DO NOT MERGE, this is just a prototype as a base for discussion.

Progress towards #2525.

The basic idea is to replace a lot of scattered scoring logic (which
might become more complex) with encoding enough information in the rank
cache.

The information is encoded in a sort key that can be sorted
descendingly. The sort key is a tuple (serialized as string into the
database) of fixed precision decimals. Each tuple is using 9 decimals
and left padded with `0`s, so it's sortable via normal DB query
operations. If sorted ascending (e.g. penalty time), then we subtract
from a very large number.

For example, with ICPC scoring, the top 2 teams from NWERC 2024 gets
these sort keys:
```
00000000000000000000013.000000000,999999999999999999998725.000000000,999999999999999999999711.000000000
00000000000000000000011.000000000,999999999999999999998918.000000000,999999999999999999999701.000000000
```

With this mechanism, we should be able to implement other planned
scoring methods (in particular partial scoring, optimization problems)
without too much complication on the business logic side.

We do use `bcmath` with fixed precision to not run into numerical
precision issues with sequencing floating point operations. This is not
important today, but will become important once we deall with
non-integers (e.g. for optimization problems).

It also caches some computation and makes scoreboard computation more
efficient today.

Author: meisterT

webapp/composer.json

@@ -64,6 +64,7 @@
 		"doctrine/orm": "^2.14",
 		"eligrey/filesaver": "2.*",
 		"enshrined/svg-sanitize": "^0.21.0",
+		"ext-bcmath": "*",
 		"fortawesome/font-awesome": "6.*",
 		"friendsofsymfony/rest-bundle": "^3.5",
 		"ircmaxell/password-compat": "*",

webapp/migrations/Version20250309122806.php

@@ -0,0 +1,40 @@
+<?php
+
+declare(strict_types=1);
+
+namespace DoctrineMigrations;
+
+use Doctrine\DBAL\Schema\Schema;
+use Doctrine\Migrations\AbstractMigration;
+
+/**
+ * Auto-generated Migration: Please modify to your needs!
+ */
+final class Version20250309122806 extends AbstractMigration
+{
+    public function getDescription(): string
+    {
+        return 'Add sort keys to rankcache, allowing us to support different scoring functions efficiently and elegantly';
+    }
+
+    public function up(Schema $schema): void
+    {
+        // this up() migration is auto-generated, please modify it to your needs
+        $this->addSql('ALTER TABLE rankcache ADD sort_key_public TEXT DEFAULT \'\' NOT NULL COMMENT \'Opaque sort key for public audience.\', ADD sort_key_restricted TEXT DEFAULT \'\' NOT NULL COMMENT \'Opaque sort key for restricted audience.\'');
+        $this->addSql('CREATE INDEX sortKeyPublic ON rankcache (sort_key_public)');
+        $this->addSql('CREATE INDEX sortKeyRestricted ON rankcache (sort_key_restricted)');
+    }
+
+    public function down(Schema $schema): void
+    {
+        // this down() migration is auto-generated, please modify it to your needs
+        $this->addSql('DROP INDEX sortKeyPublic ON rankcache');
+        $this->addSql('DROP INDEX sortKeyRestricted ON rankcache');
+        $this->addSql('ALTER TABLE rankcache DROP sort_key_public, DROP sort_key_restricted');
+    }
+
+    public function isTransactional(): bool
+    {
+        return false;
+    }
+}

webapp/src/Entity/RankCache.php

@@ -1,6 +1,7 @@
 <?php declare(strict_types=1);
 namespace App\Entity;
 
+use Doctrine\DBAL\Platforms\AbstractMySQLPlatform;
 use Doctrine\ORM\Mapping as ORM;
 
 /**
@@ -18,6 +19,8 @@
 #[ORM\Index(columns: ['cid', 'points_public', 'totaltime_public', 'totalruntime_public'], name: 'order_public')]
 #[ORM\Index(columns: ['cid'], name: 'cid')]
 #[ORM\Index(columns: ['teamid'], name: 'teamid')]
+#[ORM\Index(columns: ['sort_key_public'], name: 'sortKeyPublic')]
+#[ORM\Index(columns: ['sort_key_restricted'], name: 'sortKeyRestricted')]
 class RankCache
 {
     #[ORM\Column(options: [
@@ -62,6 +65,20 @@ class RankCache
     #[ORM\JoinColumn(name: 'teamid', referencedColumnName: 'teamid', onDelete: 'CASCADE')]
     private Team $team;
 
+    #[ORM\Column(
+        type: 'text',
+        length: AbstractMySQLPlatform::LENGTH_LIMIT_TEXT,
+        options: ['comment' => 'Opaque sort key for public audience.', 'default' => '']
+    )]
+    private string $sortKeyPublic = '';
+
+    #[ORM\Column(
+        type: 'text',
+        length: AbstractMySQLPlatform::LENGTH_LIMIT_TEXT,
+        options: ['comment' => 'Opaque sort key for restricted audience.', 'default' => '']
+    )]
+    private string $sortKeyRestricted = '';
+
     public function setPointsRestricted(int $pointsRestricted): RankCache
     {
         $this->points_restricted = $pointsRestricted;
@@ -149,4 +166,26 @@ public function getTeam(): Team
     {
         return $this->team;
     }
+
+    public function setSortKeyPublic(string $sortKeyPublic): RankCache
+    {
+        $this->sortKeyPublic = $sortKeyPublic;
+        return $this;
+    }
+
+    public function getSortKeyPublic(): string
+    {
+        return $this->sortKeyPublic;
+    }
+
+    public function setSortKeyRestricted(string $sortKeyRestricted): RankCache
+    {
+        $this->sortKeyRestricted = $sortKeyRestricted;
+        return $this;
+    }
+
+    public function getSortKeyRestricted(): string
+    {
+        return $this->sortKeyRestricted;
+    }
 }