1 files changed, 322 insertions, 0 deletions
diff --git a/backend/instance/chat.ts b/backend/instance/chat.ts
new file mode 100644
index 0000000..c0cef4f
--- /dev/null
+++ b/backend/instance/chat.ts
@@ -0,0 +1,322 @@
+import fs from 'fs';
+import crypto from 'crypto';
+import { LlamaTokenizer } from 'llama-tokenizer-js';
+
+import { ChatMsg, ChatOptions, ChatStream, ModelInfo } from './api-defs.js';
+import * as api from './api-connection.js';
+import * as notes from './notes.js';
+import * as tools from './tools.js';
+import * as u from './utils.js';
+
+export type Msg = ChatMsg;
+export type Stream = ChatStream;
+export type Options = ChatOptions;
+
+let CONTEXT_WINDOW = 12000;
+let CHAT_DIR = `../data/chats`;
+
+const tokenizer = new LlamaTokenizer();
+
+export async function setConfig( config: any ) {
+  if( config.contextWindow ) CONTEXT_WINDOW = config.contextWindow;
+  if( config.chatDir ) CHAT_DIR = config.chatDir;
+}
+
+const TITLE_GEN_MODEL = "qwen25-custom-1b";
+
+async function generateTitle( firstMsg: Msg, response: string ) {
+  const prompt =
+`Your purpose is to generate a title for a chat given the beginning of a conversation between a user and a chatbot.
+The title should be a short summary of the topic, no longer than 50 characters.
+Output the title between <TITLE></TITLE> tags.
+
+<MESSAGE_LIST>
+user: ${firstMsg.content}
+
+chatbot: ${response}
+</MESSAGE_LIST>
+
+`
+  const model = {
+    modelname: TITLE_GEN_MODEL
+  } as ModelInfo;
+
+  let res = await generate( prompt, '', { model } as Options );
+  const eraselist = [
+    "<TITLE>",
+    "</TITLE>",
+    "<title>",
+    "</title>",
+    "title: "
+  ];
+  for( let key of eraselist )
+    res = res.replace( key, "" );
+
+  return res;
+}
+
+export async function run(
+  msgs: Msg[],
+  options: Options,
+  ignoreOutput: boolean,
+  notelist: notes.Note[],
+  onChunk: Function
+) : Promise<Msg> {
+  const ctx = parseMsgs( msgs, options, notelist );
+  const body = {
+    model: options.model.modelname,
+    messages: ctx
+  };
+
+  const res = await fetch( "http://127.0.0.1:11434/api/chat", {
+    method: 'POST',
+    headers: { 'Content-Type': 'application/json' },
+    body: JSON.stringify( body )
+  } );
+
+  if( !res.ok ) {
+    console.error( res );
+    throw new Error( "failed to receive response " + res.status );
+  }
+
+  const reader = res.body?.getReader();
+  if( !reader ) throw new Error( 'cannot get reader' );
+
+  api.serverNotify( { loadedModel: options.model.name } );
+  let content = ''
+  let toolBuffer = '';
+  let toolCall: tools.Call | undefined = undefined;
+  /** this is messy as fuck but u cant pass req body as param so whatever */
+  for( let read = await reader.read(); !read.done; read = await reader.read() ) {
+    const parsed = u.parseChunkedJson( read, ( json: any ) : boolean | void => {
+      if( !json.message ) return true;
+      let msg = json.message.content;
+      toolBuffer += msg;
+      if( tools.isToolStr( toolBuffer ) ) {
+        try {
+          toolCall = JSON.parse( toolBuffer );
+          if( toolCall ) {
+            content += toolBuffer;
+            return true;
+          }
+        } catch( e ) {}
+        return;
+      }
+
+      msg = toolBuffer;
+      toolBuffer = '';
+      content += msg;
+
+      if( !ignoreOutput ) {
+        process.stdout.write( msg );
+        onChunk( msg );
+      }
+    } );
+
+    if( !parsed || read.done )
+      break;
+  }
+
+  console.log();
+  const ret: Msg = {
+    timestamp: u.getTimestamp(),
+    role: 'assistant',
+    content,
+    toolCall
+  };
+
+  if( options.generateTitle && msgs.length == 1 ) {
+    // "not busy" notif sent by generate func
+    const title = await generateTitle( msgs[0], content );
+    ret.title = title;
+  }
+  else {
+    api.serverNotify( { loadedModel: options.model.name, isBusy: false } );
+  }
+  return ret;
+}
+
+export async function generate( prompt: string, suffix: string, options: Options, onChunk: Function = () => {} ) : Promise<string> {
+  const body = {
+    model: options.model.modelname,
+    system: options.system ? getFullSystem( options, [] ) : '',
+    prompt,
+    suffix
+  };
+
+  const res = await fetch( `http://127.0.0.1:11434/api/generate`, {
+    method: 'POST',
+    headers: { 'Content-Type': 'application/json' },
+    body: JSON.stringify( body )
+  } );
+
+  if( !res.ok ) {
+    console.error( res );
+    if( res.body )
+      console.log( await res.text() );
+    throw new Error( "failed to receive response" + res.status );
+  }
+
+  const reader = res.body?.getReader();
+  if( !reader ) throw new Error( 'cannot get reader' );
+
+  api.serverNotify( { loadedModel: options.model.name, isBusy: true } );
