kidsai/html/kidsai/server_backup.js

const express = require('express');
const cors = require('cors');
const path = require('path');
const fetch = require('node-fetch');
const OpenAI = require('openai');

// Load environment variables from .env file
require('dotenv').config();

const app = express();
const PORT = process.env.PORT || 3002;

// OpenAI Configuration (Primary AI service)
const openai = new OpenAI({
    apiKey: process.env.OPENAI_API_KEY
});

// Hugging Face API configuration (Backup)
const HF_MODELS = [
    'microsoft/DialoGPT-small',           // Smaller, more reliable model
    'google/flan-t5-small',               // Good for instructions
    'facebook/blenderbot-400M-distill',   // Conversational AI
    'microsoft/DialoGPT-medium'           // Original choice
];

const HF_API_TOKEN = process.env.HUGGING_FACE_TOKEN;

// Educational prompts for AI to guide thinking instead of giving direct answers
const EDUCATIONAL_PROMPTS = {
    en: {
        systemPrompt: "You are an educational assistant for children. Instead of giving direct answers, ask 2-3 guiding questions that help children think through the problem themselves. Be encouraging and use simple language. Focus on the thinking process, not the answer.",
        prefix: "That's a great question! Let me help you think through this step by step. Instead of telling you the answer, here are some questions to guide your thinking:"
    },
    de: {
        systemPrompt: "Du bist ein Lernassistent für Kinder. Anstatt direkte Antworten zu geben, stelle 2-3 Leitfragen, die Kindern helfen, das Problem selbst zu durchdenken. Sei ermutigend und verwende einfache Sprache. Konzentriere dich auf den Denkprozess, nicht auf die Antwort.",
        prefix: "Das ist eine tolle Frage! Lass mich dir helfen, Schritt für Schritt darüber nachzudenken. Anstatt dir die Antwort zu sagen, hier sind einige Fragen, die dein Denken leiten:"
    }
};

// Middleware
app.use(cors());
app.use(express.json());
app.use(express.static('.'));

// Serve the main page
app.get('/', (req, res) => {
    res.sendFile(path.join(__dirname, 'index.html'));
});

// API endpoint for AI-powered educational guidance
app.post('/api/ask', async (req, res) => {
    const { question, language = 'en' } = req.body;
    
    if (!question || question.trim().length === 0) {
        return res.status(400).json({
            success: false,
            error: 'Question is required'
        });
    }

    try {
        // Get AI-powered guidance
        const aiGuidance = await getAIGuidance(question, language);
        
        res.json({
            success: true,
            guidance: aiGuidance,
            question: question,
            language: language
        });

    } catch (error) {
        console.error('AI API Error:', error);
        
        // Fallback to rule-based guidance if AI fails
        const fallbackGuidance = getFallbackGuidance(question, language);
        
        res.json({
            success: true,
            guidance: fallbackGuidance,
            question: question,
            language: language,
            fallback: true
        });
    }
});

// Function to get OpenAI-powered educational guidance (Primary)
async function getOpenAIGuidance(question, language) {
    console.log('🤖 Calling OpenAI with GPT-3.5-turbo...');
    
    const isGerman = language === 'de';
    
    const systemPrompt = isGerman 
        ? "Du bist ein pädagogischer Assistent für Kinder. Anstatt direkte Antworten zu geben, stellst du 3-4 durchdachte Leitfragen, die Kindern helfen, selbst über das Problem nachzudenken. Verwende einfache Sprache, sei ermutigend und konzentriere dich auf den Denkprozess. Formatiere als nummerierte Liste."
        : "You are an educational assistant for children. Instead of giving direct answers, provide 3-4 thoughtful guiding questions that help children think through the problem themselves. Use simple language, be encouraging, and focus on the thinking process. Format as a numbered list.";

    const userPrompt = isGerman 
        ? `Ein Kind hat gefragt: "${question}". Hilf ihm dabei, selbst über die Antwort nachzudenken, indem du Leitfragen stellst.`
        : `A child asked: "${question}". Help them think through the answer themselves by providing guiding questions.`;

    try {
        const completion = await openai.chat.completions.create({
            model: "gpt-3.5-turbo",
            messages: [
                { role: "system", content: systemPrompt },
                { role: "user", content: userPrompt }
            ],
            max_tokens: 200,
            temperature: 0.7
        });

        const aiResponse = completion.choices[0]?.message?.content || '';
        console.log('✅ OpenAI response received:', aiResponse.substring(0, 100) + '...');

        // Parse the response into steps
        const steps = parseOpenAIResponseToSteps(aiResponse, language);

        return {
            type: 'ai-powered',
            steps: steps,
            encouragement: getRandomEncouragement(language),
            source: 'OpenAI GPT-3.5'
        };

