'use strict';

let log = require('npmlog');
let config = require('config');
let net = require('net');
let campaigns = require('../lib/models/campaigns');

let seenIds = new Set();

let server = net.createServer(socket => {
    let remainder = '';

    let reading = false;
    let readNextChunk = () => {
        let chunk = socket.read();
        if (chunk === null) {
            reading = false;
            return;
        }
        reading = true;

        let lines = (remainder + chunk.toString()).split(/\r?\n/);
        remainder = lines.pop();

        let pos = 0;
        let checkNextLine = () => {
            if (pos >= lines.length) {
                return readNextChunk();
            }
            let line = lines[pos++];
            let match = /\bstatus=bounced\b/.test(line) && line.match(/\bpostfix\/\w+\[\d+\]:\s*([^:]+)/);
            if (match) {
                let queueId = match[1];

                if (seenIds.has(queueId)) {
                    return checkNextLine();
                }
                seenIds.add(queueId);

                campaigns.findMailByResponse(queueId, (err, message) => {
                    if (err || !message) {
                        return checkNextLine();
                    }
                    campaigns.updateMessage(message, 'bounced', true, (err, updated) => {
                        if (err) {
                            log.error('POSTFIXBOUNCE', 'Failed updating message: %s', err.stack);
                        } else if (updated) {
                            log.verbose('POSTFIXBOUNCE', 'Marked message %s as bounced', queueId);
                        }
                    });
                    return checkNextLine();
                });
                return;

            } else {
                return checkNextLine();
            }
        };

        checkNextLine();
    };


    socket.on('readable', () => {
        if (reading) {
            return false;
        }
        readNextChunk();

    });
});

server.on('error', err => {
    log.error('POSTFIXBOUNCE', err.stack);
});

module.exports = callback => {
    if (config.postfixbounce.enabled) {
        server.listen(config.postfixbounce.port, config.postfixbounce.host, () => {
            log.info('POSTFIXBOUNCE', 'Server listening on port %s', config.postfixbounce.port);
            setImmediate(callback);
        });
    } else {
        setImmediate(callback);
    }
};