Backend langchain

backend/package.json

@@ -31,6 +31,9 @@
 		"@aws-sdk/s3-request-presigner": "^3.958.0",
 		"@electric-sql/pglite": "^0.3.14",
 		"@faker-js/faker": "^10.1.0",
+		"@langchain/aws": "^1.2.0",
+		"@langchain/core": "^1.1.15",
+		"@langchain/openai": "^1.2.2",
 		"@nestjs/common": "11.1.9",
 		"@nestjs/config": "4.0.2",
 		"@nestjs/core": "11.1.9",
@@ -71,6 +74,7 @@
 		"json2csv": "^5.0.7",
 		"jsonwebtoken": "^9.0.3",
 		"knex": "3.1.0",
+		"langchain": "^1.2.10",
 		"lru-cache": "^11.2.4",
 		"nanoid": "5.1.6",
 		"nodemailer": "^7.0.11",

backend/src/ai-core/ai-core.module.ts

@@ -0,0 +1,21 @@
+import { Global, Module } from '@nestjs/common';
+import { LangchainOpenAIProvider } from './providers/langchain-openai.provider.js';
+import { LangchainBedrockProvider } from './providers/langchain-bedrock.provider.js';
+import { AICoreService } from './services/ai-core.service.js';
+
+export const AI_CORE_SERVICE = 'AI_CORE_SERVICE';
+
+@Global()
+@Module({
+	providers: [
+		LangchainOpenAIProvider,
+		LangchainBedrockProvider,
+		AICoreService,
+		{
+			provide: AI_CORE_SERVICE,
+			useExisting: AICoreService,
+		},
+	],
+	exports: [AICoreService, AI_CORE_SERVICE, LangchainOpenAIProvider, LangchainBedrockProvider],
+})
+export class AICoreModule {}

backend/src/ai-core/index.ts

@@ -0,0 +1,6 @@
+export * from './ai-core.module.js';
+export * from './interfaces/index.js';
+export * from './providers/index.js';
+export * from './services/index.js';
+export * from './tools/index.js';
+export * from './utils/index.js';

backend/src/ai-core/interfaces/ai-provider.interface.ts

@@ -0,0 +1,81 @@
+import { BaseMessage } from '@langchain/core/messages';
+import { IterableReadableStream } from '@langchain/core/utils/stream';
+
+export interface AIProviderConfig {
+	modelId?: string;
+	temperature?: number;
+	maxTokens?: number;
+	streaming?: boolean;
+	previousResponseId?: string; // For conversation continuation (OpenAI Responses API)
+}
+
+export interface AIToolDefinition {
+	name: string;
+	description: string;
+	parameters: Record<string, unknown>;
+}
+
+export interface AIToolCall {
+	id: string;
+	name: string;
+	arguments: Record<string, unknown>;
+}
+
+export interface AIToolResult {
+	toolCallId: string;
+	result: string;
+}
+
+export interface AIStreamChunk {
+	type: 'text' | 'tool_call' | 'tool_result' | 'done';
+	content?: string;
+	toolCall?: AIToolCall;
+	responseId?: string;
+}
+
+export interface AICompletionResult {
+	content: string;
+	toolCalls?: AIToolCall[];
+	responseId?: string;
+}
+
+export interface IAIProvider {
+	generateCompletion(prompt: string, config?: AIProviderConfig): Promise<string>;
+
+	generateChatCompletion(messages: BaseMessage[], config?: AIProviderConfig): Promise<AICompletionResult>;
+
+	generateStreamingCompletion(
+		messages: BaseMessage[],
+		config?: AIProviderConfig,
+	): Promise<IterableReadableStream<AIStreamChunk>>;
+
+	generateWithTools(
+		messages: BaseMessage[],
+		tools: AIToolDefinition[],
+		config?: AIProviderConfig,
+	): Promise<AICompletionResult>;
+
+	generateStreamingWithTools(
+		messages: BaseMessage[],
+		tools: AIToolDefinition[],
+		config?: AIProviderConfig,
+	): Promise<IterableReadableStream<AIStreamChunk>>;
+
+	continueWithToolResults(
+		messages: BaseMessage[],
+		toolResults: AIToolResult[],
+		tools: AIToolDefinition[],
+		config?: AIProviderConfig,
+	): Promise<AICompletionResult>;
+
+	continueStreamingWithToolResults(
+		messages: BaseMessage[],
+		toolResults: AIToolResult[],
+		tools: AIToolDefinition[],
+		config?: AIProviderConfig,
+	): Promise<IterableReadableStream<AIStreamChunk>>;
+
+	getProviderName(): string;
+
+	getDefaultModelId(): string;
+}

