From 81c9e5cfc50788df7ca62506329a830bd126577d Mon Sep 17 00:00:00 2001
From: Yonas Habteab <yonas.habteab@icinga.com>
Date: Wed, 2 Aug 2023 18:25:08 +0200
Subject: [PATCH] Introduce `MigrationManager` class

---
 .../Icinga/Application/MigrationManager.php   | 246 ++++++++++++++++++
 1 file changed, 246 insertions(+)
 create mode 100644 library/Icinga/Application/MigrationManager.php

diff --git a/library/Icinga/Application/MigrationManager.php b/library/Icinga/Application/MigrationManager.php
new file mode 100644
index 000000000..b1065261e
--- /dev/null
+++ b/library/Icinga/Application/MigrationManager.php
@@ -0,0 +1,246 @@
+<?php
+
+/* Icinga Web 2 | (c) 2023 Icinga GmbH | GPLv2+ */
+
+namespace Icinga\Application;
+
+use Countable;
+use Generator;
+use Icinga\Application\Hook\MigrationHook;
+use Icinga\Exception\NotFoundError;
+use ipl\I18n\Translation;
+
+/**
+ * Migration manager encapsulates PHP code and DB migrations and manages all pending migrations in a
+ * structured way.
+ */
+final class MigrationManager implements Countable
+{
+    use Translation;
+
+    /** @var array<string, MigrationHook> All pending migration hooks */
+    protected $pendingMigrations;
+
+    /** @var MigrationManager */
+    private static $instance;
+
+    private function __construct()
+    {
+    }
+
+    /**
+     * Get the instance of this manager
+     *
+     * @return $this
+     */
+    public static function instance(): self
+    {
+        if (self::$instance === null) {
+            self::$instance = new self();
+        }
+
+        return self::$instance;
+    }
+
+    /**
+     * Get all pending migrations
+     *
+     * @return array<string, MigrationHook>
+     */
+    public function getPendingMigrations(): array
+    {
+        if ($this->pendingMigrations === null) {
+            $this->load();
+        }
+
+        return $this->pendingMigrations;
+    }
+
+    /**
+     * Get whether there are any pending migrations
+     *
+     * @return bool
+     */
+    public function hasPendingMigrations(): bool
+    {
+        return $this->count() > 0;
+    }
+
+    public function hasMigrations(string $module): bool
+    {
+        if (! $this->hasPendingMigrations()) {
+            return false;
+        }
+
+        return isset($this->getPendingMigrations()[$module]);
+    }
+
+    /**
+     * Get pending migration matching the given module name
+     *
+     * @param string $module
+     *
+     * @return MigrationHook
+     *
+     * @throws NotFoundError When there are no pending PHP code migrations matching the given module name
+     */
+    public function getMigration(string $module): MigrationHook
+    {
+        if (! $this->hasMigrations($module)) {
+            throw new NotFoundError('There are no pending migrations matching the given name: %s', $module);
+        }
+
+        return $this->getPendingMigrations()[$module];
+    }
+
+    /**
+     * Get the number of all pending migrations
+     *
+     * @return int
+     */
+    public function count(): int
+    {
+        return count($this->getPendingMigrations());
+    }
+
+    /**
+     * Apply all pending migrations matching the given migration module name
+     *
+     * @param string $module
+     *
+     * @return bool
+     */
+    public function applyByName(string $module): bool
+    {
+        $migration = $this->getMigration($module);
+        if ($migration->isModule() && $this->hasMigrations(MigrationHook::DEFAULT_MODULE)) {
+            return false;
+        }
+
+        return $this->apply($migration);
+    }
+
+    /**
+     * Apply the given migration hook
+     *
+     * @param MigrationHook $hook
+     *
+     * @return bool
+     */
+    public function apply(MigrationHook $hook): bool
+    {
+        if ($hook->isModule() && $this->hasMigrations(MigrationHook::DEFAULT_MODULE)) {
+            Logger::error(
+                'Please apply the Icinga Web pending migration(s) first or apply all the migrations instead'
+            );
+
+            return false;
+        }
+
+        if ($hook->run()) {
+            unset($this->pendingMigrations[$hook->getModuleName()]);
+
+            Logger::info('Applied pending %s migrations successfully', $hook->getName());
+
+            return true;
+        }
+
+        return false;
+    }
+
+    /**
+     * Apply all pending modules/framework migrations
+     *
+     * @return bool
+     */
+    public function applyAll(): bool
+    {
+        $default = MigrationHook::DEFAULT_MODULE;
+        if ($this->hasMigrations($default)) {
+            $migration = $this->getMigration($default);
+            if (! $this->apply($migration)) {
+                return false;
+            }
+        }
+
+        $succeeded = true;
+        foreach ($this->getPendingMigrations() as $migration) {
+            if (! $this->apply($migration) && $succeeded) {
+                $succeeded = false;
+            }
+        }
+
+        return $succeeded;
+    }
+
+    /**
+     * Yield module and framework pending migrations separately
+     *
+     * @param bool $modules
+     *
+     * @return Generator<MigrationHook>
+     */
+    public function yieldMigrations(bool $modules = false): Generator
+    {
+        foreach ($this->getPendingMigrations() as $migration) {
+            if ($modules === $migration->isModule()) {
+                yield $migration;
+            }
+        }
+    }
+
+    protected function load(): void
+    {
+        $this->pendingMigrations = [];
+
+        /** @var MigrationHook $hook */
+        foreach (Hook::all('migration') as $hook) {
+            if (empty($hook->getMigrations())) {
+                continue;
+            }
+
+            $this->pendingMigrations[$hook->getModuleName()] = $hook;
+        }
+
+        ksort($this->pendingMigrations);
+    }
+
+    /**
+     * Get all pending migrations as an array
+     *
+     * @return array<string, mixed>
+     */
+    public function toArray(): array
+    {
+        $framework = [];
+        $serialize = function (MigrationHook $hook): array {
+            $serialized = [
+                'name'             => $hook->getName(),
+                'module'           => $hook->getModuleName(),
+                'isModule'         => $hook->isModule(),
+                'migrated_version' => $hook->getVersion(),
+                'migrations'       => []
+            ];
+
+            foreach ($hook->getMigrations() as $migration) {
+                $serialized['migrations'][$migration->getVersion()] = [
+                    'path'  => $migration->getScriptPath(),
+                    'error' => $migration->getLastState()
+                ];
+            }
+
+            return $serialized;
+        };
+
+        foreach ($this->yieldMigrations() as $migration) {
+            $framework[] = $serialize($migration);
+        }
+
+        $modules = [];
+        foreach ($this->yieldMigrations(true) as $migration) {
+            $modules[] = $serialize($migration);
+        }
+
+        return ['System'  => $framework, 'Modules' => $modules];
+    }
+}