try:
    import ConfigParser as configparser
except ImportError:
    import configparser
import email
import email.mime
import email.mime.text
import email.utils
import smtplib


class MissingEmailConfig(Exception):
    pass


def _send_system_email(config, subject, recips, body):
    try:
        fromaddr = config.get('email', 'fromaddr')
        smtphost = config.get('email', 'smtphost')
    except (configparser.NoOptionError,
            configparser.NoSectionError):
        raise MissingEmailConfig()

    msg = email.mime.text.MIMEText(body)
    msg['Subject'] = subject
    msg['From'] = fromaddr
    msg['Date'] = email.utils.formatdate()
    msg['Message-Id'] = email.utils.make_msgid('nx584')
    for addr in recips:
        msg['To'] = addr

    smtp = smtplib.SMTP(smtphost)
    smtp.sendmail(fromaddr, recips, msg.as_string())
    smtp.quit()


def send_system_email(config, deasserted, asserted):
    try:
        emails = config.get('email', 'system').split(',')
    except (configparser.NoOptionError,
            configparser.NoSectionError):
        return

    if not emails:
        return

    body = ('Security System alert.\n' +
            '\n' +
            'The following new flags have been asserted:\n' +
            ('%s\n' % ','.join(asserted)) +
            '\n' +
            'The following flags are now de-asserted:\n' +
            ('%s\n' % ','.join(deasserted)))

    try:
        _send_system_email(config, 'Security System Alert',
                           emails, body)
    except MissingEmailConfig:
        pass


def send_partition_email(config, partition, deasserted, asserted):
    try:
        emails = config.get('partition_%i' % partition.number,
                            'flags').split(',')
    except (configparser.NoOptionError,
            configparser.NoSectionError):
        return

    try:
        ignore = set(config.get('partition_%i' % partition.number,
                                'ignore_flags').split(','))
    except configparser.NoOptionError:
        ignore = set([])

    deasserted = deasserted - ignore
    asserted = asserted - ignore
    if not asserted and not deasserted:
        return
    if not emails:
        return

    body = ('Security System partition %i alert.\n' % partition.number +
            '\n' +
            'The following new flags have been asserted:\n' +
            ('%s\n' % ','.join(asserted)) +
            '\n' +
            'The following flags are now de-asserted:\n' +
            ('%s\n' % ','.join(deasserted)))

    try:
        _send_system_email(
            config,
            'Security System Partition %i Alert' % partition.number,
            emails, body)
    except MissingEmailConfig:
        pass


def send_partition_status_email(config, partition, recip_key, sub, message):
    try:
        emails = config.get('partition_%i' % partition.number,
                            recip_key).split(',')
    except (configparser.NoOptionError,
            configparser.NoSectionError):
        return

    if not emails:
        return

    body = 'Security System alert:\n%s' % message
    try:
        _send_system_email(
            config,
            'Security: %s' % sub,
            emails, body)
    except MissingEmailConfig:
        pass


def send_log_event_mail(config, event):
    try:
        alarm_emails = set(config.get('email', 'alarms').split(','))
    except (configparser.NoOptionError, configparser.NoSectionError):
        alarm_emails = set([])

    try:
        alarm_events = set(config.get('email', 'alarm_events').split(','))
    except (configparser.NoOptionError, configparser.NoSectionError):
        alarm_events = set(['Alarm', 'Alarm restore', 'Manual fire',])

    try:
        event_emails = set(config.get('email', 'events').split(','))
    except (configparser.NoOptionError, configparser.NoSectionError):
        event_emails = set([])

    emails = set(event_emails)
    if event.event in alarm_events:
        emails |= alarm_emails

    if not emails:
        return

    body = '%s at %s' % (event.event_string, event.timestamp)

    _send_system_email(
        config, 'Security: %s' % event.event,
        emails, body)