#!/bin/sh

# set some defaults
format="sh"
dbuser_varname="dbuser"
dbpass_varname="dbpass"
dbname_varname="dbname"
dbserver_varname="dbserver"
dbport_varname="dbport"
dbtype_varname="dbtype"
basepath_varname="basepath"

# the version will always be < the package version
VERSION="2.0"

version(){
	prog=$(basename $0)
	cat << EOF

$prog v$VERSION 
copyright (c) 2005 sean finney <seanius@debian.org>

EOF
}

usage(){
	version
	cat << EOF
usage: $prog [-hv] [-f format] [-a] [-d[varname]] [-u[varname]] [-p[varname]] [-s[varname]] [-P[varname]] [-t[varname]] [-C[comment]] [-O owner[:group]] [-m mode] [-U] infile [outfile]

	infile            use the given dbconfig-common config file as input
	outfile           use the given file as input (default: stdout)
	-f|--format       use the given output format (default: sh)
	-o|--options		provide output-format-specific options
	-a|--all          include all information in output (default)
	-b|--basepath     include the basepath in the output
	-d|--dbname       include the dbname in the output
	-p|--dbpass       include the dbpass in the output
	-s|--dbserver     include the dbserver in the output
	-P|--dbport       include the dbport in the output
	-u|--dbuser       include the dbuser in the output
	-t|--dbtype       include the dbtype in the output
	-C|--comment      comment out unset variables
	-O|--owner        set the owner:group of the output file
	-m|--mode         set the permissions on the output file
	-U|--ucf          register the outputfile with ucf
	-h|--help         display this helpful message
	-v|--version      output the version and exit

	format is one of a list of include-file style formats for various
	programming languages.  the current list includes:
		sh - /bin/sh style include file
		perl - perl parseable include file
		php - php parseable include file
		template - perform pattern substitution on a pre-existing template
		cpp - c-style header file, using #define'd constants

EOF
}

check_permissions(){
	local line
	if dpkg-statoverride --list "$outputfile" >/dev/null; then
		line=$(dpkg-statoverride --list "$outputfile")
		owner=$(echo $line | cut -d' ' -f1,2 | tr ' ' ':')
		perms=$(echo $line | cut -d' ' -f3)
	fi
}

# Protect strings for use in the right hand side of a sed "s" command
#
# Without protection, double backslashes are interpreted as one
# protected backslash, therefore "\\" -> "\\\\"
# Without protection, an & "refers to that portion of the pattern
# space which matched", therefore "&" -> "\\&"
# The / is used as the seperator, so it needs escaping too,
# therefore "/" -> "\\/"
sed_rhs_escape(){
    sed -e 's/\\/\\&/g' -e 's/&/\\&/g' -e 's,/,\\&,g' << EOF
$1
EOF
}

# Protect strings for use in shell files where the variable is
# quoted in single quotes
sh_sq_escape(){
	sed -e "s,','\\\\'',g" << EOF
$1
EOF
}

# Protect strings for use in php files where the variable is
# quoted in single quotes
php_sq_escape(){
	sed -e 's/\\/\\&/g' -e "s,',' . \"'\" . ',g" << EOF
$1
EOF
}

# Protect strings for use in perl files where the variable is
# quoted in single quotes
perl_sq_escape(){
	php_sq_escape "$1"
}


TEMP=$(getopt -o af:hb::d::m:o:p::u::s::t::C::O:P::Uv --long help,dbuser::,dbname::,dbpass::,dbport::,dbserver::,dbtype::,basepath::,output:,format:,options:,comment::,owner:,mode:,ucf,version -n $0 -- "$@")

if [ $? != 0 ] ; then usage >&2 ; exit 1 ; fi

eval set -- "$TEMP"

