From 37269479e483e3108f3b8ef6706ea1d701290222 Mon Sep 17 00:00:00 2001
From: Ali Mihandoost <ali.mihandoost@gmail.com>
Date: Sat, 19 Nov 2022 18:32:11 +0330
Subject: [PATCH] feat(storage-engine): storage meta and auto_increment id

---
 .../core/storage-engine/src/storage-engine.ts | 47 +++++++++++++++++--
 packages/core/storage-engine/src/type.ts      | 10 ++++
 2 files changed, 54 insertions(+), 3 deletions(-)

diff --git a/packages/core/storage-engine/src/storage-engine.ts b/packages/core/storage-engine/src/storage-engine.ts
index 2db141cf5..8bb38396b 100644
--- a/packages/core/storage-engine/src/storage-engine.ts
+++ b/packages/core/storage-engine/src/storage-engine.ts
@@ -71,6 +71,8 @@ alwatrRegisteredList.push({
  * ```
  */
 export class AlwatrStorageEngine<DocumentType extends DocumentObject> {
+  static readonly formatVersion = 3;
+
   /**
    * Storage name like database table name.
    */
@@ -117,10 +119,29 @@ export class AlwatrStorageEngine<DocumentType extends DocumentObject> {
     return this.keys.length;
   }
 
+  /**
+   * Get all data.
+   */
   get _data(): typeof this._storage.data {
     return this._storage.data;
   }
 
+  /**
+   * Get storage meta.
+   */
+  get meta(): typeof this._storage.meta {
+    return this._storage.meta;
+  }
+
+  /**
+   * Get next auto increment id for numerical document id.
+   */
+  get nextAutoIncrementId(): string {
+    const id = this._storage.meta ? +this._storage.meta.lastUpdatedId : 0;
+    if (isNaN(id)) throw new Error('doc_id_is_nan');
+    return (id + 1).toString();
+  }
+
   protected get _newStorage(): DataStorage<DocumentType> {
     return {ok: true, data: {}};
   }
@@ -226,19 +247,37 @@ export class AlwatrStorageEngine<DocumentType extends DocumentObject> {
   set(documentObject: DocumentType, fastInstance?: boolean): DocumentType {
     this._logger.logMethodArgs('set', documentObject._id);
 
-    const oldData = this._storage.data[documentObject._id];
-    if (oldData == null) this._keys = null; // Clear cached keys
-
     if (fastInstance !== true) {
       documentObject = JSON.parse(JSON.stringify(documentObject));
     }
 
+    if (documentObject._id === 'auto_increment') {
+      documentObject._id = this.nextAutoIncrementId;
+    }
+
+    const oldData = this._storage.data[documentObject._id];
+
     // update meta
     documentObject._updatedAt = Date.now();
     documentObject._createdAt = oldData?._createdAt ?? documentObject._updatedAt;
     documentObject._createdBy = oldData?._createdBy ?? documentObject._updatedBy;
     documentObject._rev = (oldData?._rev ?? 0) + 1;
 
+    this._storage.meta ??= {
+      formatVersion: AlwatrStorageEngine.formatVersion,
+      reversion: 0,
+      lastCreatedId: documentObject._id,
+      lastUpdatedId: '',
+      lastUpdatedAt: 0,
+    };
+    this._storage.meta.reversion++;
+    this._storage.meta.lastUpdatedId = documentObject._id;
+    this._storage.meta.lastUpdatedAt = documentObject._updatedAt;
+    if (oldData == null) {
+      this._keys = null; // Clear cached keys
+      this._storage.meta.lastCreatedId = documentObject._id;
+    }
+
     this._storage.data[documentObject._id] = documentObject;
 
     this.save();
@@ -266,6 +305,8 @@ export class AlwatrStorageEngine<DocumentType extends DocumentObject> {
     // Clear cached keys
     this._keys = null;
 
+    if (this._storage.meta) this._storage.meta.reversion++;
+
     this.save();
     return true;
   }
diff --git a/packages/core/storage-engine/src/type.ts b/packages/core/storage-engine/src/type.ts
index a56b5e55c..b1ea745bd 100644
--- a/packages/core/storage-engine/src/type.ts
+++ b/packages/core/storage-engine/src/type.ts
@@ -2,6 +2,9 @@ export type JSON = Record<string, unknown>;
 
 export interface DocumentObject {
   [key: string]: unknown;
+  /**
+   * Document uniq ID or `auto_increment`.
+   */
   _id: string;
   _rev?: number;
   _createdAt?: number;
@@ -12,6 +15,13 @@ export interface DocumentObject {
 
 export type DataStorage<T extends DocumentObject> = {
   ok: true;
+  meta?: {
+    formatVersion: number;
+    reversion: number;
+    lastUpdatedAt: number;
+    lastUpdatedId: string;
+    lastCreatedId: string;
+  };
   data: Record<string, T | undefined>;
 }