'use strict';

const db = require('../db');

// DELETE "path/to/mailbox"
module.exports = server => (path, session, callback) => {
    server.logger.debug(
        {
            tnx: 'delete',
            cid: session.id
        },
        '[%s] DELETE "%s"',
        session.id,
        path
    );
    db.database.collection('mailboxes').findOne({
        user: session.user.id,
        path
    }, (err, mailbox) => {
        if (err) {
            return callback(err);
        }
        if (!mailbox) {
            return callback(null, 'NONEXISTENT');
        }
        if (mailbox.specialUse) {
            return callback(null, 'CANNOT');
        }

        server.notifier.addEntries(
            session.user.id,
            path,
            {
                command: 'DROP',
                mailbox: mailbox._id
            },
            () => {
                db.database.collection('mailboxes').deleteOne({
                    _id: mailbox._id
                }, err => {
                    if (err) {
                        return callback(err);
                    }

                    // calculate mailbox size by aggregating the size's of all messages
                    db.database
                        .collection('messages')
                        .aggregate(
                            [
                                {
                                    $match: {
                                        mailbox: mailbox._id
                                    }
                                },
                                {
                                    $group: {
                                        _id: {
                                            mailbox: '$mailbox'
                                        },
                                        storageUsed: {
                                            $sum: '$size'
                                        }
                                    }
                                }
                            ],
                            {
                                cursor: {
                                    batchSize: 1
                                }
                            }
                        )
                        .toArray((err, res) => {
                            if (err) {
                                return callback(err);
                            }

                            let storageUsed = (res && res[0] && res[0].storageUsed) || 0;

                            db.database.collection('messages').deleteMany({
                                mailbox: mailbox._id
                            }, err => {
                                if (err) {
                                    return callback(err);
                                }

                                let done = () => {
                                    server.notifier.fire(session.user.id, path);
                                    callback(null, true);
                                };

                                if (!storageUsed) {
                                    return done();
                                }

                                // decrement quota counters
                                db.users.collection('users').findOneAndUpdate(
                                    {
                                        _id: mailbox.user
                                    },
                                    {
                                        $inc: {
                                            storageUsed: -Number(storageUsed) || 0
                                        }
                                    },
                                    done
                                );
                            });
                        });
                });
            }
        );
    });
};