#!/bin/bash

conffile=/etc/ssmtp/ssmtp.conf
revaliasfile=/etc/ssmtp/revalias

conffvalue()
{
	:
}

if test -s "${conffile}"
then
if awk --version > /dev/null
then
conffvalue()
{
	awk -F= '/^[\t]*[^#]/ && $1 ~ re {print $2; exit}' \
	    re="$1" "${conffile}"
}
else
echo "(You seem to be missing awk, so I can't read the values currently"
echo "stored in ${conffile}; you'll have to re-enter them manually if"
echo "you want to re-use them.  ${conffile} will not be overwritten"
echo "unless you confirm the overwrite at the end of the configuration.)"
echo
echo
fi
fi

echo "Configure sSMTP in Six Easy Steps"
echo
echo "(1) mailhub"
echo "This is the computer responsible for handling your outgoing mail."
echo "It could be the SMTP server of your ISP, or a departmental mailhub."
echo "Use the fully-qualified domain name (foo.bar.baz) of the mailhub;"
echo "if it uses an unusual SMTP port number, use the colon syntax"
echo "  foo.bar.baz:2525"
echo "Otherwise sSMTP will use the standard SMTP port number (25)."
echo "(Note that sSMTP can support a user-dependent mailhub with the"
echo "'reverse aliases' feature, for which see the man page.)"
echo

found=$(conffvalue mailhub)
found=${found:-$SMTPSERVER}

echo -n "Please enter your mailhub [$found]: "
read -e mailhub

mailhub=${mailhub:-$found}

echo
echo "(2) FromLineOverride"
echo "This specifies how sSMTP handles the From: line of outgoing mail."
echo "If FromLineOverride=YES, sSMTP will leave the From: line alone if"
echo "it already exists.  If FromLineOverride has any other value, or"
echo "there is no From: line, sSMTP creates the From: line using your"
echo "username (or the -f command-line option), and the value of the"
echo "rewriteDomain option (step (4), below)."
echo "    If you use a mail user agent (MUA; e.g. mutt, pine) I recommend"
echo "using YES and having the MUA set the From: line.  (Exception: the"
echo "'reverse aliases' feature can be used to set up a particular From:"
echo "address for each user, in which case don't use FromLineOverride=YES."
echo "See the man page.)"
echo

found=$(conffvalue FromLineOverride)
found=${found:-YES}

echo -n "FromLineOverride? [$found]: "
read -e FromLineOverride

FromLineOverride=${FromLineOverride:-$found}

echo
echo "(3) hostname"
echo "sSMTP uses the hostname of your computer to identify itself to the"
echo "mailhub, and in the Received: headers of the outgoing mail.  This"
echo "has relatively little effect on how the mail is handled."
echo "    Use the fully-qualified domain name (FQDN) of your computer"
echo "(foo.bar.baz).  If it doesn't have a FQDN, use some name for your box."
echo

found=$(conffvalue hostname)
##no --fqdn option on Cygwin
#found=$(found:-`hostname --fqdn`)

echo -n "Hostname of your box [$found]: "
read -e hostname

hostname=${hostname:-$found}

echo
echo "(4) rewriteDomain"
echo "Please enter the mail name of your system."
echo "sSMTP uses this value to add a domain to unqualified e-mail addresses"
echo "(addresses without an @-sign)."
echo "    You probably want to use the domain from your own e-mail address."
echo "You probably want to set up your MUA to handle unqualified addresses"
echo "itself, in which case sSMTP will never have to use this.  (Users of"
echo "cron note that cron always uses unqualified addresses.)"
echo

found=$(conffvalue rewriteDomain)
if test -f /etc/mailname
then found=${found:-`head -1 /etc/mailname`}
fi
found=${found:-$hostname}

echo -n "Mail name [$found]: "
read -e rewriteDomain

rewriteDomain=${rewriteDomain:-$found}

echo
echo "(5) root"
echo "If sSMTP finds an unqualified e-mail address among"
echo "the recipients, and it corresponds to a username on your local"
echo "machine with a userid less than 1000, then the e-mail is sent to"
echo "this value instead.  The idea is that mail sent to 'root' should"
echo "probably go to 'postmaster' instead."
echo "    If you set up your MUA to do its own handling of unqualified"
echo "addresses, this is irrelevant.  (But note that cron does use"
echo "unqualified addresses corresponding to local usernames.)"
echo "Use your own e-mail address unless you know a better postmaster."
echo

found=$(conffvalue root)
found=${found:-postmaster}

echo -n "System users receive mail at [$found]: "
read -e root

root=${root:-$found}

echo
echo "(6) link /usr/sbin/sendmail to /usr/sbin/ssmtp?"
echo "Some programs (e.g. cron) expect /usr/sbin/sendmail to handle mail."
/usr/sbin/alternatives --install /usr/sbin/sendmail mta /usr/sbin/ssmtp.exe 0 \
	--slave /usr/lib/sendmail mta-sendmail /usr/sbin/ssmtp.exe \
	--slave /usr/bin/mailq mta-mailq /usr/sbin/ssmtp.exe \
	--slave /usr/bin/newaliases mta-newaliases /usr/sbin/ssmtp.exe
/usr/sbin/alternatives --set mta /usr/sbin/ssmtp.exe
echo

