# Copyright (C) 2011-2012  Patrick Totzke <patricktotzke@gmail.com>
# This file is released under the GNU GPL, version 3 or a later revision.
# For further details see the COPYING file
import argparse
import datetime
import email
import glob
import logging
import os
import re
import tempfile

from twisted.internet.defer import inlineCallbacks

from . import Command, registerCommand
from . import globals
from .utils import get_keys
from .. import buffers
from .. import commands
from .. import crypto
from ..account import SendingMailFailed, StoreMailError
from ..db.errors import DatabaseError
from ..errors import GPGProblem
from ..helper import email_as_string
from ..helper import string_decode
from ..settings import settings
from ..utils.booleanaction import BooleanAction


MODE = 'envelope'


@registerCommand(
    MODE, 'attach',
    arguments=[(['path'], {'help': 'file(s) to attach (accepts wildcads)'})])
class AttachCommand(Command):
    """attach files to the mail"""
    repeatable = True

    def __init__(self, path=None, **kwargs):
        """
        :param path: files to attach (globable string)
        :type path: str
        """
        Command.__init__(self, **kwargs)
        self.path = path

    def apply(self, ui):
        envelope = ui.current_buffer.envelope

        if self.path:  # TODO: not possible, otherwise argparse error before
            files = [g for g in glob.glob(os.path.expanduser(self.path))
                     if os.path.isfile(g)]
            if not files:
                ui.notify('no matches, abort')
                return
        else:
            ui.notify('no files specified, abort')
            return

        logging.info("attaching: %s", files)
        for path in files:
            envelope.attach(path)
        ui.current_buffer.rebuild()


@registerCommand(MODE, 'unattach', arguments=[
    (['hint'], {'nargs': '?', 'help': 'which attached file to remove'}),
])
class UnattachCommand(Command):
    """remove attachments from current envelope"""
    repeatable = True

    def __init__(self, hint=None, **kwargs):
        """
        :param hint: which attached file to remove
        :type hint: str
        """
        Command.__init__(self, **kwargs)
        self.hint = hint

    def apply(self, ui):
        envelope = ui.current_buffer.envelope

        if self.hint is not None:
            for a in envelope.attachments:
                if self.hint in a.get_filename():
                    envelope.attachments.remove(a)
        else:
            envelope.attachments = []
        ui.current_buffer.rebuild()


@registerCommand(MODE, 'refine', arguments=[
    (['key'], {'help': 'header to refine'})])
class RefineCommand(Command):
    """prompt to change the value of a header"""
    def __init__(self, key='', **kwargs):
        """
        :param key: key of the header to change
        :type key: str
        """
        Command.__init__(self, **kwargs)
        self.key = key

    def apply(self, ui):
        value = ui.current_buffer.envelope.get(self.key, '')
        cmdstring = 'set %s %s' % (self.key, value)
        ui.apply_command(globals.PromptCommand(cmdstring))


@registerCommand(MODE, 'save')
class SaveCommand(Command):
    """save draft"""
    def apply(self, ui):
        envelope = ui.current_buffer.envelope

        # determine account to use
        _, saddr = email.Utils.parseaddr(envelope.get('From'))
        account = settings.get_account_by_address(saddr)
        if account is None:
            if not settings.get_accounts():
                ui.notify('no accounts set.', priority='error')
                return
            else:
                account = settings.get_accounts()[0]

        if account.draft_box is None:
            ui.notify('abort: account <%s> has no draft_box set.' % saddr,
                      priority='error')
            return

        mail = envelope.construct_mail()
        # store mail locally
        # add Date header
        mail['Date'] = email.Utils.formatdate(localtime=True)
        path = account.store_draft_mail(email_as_string(mail))

        msg = 'draft saved successfully'

        # add mail to index if maildir path available
        if path is not None:
            ui.notify(msg + ' to %s' % path)
            logging.debug('adding new mail to index')
            try:
                ui.dbman.add_message(path, account.draft_tags)
                ui.apply_command(globals.FlushCommand())
                ui.apply_command(commands.globals.BufferCloseCommand())
            except DatabaseError as e:
                logging.error(e.message)
                ui.notify('could not index message:\n%s' % e.message,
                          priority='error',
                          block=True)
        else:
            ui.apply_command(commands.globals.BufferCloseCommand())


@registerCommand(MODE, 'send')
class SendCommand(Command):
    """send mail"""
    def __init__(self, mail=None, envelope=None, **kwargs):
        """
        :param mail: email to send
        :type email: email.message.Message
        :param envelope: envelope to use to construct the outgoing mail. This
                         will be ignored in case the mail parameter is set.
        :type envelope: alot.db.envelope.envelope
        """
        Command.__init__(self, **kwargs)
        self.mail = mail
        self.envelope = envelope
        self.envelope_buffer = None

