botserver/packages/gpt.gblib/services/ChatServices.ts

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'use strict';

import { HNSWLib } from '@langchain/community/vectorstores/hnswlib';
import { StringOutputParser } from '@langchain/core/output_parsers';
import {
  AIMessagePromptTemplate,
  ChatPromptTemplate,
  HumanMessagePromptTemplate,
  MessagesPlaceholder
} from '@langchain/core/prompts';
import { RunnableSequence } from '@langchain/core/runnables';
import { convertToOpenAITool } from '@langchain/core/utils/function_calling';
import { ChatOpenAI } from '@langchain/openai';
import { GBLog, GBMinInstance } from 'botlib';
import * as Fs from 'fs';
import { jsonSchemaToZod } from 'json-schema-to-zod';
import { BufferWindowMemory } from 'langchain/memory';
import Path from 'path';
import { CollectionUtil } from 'pragmatismo-io-framework';
import { DialogKeywords } from '../../basic.gblib/services/DialogKeywords.js';
import { GBVMService } from '../../basic.gblib/services/GBVMService.js';
import { GBConfigService } from '../../core.gbapp/services/GBConfigService.js';
import { GuaribasSubject } from '../../kb.gbapp/models/index.js';
import { Serialized } from '@langchain/core/load/serializable';
import { BaseCallbackHandler } from '@langchain/core/callbacks/base';
import { pdfToPng, PngPageOutput } from 'pdf-to-png-converter';
import { DynamicStructuredTool } from '@langchain/core/tools';
import { WikipediaQueryRun } from '@langchain/community/tools/wikipedia_query_run';
import { BaseLLMOutputParser, OutputParserException } from '@langchain/core/output_parsers';
import { ChatGeneration, Generation } from '@langchain/core/outputs';
import { GBAdminService } from '../../admin.gbapp/services/GBAdminService.js';
import { GBServer } from '../../../src/app.js';
import urlJoin from 'url-join';
import { getDocument } from 'pdfjs-dist/legacy/build/pdf.mjs';
import { GBLogEx } from '../../core.gbapp/services/GBLogEx.js';

export interface CustomOutputParserFields {}
export type ExpectedOutput = any;

function isChatGeneration(llmOutput: ChatGeneration | Generation): llmOutput is ChatGeneration {
  return 'message' in llmOutput;
}

class CustomHandler extends BaseCallbackHandler {
  name = 'custom_handler';

  handleLLMNewToken(token: string) {
    GBLogEx.info(0, `LLM: token: ${JSON.stringify(token)}`);
  }

  handleLLMStart(llm: Serialized, _prompts: string[]) {
    GBLogEx.info(0, `LLM: handleLLMStart ${JSON.stringify(llm)}, Prompts: ${_prompts.join('\n')}`);
  }

  handleChainStart(chain: Serialized) {
    GBLogEx.info(0, `LLM: handleChainStart: ${JSON.stringify(chain)}`);
  }

  handleToolStart(tool: Serialized) {
    GBLogEx.info(0, `LLM: handleToolStart: ${JSON.stringify(tool)}`);
  }
}

const logHandler = new CustomHandler();

export class GBLLMOutputParser extends BaseLLMOutputParser<ExpectedOutput> {
  lc_namespace = ['langchain', 'output_parsers'];

  private toolChain: RunnableSequence;
  private min;

  constructor(min, toolChain: RunnableSequence, documentChain: RunnableSequence) {
    super();
    this.min = min;
    this.toolChain = toolChain;
  }

  async parseResult(llmOutputs: ChatGeneration[] | Generation[]): Promise<ExpectedOutput> {
    if (!llmOutputs.length) {
      throw new OutputParserException('Output parser did not receive any generations.');
    }
    let result;

    if (llmOutputs[0]['message'].lc_kwargs.additional_kwargs.tool_calls) {
      return this.toolChain.invoke({ func: llmOutputs[0]['message'].lc_kwargs.additional_kwargs.tool_calls });
    }

