#!/usr/bin/env python
#
# Electrum - Lightweight Bitcoin Client
# Copyright (C) 2015 Thomas Voegtlin
#
# Permission is hereby granted, free of charge, to any person
# obtaining a copy of this software and associated documentation files
# (the "Software"), to deal in the Software without restriction,
# including without limitation the rights to use, copy, modify, merge,
# publish, distribute, sublicense, and/or sell copies of the Software,
# and to permit persons to whom the Software is furnished to do so,
# subject to the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
# BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
# ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.

import time
import threading
import base64
from functools import partial

import smtplib
import imaplib
import email
from email.mime.multipart import MIMEMultipart
from email.mime.base import MIMEBase
from email.encoders import encode_base64

from PyQt5.QtGui import *
from PyQt5.QtCore import *
import PyQt5.QtCore as QtCore
import PyQt5.QtGui as QtGui
from PyQt5.QtWidgets import (QVBoxLayout, QLabel, QGridLayout, QLineEdit)

from electrum.plugins import BasePlugin, hook
from electrum.paymentrequest import PaymentRequest
from electrum.i18n import _
from electrum_gui.qt.util import EnterButton, Buttons, CloseButton
from electrum_gui.qt.util import OkButton, WindowModalDialog


class Processor(threading.Thread):
    polling_interval = 5*60

    def __init__(self, imap_server, username, password, callback):
        threading.Thread.__init__(self)
        self.daemon = True
        self.username = username
        self.password = password
        self.imap_server = imap_server
        self.on_receive = callback

    def poll(self):
        try:
            self.M.select()
        except:
            return
        typ, data = self.M.search(None, 'ALL')
        for num in data[0].split():
            typ, msg_data = self.M.fetch(num, '(RFC822)')
            msg = email.message_from_string(msg_data[0][1])
            p = msg.get_payload()
            if not msg.is_multipart():
                p = [p]
                continue
            for item in p:
                if item.get_content_type() == "application/bitcoin-paymentrequest":
                    pr_str = item.get_payload()
                    pr_str = base64.b64decode(pr_str)
                    self.on_receive(pr_str)

    def run(self):
        self.M = imaplib.IMAP4_SSL(self.imap_server)
        self.M.login(self.username, self.password)
        while True:
            self.poll()
            time.sleep(self.polling_interval)
        self.M.close()
        self.M.logout()

    def send(self, recipient, message, payment_request):
        msg = MIMEMultipart()
        msg['Subject'] = message
        msg['To'] = recipient
        msg['From'] = self.username
        part = MIMEBase('application', "bitcoin-paymentrequest")
        part.set_payload(payment_request)
        encode_base64(part)
        part.add_header('Content-Disposition', 'attachment; filename="payreq.btc"')
        msg.attach(part)
        s = smtplib.SMTP_SSL(self.imap_server, timeout=2)
        s.login(self.username, self.password)
        s.sendmail(self.username, [recipient], msg.as_string())
        s.quit()


class QEmailSignalObject(QObject):
    email_new_invoice_signal = pyqtSignal()


class Plugin(BasePlugin):

    def fullname(self):
        return 'Email'

    def description(self):
        return _("Send and receive payment requests via email")

    def is_available(self):
        return True

    def __init__(self, parent, config, name):
        BasePlugin.__init__(self, parent, config, name)
        self.imap_server = self.config.get('email_server', '')
        self.username = self.config.get('email_username', '')
        self.password = self.config.get('email_password', '')
        if self.imap_server and self.username and self.password:
            self.processor = Processor(self.imap_server, self.username, self.password, self.on_receive)
            self.processor.start()
        self.obj = QEmailSignalObject()
        self.obj.email_new_invoice_signal.connect(self.new_invoice)

    def on_receive(self, pr_str):
        self.print_error('received payment request')
        self.pr = PaymentRequest(pr_str)
        self.obj.email_new_invoice_signal.emit()

    def new_invoice(self):
        self.parent.invoices.add(self.pr)
        #window.update_invoices_list()

    @hook
    def receive_list_menu(self, menu, addr):
        window = menu.parentWidget()
        menu.addAction(_("Send via e-mail"), lambda: self.send(window, addr))

    def send(self, window, addr):
        from electrum import paymentrequest
        r = window.wallet.receive_requests.get(addr)
        message = r.get('memo', '')
        if r.get('signature'):
            pr = paymentrequest.serialize_request(r)
        else:
            pr = paymentrequest.make_request(self.config, r)
        if not pr:
            return
        recipient, ok = QtGui.QInputDialog.getText(window, 'Send request', 'Email invoice to:')
        if not ok:
            return
        recipient = str(recipient)
        payload = pr.SerializeToString()
        self.print_error('sending mail to', recipient)
        try:
            self.processor.send(recipient, message, payload)
        except BaseException as e:
            window.show_message(str(e))
            return

        window.show_message(_('Request sent.'))


    def requires_settings(self):
        return True

    def settings_widget(self, window):
        return EnterButton(_('Settings'), partial(self.settings_dialog, window))

    def settings_dialog(self, window):
        d = WindowModalDialog(window, _("Email settings"))
        d.setMinimumSize(500, 200)

        vbox = QVBoxLayout(d)
        vbox.addWidget(QLabel(_('Server hosting your email acount')))
        grid = QGridLayout()
        vbox.addLayout(grid)
        grid.addWidget(QLabel('Server (IMAP)'), 0, 0)
        server_e = QLineEdit()
        server_e.setText(self.imap_server)
        grid.addWidget(server_e, 0, 1)

        grid.addWidget(QLabel('Username'), 1, 0)
        username_e = QLineEdit()
        username_e.setText(self.username)
        grid.addWidget(username_e, 1, 1)

        grid.addWidget(QLabel('Password'), 2, 0)
        password_e = QLineEdit()
        password_e.setText(self.password)
        grid.addWidget(password_e, 2, 1)

        vbox.addStretch()
        vbox.addLayout(Buttons(CloseButton(d), OkButton(d)))

        if not d.exec_():
            return

        server = str(server_e.text())
        self.config.set_key('email_server', server)

        username = str(username_e.text())
        self.config.set_key('email_username', username)

        password = str(password_e.text())
        self.config.set_key('email_password', password)
