smartai/ts/provider.ollama.ts

import * as plugins from './plugins.js';
import * as paths from './paths.js';
import { MultiModalModel } from './abstract.classes.multimodal.js';
import type { ChatOptions, ChatResponse, ChatMessage } from './abstract.classes.multimodal.js';

export interface IOllamaProviderOptions {
  baseUrl?: string;
  model?: string;
}

export class OllamaProvider extends MultiModalModel {
  private options: IOllamaProviderOptions;
  private baseUrl: string;
  private model: string;

  constructor(optionsArg: IOllamaProviderOptions = {}) {
    super();
    this.options = optionsArg;
    this.baseUrl = optionsArg.baseUrl || 'http://localhost:11434';
    this.model = optionsArg.model || 'llama2';
  }

  async start() {
    // Verify Ollama is running
    try {
      const response = await fetch(`${this.baseUrl}/api/tags`);
      if (!response.ok) {
        throw new Error('Failed to connect to Ollama server');
      }
    } catch (error) {
      throw new Error(`Failed to connect to Ollama server at ${this.baseUrl}: ${error.message}`);
    }
  }

  async stop() {}

  public async chatStream(input: ReadableStream<Uint8Array>): Promise<ReadableStream<string>> {
    // Create a TextDecoder to handle incoming chunks
    const decoder = new TextDecoder();
    let buffer = '';
    let currentMessage: { role: string; content: string; } | null = null;

    // Create a TransformStream to process the input
    const transform = new TransformStream<Uint8Array, string>({
      async transform(chunk, controller) {
        buffer += decoder.decode(chunk, { stream: true });

        // Try to parse complete JSON messages from the buffer
        while (true) {
          const newlineIndex = buffer.indexOf('\n');
          if (newlineIndex === -1) break;

          const line = buffer.slice(0, newlineIndex);
          buffer = buffer.slice(newlineIndex + 1);

          if (line.trim()) {
            try {
              const message = JSON.parse(line);
              currentMessage = {
                role: message.role || 'user',
                content: message.content || '',
              };
            } catch (e) {
              console.error('Failed to parse message:', e);
            }
          }
        }

        // If we have a complete message, send it to Ollama
        if (currentMessage) {
          const response = await fetch(`${this.baseUrl}/api/chat`, {
            method: 'POST',
            headers: {
              'Content-Type': 'application/json',
            },
            body: JSON.stringify({
              model: this.model,
              messages: [{ role: currentMessage.role, content: currentMessage.content }],
              stream: true,
            }),
          });

          // Process each chunk from Ollama
          const reader = response.body?.getReader();
          if (reader) {
            try {
              while (true) {
                const { done, value } = await reader.read();
                if (done) break;

                const chunk = new TextDecoder().decode(value);
                const lines = chunk.split('\n');

                for (const line of lines) {
                  if (line.trim()) {
                    try {
                      const parsed = JSON.parse(line);
                      const content = parsed.message?.content;
                      if (content) {
                        controller.enqueue(content);
                      }
                    } catch (e) {
                      console.error('Failed to parse Ollama response:', e);
                    }
                  }
                }
              }
            } finally {
              reader.releaseLock();
            }
          }

          currentMessage = null;
        }
      },

      flush(controller) {
        if (buffer) {
          try {
            const message = JSON.parse(buffer);
            controller.enqueue(message.content || '');
          } catch (e) {
            console.error('Failed to parse remaining buffer:', e);
          }
        }
      }
    });

    // Connect the input to our transform stream
    return input.pipeThrough(transform);
  }

  // Implementing the synchronous chat interaction
  public async chat(optionsArg: ChatOptions): Promise<ChatResponse> {
    // Format messages for Ollama
    const messages = [
      { role: 'system', content: optionsArg.systemMessage },
      ...optionsArg.messageHistory,
      { role: 'user', content: optionsArg.userMessage }
    ];

    // Make API call to Ollama
    const response = await fetch(`${this.baseUrl}/api/chat`, {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json',
      },
      body: JSON.stringify({
        model: this.model,
        messages: messages,
        stream: false
      }),
    });

    if (!response.ok) {
      throw new Error(`Ollama API error: ${response.statusText}`);
    }

    const result = await response.json();
    
    return {
      role: 'assistant' as const,
      message: result.message.content,
    };
  }

  public async audio(optionsArg: { message: string }): Promise<NodeJS.ReadableStream> {
    throw new Error('Audio generation is not supported by Ollama.');
  }
}