    if (isChatGeneration(llmOutputs[0])) {
      result = llmOutputs[0].message.content;
    } else {
      result = llmOutputs[0].text;
    }

    let res;
    try {
      GBLogEx.info(this.min, result);
      result = result.replace(/\\n/g, '');
      res = JSON.parse(result);
    } catch {
      return result;
    }

    let { sources, text } = res;

    await CollectionUtil.asyncForEach(sources, async source => {
      let found = false;
      if (source && source.file.endsWith('.pdf')) {
        const gbaiName = DialogKeywords.getGBAIPath(this.min.botId, 'gbkb');
        const localName = Path.join(process.env.PWD, 'work', gbaiName, 'docs', source.file);

        if (localName) {
          const { url } = await ChatServices.pdfPageAsImage(this.min, localName, source.page);
          text = `![alt text](${url})
          ${text}`;
          found = true;
          source.file = localName;
        }
      }

      if (found) {
        GBLogEx.info(this.min, `File not found referenced in other .pdf: ${source.file}`);
      }
    });

    return { text, sources };
  }
}

export class ChatServices {
  public static async pdfPageAsImage(min, filename, pageNumber) {
    // Converts the PDF to PNG.

    GBLogEx.info(min, `Converting ${filename}, page: ${pageNumber}...`);
    const pngPages: PngPageOutput[] = await pdfToPng(filename, {
      disableFontFace: true,
      useSystemFonts: true,
      viewportScale: 2.0,
      pagesToProcess: [pageNumber],
      strictPagesToProcess: false,
      verbosityLevel: 0
    });

    // Prepare an image on cache and return the GBFILE information.

    if (pngPages.length > 0) {
      const buffer = pngPages[0].content;
      const gbaiName = DialogKeywords.getGBAIPath(min.botId, null);
      const localName = Path.join('work', gbaiName, 'cache', `img${GBAdminService.getRndReadableIdentifier()}.png`);
      const url = urlJoin(GBServer.globals.publicAddress, min.botId, 'cache', Path.basename(localName));
      Fs.writeFileSync(localName, buffer, { encoding: null });
      return { localName: localName, url: url, data: buffer };
    }
  }

  private static async getRelevantContext(
    vectorStore: HNSWLib,
    sanitizedQuestion: string,
    numDocuments: number = 100
  ): Promise<string> {
    if (sanitizedQuestion === '') {
      return '';
    }

    let documents = await vectorStore.similaritySearch(sanitizedQuestion, numDocuments);
    const uniqueDocuments = {};

    for (const document of documents) {
      if (!uniqueDocuments[document.metadata.source]) {
        uniqueDocuments[document.metadata.source] = document;
      }
    }

    let output = '';

    for (const filePaths of Object.keys(uniqueDocuments)) {
      const doc = uniqueDocuments[filePaths];
      const metadata = doc.metadata;
      const filename = Path.basename(metadata.source);
      let page = 0;
      if (metadata.source.endsWith('.pdf')) {
        page = await ChatServices.findPageForText(metadata.source, doc.pageContent);
      }

      output = `${output}\n\n\n\nUse also the following context which is coming from Source Document: ${filename} at page: ${
        page ? page : 'entire document'
      } 
      (you will fill the JSON sources collection field later), 
      memorize this block among document information and return when you are refering this part of content:\n\n\n\n ${
        doc.pageContent
      } \n\n\n\n.`;
    }
    return output;
  }

  private static async findPageForText(pdfPath, searchText) {
    const data = new Uint8Array(Fs.readFileSync(pdfPath));
    const pdf = await getDocument({ data }).promise;

    searchText = searchText.replace(/\s/g, '');

    for (let i = 1; i <= pdf.numPages; i++) {
      const page = await pdf.getPage(i);
      const textContent = await page.getTextContent();
      const text = textContent.items
        .map(item => item['str'])
        .join('')
        .replace(/\s/g, '');

