/*
* This file is part of PKM (Persistent Knowledge Monitor).
* Copyright (c) 2020 Capgemini Group, Commissariat à l'énergie atomique et aux énergies alternatives,
* OW2, Sysgo AG, Technikon, Tree Technology, Universitat Politècnica de València.
*
* PKM is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License version 3 as published by
* the Free Software Foundation.
*
* PKM is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with PKM. If not, see <https://www.gnu.org/licenses/>.
*/
/**
* Count documents in a generic manner of a collection of a database
*
* @memberof PKM
* @instance
* @param {string} dbName - database name
* @param {string} collection_name - collection name
* @param {Object} [query] - query
* @param {Object} [options] - options
*
* @return {Promise} a promise
*/
function count_documents(dbName, collection_name, query = {}, options = {})
{
return new Promise(function(resolve, reject)
{
const debug = this.debug;
if(debug)
{
console.log('PKM.count_documents(' + JSON.stringify(dbName) + ',' + JSON.stringify(collection_name) + ',' + JSON.stringify(query) + ',' + JSON.stringify(options) + ')');
}
const has_postprocess = (this.has_postprocess[collection_name] !== undefined) && this.has_postprocess[collection_name](options);
this.get_collection(dbName, collection_name).then((documents_collection) =>
{
if(has_postprocess)
{
let documents = [];
let find_options = Object.assign({}, options);
if(options.skip !== undefined) delete find_options.skip;
if(options.limit !== undefined) delete find_options.limit;
let document_cursor = documents_collection.find(query, find_options);
document_cursor.forEach((document) =>
{
documents.push(this.fix_document(document, collection_name));
}, (err) =>
{
if(err)
{
reject(this.Error(err));
}
else
{
let count = documents.length;
if(count)
{
if(debug)
{
console.log('Counted ' + count + ' document(s) for ' + JSON.stringify(query) + ' in collection \'' + collection_name + '\' of database \'' + dbName + '\'');
}
const postprocess = this.postprocess[collection_name];
const postprocess_slicing = has_postprocess && (options.skip || options.limit);
if(postprocess !== undefined)
{
count = postprocess(documents, options).length;
if(debug)
{
console.log('After postprocessing, counted ' + count + ' document(s) from collection for ' + JSON.stringify(query) + ' in \'' + collection_name + '\' of database \'' + dbName + '\'');
}
if(postprocess_slicing)
{
const start = options.skip || 0;
const end = start + (options.limit ? options.limit : count);
count = end - start;
if(debug)
{
console.log('After slicing [' + start + ',' + end + '[, counted ' + count + ' document(s) for ' + JSON.stringify(query) + ' in collection \'' + collection_name + '\' of database \'' + dbName + '\'');
}
}
}
if(debug && ((postprocess !== undefined) || postprocess_slicing))
{
console.log('Overall counted ' + count + ' document(s) for ' + JSON.stringify(query) + ' in collection \'' + collection_name + '\' of database \'' + dbName + '\'');
}
}
resolve(count);
}
});
}
else
{
documents_collection.countDocuments(query, options).then((count) =>
{
if(debug)
{
console.log('Counted ' + count + ' document(s) for ' + JSON.stringify(query) + ' in collection \'' + collection_name + '\'');
}
resolve(count);
}).catch((err) =>
{
reject(this.Error(err));
});
}
}).catch((err) =>
{
reject(this.Error(err));
});
}.bind(this));
}
module.exports.count_documents = count_documents;