refactor: migrate WASignalGroup to TypeScript and remove deprecated files (#1320)

* refactor: migrate WASignalGroup to TypeScript and remove deprecated files

* chore: remove WASignalGroup JavaScript files from package.json

* refactor: update SenderKeyStore and SenderKeyStateStructure interfaces to export and add deserialize method. Fix types

* chore: lint issue

* refactor: improve constructor type checking and getSeed method in SenderChainKey

* refactor: update key handling to use Buffer for improved consistency

* signal: consistent naming and dir structure + add some missing types

* fix: lint issues

---------

Co-authored-by: Rajeh Taher <rajeh@reforward.dev>

src/Signal/Group/group-session-builder.ts

@@ -0,0 +1,56 @@
+import * as keyhelper from './keyhelper'
+import { SenderKeyDistributionMessage } from './sender-key-distribution-message'
+import { SenderKeyName } from './sender-key-name'
+import { SenderKeyRecord } from './sender-key-record'
+
+interface SenderKeyStore {
+	loadSenderKey(senderKeyName: SenderKeyName): Promise<SenderKeyRecord>
+	storeSenderKey(senderKeyName: SenderKeyName, record: SenderKeyRecord): Promise<void>
+}
+
+export class GroupSessionBuilder {
+	private readonly senderKeyStore: SenderKeyStore
+
+	constructor(senderKeyStore: SenderKeyStore) {
+		this.senderKeyStore = senderKeyStore
+	}
+
+	public async process(
+		senderKeyName: SenderKeyName,
+		senderKeyDistributionMessage: SenderKeyDistributionMessage
+	): Promise<void> {
+		const senderKeyRecord = await this.senderKeyStore.loadSenderKey(senderKeyName)
+		senderKeyRecord.addSenderKeyState(
+			senderKeyDistributionMessage.getId(),
+			senderKeyDistributionMessage.getIteration(),
+			senderKeyDistributionMessage.getChainKey(),
+			senderKeyDistributionMessage.getSignatureKey()
+		)
+		await this.senderKeyStore.storeSenderKey(senderKeyName, senderKeyRecord)
+	}
+
+	public async create(senderKeyName: SenderKeyName): Promise<SenderKeyDistributionMessage> {
+		const senderKeyRecord = await this.senderKeyStore.loadSenderKey(senderKeyName)
+
+		if (senderKeyRecord.isEmpty()) {
+			const keyId = keyhelper.generateSenderKeyId()
+			const senderKey = keyhelper.generateSenderKey()
+			const signingKey = keyhelper.generateSenderSigningKey()
+
+			senderKeyRecord.setSenderKeyState(keyId, 0, senderKey, signingKey)
+			await this.senderKeyStore.storeSenderKey(senderKeyName, senderKeyRecord)
+		}
+
+		const state = senderKeyRecord.getSenderKeyState()
+		if (!state) {
+			throw new Error('No session state available')
+		}
+
+		return new SenderKeyDistributionMessage(
+			state.getKeyId(),
+			state.getSenderChainKey().getIteration(),
+			state.getSenderChainKey().getSeed(),
+			state.getSigningKeyPublic()
+		)
+	}
+}