    } catch (error) {
        console.log('❌ OpenAI error:', error.message);
        throw error;
    }
}

// Function to parse OpenAI response into thinking steps
function parseOpenAIResponseToSteps(text, language) {
    const lines = text.split('\n').filter(line => line.trim());
    const steps = [];
    
    lines.forEach((line, index) => {
        const trimmed = line.trim();
        // Look for numbered items or questions
        if (trimmed && (trimmed.match(/^\d+\./) || trimmed.includes('?') || trimmed.length > 10)) {
            // Clean up numbering and formatting
            const cleaned = trimmed.replace(/^\d+\.\s*/, '').replace(/^-\s*/, '').trim();
            if (cleaned.length > 5) {
                steps.push({
                    id: steps.length + 1,
                    text: cleaned,
                    type: 'question'
                });
            }
        }
    });
    
    // Ensure we have at least 2 steps
    if (steps.length < 2) {
        const fallback = getFallbackGuidance('', language);
        return fallback.steps.slice(0, 3);
    }
    
    return steps.slice(0, 4); // Limit to 4 steps max
}

// Function to get AI-powered educational guidance with model fallbacks (Backup)
async function getHuggingFaceGuidance(question, language) {
    console.log('🤖 Trying Hugging Face as backup...');
    
    // Try each model until one works
    for (let i = 0; i < HF_MODELS.length; i++) {
        const model = HF_MODELS[i];
        const apiUrl = `https://api-inference.huggingface.co/models/${model}`;
        
        try {
            console.log(`📡 Trying model ${i + 1}/${HF_MODELS.length}: ${model}`);
            
            // Create educational prompt
            const educationalPrompt = `Help a child think about this question: "${question}". 
Don't give the answer. Instead, ask 3 guiding questions that help them discover it themselves.
Format: 1. [question] 2. [question] 3. [question]`;

            const response = await fetch(apiUrl, {
                method: 'POST',
                headers: {
                    'Authorization': HF_API_TOKEN ? `Bearer ${HF_API_TOKEN}` : undefined,
                    'Content-Type': 'application/json',
                },
                body: JSON.stringify({
                    inputs: educationalPrompt,
                    parameters: {
                        max_length: 120,
                        temperature: 0.8,
                        do_sample: true,
                        pad_token_id: 50256
                    }
                })
            });

            if (response.ok) {
                const data = await response.json();
                
                // Check if the model is still loading
                if (data.error && data.error.includes('loading')) {
                    console.log(`⏳ Model ${model} is loading, trying next...`);
                    continue;
                }
                
                if (data.error) {
                    console.log(`❌ Model ${model} error:`, data.error);
                    continue;
                }

                console.log(`✅ Success with model ${model}`);
                
                // Extract and format the AI response
                let aiText = data[0]?.generated_text || '';
                
                if (aiText.trim().length > 10) {
                    const steps = parseAIResponseToSteps(aiText, language);
                    
                    return {
                        type: 'ai-powered',
                        steps: steps,
                        encouragement: getRandomEncouragement(language),
                        source: `Hugging Face (${model.split('/')[1]})`
                    };
                }
            }
            
        } catch (error) {
            console.log(`⚠️ Model ${model} failed:`, error.message);
            continue;
        }
    }
    
    // If all models fail, throw error to trigger fallback
    throw new Error('All Hugging Face models are currently unavailable');
}

// Updated main function that tries OpenAI first, then Hugging Face, then local fallback
async function getAIGuidance(question, language) {
    // Try OpenAI first (most reliable)
    if (process.env.OPENAI_API_KEY) {
        try {
            return await getOpenAIGuidance(question, language);
        } catch (error) {
            console.log('⚠️ OpenAI failed, trying Hugging Face...');
        }
    }
    
    // Try Hugging Face as backup
    if (process.env.HUGGING_FACE_TOKEN) {
        try {
            return await getHuggingFaceGuidance(question, language);
        } catch (error) {
            console.log('⚠️ Hugging Face failed, using local fallback...');
        }
    }
    
    // Final fallback - this will throw error to trigger local guidance
    throw new Error('All AI services are currently unavailable');
}
    
    // Try each model until one works
    for (let i = 0; i < HF_MODELS.length; i++) {
        const model = HF_MODELS[i];
        const apiUrl = `https://api-inference.huggingface.co/models/${model}`;
        
        try {
            console.log(`📡 Trying model ${i + 1}/${HF_MODELS.length}: ${model}`);
            
