# mail.py - mail sending bits for mercurial
#
# Copyright 2006 Matt Mackall <mpm@selenic.com>
#
# This software may be used and distributed according to the terms
# of the GNU General Public License, incorporated herein by reference.

from i18n import _
import os, smtplib, socket
import email.Header, email.MIMEText, email.Utils
import util

def _smtp(ui):
    '''build an smtp connection and return a function to send mail'''
    local_hostname = ui.config('smtp', 'local_hostname')
    s = smtplib.SMTP(local_hostname=local_hostname)
    mailhost = ui.config('smtp', 'host')
    if not mailhost:
        raise util.Abort(_('no [smtp]host in hgrc - cannot send mail'))
    mailport = int(ui.config('smtp', 'port', 25))
    ui.note(_('sending mail: smtp host %s, port %s\n') %
            (mailhost, mailport))
    s.connect(host=mailhost, port=mailport)
    if ui.configbool('smtp', 'tls'):
        if not hasattr(socket, 'ssl'):
            raise util.Abort(_("can't use TLS: Python SSL support "
                               "not installed"))
        ui.note(_('(using tls)\n'))
        s.ehlo()
        s.starttls()
        s.ehlo()
    username = ui.config('smtp', 'username')
    password = ui.config('smtp', 'password')
    if username and not password:
        password = ui.getpass()
    if username and password:
        ui.note(_('(authenticating to mail server as %s)\n') %
                  (username))
        s.login(username, password)

    def send(sender, recipients, msg):
        try:
            return s.sendmail(sender, recipients, msg)
        except smtplib.SMTPRecipientsRefused, inst:
            recipients = [r[1] for r in inst.recipients.values()]
            raise util.Abort('\n' + '\n'.join(recipients))
        except smtplib.SMTPException, inst:
            raise util.Abort(inst)

    return send

def _sendmail(ui, sender, recipients, msg):
    '''send mail using sendmail.'''
    program = ui.config('email', 'method')
    cmdline = '%s -f %s %s' % (program, util.email(sender),
                               ' '.join(map(util.email, recipients)))
    ui.note(_('sending mail: %s\n') % cmdline)
    fp = util.popen(cmdline, 'w')
    fp.write(msg)
    ret = fp.close()
    if ret:
        raise util.Abort('%s %s' % (
            os.path.basename(program.split(None, 1)[0]),
            util.explain_exit(ret)[0]))

def connect(ui):
    '''make a mail connection. return a function to send mail.
    call as sendmail(sender, list-of-recipients, msg).'''
    if ui.config('email', 'method', 'smtp') == 'smtp':
        return _smtp(ui)
    return lambda s, r, m: _sendmail(ui, s, r, m)

def sendmail(ui, sender, recipients, msg):
    send = connect(ui)
    return send(sender, recipients, msg)

def validateconfig(ui):
    '''determine if we have enough config data to try sending email.'''
    method = ui.config('email', 'method', 'smtp')
    if method == 'smtp':
        if not ui.config('smtp', 'host'):
            raise util.Abort(_('smtp specified as email transport, '
                               'but no smtp host configured'))
    else:
        if not util.find_exe(method):
            raise util.Abort(_('%r specified as email transport, '
                               'but not in PATH') % method)

def mimetextpatch(s, subtype='plain', display=False):
    '''If patch in utf-8 transfer-encode it.'''
    if not display:
        for cs in ('us-ascii', 'utf-8'):
            try:
                s.decode(cs)
                return email.MIMEText.MIMEText(s, subtype, cs)
            except UnicodeDecodeError:
                pass
    return email.MIMEText.MIMEText(s, subtype)

def _charsets(ui):
    '''Obtains charsets to send mail parts not containing patches.'''
    charsets = [cs.lower() for cs in ui.configlist('email', 'charsets')]
    fallbacks = [util._fallbackencoding.lower(),
                 util._encoding.lower(), 'utf-8']
    for cs in fallbacks: # util.unique does not keep order
        if cs not in charsets:
            charsets.append(cs)
    return [cs for cs in charsets if not cs.endswith('ascii')]

def _encode(ui, s, charsets):
    '''Returns (converted) string, charset tuple.
    Finds out best charset by cycling through sendcharsets in descending
    order. Tries both _encoding and _fallbackencoding for input. Only as
    last resort send as is in fake ascii.
    Caveat: Do not use for mail parts containing patches!'''
    try:
        s.decode('ascii')
    except UnicodeDecodeError:
        sendcharsets = charsets or _charsets(ui)
        for ics in (util._encoding, util._fallbackencoding):
            try:
                u = s.decode(ics)
            except UnicodeDecodeError:
                continue
            for ocs in sendcharsets:
                try:
                    return u.encode(ocs), ocs
                except UnicodeEncodeError:
                    pass
                except LookupError:
                    ui.warn(_('ignoring invalid sendcharset: %s\n') % ocs)
    # if ascii, or all conversion attempts fail, send (broken) ascii
    return s, 'us-ascii'

def headencode(ui, s, charsets=None, display=False):
    '''Returns RFC-2047 compliant header from given string.'''
    if not display:
        # split into words?
        s, cs = _encode(ui, s, charsets)
        return str(email.Header.Header(s, cs))
    return s

def addressencode(ui, address, charsets=None, display=False):
    '''Turns address into RFC-2047 compliant header.'''
    if display or not address:
        return address or ''
    name, addr = email.Utils.parseaddr(address)
    name = headencode(ui, name, charsets)
    try:
        acc, dom = addr.split('@')
        acc = acc.encode('ascii')
        dom = dom.encode('idna')
        addr = '%s@%s' % (acc, dom)
    except UnicodeDecodeError:
        raise util.Abort(_('invalid email address: %s') % addr)
    except ValueError:
        try:
            # too strict?
            addr = addr.encode('ascii')
        except UnicodeDecodeError:
            raise util.Abort(_('invalid local address: %s') % addr)
    return email.Utils.formataddr((name, addr))

def mimeencode(ui, s, charsets=None, display=False):
    '''creates mime text object, encodes it if needed, and sets
    charset and transfer-encoding accordingly.'''
    cs = 'us-ascii'
    if not display:
        s, cs = _encode(ui, s, charsets)
    return email.MIMEText.MIMEText(s, 'plain', cs)
