supabase/functions/guess-word/index.ts

import { serve } from "https://deno.land/[email protected]/http/server.ts";
import { Mistral } from "npm:@mistralai/mistralai";

const corsHeaders = {
  'Access-Control-Allow-Origin': '*',
  'Access-Control-Allow-Headers': 'authorization, x-client-info, apikey, content-type',
};

const languagePrompts = {
  en: {
    systemPrompt: "You are helping in a word guessing game. Given a description, guess what single word is being described.",
    instruction: "Based on this description"
  },
  fr: {
    systemPrompt: "Vous aidez dans un jeu de devinettes. À partir d'une description, devinez le mot unique qui est décrit.",
    instruction: "D'après cette description"
  },
  de: {
    systemPrompt: "Sie helfen bei einem Worträtsel. Erraten Sie anhand einer Beschreibung, welches einzelne Wort beschrieben wird.",
    instruction: "Basierend auf dieser Beschreibung"
  },
  it: {
    systemPrompt: "Stai aiutando in un gioco di indovinelli. Data una descrizione, indovina quale singola parola viene descritta.",
    instruction: "Basandoti su questa descrizione"
  },
  es: {
    systemPrompt: "Estás ayudando en un juego de adivinanzas. Dada una descripción, adivina qué palabra única se está describiendo.",
    instruction: "Basándote en esta descripción"
  }
};

const openRouterModels = [
  'sophosympatheia/rogue-rose-103b-v0.2:free',
  'google/gemini-2.0-flash-exp:free',
  'meta-llama/llama-3.1-70b-instruct:free',
  'microsoft/phi-3-medium-128k-instruct:free'
];

async function tryMistral(sentence: string, language: string) {
  const client = new Mistral({
    apiKey: Deno.env.get('MISTRAL_API_KEY'),
  });

  const prompts = languagePrompts[language as keyof typeof languagePrompts] || languagePrompts.en;

  const response = await client.chat.complete({
    model: "mistral-large-latest",
    messages: [
      {
        role: "system",
        content: `${prompts.systemPrompt} Respond with ONLY the word you think is being described, in uppercase letters. Do not add any explanation or punctuation.`
      },
      {
        role: "user",
        content: `${prompts.instruction} "${sentence}"`
      }
    ],
    maxTokens: 50,
    temperature: 0.1
  });

  return response.choices[0].message.content.trim().toUpperCase();
}

async function tryOpenRouter(sentence: string, language: string) {
  const prompts = languagePrompts[language as keyof typeof languagePrompts] || languagePrompts.en;
  const randomModel = openRouterModels[Math.floor(Math.random() * openRouterModels.length)];

  console.log('Trying OpenRouter with model:', randomModel);

  const response = await fetch("https://openrouter.ai/api/v1/chat/completions", {
    method: "POST",
    headers: {
      "Authorization": `Bearer ${Deno.env.get('OPENROUTER_API_KEY')}`,
      "HTTP-Referer": "https://think-in-sync.com",
      "X-Title": "Think in Sync",
      "Content-Type": "application/json"
    },
    body: JSON.stringify({
      model: randomModel,
      messages: [
        {
          role: "system",
          content: `${prompts.systemPrompt} Respond with ONLY the word you think is being described, in uppercase letters. Do not add any explanation or punctuation.`
        },
        {
          role: "user",
          content: `${prompts.instruction} "${sentence}"`
        }
      ]
    })
  });

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

  const data = await response.json();
  return data.choices[0].message.content.trim().toUpperCase();
}

serve(async (req) => {
  if (req.method === 'OPTIONS') {
    return new Response(null, { headers: corsHeaders });
  }

  try {
    const { sentence, language = 'en' } = await req.json();
    console.log('Trying to guess word from sentence:', sentence, 'language:', language);

    try {
      console.log('Attempting with Mistral...');
      const guess = await tryMistral(sentence, language);
      console.log('Successfully generated guess with Mistral:', guess);
      return new Response(
        JSON.stringify({ guess }),
        { headers: { ...corsHeaders, 'Content-Type': 'application/json' } }
      );
    } catch (mistralError) {
      console.error('Mistral error:', mistralError);
      console.log('Falling back to OpenRouter...');
      
      const guess = await tryOpenRouter(sentence, language);
      console.log('Successfully generated guess with OpenRouter:', guess);
      return new Response(
        JSON.stringify({ guess }),
        { headers: { ...corsHeaders, 'Content-Type': 'application/json' } }
      );
    }
  } catch (error) {
    console.error('Error generating guess:', error);
    return new Response(
      JSON.stringify({ error: error.message }),
      { 
        status: 500,
        headers: { ...corsHeaders, 'Content-Type': 'application/json' }
      }
    );
  }
});