// MacroPlanner.js
// Node.js script skeleton for meal planning + nutritional analysis pipeline using USDA FoodData Central

const fs = require('fs');
const xlsx = require('xlsx');
const axios = require('axios');
require('dotenv').config();

// === CONFIG ===
const EXCEL_FILE = 'plantilla_plan_comidas.xlsx';
const SHEET_NAME = 'Semana 1';
const OPENAI_API_KEY = process.env.OPENAI_API_KEY;
const USDA_API_KEY = process.env.USDA_API_KEY;

// === STEP 1: Load Excel and parse meals ===
function parseMealsFromExcel(filePath, sheetName) {
    const workbook = xlsx.readFile(filePath);
    const sheet = workbook.Sheets[sheetName];
    const json = xlsx.utils.sheet_to_json(sheet, { defval: '' });
    return json.map(row => ({
        dia: row['Día'],
        desayuno: row['Desayuno'],
        comida: row['Comida'],
        cena: row['Cena']
    }));
}

// === STEP 2: Call ChatGPT to extract ingredients ===
async function getIngredientsFromMeal(description) {
    const prompt = `Extrae los ingredientes clave con cantidades aproximadas de esta comida: "${description}". Devuélvelo como lista en JSON con nombre y cantidad.`;

    const response = await axios.post('https://api.openai.com/v1/chat/completions', {
        model: 'gpt-4',
        messages: [{ role: 'user', content: prompt }],
        temperature: 0.2
    }, {
        headers: { 'Authorization': `Bearer ${OPENAI_API_KEY}` }
    });

    const text = response.data.choices[0].message.content;
    return JSON.parse(text);
}

// === STEP 3: Use USDA API to get nutrient info ===
async function getNutritionFromIngredients(ingredients) {
    let totals = { protein: 0, carbs: 0, fat: 0 };

    for (const item of ingredients) {
        try {
            const searchRes = await axios.get(`https://api.nal.usda.gov/fdc/v1/foods/search`, {
                params: {
                    api_key: USDA_API_KEY,
                    query: item.nombre,
                    pageSize: 1
                }
            });

            const food = searchRes.data.foods[0];
            if (!food || !food.fdcId) continue;

            const foodRes = await axios.get(`https://api.nal.usda.gov/fdc/v1/food/${food.fdcId}`, {
                params: { api_key: USDA_API_KEY }
            });

            for (const nutrient of foodRes.data.foodNutrients) {
                if (nutrient.nutrientName === 'Protein') totals.protein += nutrient.value;
                if (nutrient.nutrientName === 'Carbohydrate, by difference') totals.carbs += nutrient.value;
                if (nutrient.nutrientName === 'Total lipid (fat)') totals.fat += nutrient.value;
            }
        } catch (error) {
            console.warn(`Error retrieving data for ingredient: ${item.nombre}`, error.message);
        }
    }

    return totals;
}

// === STEP 4: Combine and write back to Excel ===
async function processAndWriteBack() {
    const meals = parseMealsFromExcel(EXCEL_FILE, SHEET_NAME);
    const updatedMeals = [];

    for (const entry of meals) {
        const daySummary = { ...entry, protein: 0, carbs: 0, fat: 0 };

        for (const meal of ['desayuno', 'comida', 'cena']) {
            if (!entry[meal]) continue;
            try {
                const ingredients = await getIngredientsFromMeal(entry[meal]);
                const macros = await getNutritionFromIngredients(ingredients);
                daySummary.protein += macros.protein;
                daySummary.carbs += macros.carbs;
                daySummary.fat += macros.fat;
            } catch (err) {
                console.error(`Error processing ${entry.dia} - ${meal}:`, err);
            }
        }

        updatedMeals.push({
            'Día': daySummary.dia,
            'Desayuno': entry.desayuno,
            'Comida': entry.comida,
            'Cena': entry.cena,
            'Proteínas (g)': daySummary.protein.toFixed(1),
            'Carbohidratos (g)': daySummary.carbs.toFixed(1),
            'Grasas (g)': daySummary.fat.toFixed(1)
        });
    }

    const newSheet = xlsx.utils.json_to_sheet(updatedMeals);
    const newBook = xlsx.utils.book_new();
    xlsx.utils.book_append_sheet(newBook, newSheet, SHEET_NAME);
    xlsx.writeFile(newBook, 'resultado_macros.xlsx');
    console.log('Macros calculados y archivo actualizado: resultado_macros.xlsx');
}

processAndWriteBack();