      if (text.includes(searchText)) return i;
    }

    return -1;
  }

  /**
   * Generate text
   *
   * CONTINUE keword.
   *
   * result = CONTINUE text
   *
   */
  public static async continue(min: GBMinInstance, question: string, chatId) {}

  private static memoryMap = {};
  public static userSystemPrompt = {};

  public static async answerByGPT(min: GBMinInstance, user, question: string, mode = null) {
    if (!process.env.OPENAI_API_KEY) {
      return { answer: undefined, questionId: 0 };
    }

    const LLMMode = mode ?? min.core.getParam(min.instance, 'Answer Mode', 'direct');

    const docsContext = min['vectorStore'];

    const memory = new BufferWindowMemory({
      returnMessages: true,
      memoryKey: 'chat_history',
      inputKey: 'input',
      k: 2
    });

    if (user && !this.memoryMap[user.userSystemId]) {
      this.memoryMap[user.userSystemId] = memory;
    }

    const systemPrompt = user ? this.userSystemPrompt[user.userSystemId] : '';

    const model = new ChatOpenAI({
      openAIApiKey: process.env.OPENAI_API_KEY,
      modelName: 'gpt-3.5-turbo-0125',
      temperature: 0,
      callbacks: [logHandler]
    });

    let tools = await ChatServices.getTools(min);
    let toolsAsText = ChatServices.getToolsAsText(tools);

    const modelWithTools = model.bind({
      tools: tools.map(convertToOpenAITool)
    });

    const questionGeneratorTemplate = ChatPromptTemplate.fromMessages([
      AIMessagePromptTemplate.fromTemplate(
        `
        Answer the question without calling any tool, but if there is a need to call:
        You have access to the following set of tools. 
        Here are the names and descriptions for each tool:

          ${toolsAsText}

          Do not use any previous tools output in the chat_history. 
        `
      ),
      new MessagesPlaceholder('chat_history'),
      AIMessagePromptTemplate.fromTemplate(`Follow Up Input: {question}
    Standalone question:`)
    ]);

    const toolsResultPrompt = ChatPromptTemplate.fromMessages([
      AIMessagePromptTemplate.fromTemplate(
        `The tool just returned value in last call. Using {chat_history}
        rephrase the answer to the user using this tool output.
        `
      ),
      new MessagesPlaceholder('chat_history'),
      AIMessagePromptTemplate.fromTemplate(`Tool output: {tool_output} 
    Standalone question:`)
    ]);

    const jsonInformation = `VERY IMPORTANT: ALWAYS return VALID standard JSON with the folowing structure: 'text' as answer, 
    sources as an array of ('file' indicating the PDF filename and 'page' indicating the page number) listing all segmented context. 
    Example JSON format: "text": "this is the answer, anything LLM output as text answer shoud be here.", 
    "sources": [{{"file": "filename.pdf", "page": 3}}, {{"file": "filename2.pdf", "page": 1}}],
    return valid JSON with brackets. Avoid explaining the context directly
    to the user; instead, refer to the document source, always return more than one source document
    and check if the answer can be extended by using additional contexts in 
    other files, as specified before.
    
    Double check if the output is a valid JSON with brackets. all fields are required: text, file, page.
  `;

    const combineDocumentsPrompt = ChatPromptTemplate.fromMessages([
      AIMessagePromptTemplate.fromTemplate(
        `
        This is a segmented context.
        
        \n\n{context}\n\n
        
        And based on \n\n{chat_history}\n\n
        rephrase the response to the user using the aforementioned context. If you're unsure of the answer, 
        utilize any relevant context provided to answer the question effectively. Don´t output MD images tags url previously shown.