while true; do
	case "$1" in
	-a|--all)
		use_all="yes"
		shift
	;;
	-b|--basepath)
		use_basepath="yes"
		if [ ! -z "$2" ]; then
			basepath_varname="$2"
		fi
		shift 2
	;;
	-d|--dbname)
		use_dbname="yes"
		if [ ! -z "$2" ]; then
			dbname_varname="$2"
		fi
		shift 2
	;;
	-u|--dbuser)
		use_dbuser="yes"
		if [ ! -z "$2" ]; then
			dbuser_varname="$2"
		fi
		shift 2
	;;
	-p|--dbpass)
		use_dbpass="yes"
		if [ ! -z "$2" ]; then
			dbpass_varname="$2"
		fi
		shift 2
	;;
	-s|--dbserver)
		use_dbserver="yes"
		if [ ! -z "$2" ]; then
			dbserver_varname="$2"
		fi
		shift 2
	;;
	-P|--dbport)
		use_dbport="yes"
		if [ ! -z "$2" ]; then
			dbport_varname="$2"
		fi
		shift 2
	;;
	-t|--dbtype)
		use_dbtype="yes"
		if [ ! -z "$2" ]; then
			dbtype_varname="$2"
		fi
		shift 2
	;;
	-f|--format)
		format="$2"
		shift 2
	;;
	-C|--comment)
		use_comment="yes"
		if [ ! -z "$2" ]; then
			comment_string="$2"
		fi
		shift 2
	;;		
	-O|--owner)
		owner="$2"
		shift 2
	;;		
	-m|--mode)
		perms="$2"
		shift 2
	;;	
	-h|--help)
		usage
		exit
	;;
	-v|--version)
		version
		exit
	;;
	-U|--ucf)
		do_ucf=1
		shift
	;;
	-o|--options)
		eval $2
		shift 2
	;;
	--)
		shift
		break
	;;
	*)
		echo "eh? $1" >&2
		exit 1
	;;
	esac
done

# if they asked for all vars, or didn't ask for anything (which defaults to all)
if [ "$use_all" ] || [ ! "${use_dbuser}${use_dbpass}${use_basepath}${use_dbname}${use_dbserver}${use_dbtype}${use_dbport}" ]; then
		use_dbuser="yes"
		use_dbpass="yes"
		use_basepath="yes"
		use_dbname="yes"
		use_dbserver="yes"
		use_dbport="yes"
		use_dbtype="yes"
fi

inputfile=$1
outputfile=$2

if [ ! "$inputfile" ]; then
	echo "you must specify an inputfile" >&2
	usage >&2
	exit 1
fi

if [ "$outputfile" ]; then
	tmpout=$(mktemp -t dbconfig-generate-include.XXXXXX)
	if [ ! -f "$tmpout" ]; then
		echo "unable to create temporary file $tmpout" >&2
		exit 1
	fi
	exec > $tmpout
fi

if [ ! -f "$inputfile" ] || [ ! -r "$inputfile" ]; then
	echo "unable to read input file $inputfile" >&2
	exit 1
fi

if ! . $inputfile ; then
	echo "error processing $inputfile, check file contents" >&2
	exit 1
fi

# if commenting-out is enabled
if [ "$use_comment" ]; then
	# if a comment string was not explicitly specified set a default
	if [ ! "$comment_string" ]; then
		case $format in
		sh|php|perl)
			comment_string="#"
		;;
		cpp)
			comment_string="//"
		;;
		template)
			echo "E: must specify a comment string for 'template' format" >&2
			exit 1
		;;
		esac
	fi
	# now determine which things should be commented out if any
	[ ! "$dbc_dbuser" ] && comment_dbuser="${comment_string}"
	[ ! "$dbc_dbpass" ] && comment_dbpass="${comment_string}"
	[ ! "$dbc_basepath" ] && comment_basepath="${comment_string}"
	[ ! "$dbc_dbname" ] && comment_dbname="${comment_string}"
	[ ! "$dbc_dbserver" ] && comment_dbserver="${comment_string}"
	[ ! "$dbc_dbport" ] && comment_dbport="${comment_string}"
	[ ! "$dbc_dbtype" ] && comment_dbtype="${comment_string}"
fi

case $format in
sh)
	cat << EOF 
##
## database access settings in /bin/sh format
## automatically generated from $inputfile
## by $0
##
## by default this file is managed via ucf, so you shouldn't have to
## worry about manual changes being silently discarded.  *however*,
## you'll probably also want to edit the configuration file mentioned
## above too.
##

