Move document improvements (#927)

* Show all collections in UI

* Introduce command pattern

* Actually remove from previous collection

* Stash

* Fixes: Promises resolved outside of response lifecycle

* 💚

* 💚

* documentMover tests

* Transaction

* Perf. More in transactions

server/commands/documentMover.js

@@ -0,0 +1,83 @@
+// @flow
+import { Document, Collection } from '../models';
+import { sequelize } from '../sequelize';
+
+export default async function documentMover({
+  document,
+  collectionId,
+  parentDocumentId,
+  index,
+}: {
+  document: Document,
+  collectionId: string,
+  parentDocumentId: string,
+  index?: number,
+}) {
+  let transaction;
+  const result = { collections: [], documents: [] };
+  const collectionChanged = collectionId !== document.collectionId;
+
+  try {
+    transaction = await sequelize.transaction();
+
+    // remove from original collection
+    const collection = await document.getCollection({ transaction });
+    const documentJson = await collection.removeDocumentInStructure(document, {
+      save: false,
+    });
+
+    // if the collection is the same then it will get saved below, this
+    // line prevents a pointless intermediate save from occurring.
+    if (collectionChanged) await collection.save({ transaction });
+
+    // add to new collection (may be the same)
+    document.collectionId = collectionId;
+    document.parentDocumentId = parentDocumentId;
+
+    const newCollection: Collection = collectionChanged
+      ? await Collection.findById(collectionId, { transaction })
+      : collection;
+    await newCollection.addDocumentToStructure(document, index, {
+      documentJson,
+    });
+    result.collections.push(collection);
+
+    // if collection does not remain the same loop through children and change their
+    // collectionId too. This includes archived children, otherwise their collection
+    // would be wrong once restored.
+    if (collectionChanged) {
+      result.collections.push(newCollection);
+
+      const loopChildren = async documentId => {
+        const childDocuments = await Document.findAll({
+          where: { parentDocumentId: documentId },
+        });
+
+        await Promise.all(
+          childDocuments.map(async child => {
+            await loopChildren(child.id);
+            await child.update({ collectionId }, { transaction });
+            child.collection = newCollection;
+            result.documents.push(child);
+          })
+        );
+      };
+
+      await loopChildren(document.id);
+    }
+
+    await document.save({ transaction });
+    document.collection = newCollection;
+    result.documents.push(document);
+
+    await transaction.commit();
+  } catch (err) {
+    if (transaction) {
+      await transaction.rollback();
+    }
+    throw err;
+  }
+
+  // we need to send all updated models back to the client
+  return result;
+}