smartai/ts/provider.perplexity.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 IPerplexityProviderOptions {
  perplexityToken: string;
}

export class PerplexityProvider extends MultiModalModel {
  private options: IPerplexityProviderOptions;

  constructor(optionsArg: IPerplexityProviderOptions) {
    super();
    this.options = optionsArg;
  }

  async start() {
    // Initialize any necessary clients or resources
  }

  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 Perplexity
        if (currentMessage) {
          const response = await fetch('https://api.perplexity.ai/chat/completions', {
            method: 'POST',
            headers: {
              'Authorization': `Bearer ${this.options.perplexityToken}`,
              'Content-Type': 'application/json',
            },
            body: JSON.stringify({
              model: 'mixtral-8x7b-instruct',
              messages: [{ role: currentMessage.role, content: currentMessage.content }],
              stream: true,
            }),
          });

          // Process each chunk from Perplexity
          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.startsWith('data: ')) {
                    const data = line.slice(6);
                    if (data === '[DONE]') break;

                    try {
                      const parsed = JSON.parse(data);
                      const content = parsed.choices[0]?.delta?.content;
                      if (content) {
                        controller.enqueue(content);
                      }
                    } catch (e) {
                      console.error('Failed to parse SSE data:', 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> {
    // Make API call to Perplexity
    const response = await fetch('https://api.perplexity.ai/chat/completions', {
      method: 'POST',
      headers: {
        'Authorization': `Bearer ${this.options.perplexityToken}`,
        'Content-Type': 'application/json',
      },
      body: JSON.stringify({
        model: 'mixtral-8x7b-instruct',  // Using Mixtral model
        messages: [
          { role: 'system', content: optionsArg.systemMessage },
          ...optionsArg.messageHistory,
          { role: 'user', content: optionsArg.userMessage }
        ],
      }),
    });

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

    const result = await response.json();
    
    return {
      role: 'assistant' as const,
      message: result.choices[0].message.content,
    };
  }

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