'use strict';

const config = require('wild-config');
const maildrop = require('./maildrop');
const db = require('./db');

module.exports = (options, callback) => {
    if (!config.sender.enabled) {
        return callback(null, false);
    }

    let mail = {
        parentId: options.parentId,
        reason: 'forward',

        from: options.sender,
        to: options.recipient,

        targets: options.targets,

        interface: 'forwarder'
    };

    let message = maildrop(mail, (err, ...args) => {
        if (err || !args[0]) {
            return callback(err, ...args);
        }
        db.database.collection('messagelog').insertOne({
            id: args[0].id,
            messageId: args[0].messageId,
            action: 'FORWARD',
            parentId: options.parentId,
            from: options.sender,
            to: options.recipient,
            targets: options.targets,
            created: new Date()
        }, () => callback(err, args && args[0] && args[0].id));
    });

    if (options.stream) {
        options.stream.pipe(message);
        options.stream.once('error', err => {
            message.emit('error', err);
        });
        return;
    }

    setImmediate(() => {
        let pos = 0;
        let writeNextChunk = () => {
            if (pos >= options.chunks.length) {
                return message.end();
            }
            let chunk = options.chunks[pos++];
            if (!message.write(chunk)) {
                return message.once('drain', writeNextChunk);
            } else {
                setImmediate(writeNextChunk);
            }
        };
        setImmediate(writeNextChunk);
    });
};