const advancedResult =(model)=> async (req, res, next) => {
    //search : l'information que je cherche
    //fields : les colonnes je veux utiliser pour la recherche

    const fields = req.query.fields;
    const search = req.query.search;
    let page = req.query.page;
    let rows = req.query.rows;

    let reqQuery = {...req.query};
    const noField = ['page','rows', 'fields', 'search','sort','select'];
    noField.forEach(param=> delete reqQuery[param]);

    //4. Create query string
    let queryStr = JSON.stringify(reqQuery);

    //5. Create operators mongo db query ['$lte'] = 30
    queryStr = queryStr.replace(/\b(gt|gte|lt|lte|in|ne|or|nin)\b/g, match => `$${match}`);

    let find = JSON.parse(queryStr);
    console.log("varien", find);

    //Recherche
    if (fields) {

        //search = be
        // mark , model, matrcle
        //Recherche l'element search dans le tableau de propriété fields
        const query = {
            $or: fields.map(property => ({
                [property]: {$regex: search, $options: 'i'}
            }))
        };

        find = {
            $and: [
                find,
                query,
            ]
        };
    }

    //Pagination
    page = parseInt(page, 10) || 0;
    rows = parseInt(rows, 10) || 3000;
    const startIndex = page * rows;
    const endIndex = page * rows;
    const total = await model.find(find).countDocuments();

    //declaration
    let query =  model.find(find);

    query = query.skip(startIndex).limit(rows);  // (5,8) 5,6,7,8,9,10,11, 12

    //exécuté
    let results = await query;

    const pagination = {};

    if (endIndex < total) {
        pagination.next = {
            page: page + 1,
            rows
        };
    }

    if (startIndex > 0) {
        pagination.prev = {
            page: page - 1,
            rows
        };
    }

    res.advancedResults = {
        success: true,
        count: results.length,
        pagination: pagination,
        data: results,
        startIndex: startIndex,
        endIndex: results.length,
        totalRecords: total,
        rows: Number(rows),
        page: page
    };
    next();
};

module.exports = advancedResult;