    @inlineCallbacks
    def apply(self, ui):
        if self.mail is None:
            if self.envelope is None:
                # needed to close later
                self.envelope_buffer = ui.current_buffer
                self.envelope = self.envelope_buffer.envelope

            # This is to warn the user before re-sending
            # an already sent message in case the envelope buffer
            # was not closed because it was the last remaining buffer.
            if self.envelope.sent_time:
                mod = self.envelope.modified_since_sent
                when = self.envelope.sent_time
                warning = 'A modified version of ' * mod
                warning += 'this message has been sent at %s.' % when
                warning += ' Do you want to resend?'
                if (yield ui.choice(warning, cancel='no',
                                    msg_position='left')) == 'no':
                    return

            # don't do anything if another SendCommand is in the middle of
            # sending the message and we were triggered accidentally
            if self.envelope.sending:
                logging.debug('sending this message already!')
                return

            clearme = ui.notify(u'constructing mail (GPG, attachments)\u2026',
                                timeout=-1)

            try:
                self.mail = self.envelope.construct_mail()
                self.mail['Date'] = email.Utils.formatdate(localtime=True)
                self.mail = email_as_string(self.mail)
            except GPGProblem as e:
                ui.clear_notify([clearme])
                ui.notify(e.message, priority='error')
                return

            ui.clear_notify([clearme])

        # determine account to use for sending
        msg = self.mail
        if not isinstance(msg, email.message.Message):
            msg = email.message_from_string(self.mail)
        _, saddr = email.Utils.parseaddr(msg.get('From', ''))
        account = settings.get_account_by_address(saddr)
        if account is None:
            if not settings.get_accounts():
                ui.notify('no accounts set', priority='error')
                return
            else:
                account = settings.get_accounts()[0]

        # make sure self.mail is a string
        logging.debug(self.mail.__class__)
        if isinstance(self.mail, email.message.Message):
            self.mail = str(self.mail)

        # define callback
        def afterwards(_):
            initial_tags = []
            if self.envelope is not None:
                self.envelope.sending = False
                self.envelope.sent_time = datetime.datetime.now()
                initial_tags = self.envelope.tags
            logging.debug('mail sent successfully')
            ui.clear_notify([clearme])
            if self.envelope_buffer is not None:
                cmd = commands.globals.BufferCloseCommand(self.envelope_buffer)
                ui.apply_command(cmd)
            ui.notify('mail sent successfully')

            # store mail locally
            # This can raise StoreMailError
            path = account.store_sent_mail(self.mail)

            # add mail to index if maildir path available
            if path is not None:
                logging.debug('adding new mail to index')
                ui.dbman.add_message(path, account.sent_tags + initial_tags)
                ui.apply_command(globals.FlushCommand())

        # define errback
        def send_errb(failure):
            if self.envelope is not None:
                self.envelope.sending = False
            ui.clear_notify([clearme])
            failure.trap(SendingMailFailed)
            logging.error(failure.getTraceback())
            errmsg = 'failed to send: %s' % failure.value
            ui.notify(errmsg, priority='error', block=True)

        def store_errb(failure):
            failure.trap(StoreMailError)
            logging.error(failure.getTraceback())
            errmsg = 'could not store mail: %s' % failure.value
            ui.notify(errmsg, priority='error', block=True)

        # send out
        clearme = ui.notify('sending..', timeout=-1)
        if self.envelope is not None:
            self.envelope.sending = True
        d = account.send_mail(self.mail)
        d.addCallback(afterwards)
        d.addErrback(send_errb)
        d.addErrback(store_errb)


@registerCommand(MODE, 'edit', arguments=[
    (['--spawn'], {'action': BooleanAction, 'default': None,
                   'help': 'spawn editor in new terminal'}),
    (['--refocus'], {'action': BooleanAction, 'default': True,
                     'help': 'refocus envelope after editing'})])
class EditCommand(Command):
    """edit mail"""
    def __init__(self, envelope=None, spawn=None, refocus=True, **kwargs):
        """
        :param envelope: email to edit
        :type envelope: :class:`~alot.db.envelope.Envelope`
        :param spawn: force spawning of editor in a new terminal
        :type spawn: bool
        :param refocus: m
        """
        self.envelope = envelope
        self.openNew = (envelope is not None)
        self.force_spawn = spawn
        self.refocus = refocus
        self.edit_only_body = False
        Command.__init__(self, **kwargs)

    def apply(self, ui):
        ebuffer = ui.current_buffer
        if not self.envelope:
            self.envelope = ui.current_buffer.envelope

        # determine editable headers
        edit_headers = set(settings.get('edit_headers_whitelist'))
        if '*' in edit_headers:
            edit_headers = set(self.envelope.headers)
        blacklist = set(settings.get('edit_headers_blacklist'))
        if '*' in blacklist:
            blacklist = set(self.envelope.headers)
        edit_headers = edit_headers - blacklist
        logging.info('editable headers: %s', edit_headers)

        def openEnvelopeFromTmpfile():
            # This parses the input from the tempfile.
            # we do this ourselves here because we want to be able to
            # just type utf-8 encoded stuff into the tempfile and let alot
            # worry about encodings.

