LexAI/entrypoints/background.ts

import { defineBackground } from 'wxt/sandbox';

export default defineBackground(() => {
  console.log('LexAI background service worker started');

  // Handle messages from content scripts
  chrome.runtime.onMessage.addListener((message, sender, sendResponse) => {
    if (message.type === 'ANALYZE_TEXT') {
      handleAnalyzeText(message.payload).then(sendResponse);
      return true; // Keep channel open for async response
    }
  });
});

async function handleAnalyzeText(payload: { text: string; action: string }) {
  try {
    const config = await chrome.storage.local.get(['provider', 'apiKey', 'model']);

    if (!config.apiKey) {
      return { error: 'No API key configured. Please open LexAI settings.' };
    }

    // Route to correct provider
    switch (config.provider) {
      case 'openai':
        return await callOpenAI(payload, config);
      case 'anthropic':
        return await callAnthropic(payload, config);
      case 'groq':
        return await callGroq(payload, config);
      default:
        return { error: 'Unknown provider. Please check settings.' };
    }
  } catch (err) {
    return { error: String(err) };
  }
}

async function callOpenAI(payload: { text: string; action: string }, config: any) {
  const res = await fetch('https://api.openai.com/v1/chat/completions', {
    method: 'POST',
    headers: {
      'Content-Type': 'application/json',
      'Authorization': `Bearer ${config.apiKey}`,
    },
    body: JSON.stringify({
      model: config.model || 'gpt-4o-mini',
      messages: [
        { role: 'system', content: getSystemPrompt(payload.action) },
        { role: 'user', content: payload.text },
      ],
    }),
  });
  const data = await res.json();
  return { result: data.choices?.[0]?.message?.content };
}

async function callAnthropic(payload: { text: string; action: string }, config: any) {
  const res = await fetch('https://api.anthropic.com/v1/messages', {
    method: 'POST',
    headers: {
      'Content-Type': 'application/json',
      'x-api-key': config.apiKey,
      'anthropic-version': '2023-06-01',
    },
    body: JSON.stringify({
      model: config.model || 'claude-3-5-haiku-20241022',
      max_tokens: 1024,
      system: getSystemPrompt(payload.action),
      messages: [{ role: 'user', content: payload.text }],
    }),
  });
  const data = await res.json();
  return { result: data.content?.[0]?.text };
}

async function callGroq(payload: { text: string; action: string }, config: any) {
  const res = await fetch('https://api.groq.com/openai/v1/chat/completions', {
    method: 'POST',
    headers: {
      'Content-Type': 'application/json',
      'Authorization': `Bearer ${config.apiKey}`,
    },
    body: JSON.stringify({
      model: config.model || 'llama-3.3-70b-versatile',
      messages: [
        { role: 'system', content: getSystemPrompt(payload.action) },
        { role: 'user', content: payload.text },
      ],
    }),
  });
  const data = await res.json();
  return { result: data.choices?.[0]?.message?.content };
}

function getSystemPrompt(action: string): string {
  const prompts: Record<string, string> = {
    grammar: 'You are a grammar checker. Fix grammar, spelling, and punctuation errors in the text. Return only the corrected text without explanations.',
    rephrase: 'You are a writing assistant. Rephrase the given text to be clearer and more professional. Return only the rephrased text.',
    tone: 'You are a writing coach. Analyze the tone of the text and suggest improvements. Be concise.',
    shorten: 'You are an editor. Shorten the text while keeping the key message. Return only the shortened version.',
    expand: 'You are a writer. Expand the given text with more detail and context. Return only the expanded version.',
  };
  return prompts[action] || prompts.grammar;
}