backend/src/ai-core/interfaces/ai-service.interface.ts

@@ -0,0 +1,81 @@
+import { BaseMessage } from '@langchain/core/messages';
+import {
+	AICompletionResult,
+	AIProviderConfig,
+	AIStreamChunk,
+	AIToolDefinition,
+	AIToolResult,
+} from './ai-provider.interface.js';
+import { IterableReadableStream } from '@langchain/core/utils/stream';
+
+export enum AIProviderType {
+	OPENAI = 'openai',
+	BEDROCK = 'bedrock',
+}
+
+export interface IAIService {
+
+	complete(prompt: string, config?: AIProviderConfig): Promise<string>;
+
+	completeWithProvider(provider: AIProviderType, prompt: string, config?: AIProviderConfig): Promise<string>;
+
+	chat(messages: BaseMessage[], config?: AIProviderConfig): Promise<AICompletionResult>;
+
+	chatWithProvider(
+		provider: AIProviderType,
+		messages: BaseMessage[],
+		config?: AIProviderConfig,
+	): Promise<AICompletionResult>;
+
+	streamChat(messages: BaseMessage[], config?: AIProviderConfig): Promise<IterableReadableStream<AIStreamChunk>>;
+
+	streamChatWithProvider(
+		provider: AIProviderType,
+		messages: BaseMessage[],
+		config?: AIProviderConfig,
+	): Promise<IterableReadableStream<AIStreamChunk>>;
+
+	chatWithTools(
+		messages: BaseMessage[],
+		tools: AIToolDefinition[],
+		config?: AIProviderConfig,
+	): Promise<AICompletionResult>;
+
+	chatWithToolsAndProvider(
+		provider: AIProviderType,
+		messages: BaseMessage[],
+		tools: AIToolDefinition[],
+		config?: AIProviderConfig,
+	): Promise<AICompletionResult>;
+
+	streamChatWithTools(
+		messages: BaseMessage[],
+		tools: AIToolDefinition[],
+		config?: AIProviderConfig,
+	): Promise<IterableReadableStream<AIStreamChunk>>;
+
+	streamChatWithToolsAndProvider(
+		provider: AIProviderType,
+		messages: BaseMessage[],
+		tools: AIToolDefinition[],
+		config?: AIProviderConfig,
+	): Promise<IterableReadableStream<AIStreamChunk>>;
+
+	continueAfterToolCall(
+		messages: BaseMessage[],
+		toolResults: AIToolResult[],
+		tools: AIToolDefinition[],
+		config?: AIProviderConfig,
+	): Promise<AICompletionResult>;
+
+	continueStreamingAfterToolCall(
+		messages: BaseMessage[],
+		toolResults: AIToolResult[],
+		tools: AIToolDefinition[],
+		config?: AIProviderConfig,
+	): Promise<IterableReadableStream<AIStreamChunk>>;
+
+	getDefaultProvider(): AIProviderType;
+
+	setDefaultProvider(provider: AIProviderType): void;
+}

backend/src/ai-core/interfaces/index.ts

@@ -0,0 +1,2 @@
+export * from './ai-provider.interface.js';
+export * from './ai-service.interface.js';

backend/src/ai-core/providers/index.ts

@@ -0,0 +1,2 @@
+export * from './langchain-openai.provider.js';
+export * from './langchain-bedrock.provider.js';