feat(store): finish ContributionStore and add typed entities

- Fix add()'s upsert SQL (was invalid SQL from typos) and use it for
  the new merge() as well.
- Fix remove()'s missing FROM keyword and drop the unindexed LIKE scan
  in favor of an exact match.
- Add latestDate(), all() with optional sinceDays filtering, and
  prune() with a retention-day cutoff.
- Add Contribution (immutable value object) and ContributionCollection
  (IteratorAggregate + Countable) so all() returns something typed
  instead of a raw date => count array.
- Cover all of the above with unit tests against an in-memory SQLite
  database.

src/Service/ContributionStore.php

@@ -4,24 +4,30 @@ declare(strict_types=1);
 
 namespace App\Service;
 
+use App\Entity\Contribution;
+use App\Entity\ContributionCollection;
 use PDO;
 
-class ContributionStore {
+class ContributionStore
+{
     private PDO $pdo;
+    private const int DAY_IN_SECONDS = 86400;
 
     public function __construct(
         private readonly string $dbPath = "%kernel.project_dir%/var/data/contributions.db",
         private readonly ?int $retentionDays = null,
-    ){
-        if(!is_dir(\dirname($this->dbPath))){
-            mkdir(\dirname($this->dbPath), 0755, recursive: true);
+    ) {
+        $dir = \dirname($this->dbPath);
+        if (!is_dir($dir)) {
+            mkdir($dir, 0755, recursive: true);
         }
         $this->pdo = new PDO('sqlite:' . $this->dbPath);
-        $this->pdo->setAttribute(PDO::ATTR_ERRMODE,PDO::ERRMODE_EXCEPTION);
+        $this->pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
         $this->prepareSchema();
     }
 
-    private function prepareSchema():void{
+    private function prepareSchema(): void
+    {
         $this->pdo->exec('
             CREATE TABLE IF NOT EXISTS contributions (
                 provider TEXT NOT NULL,
@@ -32,28 +38,74 @@ class ContributionStore {
         ');
     }
 
-    public function add(string $provider, int $unixtime, int $count):void{
-       $stmt = $this->pdo->prepare('
-            INSERT INTO contributions (
-                provider, date, count
-            )
-            VALUES(
-            ?,?,?
-            )
+    public function add(string $provider, int $unixtime, int $count): void
+    {
+        $stmt = $this->pdo->prepare('
+            INSERT INTO contributions (provider, date, count)
+            VALUES (?, ?, ?)
+            ON CONFLICT(provider, date) DO UPDATE SET count = excluded.count
         ');
-        $stmt->execute([$provider,$unixtime,$count]);
+        $stmt->execute([$provider, $unixtime, $count]);
     }
 
-    public function remove(string $provider, int $unixtime):void{
-         $stmt = $this->pdo->prepare('
-            DELETE contributions
-            WHERE provider LIKE ? and date = ?
+    public function remove(string $provider, int $unixtime): void
+    {
+        $stmt = $this->pdo->prepare('
+            DELETE FROM contributions
+            WHERE provider = ? AND date = ?
         ');
-        $stmt->execute([$provider,$unixtime]);
+        $stmt->execute([$provider, $unixtime]);
     }
 
-    public function all():void{
+    /**
+     * @param array<int, int> $dateCounts unix timestamp => count
+     */
+    public function merge(string $provider, array $dateCounts): void
+    {
+        foreach ($dateCounts as $unixtime => $count) {
+            $this->add($provider, $unixtime, $count);
+        }
+    }
 
+    public function latestDate(string $provider): ?int
+    {
+        $stmt = $this->pdo->prepare('SELECT MAX(date) FROM contributions WHERE provider = ?');
+        $stmt->execute([$provider]);
+        $result = $stmt->fetchColumn();
+
+        return $result !== null ? (int) $result : null;
+    }
+
+    public function all(string $provider, ?int $sinceDays = null): ContributionCollection
+    {
+        $sql = 'SELECT provider, date, count FROM contributions WHERE provider = ?';
+        $params = [$provider];
+
+        if ($sinceDays !== null) {
+            $sql .= ' AND date >= ?';
+            $params[] = time() - $sinceDays * self::DAY_IN_SECONDS;
+        }
+
+        $stmt = $this->pdo->prepare($sql);
+        $stmt->execute($params);
+
+        $contributions = array_map(
+            static fn (array $row): Contribution => new Contribution($row['provider'], (int) $row['date'], (int) $row['count']),
+            $stmt->fetchAll(PDO::FETCH_ASSOC),
+        );
+
+        return new ContributionCollection(...$contributions);
+    }
+
+    public function prune(): void
+    {
+        if ($this->retentionDays === null || $this->retentionDays === 0) {
+            return;
+        }
+
+        $cutoff = time() - $this->retentionDays * self::DAY_IN_SECONDS;
+
+        $stmt = $this->pdo->prepare('DELETE FROM contributions WHERE date < ?');
+        $stmt->execute([$cutoff]);
     }
-    
 }