From 5b1147da5db4f04eb622633ad5397d6a6c8056b0 Mon Sep 17 00:00:00 2001
From: SwiftHawk <SwiftHawk@SwiftHawk.com>
Date: Thu, 30 May 2024 22:26:57 +0500
Subject: [PATCH] feat: added a local cache based on browsers built in indexDB

---
 package-lock.json            |  6 ++++
 package.json                 |  1 +
 src/services/cache/index.ts  | 54 ++++++++++++++++++++++++++++++++++++
 src/services/cache/schema.ts |  9 ++++++
 src/services/index.ts        |  1 +
 src/types/cache.ts           |  6 ++++
 src/types/index.ts           |  3 +-
 7 files changed, 79 insertions(+), 1 deletion(-)
 create mode 100644 src/services/cache/index.ts
 create mode 100644 src/services/cache/schema.ts
 create mode 100644 src/services/index.ts
 create mode 100644 src/types/cache.ts

diff --git a/package-lock.json b/package-lock.json
index ac416f3..90f0319 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -21,6 +21,7 @@
         "crypto-js": "^4.2.0",
         "dnd-core": "16.0.1",
         "file-saver": "2.0.5",
+        "idb": "8.0.0",
         "jszip": "3.10.1",
         "lodash": "4.17.21",
         "mui-file-input": "4.0.4",
@@ -3592,6 +3593,11 @@
       "resolved": "https://registry.npmjs.org/react-is/-/react-is-16.13.1.tgz",
       "integrity": "sha512-24e6ynE2H+OKt4kqsOvNd8kBpV65zoxbA4BVsEOB3ARVWQki/DHzaUoC5KuON/BiccDaCCTZBuOcfZs70kR8bQ=="
     },
+    "node_modules/idb": {
+      "version": "8.0.0",
+      "resolved": "https://registry.npmjs.org/idb/-/idb-8.0.0.tgz",
+      "integrity": "sha512-l//qvlAKGmQO31Qn7xdzagVPPaHTxXx199MhrAFuVBTPqydcPYBWjkrbv4Y0ktB+GmWOiwHl237UUOrLmQxLvw=="
+    },
     "node_modules/ignore": {
       "version": "5.3.1",
       "resolved": "https://registry.npmjs.org/ignore/-/ignore-5.3.1.tgz",
diff --git a/package.json b/package.json
index da3e20a..c7449ba 100644
--- a/package.json
+++ b/package.json
@@ -27,6 +27,7 @@
     "crypto-js": "^4.2.0",
     "dnd-core": "16.0.1",
     "file-saver": "2.0.5",
+    "idb": "8.0.0",
     "jszip": "3.10.1",
     "lodash": "4.17.21",
     "mui-file-input": "4.0.4",
diff --git a/src/services/cache/index.ts b/src/services/cache/index.ts
new file mode 100644
index 0000000..694c593
--- /dev/null
+++ b/src/services/cache/index.ts
@@ -0,0 +1,54 @@
+import { IDBPDatabase, openDB } from 'idb'
+import { Event } from 'nostr-tools'
+import { CachedMetadataEvent } from '../../types'
+import { SchemaV1 } from './schema'
+
+class LocalCache {
+  // Static property to hold the single instance of LocalCache
+  private static instance: LocalCache | null = null
+  private db!: IDBPDatabase<SchemaV1>
+
+  // Private constructor to prevent direct instantiation
+  private constructor() {}
+
+  // Method to initialize the database
+  private async init() {
+    this.db = await openDB<SchemaV1>('sigit-cache', 1, {
+      upgrade(db) {
+        db.createObjectStore('userMetadata', { keyPath: 'event.pubkey' })
+      }
+    })
+  }
+
+  // Static method to get the single instance of LocalCache
+  public static async getInstance(): Promise<LocalCache> {
+    // If the instance doesn't exist, create it
+    if (!LocalCache.instance) {
+      LocalCache.instance = new LocalCache()
+      await LocalCache.instance.init()
+    }
+    // Return the single instance of LocalCache
+    return LocalCache.instance
+  }
+
+  // Method to add user metadata
+  public async addUserMetadata(event: Event) {
+    await this.db.put('userMetadata', { event, cachedAt: Date.now() })
+  }
+
+  // Method to get user metadata by key
+  public async getUserMetadata(
+    key: string
+  ): Promise<CachedMetadataEvent | null> {
+    const data = await this.db.get('userMetadata', key)
+    return data || null
+  }
+
+  // Method to delete user metadata by key
+  public async deleteUserMetadata(key: string) {
+    await this.db.delete('userMetadata', key)
+  }
+}
+
+// Export the single instance of LocalCache
+export const localCache = await LocalCache.getInstance()
diff --git a/src/services/cache/schema.ts b/src/services/cache/schema.ts
new file mode 100644
index 0000000..869aabf
--- /dev/null
+++ b/src/services/cache/schema.ts
@@ -0,0 +1,9 @@
+import { DBSchema } from 'idb'
+import { CachedMetadataEvent } from '../../types'
+
+export interface SchemaV1 extends DBSchema {
+  userMetadata: {
+    key: string
+    value: CachedMetadataEvent
+  }
+}
diff --git a/src/services/index.ts b/src/services/index.ts
new file mode 100644
index 0000000..79b5128
--- /dev/null
+++ b/src/services/index.ts
@@ -0,0 +1 @@
+export * from './cache'
diff --git a/src/types/cache.ts b/src/types/cache.ts
new file mode 100644
index 0000000..2a0edcd
--- /dev/null
+++ b/src/types/cache.ts
@@ -0,0 +1,6 @@
+import { Event } from 'nostr-tools'
+
+export interface CachedMetadataEvent {
+  event: Event
+  cachedAt: number
+}
diff --git a/src/types/index.ts b/src/types/index.ts
index 9397745..6c9f259 100644
--- a/src/types/index.ts
+++ b/src/types/index.ts
@@ -1,5 +1,6 @@
+export * from './cache'
 export * from './core'
 export * from './nostr'
 export * from './profile'
-export * from './zip'
 export * from './relay'
+export * from './zip'