+  let content = '';
+  for( let read = await reader.read(); !read.done; read = await reader.read() ) {
+    const parsed = u.parseChunkedJson( read, ( json: any ) : boolean | void => {
+      let msg = json.response;
+      if( !msg ) return true;
+      content += msg;
+      process.stdout.write( msg );
+      onChunk( msg );
+    } );
+
+    if( !parsed || read.done )
+      break;
+  }
+  api.serverNotify( { loadedModel: options.model.name, isBusy: false } );
+
+  console.log();
+  return content;
+}
+
+export function save( msglog: Msg[], uuid: string ) {
+  const chatfile = `${CHAT_DIR}/${uuid}.json`;
+  const chatJson = JSON.stringify( msglog );
+
+  const salt = crypto.randomBytes( 16 );
+  const key = crypto.pbkdf2Sync( u.jwt_secret(), salt, 100000, 32, 'sha512' );
+  const iv = crypto.randomBytes( 12 );
+
+  const cipher = crypto.createCipheriv( 'aes-256-gcm', key, iv );
+  let encrypted = cipher.update( chatJson, 'utf8', 'hex' );
+  encrypted += cipher.final( 'hex' );
+  const authTag = cipher.getAuthTag().toString( 'hex' );
+
+  let fullStr = salt.toString( 'hex' ) + iv.toString( 'hex' ) + authTag + encrypted;
+
+  fs.writeFileSync( chatfile, fullStr );
+  console.log( "== [ chat saved ] ==" );
+}
+
+export function load( filename: string ) : Msg[] {
+  const chatfile = `${CHAT_DIR}/${filename}.json`;
+  try {
+    const contents = fs.readFileSync( chatfile, 'utf8' );
+    const salt = Buffer.from( contents.slice( 0, 32 ), 'hex' );
+    const iv = Buffer.from( contents.slice( 32, 56 ), 'hex' );
+    const authTag = Buffer.from( contents.slice( 56, 88 ), 'hex' );
+    const data = contents.slice( 88 );
+
+    const key = crypto.pbkdf2Sync( u.jwt_secret(), salt, 100000, 32, 'sha512' );
+    const decipher = crypto.createDecipheriv( 'aes-256-gcm', key, iv );
+    decipher.setAuthTag( authTag );
+
+    let decrypted = decipher.update( data, 'hex', 'utf8' );
+    decrypted += decipher.final( 'utf8' );
+
+    return JSON.parse( decrypted );
+  } catch( e ) {
+    return [];
+  }
+}
+
+export function parseMsgs( msgs: Msg[], options: Options, notelist: notes.Note[] ) : Msg[] {
+  let padTokens = 0;
+  let fullSystem = '';
+
+  if( options.system ) {
+    fullSystem = getFullSystem( options, notelist );
+  }
+
+  let res = truncateMsgs( msgs, padTokens );
+
+  if( fullSystem.length > 1 ) {
+    res.unshift( {
+      timestamp: u.getTimestamp(),
+      role: 'system',
+      content: fullSystem
+    } );
+  }
+
+  return res;
+}
+
+export function getFullSystem( options: Options, notelist: notes.Note[] ) : string {
+  if( !options.system )
+    return '';
+
+  let notesPrompt = notes.getPromptStr( notelist );
+  let fullSystem = '';
+  if( options.system.model )
+    fullSystem += options.system.model;
+  if( options.system.user )
+    fullSystem += options.system.user;
+
+  fullSystem = fullSystem.replace( '<|system_time|>', `the current system time is ${u.getTimestamp()}.` );
+  fullSystem = fullSystem.replace( '<|tools_list|>', tools.getPromptStr( options ) );
+  fullSystem = fullSystem.replace( '<|notes_str|>', notesPrompt );
+
+  return fullSystem;
+};
+
+function parseMsgFiles( msg: Msg ) : string {
+  if( !msg.files || !msg.files.length ) return '';
+
+  let files = msg.files;
+  let attachmentStr = 'attached files:';
+  for( let [key, f] of Object.entries( files ) ) {
+    if( f.type != 'text' )
+      continue;
+
+    attachmentStr += `\n\n[file: ${f.name}]\n`;
+    attachmentStr += f.content;
+  }
+
+  return attachmentStr;
+}
+
+function truncateMsgs( msgs: Msg[], reservedTokens: number ) : Msg[] {
+  let maxTokens = CONTEXT_WINDOW - 768 - reservedTokens;
+  let totalTokens = 0;
+  let totalLength = 0;
+  let loopEnd = false;
+
+  let start = Date.now();
+
+  let ret: Msg[] = [];
+  for( let i = msgs.length - 1; i >= 0; --i ) {
+    // javascript is fucking stupid.
+    let msg = JSON.parse( JSON.stringify( msgs[i] ) );
+    let content = msg.content + parseMsgFiles( msg );
+
+    let tokens = tokenizer.encode( content );
+
+    if( totalTokens + tokens.length > maxTokens ) {
+      if( content.length <= 20 )
+        break;
+
+      let diff = totalTokens + tokens.length + 10 - maxTokens;
+      let lenPercentage = diff / ( tokens.length + 10 );
+
+      let newLen = Math.floor( content.length * lenPercentage );
+      content = "<MESSAGE TRUNCATED>..." + content.slice( content.length - newLen );
+      loopEnd = true;
+    }
+
+    totalLength += content.length;
+    totalTokens += tokens.length + 2;
+
+    delete msg.files;
+    msg.content = content;
+    ret.unshift( msg );
+    if( loopEnd )
+      break;
+  }
+
+  let end = Date.now();
+  console.log( `tokenized ${ret.length} messages in ${end - start}ms` );
+
+  return ret;
+}
+