#!/bin/bash
#
# /usr/sbin/php-select
#		Tool for managing PHP symlinks on Gentoo Linux
#
# Author	Stuart Herbert
#		(stuart@gentoo.org)
#
# Copyright	(c) 2005 Gentoo Foundation, Inc.
#		Released under v2 of the GNU General Public License
#
# ========================================================================
#
# USAGE
# -----
#
# php-select <component> [<php-version>]
#
# where
#    <component> is one of
#      php|php-cgi|php-devel|apache|apache2
#
#    <php-version> is the directory under /usr/lib where PHP is installed
#
# php-select with no arguments will list all components for each installed
# php-version
#
# php-select <component> will list the current php-version in use for that
# component
#
# php-select <component> <php-version> will reconfigure Gentoo to use 
# <php-version> of <component>.  This normally involves replacing symlinks
# on the system

# ========================================================================

G_ACTION=
G_COMPONENT=
G_COPYRIGHT[0]="Copyright (c) 2005 Gentoo Foundation, Inc."
G_COPYRIGHT[1]="Released under v2 of the GNU General Public License"
G_EXITSTATUS=0
G_LIBDIR[0]="/usr/lib64"
G_LIBDIR[1]="/usr/lib32"
G_LIBDIR[2]="/usr/lib"
G_MODULE_PATH="/usr/share/php-select"
G_NEED_COMPONENT=0
G_NEED_PHPVERSION=0
G_PN="$0"
G_PN_BASE="`basename $G_PN`"
G_PVR="1.0.1"
G_PHPVERSION=

G_STATUS_OK=0
G_STATUS_USAGE=1
G_STATUS_NOTINSTALLED=2
G_STATUS_NOTCOMPATIBLE=3
G_STATUS_USINGOTHER=4
G_STATUS_USINGNONE=5

# ========================================================================
# The Main Actions
# ========================================================================

# ------------------------------------------------------------------------
# doCopyright() - output the copyright info
#
# No arguments

doCopyright ()
{
	local i

	for (( i = 0 ; i < ${#G_COPYRIGHT[@]} ; i = i + 1 )) ; do
		echo ${G_COPYRIGHT[$i]}
	done
}

# ------------------------------------------------------------------------
# doHelp() - show full help
#
# No arguments

doHelp ()
{
	doVerboseVersion
	echo
	
	doUsageShort
	echo
	echo "    $G_PN_BASE <component>"
	echo "        Show which version of PHP is used for <component>"
	echo
	echo "    $G_PN_BASE -t <component> <php-version>"
	echo "        Test if <component> uses <php-version> or not"
	echo
	echo "    $G_PN_BASE <component> <php-version>"
	echo "        Set which version of PHP is used for <component>"
	echo
	echo "    $G_PN_BASE -v"
	echo "        Show version number"
	echo
	echo "    $G_PN_BASE -h"
	echo "        Show this help"
	echo
	echo "where <component> is one of:"
	echo
	echo "    apache1   - Apache webserver v1.x"
	echo "    apache2   - Apache webserver v2.x"
	echo "    php       - /usr/bin/php (the CLI SAPI)"
	echo "    php-cgi   - /usr/bin/php-cgi (the CGI SAPI)"
	echo "    php-devel - the scripts used to build PECL extensions"
	echo
	echo "and where <php-version> is one of:"
	echo
	echo "    php4      - php 4.x"
	echo "    php5      - php 5.x"
	echo
	echo "NOTE: none of these settings affect how Portage installs PHP or PEAR"
	echo "      packages or PECL extensions."
	echo
	echo "Exit status is one of:"
	echo
	echo "  0 == ok"
	echo "  1 == usage error"
	echo "  2 == no compatible PHP version found"
	echo "  3 == incompatible PHP version specified"
	echo "  4 == component uses a different PHP version"
	echo "  5 == component not configured to use PHP"

	echo
	# doManPageDetails
}

# ------------------------------------------------------------------------
# doManPageDetails() - show man page details
#
# No arguments

doManPageDetails ()
{
	echo "See 'man $G_PN_BASE' for full details"
}

# ------------------------------------------------------------------------
# doSetComponent() - set a component to use a particular php version
#
# $1: component to set
# $2: php version to set the component to

