const gen = require('gen-thread');
const MailParser = require('mailparser').MailParser;
const htmlawed = require('htmlawed');

const express = require('express');
const express_session = require('express-session');
const bodyparser = require('body-parser');
const multer = require('multer');

module.exports = SyncerWeb;

function SyncerWeb(syncer, pg, cfg)
{
    this.syncer = syncer;
    this.pg = pg;
    this.cfg = cfg;
    this.app = express();
    this.app.use(bodyparser.urlencoded({ extended: false }));
    this.app.use(express_session({
        secret: this.cfg.sessionSecret || '1083581xm1l3s1l39k',
        resave: false,
        saveUninitialized: false
    }));
    this.app.get('/auth', this.get_auth);
    this.app.post('/auth', this.post_auth);
    this.app.get('/folders', genRequest(this.get_folders.bind(this)));
    this.app.get('/messages', genRequest(this.get_messages.bind(this)));
    this.app.get('/message', genRequest(this.get_message.bind(this)));
    this.app.post('/sync', genRequest(this.post_sync.bind(this)));
}

SyncerWeb.prototype.get_auth = function(req, res)
{
    return res.type('html').send(
        '<form action="/auth" method="post"><input name="login" />'+
        ' <input name="password" type="password" /> <input type="submit" /></form>'
    );
}

SyncerWeb.prototype.post_auth = function(req, res)
{
    if (!req.body)
        return res.sendStatus(400);
    if (req.body.login == this.cfg.login && req.body.password == this.cfg.password)
    {
        req.session.auth = true;
        return res.send({ ok: true });
    }
    return res.send({ ok: false });
}

SyncerWeb.prototype.get_folders = function*(req, res)
{
    if (this.cfg.login && (!req.session || !req.session.auth))
    {
        return res.sendStatus(401);
    }
    var [ accounts ] = yield this.pg.select(
        'id, name, email, settings->\'folders\' folderMap,'+
        ' (select count(*) from messages m, folders f where m.folder_id=f.id and f.account_id=a.id and (flags @> array[\'pinned\',\'unread\']::varchar(255)[])) pinned_unread_count'
    ).from('accounts a').rows(gen.ef());
    var [ folders ] = yield this.pg.select(
        'id, account_id, name,'+
        ' (select count(*) from messages m where m.folder_id=f.id) total_count,'+
        ' (select count(*) from messages m where m.folder_id=f.id and (flags @> array[\'unread\']::varchar(255)[])) unread_count'
    ).from('folders f').orderBy('account_id, name').rows(gen.ef());
    var fh = {};
    for (let i = 0; i < folders.length; i++)
    {
        fh[folders[i].account_id] = fh[folders[i].account_id] || [];
        fh[folders[i].account_id].push(folders[i]);
    }
    for (let i = 0; i < accounts.length; i++)
    {
        accounts[i].folders = fh[accounts[i].id] || [];
    }
    return res.send({ accounts: accounts });
}

SyncerWeb.prototype.get_messages = function*(req, res)
{
    if (this.cfg.login && (!req.session || !req.session.auth))
        return res.sendStatus(401);
    var folderId = req.query.folderId;
    if (!folderId)
        return res.status(500).send('Need `folderId` query parameter');
    var limit = req.query.limit || 50;
    var offset = req.query.offset || 0;
    var [ msgs ] = yield this.pg.select('*').from('messages').where({ folder_id: folderId })
        .orderBy('time desc').limit(limit).offset(offset).rows(gen.ef());
    for (var i = 0; i < msgs.length; i++)
    {
        delete msgs[i].text_index;
    }
    return res.send({ messages: msgs });
}

SyncerWeb.prototype.get_message = function*(req, res)
{
    if (this.cfg.login && (!req.session || !req.session.auth))
        return res.sendStatus(401);
    var msgId = req.query.msgId;
    var [ msg ] = yield this.pg.select('m.*, f.name folder_name, f.account_id')
        .from('messages m').join('folders f', this.pg.sql('f.id=m.folder_id'))
        .where({ 'm.id': msgId }).rows(gen.ef());
    if (!msg.length)
        return res.send({ error: 'not-found' });
    msg = msg[0];
    delete msg.text_index;
    if (!msg.body_html && !msg.body_text)
    {
        var srv = yield* this.syncer.imap.getConnection(msg.account_id, msg.folder_name);
        var [ upd ] = yield* this.syncer.imap.runFetch(
            srv, msg.uid, { bodies: '' },
            (messages, state) => getBody(this.pg, messages, msg.folder_id)
        );
        this.syncer.imap.releaseConnection(msg.account_id);
        return res.send({ msg: { ...msg, ...upd } });
    }
    return res.send({ msg: msg });
}

SyncerWeb.prototype.post_sync = function*(req, res)
{
    if (this.cfg.login && (!req.session || !req.session.auth))
        return res.sendStatus(401);
    if (self.syncer.syncInProgress)
        return res.send({ error: 'already-running' });
    gen.run(self.syncer.syncAll());
    return res.send({ status: 'started' });
}

function* getBody(pg, messages, boxId)
{
    var p = new MailParser({ streamAttachments: false, defaultCharset: 'windows-1251' });
    for (var i = 0; i < messages.length; i++)
    {
        let msg = messages[i];
        p.on('end', gen.cb());
        p.write(msg[0].headers);
        let [ obj ] = yield p.end();
        let styles = '';
        obj.html = (obj.html||'').replace(/<style[^<>]*>([\s\S]*?)<\/style\s*>/ig, function(m, m1)
        {
            styles += m1+'\n';
            return '';
        });
        obj.html = obj.html.replace(/^[\s\S]*?<body[^<>]*>([\s\S]*)<\/body>[\s\S]*$/i, '$1');
        obj.html = obj.html.replace(/^[\s\S]*?<html[^<>]*>([\s\S]*)<\/html>[\s\S]*$/i, '$1');
        if (styles)
        {
            obj.html = '<style>\n'+styles+'</style>\n'+obj.html;
        }
        obj.html = htmlawed.sanitize(obj.html||'', { safe: 1, elements: '* +style', keep_bad: 2, comment: 1 });
        let upd = { body_text: obj.text||'', body_html: obj.html };
        upd.body_html_text = obj.html.replace(/<style[^>]*>.*<\/style\s*>|<\/?[^>]*>/g, '');
        yield pg.update('messages m', upd).where({ folder_id: boxId, uid: msg[0].uid }).run(gen.ef());
        if (messages.length == 1)
            return [ upd ];
    }
}

function genRequest(fn)
{
    return (req, res) => gen.run(fn(req, res), null, e => res.status(500).send('Internal Error: '+e.stack));
}