EOF
	[ "$use_dbuser" ] && echo "${comment_dbuser}$dbuser_varname='$(sh_sq_escape "$dbc_dbuser")'"
	[ "$use_dbpass" ] && echo "${comment_dbpass}$dbpass_varname='$(sh_sq_escape "$dbc_dbpass")'"
	[ "$use_basepath" ] && echo "${comment_basepath}$basepath_varname='$(sh_sq_escape "$dbc_basepath")'"
	[ "$use_dbname" ] && echo "${comment_dbname}$dbname_varname='$(sh_sq_escape "$dbc_dbname")'"
	[ "$use_dbserver" ] && echo "${comment_dbserver}$dbserver_varname='$(sh_sq_escape "$dbc_dbserver")'"
	[ "$use_dbport" ] && echo "${comment_dbport}$dbport_varname='$(sh_sq_escape "$dbc_dbport")'"
	[ "$use_dbtype" ] && echo "${comment_dbtype}$dbtype_varname='$(sh_sq_escape "$dbc_dbtype")'"
;;

php)
	cat << EOF 
<?php
##
## database access settings in php format
## automatically generated from $inputfile
## by $0
##
## by default this file is managed via ucf, so you shouldn't have to
## worry about manual changes being silently discarded.  *however*,
## you'll probably also want to edit the configuration file mentioned
## above too.
##
EOF
	[ "$use_dbuser" ] && echo "${comment_dbuser}\$$dbuser_varname='$(php_sq_escape "$dbc_dbuser")';"
	[ "$use_dbpass" ] && echo "${comment_dbpass}\$$dbpass_varname='$(php_sq_escape "$dbc_dbpass")';"
	[ "$use_basepath" ] && echo "${comment_basepath}\$$basepath_varname='$(php_sq_escape "$dbc_basepath")';"
	[ "$use_dbname" ] && echo "${comment_dbname}\$$dbname_varname='$(php_sq_escape "$dbc_dbname")';"
	[ "$use_dbserver" ] && echo "${comment_dbserver}\$$dbserver_varname='$(php_sq_escape "$dbc_dbserver")';"
	[ "$use_dbport" ] && echo "${comment_dbport}\$$dbport_varname='$(php_sq_escape "$dbc_dbport")';"
	[ "$use_dbtype" ] && echo "${comment_dbtype}\$$dbtype_varname='$(php_sq_escape "$dbc_dbtype")';"
	cat << EOF 
EOF
;;

