Galaxy improvements (#628)

* galaxy: improve logging and performance reporting

* galaxy: add a full galaxy state test

* galaxy: optimize user self score computation

* galaxy: add 'generate_galaxy_test_data' command for development at scale

* galaxy: big refactor

Main changes:
  - Multiple Galaxy objects can now exist at the same time in DB. This allows for ruling a new galaxy while still
    displaying the old one.
  - The criteria to quickly know whether a user is a possible citizen is now a simple query on picture count. This
    avoids a very complicated query to database, that could often result in huge working memory load. With this change,
    it should be possible to run the galaxy even on a vanilla Postgres that didn't receive fine tuning for the Sith's
    galaxy.

* galaxy: template: make the galaxy graph work and be usable with a lot of stars

- Display focused star and its connections clearly
- Display star label faintly by default for other stars to avoid overloading the graph
- Hide non-focused lanes
- Avoid clicks on non-highlighted, too far stars
- Make the canva adapt its width to initial screen size, doesn't work dynamically

* galaxy: better docstrings

* galaxy: use bulk_create whenever possible

This is a big performance gain, especially for the tests.

Examples:

----

`./manage.py test galaxy.tests.GalaxyTest.test_full_galaxy_state`

Measurements averaged over 3 run on *my machine*™:
Before: 2min15s
After: 1m41s

----

`./manage.py generate_galaxy_test_data --user-pack-count 1`

Before: 48s
After: 25s

----

`./manage.py rule_galaxy` (for 600 citizen, corresponding to 1 user-pack)

Before: 14m4s
After: 12m34s

* core: populate: use a less ambiguous 'timezone.now()'

When running the tests around midnight, the day is changing, leading to some values being offset to the next day
depending on the timezone, and making some tests to fail. This ensure to use a less ambiguous `now` when populating
the database.

* write more extensive documentation

- add documentation to previously documented classes and functions and refactor some of the documented one, in accordance to the PEP257 and ReStructuredText standards ;
- add some type hints ;
- use a NamedTuple for the `Galaxy.compute_users_score` method instead of a raw tuple. Also change a little bit the logic in the function which call the latter ;
- add some additional parameter checks on a few functions ;
- change a little bit the logic of the log level setting for the galaxy related commands.

* galaxy: tests: split Model and View for more efficient data usage

---------

Co-authored-by: maréchal <thgirod@hotmail.com>

galaxy/tests.py

@@ -22,14 +22,19 @@
 #
 #
 
-from django.test import TestCase
+import json
+
+from pathlib import Path
+
 from django.core.management import call_command
+from django.test import TestCase
+from django.urls import reverse
 
 from core.models import User
 from galaxy.models import Galaxy
 
 
-class GalaxyTest(TestCase):
+class GalaxyTestModel(TestCase):
     def setUp(self):
         self.root = User.objects.get(username="root")
         self.skia = User.objects.get(username="skia")
@@ -41,6 +46,9 @@ class GalaxyTest(TestCase):
         self.com = User.objects.get(username="comunity")
 
     def test_user_self_score(self):
+        """
+        Test that individual user scores are correct
+        """
         with self.assertNumQueries(8):
             self.assertEqual(Galaxy.compute_user_score(self.root), 9)
             self.assertEqual(Galaxy.compute_user_score(self.skia), 10)
@@ -52,6 +60,10 @@ class GalaxyTest(TestCase):
             self.assertEqual(Galaxy.compute_user_score(self.com), 1)
 
     def test_users_score(self):
+        """
+        Test on the default dataset generated by the `populate` command
+        that the relation scores are correct
+        """
         expected_scores = {
             "krophil": {
                 "comunity": {"clubs": 0, "family": 0, "pictures": 0, "score": 0},
@@ -112,33 +124,78 @@ class GalaxyTest(TestCase):
             while len(users) > 0:
                 user1 = users.pop(0)
                 for user2 in users:
-                    score, family, pictures, clubs = Galaxy.compute_users_score(
-                        user1, user2
-                    )
+                    score = Galaxy.compute_users_score(user1, user2)
                     u1 = computed_scores.get(user1.username, {})
                     u1[user2.username] = {
-                        "score": score,
-                        "family": family,
-                        "pictures": pictures,
-                        "clubs": clubs,
+                        "score": sum(score),
+                        "family": score.family,
+                        "pictures": score.pictures,
+                        "clubs": score.clubs,
                     }
                     computed_scores[user1.username] = u1
 
         self.maxDiff = None  # Yes, we want to see the diff if any
         self.assertDictEqual(expected_scores, computed_scores)
 
+    def test_rule(self):
+        """
+        Test on the default dataset generated by the `populate` command
+        that the number of queries to rule the galaxy is stable.
+        """
+        galaxy = Galaxy.objects.create()
+        with self.assertNumQueries(58):
+            galaxy.rule(0)  # We want everybody here
+
+
+class GalaxyTestView(TestCase):
+    @classmethod
+    def setUpTestData(cls):
+        """
+        Generate a plausible Galaxy once for every test
+        """
+        call_command("generate_galaxy_test_data", "-v", "0")
+        galaxy = Galaxy.objects.create()
+        galaxy.rule(26)  # We want a fast test
+
     def test_page_is_citizen(self):
-        Galaxy.rule()
+        """
+        Test that users can access the galaxy page of users who are citizens
+        """
         self.client.login(username="root", password="plop")
-        response = self.client.get("/galaxy/1/")
+        user = User.objects.get(last_name="n°500")
+        response = self.client.get(reverse("galaxy:user", args=[user.id]))
         self.assertContains(
             response,
-            '<a onclick="focus_node(get_node_from_id(8))">Locate</a>',
+            f'<a onclick="focus_node(get_node_from_id({user.id}))">Reset on {user}</a>',
             status_code=200,
         )
 
     def test_page_not_citizen(self):
-        Galaxy.rule()
+        """
+        Test that trying to access the galaxy page of a user who is not
+        citizens return a 404
+        """
         self.client.login(username="root", password="plop")
-        response = self.client.get("/galaxy/2/")
+        user = User.objects.get(last_name="n°1")
+        response = self.client.get(reverse("galaxy:user", args=[user.id]))
         self.assertEquals(response.status_code, 404)
+
+    def test_full_galaxy_state(self):
+        """
+        Test on the more complex dataset generated by the `generate_galaxy_test_data`
+        command that the relation scores are correct, and that the view exposes the
+        right data.
+        """
+        self.client.login(username="root", password="plop")
+        response = self.client.get(reverse("galaxy:data"))
+        state = response.json()
+
+        galaxy_dir = Path(__file__).parent
+
+        # Dump computed state, either for easier debugging, or to copy as new reference if changes are legit
+        (galaxy_dir / "test_galaxy_state.json").write_text(json.dumps(state))
+
+        self.assertEqual(
+            state,
+            json.loads((galaxy_dir / "ref_galaxy_state.json").read_text()),
+        )