preparing for proposal composition

app/Models/Proposal.php

@@ -3,6 +3,8 @@
 namespace App\Models;
 
 use App\Models\Concerns\Reportable;
+use App\Tables\Changeset;
+use MightyPork\Exceptions\NotApplicableException;
 
 /**
  * Change proposal
@@ -14,7 +16,7 @@ use App\Models\Concerns\Reportable;
  * @property int $revision_id
  * @property int $author_id
  * @property string $note
- * @property object $changes - JSONB
+ * @property Proposal $changes - JSONB
  * @property-read User $author
  * @property-read Table $table
  * @property-read Revision $revision
@@ -43,4 +45,60 @@ class Proposal extends BaseModel
     {
         return $this->belongsTo(Table::class);
     }
+
+    public function getChangesAttribute($value)
+    {
+        $changeset = Changeset::fromObject(fromJSON($value));
+        $changeset->revision = $this->revision;
+        $changeset->table = $this->table;
+        $changeset->note = $this->note;
+
+        return $changeset;
+    }
+
+    public function setChangesAttribute($value)
+    {
+        if ($value instanceof Changeset) {
+            $this->attributes['changes'] = toJSON($value->toObject());
+        } else {
+            throw new NotApplicableException("Only a Changeset may be set to Proposal->changes");
+        }
+    }
+
+    /**
+     * Create a new Proposal instance wrapping this changeset,
+     * owned by the currently logged in User. The created instance
+     * is NOT saved yet.
+     *
+     * @param Changeset $changeset - changeset to hydrate the proposal with
+     * @return Proposal
+     */
+    public static function fromChangeset(Changeset $changeset)
+    {
+        if (!$changeset->hasAnyChanges()) {
+            throw new NotApplicableException('No changes to propose.');
+        }
+
+        if ($changeset->note == null) {
+            throw new NotApplicableException('Proposal note must be filled.');
+        }
+
+        if ($changeset->table == null || !$changeset->table instanceof Table) {
+            throw new NotApplicableException('Table not assigned to Changeset');
+        }
+
+        if ($changeset->revision == null || !$changeset->revision instanceof Revision) {
+            throw new NotApplicableException('Revision not assigned to Changeset');
+        }
+
+        return new Proposal([
+            // relations
+            'table_id' => $changeset->table->getKey(),
+            'revision_id' => $changeset->revision->getKey(),
+            'author_id' => \Auth::user()->getKey(),
+            // the proposal info
+            'note' => $changeset->note,
+            'changes' => $changeset->toObject(),
+        ]);
+    }
 }