const formatProductNameForDisplay = (name) => {
    return String(name || '')
        .toLocaleLowerCase('pt-BR')
        .replace(/(^|[\s/-])(\p{L})/gu, (_, separator, letter) => {
            return `${separator}${letter.toLocaleUpperCase('pt-BR')}`;
        });
};

const formatProductList = (productNames) => {
    const displayNames = productNames.map(formatProductNameForDisplay);

    if (displayNames.length <= 2) {
        return displayNames.join(' e ');
    }

    return `${displayNames.slice(0, -1).join(', ')} e ${displayNames[displayNames.length - 1]}`;
};

const groupCampaignRowsByBaseProduct = (rows) => {
    return rows.reduce((acc, row) => {
        if (!acc[row.base_product_name]) acc[row.base_product_name] = [];
        acc[row.base_product_name].push(row);
        return acc;
    }, {});
};

const mapCampaignProducts = (groups) => {
    return Object.entries(groups)
        .sort(([, aItems], [, bItems]) => {
            return new Date(aItems[0].created_at).getTime() - new Date(bItems[0].created_at).getTime();
        })
        .map(([baseProductName, items]) => {
            const sortedItems = [...items].sort((a, b) => String(a.nome).localeCompare(String(b.nome), 'pt-BR'));

            return {
                baseProduct: formatProductNameForDisplay(baseProductName),
                total_delta: sortedItems.reduce((sum, item) => sum + Number(item.delta_estoque || 0), 0),
                sizes: sortedItems.map(item => ({
                    id: item.produto_id,
                    nome: item.nome,
                    delta: item.delta_estoque,
                    saldo: item.saldo
                })),
                itemIds: sortedItems.map(item => item.id)
            };
        });
};

const buildWhatsappCampaignPayload = (products, customers) => {
    const productNames = products.map(product => product.baseProduct);
    const productsText = formatProductList(productNames);
    const allSizes = products.flatMap(product => product.sizes);
    const totalDelta = products.reduce((sum, product) => sum + product.total_delta, 0);

    return {
        baseProduct: productsText,
        productsText,
        total_delta: totalDelta,
        sizes: allSizes,
        products: products.map(({ itemIds, ...product }) => product),
        customers
    };
};

const groupCampaignRows = (rows) => {
    return Object.values(rows.reduce((acc, row) => {
        const key = `${row.base_product_name}:${row.status}`;
        if (!acc[key]) {
            acc[key] = {
                key,
                baseProductName: row.base_product_name,
                status: row.status,
                totalDelta: 0,
                rowCount: 0,
                attempts: 0,
                lastError: null,
                createdAt: row.created_at,
                updatedAt: row.updated_at,
                sentAt: row.sent_at,
                items: []
            };
        }

        acc[key].totalDelta += Number(row.delta_estoque || 0);
        acc[key].rowCount += 1;
        acc[key].attempts = Math.max(acc[key].attempts, Number(row.attempts || 0));
        acc[key].lastError = row.last_error || acc[key].lastError;
        acc[key].createdAt = new Date(row.created_at) < new Date(acc[key].createdAt) ? row.created_at : acc[key].createdAt;
        acc[key].updatedAt = new Date(row.updated_at) > new Date(acc[key].updatedAt) ? row.updated_at : acc[key].updatedAt;
        acc[key].sentAt = row.sent_at || acc[key].sentAt;
        acc[key].items.push(row);
        return acc;
    }, {})).sort((a, b) => new Date(b.updatedAt).getTime() - new Date(a.updatedAt).getTime());
};

module.exports = {
    buildWhatsappCampaignPayload,
    formatProductNameForDisplay,
    formatProductList,
    groupCampaignRows,
    groupCampaignRowsByBaseProduct,
    mapCampaignProducts
};