Make component_tag a polymorphic structure

app/Foundation/Providers/AppServiceProvider.php

@@ -54,6 +54,7 @@ class AppServiceProvider extends ServiceProvider
             'metrics'    => \CachetHQ\Cachet\Models\Metric::class,
             'schedules'  => \CachetHQ\Cachet\Models\Schedule::class,
             'subscriber' => \CachetHQ\Cachet\Models\Subscriber::class,
+            'tags'       => \CachetHQ\Cachet\Models\Tag::class,
         ]);
     }
 

app/Models/Taggable.php

@@ -0,0 +1,65 @@
+<?php
+
+/*
+ * This file is part of Cachet.
+ *
+ * (c) Alt Three Services Limited
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace CachetHQ\Cachet\Models;
+
+use Illuminate\Database\Eloquent\Model;
+
+/**
+ * This is the taggable model class.
+ *
+ * @author James Brooks <james@alt-three.com>
+ */
+class Taggable extends Model
+{
+    /**
+     * The attributes that should be casted to native types.
+     *
+     * @var string[]
+     */
+    protected $casts = [
+        'id'            => 'int',
+        'tag_id'        => 'int',
+        'taggable_id'   => 'int',
+        'taggable_type' => 'string',
+    ];
+
+    /**
+     * The attributes that are mass assignable.
+     *
+     * @var array
+     */
+    protected $fillable = [
+        'tag_id',
+        'taggable_id',
+        'taggable_type',
+    ];
+
+    /**
+     * Get the tag relation.
+     *
+     * @return \Illuminate\Database\Eloquent\Relations\BelongsTo
+     */
+    public function tag()
+    {
+        return $this->belongsTo(Tag::class);
+    }
+
+    /**
+     * Get the taggable relation.
+     *
+     * @return \Illuminate\Database\Eloquent\Relations\MorphTo
+     */
+    public function taggable()
+    {
+        return $this->morphTo();
+    }
+}

database/migrations/2018_04_02_163328_CreateTaggablesTable.php

@@ -0,0 +1,42 @@
+<?php
+
+/*
+ * This file is part of Cachet.
+ *
+ * (c) Alt Three Services Limited
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+class CreateTaggablesTable extends Migration
+{
+    /**
+     * Run the migrations.
+     *
+     * @return void
+     */
+    public function up()
+    {
+        Schema::create('taggables', function (Blueprint $table) {
+            $table->increments('id');
+            $table->integer('tag_id')->unsigned()->index();
+            $table->morphs('taggable');
+            $table->timestamps();
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     *
+     * @return void
+     */
+    public function down()
+    {
+        Schema::dropIfExists('taggables');
+    }
+}

database/migrations/2018_04_02_163658_MigrateComponentTagTable.php

@@ -0,0 +1,57 @@
+<?php
+
+/*
+ * This file is part of Cachet.
+ *
+ * (c) Alt Three Services Limited
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+use CachetHQ\Cachet\Models\Taggable;
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\DB;
+use Illuminate\Support\Facades\Schema;
+
+class MigrateComponentTagTable extends Migration
+{
+    /**
+     * Run the migrations.
+     *
+     * @return void
+     */
+    public function up()
+    {
+        // Start by migrating the data into the new taggables field.
+        DB::table('component_tag')->get()->each(function ($tag) {
+            Taggable::create([
+                'tag_id'        => $tag->tag_id,
+                'taggable_type' => 'components',
+                'taggable_id'   => $tag->component_id,
+            ]);
+        });
+
+        Schema::dropIfExists('component_tag');
+    }
+
+    /**
+     * Reverse the migrations.
+     *
+     * @return void
+     */
+    public function down()
+    {
+        Schema::create('component_tag', function (Blueprint $table) {
+            $table->engine = 'InnoDB';
+
+            $table->increments('id');
+            $table->integer('component_id');
+            $table->integer('tag_id');
+
+            $table->index('component_id');
+            $table->index('tag_id');
+        });
+    }
+}