#
# Generate revalias file
#
if ! test -e "${revaliasfile}"
then
  cat > "${revaliasfile}" <<-EOF
	# sSMTP aliases
	#
	# Format:       local_account:outgoing_address:mailhub
	#
	# Example: root:your_login@your.domain:mailhub.your.domain[:port]
	# where [:port] is an optional port number that defaults to 25.
	EOF
fi

#
# Generate configuration file
#
if test -s "${conffile}"
then
    echo
    echo
    echo "Configuration file ${conffile} already exists."
    echo -n "Reconfigure and lose your previous settings (y/N)? "
    read -e ans

    if test "$ans" = "y"  -o  "$ans" = "Y"
    then
	true
    else
	exit 0
    fi
fi

cat > "${conffile}" <<EOF
#
# /etc/ssmtp/ssmtp.conf -- a config file for sSMTP sendmail.
#

mailhub=$mailhub
FromLineOverride=$FromLineOverride
hostname=$hostname
rewriteDomain=$rewriteDomain
root=$root

#UseTLS=YES
#AuthUser=your_email_login
#AuthPass=do_you_really_want_to_do_this?
#UseTLSCert=YES
#TLSCert=/etc/ssl/certs/ssmtp.pem
#Debug=YES

# Configure sSMTP in Six Easy Steps (or so)
# 
# (1) mailhub
# This is the computer responsible for handling your outgoing mail.
# It could be the SMTP server of your ISP, or a departmental mailhub.
# Use the fully-qualified domain name (foo.bar.baz) of the mailhub;
# if it uses an unusual SMTP port number, use the colon syntax
#   foo.bar.baz:2525
# Otherwise sSMTP will use the standard SMTP port number (25).
# (Note that sSMTP can support a user-dependent mailhub with the
# 'reverse aliases' feature, for which see the man page.)
# 
# (2) FromLineOverride
# This specifies how sSMTP handles the From: line of outgoing mail.
# If FromLineOverride=YES, sSMTP will leave the From: line alone if
# it already exists.  If FromLineOverride has any other value, or
# there is no From: line, sSMTP creates the From: line using your
# username (or the -f command-line option), and the value of the
# rewriteDomain option (step (4), below).
#     If you use a mail user agent (MUA; e.g. mutt, pine) I recommend
# using YES and having the MUA set the From: line.  (Exception: the
# 'reverse aliases' feature can be used to set up a particular From:
# address for each user, in which case don't use FromLineOverride=YES.
# See the man page.)
# 
# (3) hostname
# sSMTP uses the hostname of your computer to identify itself to the
# mailhub, and in the Received: headers of the outgoing mail.  This
# has relatively little effect on how the mail is handled.
#     Use the fully-qualified domain name (FQDN) of your computer
# (foo.bar.baz).  If it doesn't have a FQDN, use some name for your box.
# 
# (4) rewriteDomain
# Please enter the mail name of your system.
# sSMTP uses this value to add a domain to unqualified e-mail addresses
# (addresses without an @-sign).
#     You probably want to use the domain from your own e-mail address.
# You probably want to set up your MUA to handle unqualified addresses
# itself, in which case sSMTP will never have to use this.  (Users of
# cron note that cron always uses unqualified addresses.)
# 
# (5) root
# If sSMTP finds an unqualified e-mail address among
# the recipients, and it corresponds to a username on your local
# machine with a userid less than 1000, then the e-mail is sent to
# this value instead.  The idea is that mail sent to 'root' should
# probably go to 'postmaster' instead.
#     If you set up your MUA to do its own handling of unqualified
# addresses, this is irrelevant.  (But note that cron does use
# unqualified addresses corresponding to local usernames.)
# Use your own e-mail address unless you know a better postmaster.
# 
# (6) link /usr/sbin/sendmail to /usr/sbin/ssmtp?
# Some programs (e.g. cron) expect /usr/sbin/sendmail to handle mail.
# You may wish to ensure that it is a symbolic link to /usr/sbin/ssmtp.
#
# (7) Miscellaneous SSL/TLS configuration
# Use SSL/TLS to send secure messages to server.
#	UseTLS=YES
# Use SSL/TLS certificate to authenticate against smtp host.
#	UseTLSCert=YES
# Use this RSA certificate.
#	TLSCert=/etc/ssl/certs/ssmtp.pem
#
# (8) Debugging
# Get enhanced (*really* enhanced) debugging information in the logs
# If you want to have debugging of the config file parsing, move this option
# to the top of the config file and uncomment
#	Debug=YES
EOF

echo
echo
echo "Please check the configuration file ${conffile} for correctness."
echo
echo