+    course_id = CourseKeyField(max_length=255, db_index=True)
+    user = models.ForeignKey(USER_MODEL, db_index=True, on_delete=models.CASCADE)
+    role = models.CharField(max_length=64)
+    content = models.TextField()