perl)
	cat << EOF 
##
## database access settings in perl format
## automatically generated from $inputfile
## by $0
##
## by default this file is managed via ucf, so you shouldn't have to
## worry about manual changes being silently discarded.  *however*,
## you'll probably also want to edit the configuration file mentioned
## above too.
##
EOF
	[ "$use_dbuser" ] && echo "${comment_dbuser}our \$$dbuser_varname='$(perl_sq_escape "$dbc_dbuser")';"
	[ "$use_dbpass" ] && echo "${comment_dbpass}our \$$dbpass_varname='$(perl_sq_escape "$dbc_dbpass")';"
	[ "$use_basepath" ] && echo "${comment_basepath}our \$$basepath_varname='$(perl_sq_escape "$dbc_basepath")';"
	[ "$use_dbname" ] && echo "${comment_dbname}our \$$dbname_varname='$(perl_sq_escape "$dbc_dbname")';"
	[ "$use_dbserver" ] && echo "${comment_dbserver}our \$$dbserver_varname='$(perl_sq_escape "$dbc_dbserver")';"
	[ "$use_dbport" ] && echo "${comment_dbport}our \$$dbport_varname='$(perl_sq_escape "$dbc_dbport")';"
	[ "$use_dbtype" ] && echo "${comment_dbtype}our \$$dbtype_varname='$(perl_sq_escape "$dbc_dbtype")';"
	cat << EOF 
1;
EOF
;;
cpp)
	cat << EOF 
/*
 * database access settings in cpp header format
 * why you would ever need this, who knows? :)
 * automatically generated from $inputfile
 * by $0
 *
 * by default this file is managed via ucf, so you shouldn't have to
 * worry about manual changes being silently discarded.  *however*,
 * you'll probably also want to edit the configuration file mentioned
 * above too.
 *
 */
#ifndef _DBCONFIG_COMMON_CONFIG_
 #define _DBCONFIG_COMMON_CONFIG_
EOF
	[ "$use_dbuser" ] && echo " ${comment_dbuser}#define $dbuser_varname \"$dbc_dbuser\";"
	[ "$use_dbpass" ] && echo " ${comment_dbpass}#define $dbpass_varname \"$dbc_dbpass\";"
	[ "$use_basepath" ] && echo "${comment_basepath}#define $basepath_varname \"$dbc_basepath\";"
	[ "$use_dbname" ] && echo " ${comment_dbname}#define $dbname_varname \"$dbc_dbname\";"
	[ "$use_dbserver" ] && echo " ${comment_dbserver}#define $dbserver_varname \"$dbc_dbserver\";"
	[ "$use_dbport" ] && echo " ${comment_dbport}#define $dbport_varname \"$dbc_dbport\";"
	[ "$use_dbtype" ] && echo " ${comment_dbtype}#define $dbtype_varname \"$dbc_dbtype\";"
	cat << EOF 
#endif /* _DBCONFIG_COMMON_CONFIG_ */
EOF
;;
template)
	if [ ! "$template_infile" ]; then
		cat << EOF >&2
error: you must specify a template file. for example: '-o template_infile=foo'
EOF
		exit 1
	elif [ ! -f "$template_infile" ]; then
		echo "error: template infile $template_infile does not exist" >&2
		exit 1
	fi
	sedtmp=$(mktemp -t dbconfig-generate-include.sed.XXXXXX)
	if [ ! -f "$sedtmp" ]; then
		echo "unable to create temporary file $sedtmp" >&2
		exit 1
	fi
	# we do not want _DBC_DBSERVER_ to be expanded to "" (which means "use
	# the best available method to connect to the local db): expand it to
	# "localhost" if needed
	if [ -z "$dbc_dbserver" ] ; then
		_dbc_dbserver="localhost"
	else
		_dbc_dbserver="$dbc_dbserver"
	fi
	cat << EOF > "$sedtmp"
s/^\(.*\)_DBC_DBUSER_/${comment_dbuser}\1$(sed_rhs_escape "$dbc_dbuser")/g
s/^\(.*\)_DBC_DBPASS_/${comment_dbpass}\1$(sed_rhs_escape "$dbc_dbpass")/g
s/^\(.*\)_DBC_BASEPATH_/${comment_basepath}\1$(sed_rhs_escape "$dbc_basepath")/g
s/^\(.*\)_DBC_DBNAME_/${comment_dbname}\1$(sed_rhs_escape "$dbc_dbname")/g
s/^\(.*\)_DBC_DBSERVER_/${comment_dbserver}\1$(sed_rhs_escape "$_dbc_dbserver")/g
s/^\(.*\)_DBC_DBPORT_/${comment_dbport}\1$(sed_rhs_escape "$dbc_dbport")/g
s/^\(.*\)_DBC_DBTYPE_/${comment_dbtype}\1$(sed_rhs_escape "$dbc_dbtype")/g
EOF
	sed -f "$sedtmp" < "$template_infile" 
	rm -f "$sedtmp"
;;
esac

if [ "$outputfile" ]; then
	if [ -e "$outputfile" ] ; then
		# In order to preserve all local attributes of the
		# original file, copy them to the tmpout file, so that
		# later on they are copied back (by ucf or mv command).
		cp --preserve=all --attributes-only "$outputfile" "$tmpout"
	fi
	if [ "$do_ucf" ]; then
		ucf --debconf-ok "$tmpout" "$outputfile" >&2
		rm -f "$tmpout"
	else
		mv "$tmpout" "$outputfile"
	fi
	check_permissions
	if [ -e "$outputfile" ] ; then
	    [ "$owner" ] && chown $owner $outputfile
	    [ "$perms" ] && chmod $perms $outputfile
	fi
fi

exit 0
