1 files changed, 52 insertions, 0 deletions
diff --git a/WpfTest/Db/Migrator.php b/WpfTest/Db/Migrator.php
new file mode 100644
index 0000000..ea7f92a
--- /dev/null
+++ b/WpfTest/Db/Migrator.php
@@ -0,0 +1,52 @@
+<?php
+namespace WpfTest\Db;
+
+use WpfTest\Db;
+use WpfTest\Singleton;
+
+class Migrator extends Singleton {
+    private array $migrations = [];
+
+    public function register(int $newVersion, callable $fn) {
+        $this->migrations[$newVersion] = $fn;
+    }
+
+    /**
+     * Runs all available migrations
+     * @return void
+     */
+    public function migrate() {
+        $db = Db::getInstance();
+        $currentVersion = null;
+        try {
+            $currentVersion = $db->getDbVersion();
+            error_log('starting on version ' . $currentVersion);
+        } catch (\PDOException $e) {
+            if ($e->getCode() == '42P01') { // undefined table
+                error_log("initialising database because db version table doesn't exist");
+                $db->runInitialSchema();
+                $currentVersion = $db->getDbVersion();
+                error_log('starting on version ' . $currentVersion);
+            } else
+                throw $e;
+        }
+
+        // find migrations that haven't been run yet
+        $available = array_filter($this->migrations, function (int $key) use ($currentVersion) {
+            return $key > $currentVersion;
+        }, ARRAY_FILTER_USE_KEY);
+
+        try {
+            // run them in order (at least they should be in order?)
+            foreach (array_keys($available) as $version) {
+                $fn = $available[$version];
+                $filename = basename((new \ReflectionFunction($fn))->getFileName());
+                error_log("running migration $filename");
+                $available[$version]($db->getPdo());
+                $db->setDbVersion($version);
+            }
+        } finally {
+            error_log('now on version ' . $db->getDbVersion());
+        }
+    }
+}
+\ No newline at end of file