"use strict";

function getPagination( query ){
	let limit = {
		page : 0,
		elements : 10
	};
	
	if( query.page ){
		limit.page = parseInt( query.page ) || 0;
		if( limit.page < 0 ){
			limit.page = 0;
		}
	}
	if( query.elements ){
		limit.elements = parseInt( query.elements ) || 10;
		/** Safe pagination limit */
		if( limit.elements > 1000 ){
			limit.elements = 1000;
		}
		else if( limit.elements < 0 ){
			limit.elements = 10;
		}
	}
	return limit;
}

async function getPage( page, elements, model, filter=null, projection=null){
    const skip = elements * page;
	const total = await model.count( filter );
	const list = await model.find( filter , projection, { skip : skip , limit : elements } );
	return {
        total : total,
        limit : elements,
        skip : skip,
		data : list 
	}
}

async function queryPage(page, elements, model, filter=null, projection=null){
    const skip = elements * page;
	const total = await model.count( filter );
	return {
		query : model.find( filter , projection, { skip : skip , limit : elements } ),
		total : total,
		skip : skip
	};
}

module.exports = { getPagination , getPage, queryPage };