            # get input
            # tempfile will be removed on buffer cleanup
            enc = settings.get('editor_writes_encoding')
            with open(self.envelope.tmpfile.name) as f:
                template = string_decode(f.read(), enc)

            # call post-edit translate hook
            translate = settings.get_hook('post_edit_translate')
            if translate:
                template = translate(template, ui=ui, dbm=ui.dbman)
            self.envelope.parse_template(template,
                                         only_body=self.edit_only_body)
            if self.openNew:
                ui.buffer_open(buffers.EnvelopeBuffer(ui, self.envelope))
            else:
                ebuffer.envelope = self.envelope
                ebuffer.rebuild()

        # decode header
        headertext = u''
        for key in edit_headers:
            vlist = self.envelope.get_all(key)
            if not vlist:
                # ensure editable headers are present in template
                vlist = ['']
            else:
                # remove to be edited lines from envelope
                del self.envelope[key]

            for value in vlist:
                # newlines (with surrounding spaces) by spaces in values
                value = value.strip()
                value = re.sub('[ \t\r\f\v]*\n[ \t\r\f\v]*', ' ', value)
                headertext += '%s: %s\n' % (key, value)

        # determine editable content
        bodytext = self.envelope.body
        if headertext:
            content = '%s\n%s' % (headertext, bodytext)
            self.edit_only_body = False
        else:
            content = bodytext
            self.edit_only_body = True

        # call pre-edit translate hook
        translate = settings.get_hook('pre_edit_translate')
        if translate:
            content = translate(content, ui=ui, dbm=ui.dbman)

        # write stuff to tempfile
        old_tmpfile = None
        if self.envelope.tmpfile:
            old_tmpfile = self.envelope.tmpfile
        with tempfile.NamedTemporaryFile(
                delete=False, prefix='alot.', suffix='.eml') as tmpfile:
            tmpfile.write(content.encode('utf-8'))
            tmpfile.flush()
            self.envelope.tmpfile = tmpfile
        if old_tmpfile:
            os.unlink(old_tmpfile.name)
        cmd = globals.EditCommand(self.envelope.tmpfile.name,
                                  on_success=openEnvelopeFromTmpfile,
                                  spawn=self.force_spawn,
                                  thread=self.force_spawn,
                                  refocus=self.refocus)
        ui.apply_command(cmd)


@registerCommand(MODE, 'set', arguments=[
    (['--append'], {'action': 'store_true', 'help': 'keep previous values'}),
    (['key'], {'help': 'header to refine'}),
    (['value'], {'nargs': '+', 'help': 'value'})])
class SetCommand(Command):
    """set header value"""
    def __init__(self, key, value, append=False, **kwargs):
        """
        :param key: key of the header to change
        :type key: str
        :param value: new value
        :type value: str
        """
        self.key = key
        self.value = ' '.join(value)
        self.reset = not append
        Command.__init__(self, **kwargs)

    def apply(self, ui):
        envelope = ui.current_buffer.envelope
        if self.reset:
            if self.key in envelope:
                del envelope[self.key]
        envelope.add(self.key, self.value)
        ui.current_buffer.rebuild()


@registerCommand(MODE, 'unset', arguments=[
    (['key'], {'help': 'header to refine'})])
class UnsetCommand(Command):
    """remove header field"""
    def __init__(self, key, **kwargs):
        """
        :param key: key of the header to remove
        :type key: str
        """
        self.key = key
        Command.__init__(self, **kwargs)

    def apply(self, ui):
        del ui.current_buffer.envelope[self.key]
        ui.current_buffer.rebuild()


@registerCommand(MODE, 'toggleheaders')
class ToggleHeaderCommand(Command):
    """toggle display of all headers"""
    repeatable = True

    def apply(self, ui):
        ui.current_buffer.toggle_all_headers()


