const db = require("../config/database");
const ProductRepository = require("../repositories/ProductRepository");


function normalizeName(name) {
    return name.trim().toLowerCase().replace(/\s+/g, " ");
}


class MenuService {


    async generate(preferences) {
        const apiKey = process.env.OPENAI_API_KEY;
        if (!apiKey) {
            throw new Error("OPENAI_API_KEY ontbreekt in de configuratie.");
        }

        const response = await fetch("https://api.openai.com/v1/chat/completions", {
            method: "POST",
            headers: {
                "Content-Type": "application/json",
                Authorization: `Bearer ${apiKey}`
            },
            body: JSON.stringify({
                model: process.env.OPENAI_MODEL || "gpt-4o-mini",
                response_format: { type: "json_object" },
                messages: [
                    {
                        role: "system",
                        content: "Je maakt praktische weekmenu's. Geef uitsluitend geldige JSON terug met precies de structuur {days:[{day,recipe,ingredients:[{name,amount,unit}]}]}. Gebruik zeven dagen, Nederlandse productnamen, positieve numerieke hoeveelheden en korte recepten."
                    },
                    {
                        role: "user",
                        content: `Maak een weekmenu voor ${preferences.people} personen. Dieet: ${preferences.diet || "geen specifiek dieet"}. Niet gewenst: ${preferences.exclude || "niets"}. Budget: ${preferences.budget || "geen voorkeur"}.`
                    }
                ]
            })
        });

        if (!response.ok) {
            let providerMessage = "onbekende fout";
            try {
                const errorPayload = await response.json();
                providerMessage = errorPayload.error?.message || providerMessage;
            } catch (error) {
                providerMessage = `HTTP ${response.status}`;
            }
            throw new Error(`AI-service fout (${response.status}): ${providerMessage}`);
        }

        const payload = await response.json();
        if (!payload.choices?.[0]?.message?.content) {
            throw new Error("De AI-service gaf geen menu-inhoud terug.");
        }
        let menu;
        try {
            menu = JSON.parse(payload.choices?.[0]?.message?.content || "{}");
        } catch (error) {
            throw new Error("De AI-service gaf geen geldig menu terug.");
        }

        if (!Array.isArray(menu.days) || menu.days.length === 0) {
            throw new Error("De AI-service gaf een leeg menu terug.");
        }

        menu.days = menu.days.map(day => ({
            day: String(day.day || "Dag"),
            recipe: String(day.recipe || "Onbekend recept"),
            ingredients: Array.isArray(day.ingredients)
                ? day.ingredients
                    .filter(item => item && String(item.name || "").trim())
                    .map(item => ({
                        name: String(item.name).trim(),
                        amount: Number.isFinite(Number(item.amount)) ? Number(item.amount) : 1,
                        unit: String(item.unit || "")
                    }))
                : []
        }));

        return menu;
    }


    getNewProducts(menu) {
        const existingNames = new Set(
            ProductRepository.getAll().map(product => normalizeName(product.name))
        );
        const seen = new Set();
        const newProducts = [];

        for (const day of menu.days) {
            for (const ingredient of day.ingredients) {
                const key = normalizeName(ingredient.name);
                if (!existingNames.has(key) && !seen.has(key)) {
                    seen.add(key);
                    newProducts.push(ingredient.name);
                }
            }
        }

        return newProducts;
    }


    addToShoppingList(householdId, name, menu) {
        const products = ProductRepository.getAll();
        const productsByName = new Map(
            products.map(product => [normalizeName(product.name), product])
        );
        const insertProduct = db.prepare(`
            INSERT INTO products (name, category_id, barcode) VALUES (?, NULL, NULL)
        `);
        const insertList = db.prepare(`
            INSERT INTO shopping_lists (household_id, name) VALUES (?, ?)
        `);
        const insertItem = db.prepare(`
            INSERT INTO shopping_list_items (list_id, product_id, amount, sort_order)
            VALUES (?, ?, ?, ?)
        `);

        const create = db.transaction(() => {
            const listResult = insertList.run(householdId, name);
            const listId = listResult.lastInsertRowid;
            let sortOrder = 0;
            const added = new Set();

            for (const day of menu.days) {
                for (const ingredient of day.ingredients) {
                    const key = normalizeName(ingredient.name);
                    if (added.has(key)) continue;

                    let product = productsByName.get(key);
                    if (!product) {
                        const result = insertProduct.run(ingredient.name);
                        product = { id: result.lastInsertRowid, name: ingredient.name };
                        productsByName.set(key, product);
                    }

                    const amount = Number(ingredient.amount);
                    insertItem.run(listId, product.id, amount > 0 ? amount : 1, sortOrder);
                    added.add(key);
                    sortOrder += 1;
                }
            }

            return listId;
        });

        return create();
    }


}


module.exports = new MenuService();