            // Create educational prompt
            const educationalPrompt = `Help a child think about this question: "${question}". 
Don't give the answer. Instead, ask 3 guiding questions that help them discover it themselves.
Format: 1. [question] 2. [question] 3. [question]`;

            const response = await fetch(apiUrl, {
                method: 'POST',
                headers: {
                    'Authorization': HF_API_TOKEN ? `Bearer ${HF_API_TOKEN}` : undefined,
                    'Content-Type': 'application/json',
                },
                body: JSON.stringify({
                    inputs: educationalPrompt,
                    parameters: {
                        max_length: 120,
                        temperature: 0.8,
                        do_sample: true,
                        pad_token_id: 50256
                    }
                })
            });

            console.log(`<EFBFBD> Model ${model} response status:`, response.status);

            if (response.ok) {
                const data = await response.json();
                
                // Check if the model is still loading
                if (data.error && data.error.includes('loading')) {
                    console.log(`⏳ Model ${model} is loading, trying next...`);
                    continue;
                }
                
                if (data.error) {
                    console.log(`❌ Model ${model} error:`, data.error);
                    continue;
                }

                console.log(`✅ Success with model ${model}:`, JSON.stringify(data, null, 2));
                
                // Extract and format the AI response
                let aiText = data[0]?.generated_text || '';
                
                if (aiText.trim().length > 10) {
                    const steps = parseAIResponseToSteps(aiText, language);
                    
                    return {
                        type: 'ai-powered',
                        steps: steps,
                        encouragement: getRandomEncouragement(language),
                        source: `Hugging Face AI (${model.split('/')[1]})`
                    };
                }
            } else {
                const errorText = await response.text();
                console.log(`❌ Model ${model} HTTP error ${response.status}:`, errorText);
            }
            
        } catch (error) {
            console.log(`⚠️ Model ${model} failed:`, error.message);
            continue;
        }
    }
    
    // If all models fail, throw error to trigger fallback
    throw new Error('All AI models are currently unavailable');
}

// Function to parse AI response into thinking steps
function parseAIResponseToSteps(text, language) {
    const lines = text.split('\n').filter(line => line.trim());
    const steps = [];
    
    lines.forEach((line, index) => {
        const trimmed = line.trim();
        if (trimmed && trimmed.length > 10) {
            // Remove numbering if present
            const cleaned = trimmed.replace(/^\d+\.\s*/, '').replace(/^-\s*/, '');
            if (cleaned.length > 5) {
                steps.push({
                    id: index + 1,
                    text: cleaned,
                    type: 'question'
                });
            }
        }
    });
    
    // Ensure we have at least 2 steps
    if (steps.length < 2) {
        const fallback = getFallbackGuidance('', language);
        return fallback.steps.slice(0, 3);
    }
    
    return steps.slice(0, 4); // Limit to 4 steps max
}

// Fallback guidance for when AI is unavailable
function getFallbackGuidance(question, language) {
    const isGerman = language === 'de';
    
    const fallbackSteps = isGerman ? [
        { id: 1, text: "Was weißt du bereits über dieses Thema?", type: 'question' },
        { id: 2, text: "Welche Teile der Frage verstehst du, und welche sind unklar?", type: 'question' },
        { id: 3, text: "Wo könntest du mehr Informationen finden?", type: 'question' },
        { id: 4, text: "Kannst du das Problem in kleinere Teile aufteilen?", type: 'question' }
    ] : [
        { id: 1, text: "What do you already know about this topic?", type: 'question' },
        { id: 2, text: "Which parts of the question do you understand, and which are unclear?", type: 'question' },
        { id: 3, text: "Where could you find more information about this?", type: 'question' },
        { id: 4, text: "Can you break this problem down into smaller parts?", type: 'question' }
    ];

    return {
        type: 'rule-based',
        steps: fallbackSteps,
        encouragement: getRandomEncouragement(language),
        source: 'Educational Framework'
    };
}

// Get random encouragement
function getRandomEncouragement(language) {
    const encouragements = language === 'de' ? [
        "Großartige Frage! Du denkst wie ein echter Forscher! 🔬",
        "Super! Lass uns das zusammen herausfinden! 🚀",
        "Wow, das ist eine kluge Frage! 🤔",
        "Du bist auf dem richtigen Weg! 🌟"
    ] : [
        "Great question! You're thinking like a real scientist! 🔬",
        "Awesome! Let's figure this out together! 🚀",
        "Wow, that's a smart question! 🤔",
        "You're on the right track! 🌟"
    ];
    
    return encouragements[Math.floor(Math.random() * encouragements.length)];
}

// Health check endpoint
app.get('/api/health', (req, res) => {
    res.json({ status: 'healthy', timestamp: new Date().toISOString() });
});

app.listen(PORT, () => {
    console.log(`🚀 KidsAI Explorer server running on port ${PORT}`);
    console.log(`📖 Visit http://localhost:${PORT} to start exploring!`);
});

module.exports = app;