@registerCommand(
    MODE, 'sign', forced={'action': 'sign'},
    arguments=[
        (['keyid'],
         {'nargs': argparse.REMAINDER, 'help': 'which key id to use'})],
    help='mark mail to be signed before sending')
@registerCommand(MODE, 'unsign', forced={'action': 'unsign'},
                 help='mark mail not to be signed before sending')
@registerCommand(
    MODE, 'togglesign', forced={'action': 'toggle'}, arguments=[
        (['keyid'],
         {'nargs': argparse.REMAINDER, 'help': 'which key id to use'})],
    help='toggle sign status')
class SignCommand(Command):
    """toggle signing this email"""
    repeatable = True

    def __init__(self, action=None, keyid=None, **kwargs):
        """
        :param action: whether to sign/unsign/toggle
        :type action: str
        :param keyid: which key id to use
        :type keyid: str
        """
        self.action = action
        self.keyid = keyid
        Command.__init__(self, **kwargs)

    def apply(self, ui):
        sign = None
        key = None
        envelope = ui.current_buffer.envelope
        # sign status
        if self.action == 'sign':
            sign = True
        elif self.action == 'unsign':
            sign = False
        elif self.action == 'toggle':
            sign = not envelope.sign
        envelope.sign = sign

        # try to find key if hint given as parameter
        if sign:
            if len(self.keyid) > 0:
                keyid = str(' '.join(self.keyid))
                try:
                    key = crypto.get_key(keyid, validate=True, sign=True)
                except GPGProblem as e:
                    envelope.sign = False
                    ui.notify(e.message, priority='error')
                    return
                envelope.sign_key = key
        else:
            envelope.sign_key = None

        # reload buffer
        ui.current_buffer.rebuild()


@registerCommand(
    MODE, 'encrypt', forced={'action': 'encrypt'}, arguments=[
        (['--trusted'], {'action': 'store_true',
                         'help': 'only add trusted keys'}),
        (['keyids'], {'nargs': argparse.REMAINDER,
                      'help': 'keyid of the key to encrypt with'})],
    help='request encryption of message before sendout')
@registerCommand(
    MODE, 'unencrypt', forced={'action': 'unencrypt'},
    help='remove request to encrypt message before sending')
@registerCommand(
    MODE, 'toggleencrypt', forced={'action': 'toggleencrypt'},
    arguments=[
        (['--trusted'], {'action': 'store_true',
                         'help': 'only add trusted keys'}),
        (['keyids'], {'nargs': argparse.REMAINDER,
                      'help': 'keyid of the key to encrypt with'})],
    help='toggle if message should be encrypted before sendout')
@registerCommand(
    MODE, 'rmencrypt', forced={'action': 'rmencrypt'},
    arguments=[
        (['keyids'], {'nargs': argparse.REMAINDER,
                      'help': 'keyid of the key to encrypt with'})],
    help='do not encrypt to given recipient key')
class EncryptCommand(Command):
    def __init__(self, action=None, keyids=None, trusted=False, **kwargs):
        """
        :param action: wether to encrypt/unencrypt/toggleencrypt
        :type action: str
        :param keyid: the id of the key to encrypt
        :type keyid: str
        :param trusted: wether to filter keys and only use trusted ones
        :type trusted: bool
        """

        self.encrypt_keys = keyids
        self.action = action
        self.trusted = trusted
        Command.__init__(self, **kwargs)

    @inlineCallbacks
    def apply(self, ui):
        envelope = ui.current_buffer.envelope
        if self.action == 'rmencrypt':
            try:
                for keyid in self.encrypt_keys:
                    tmp_key = crypto.get_key(keyid)
                    del envelope.encrypt_keys[crypto.hash_key(tmp_key)]
            except GPGProblem as e:
                ui.notify(e.message, priority='error')
            if not envelope.encrypt_keys:
                envelope.encrypt = False
            ui.current_buffer.rebuild()
            return
        elif self.action == 'encrypt':
            encrypt = True
        elif self.action == 'unencrypt':
            encrypt = False
        elif self.action == 'toggleencrypt':
            encrypt = not envelope.encrypt
        envelope.encrypt = encrypt
        if encrypt:
            if not self.encrypt_keys:
                for recipient in envelope.headers['To'][0].split(','):
                    if not recipient:
                        continue
                    match = re.search("<(.*@.*)>", recipient)
                    if match:
                        recipient = match.group(1)
                    self.encrypt_keys.append(recipient)

            logging.debug("encryption keys: %s", self.encrypt_keys)
            keys = yield get_keys(ui, self.encrypt_keys,
                                  signed_only=self.trusted)
            if self.trusted:
                logging.debug("filtered encrytion keys: " +
                              " ".join(x.uids[0].uid for x in keys.itervalues()))
            if keys:
                envelope.encrypt_keys.update(keys)
            else:
                envelope.encrypt = False
        if not envelope.encrypt:
            # This is an extra conditional as it can even happen if encrypt is
            # True.
            envelope.encrypt_keys = {}
        # reload buffer
        ui.current_buffer.rebuild()