feat(core): add PDO database wrapper and migration runner

src/Core/Database.php

@@ -0,0 +1,114 @@
+<?php
+
+namespace Bazaar\Core;
+
+use PDO;
+use PDOStatement;
+
+final class Database
+{
+    private static ?Database $instance = null;
+
+    private function __construct(private readonly PDO $pdo)
+    {
+    }
+
+    public static function instance(): Database
+    {
+        if (self::$instance === null) {
+            self::$instance = new self(self::connect());
+        }
+        return self::$instance;
+    }
+
+    public static function swap(Database $database): void
+    {
+        self::$instance = $database;
+    }
+
+    public static function fromPdo(PDO $pdo): Database
+    {
+        return new self($pdo);
+    }
+
+    private static function connect(): PDO
+    {
+        $driver = (string) Config::get('DB_DRIVER', 'sqlite');
+        $options = [
+            PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
+            PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
+            PDO::ATTR_EMULATE_PREPARES => false,
+        ];
+
+        if ($driver === 'sqlite') {
+            $path = (string) Config::get('DB_DATABASE');
+            if ($path !== ':memory:' && !str_starts_with($path, '/')) {
+                $path = basePath($path);
+            }
+            $pdo = new PDO('sqlite:' . $path, null, null, $options);
+            $pdo->exec('PRAGMA foreign_keys = ON');
+            return $pdo;
+        }
+
+        $dsn = sprintf(
+            '%s:host=%s;port=%s;dbname=%s;charset=utf8mb4',
+            $driver,
+            Config::get('DB_HOST'),
+            Config::get('DB_PORT'),
+            Config::get('DB_DATABASE')
+        );
+        return new PDO($dsn, (string) Config::get('DB_USERNAME'), (string) Config::get('DB_PASSWORD'), $options);
+    }
+
+    public function pdo(): PDO
+    {
+        return $this->pdo;
+    }
+
+    private function run(string $sql, array $bindings): PDOStatement
+    {
+        $statement = $this->pdo->prepare($sql);
+        $statement->execute($bindings);
+        return $statement;
+    }
+
+    public function select(string $sql, array $bindings = []): array
+    {
+        return $this->run($sql, $bindings)->fetchAll();
+    }
+
+    public function selectOne(string $sql, array $bindings = []): ?array
+    {
+        $row = $this->run($sql, $bindings)->fetch();
+        return $row === false ? null : $row;
+    }
+
+    public function scalar(string $sql, array $bindings = []): mixed
+    {
+        return $this->run($sql, $bindings)->fetchColumn();
+    }
+
+    public function statement(string $sql, array $bindings = []): int
+    {
+        return $this->run($sql, $bindings)->rowCount();
+    }
+
+    public function insert(string $sql, array $bindings = []): int
+    {
+        $this->run($sql, $bindings);
+        return (int) $this->pdo->lastInsertId();
+    }
+
+    public function transaction(callable $work): mixed
+    {
+        $this->pdo->beginTransaction();
+        try {
+            $outcome = $work($this);
+            $this->pdo->commit();
+            return $outcome;
+        } catch (\Throwable $error) {
+            $this->pdo->rollBack();
+            throw $error;
+        }
+    }
+}

src/Core/Migrator.php

@@ -0,0 +1,54 @@
+<?php
+
+namespace Bazaar\Core;
+
+final class Migrator
+{
+    public function __construct(
+        private readonly Database $db,
+        private readonly string $migrationsPath
+    ) {
+    }
+
+    public function run(): array
+    {
+        $this->db->statement(
+            'CREATE TABLE IF NOT EXISTS migrations (
+                id INTEGER PRIMARY KEY AUTOINCREMENT,
+                name TEXT NOT NULL UNIQUE,
+                appliedAt TEXT NOT NULL
+            )'
+        );
+
+        $applied = array_column(
+            $this->db->select('SELECT name FROM migrations'),
+            'name'
+        );
+
+        $ran = [];
+        foreach ($this->files() as $name => $path) {
+            if (in_array($name, $applied, true)) {
+                continue;
+            }
+            $this->db->pdo()->exec((string) file_get_contents($path));
+            $this->db->insert(
+                'INSERT INTO migrations (name, appliedAt) VALUES (?, ?)',
+                [$name, gmdate('c')]
+            );
+            $ran[] = $name;
+        }
+
+        return $ran;
+    }
+
+    private function files(): array
+    {
+        $files = glob($this->migrationsPath . '/*.sql') ?: [];
+        sort($files);
+        $indexed = [];
+        foreach ($files as $file) {
+            $indexed[basename($file)] = $file;
+        }
+        return $indexed;
+    }
+}