        ${LLMMode==='document-ref'? jsonInformation: ''}
        `
      ),
      new MessagesPlaceholder('chat_history'),
      HumanMessagePromptTemplate.fromTemplate('Question: {question}')
    ]);

    const callToolChain = RunnableSequence.from([
      {
        tool_output: async (output: object) => {
          const name = output['func'][0].function.name;
          const args = JSON.parse(output['func'][0].function.arguments);
          GBLogEx.info(min, `Running .gbdialog '${name}' as GPT tool...`);
          const pid = GBVMService.createProcessInfo(null, min, 'gpt', null);

          return await GBVMService.callVM(name, min, false, pid, false, args);
        },
        chat_history: async () => {
          const { chat_history } = await memory.loadMemoryVariables({});
          return chat_history;
        }
      },
      toolsResultPrompt,
      model,
      new StringOutputParser()
    ]);

    const combineDocumentsChain = RunnableSequence.from([
      {
        question: (question: string) => question,
        chat_history: async () => {
          const { chat_history } = await memory.loadMemoryVariables({});
          return chat_history;
        },
        context: async (output: string) => {
          const c = await ChatServices.getRelevantContext(docsContext, output);
          return `${systemPrompt} \n ${c ? 'Use this context to answer:\n' + c : 'answer just with user question.'}`;
        }
      },
      combineDocumentsPrompt,
      model,
      new GBLLMOutputParser(min, null, null)
    ]);

    const conversationalToolChain = RunnableSequence.from([
      {
        question: (i: { question: string }) => i.question,
        chat_history: async () => {
          const { chat_history } = await memory.loadMemoryVariables({});
          return chat_history;
        }
      },
      questionGeneratorTemplate,
      modelWithTools,
      new GBLLMOutputParser(min, callToolChain, docsContext?.docstore?._docs.length > 0 ? combineDocumentsChain : null),
      new StringOutputParser()
    ]);

    let result, sources;
    let text, file, page;

    // Choose the operation mode of answer generation, based on
    // .gbot switch LLMMode and choose the corresponding chain.

    if (LLMMode === 'direct') {
      result = await (tools.length > 0 ? modelWithTools : model).invoke(`
      ${systemPrompt}
      
      ${question}`);

      result = result.content;
    } else if (LLMMode === 'document-ref' || LLMMode === 'document')  {
      const res = await combineDocumentsChain.invoke(question);
      
      result = res.text? res.text: res;
      sources = res.sources;
    } else if (LLMMode === 'function') {
      result = await conversationalToolChain.invoke({
        question
      });
    } else if (LLMMode === 'full') {
      throw new Error('Not implemented.'); // TODO: #407.
    } else {
      GBLogEx.info(min, `Invalid Answer Mode in Config.xlsx: ${LLMMode}.`);
    }

    await memory.saveContext(
      {
        input: question
      },
      {
        output: result ? result.replace(/\!\[.*\)/gi, '') : 'no answer' // Removes .MD url beforing adding to history.
      }
    );

    GBLogEx.info(min, `GPT Result: ${result.toString()}`);
    return { answer: result.toString(), sources, questionId: 0, page };
  }

  private static getToolsAsText(tools) {
    return Object.keys(tools)
      .map(toolname => `- ${tools[toolname].name}: ${tools[toolname].description}`)
      .join('\n');
  }

  private static async getTools(min: GBMinInstance) {
    let functions = [];

    // Adds .gbdialog as functions if any to GPT Functions.
    await CollectionUtil.asyncForEach(Object.keys(min.scriptMap), async script => {
      const path = DialogKeywords.getGBAIPath(min.botId, 'gbdialog', null);
      const jsonFile = Path.join('work', path, `${script}.json`);

      if (Fs.existsSync(jsonFile) && script.toLowerCase() !== 'start.vbs') {
        const funcJSON = JSON.parse(Fs.readFileSync(jsonFile, 'utf8'));
        const funcObj = funcJSON?.function;

        if (funcObj) {
          // TODO: Use ajv.
          funcObj.schema = eval(jsonSchemaToZod(funcObj.parameters));
          functions.push(new DynamicStructuredTool(funcObj));
        }
      }
    });

    if (process.env.WIKIPEDIA_TOOL) {
      const tool = new WikipediaQueryRun({
        topKResults: 3,
        maxDocContentLength: 4000
      });
      functions.push(tool);
    }
    return functions;
  }
}