doSetComponent ()
{
	loadComponent $1 || exit 1
	actionSet $2
}

# ------------------------------------------------------------------------
# doShowComponent() - show which version of php a particular component is
# currently using
#
# $1: component to show

doShowComponent ()
{
	loadComponent $1 || exit 1
	actionShow
}

# ------------------------------------------------------------------------
# doTest() - check to see if a particular component is using a specified
# version or not
#
# $1: component to test

doTest ()
{
	loadComponent $1 || exit 1
	actionTest
}

# ------------------------------------------------------------------------
# doUsage() - tell the user to stop being a muppet :)
#
# No arguments

doUsage ()
{
	doUsageShort
	echo "use $G_PN_BASE --help for full details"
	G_EXITSTATUS=1
}

# ------------------------------------------------------------------------
# doUsageShort() - print out just the line to tell the user what to do
#
# No arguments

doUsageShort ()
{
	echo "usage: $G_PN_BASE [-htv] [<component> [<php-version>] ]"
}

# ------------------------------------------------------------------------
# doVerboseVersion() - show more version info
#
# No arguments

doVerboseVersion ()
{
	doVersion
	doCopyright
}

# ------------------------------------------------------------------------
# doVersion() - show version info
#
# No arguments

doVersion ()
{
	echo "$G_PN_BASE v$G_PVR"
}

# ========================================================================
# Helping Functions
# ========================================================================

# ------------------------------------------------------------------------
# loadComponent() - load a component's code into the script
#
# $1: component to load

loadComponent ()
{
	# only load one component, and only do it once

	if [[ -n $G_COMPONENT_LOADED ]] ; then
		return
	fi

	local l_module="$G_MODULE_PATH/$1.sh"

	if [[ ! -f $l_module ]] ; then
		echo "Error: module $l_module not found"
		return 1
	fi

	if [[ ! -r $l_module ]] ; then
		echo "Error: module $l_module not readable"
		return 1
	fi

	. "$l_module" && G_COMPONENT_LOADED=1
	[[ $? != 0 ]] && echo "Error: component $l_module not loadable"

	return 0
}

# ------------------------------------------------------------------------
# missingComponent() - check to see if the user did not specify which
# component to work on
#
# No arguments

missingComponent ()
{
	if [[ -z $G_COMPONENT && $G_NEED_COMPONENT == 1 ]] ; then
		echo "*** error: missing <component> argument"
		return 0
	fi

	return 1
}

# ------------------------------------------------------------------------
# missingPhpVersion() - check to see if the user did not specify which
# PHP version to use
#
# No arguments

missingPhpVersion ()
{
	if [[ -z $G_PHPVERSION && $G_NEED_PHPVERSION == 1 ]] ; then
		echo "*** error: missing <php-version> argument"
		return 0
	fi

	return 1
}

# ------------------------------------------------------------------------
# parseArgs() - work out what the user has asked us to do
#
# $1: a php component (optional)
# $2: a php version (optional)

parseArgs ()
{
	# do we have any parameters at all?

	if [[ -z $1 ]]; then
		G_ACTION=doUsage
		return
	fi

	# handle switches

	while [[ -n $1 && ${1:0:1} == '-' ]]; do
		case "$1" in
			-v|--version)
				G_ACTION=doVersion
				return
				;;
			-V)
				G_ACTION=doVerboseVersion
				return
				;;
			-h|-\?|--help)
				G_ACTION=doHelp
				return
				;;
			-t|--test)
				G_ACTION=doTest
				G_NEED_COMPONENT=1
				G_NEED_PHPVERSION=1
				;;
			*)
				G_ACTION=doUsage
				return
				;;
		esac

		shift
	done

	# if we get here, we have a non-switch to examine, or we
	# don't have anything at all to look at

	if [[ -z $1 ]]; then
		if missingComponent || missingPhpVersion ; then
			G_ACTION=doUsage
		fi
		return
	fi
	
	# we have a component - make a note of it

	G_COMPONENT="$1"
	shift

	# do we have a php version too?

	if [[ -z $1 ]]; then
		if missingComponent || missingPhpVersion ; then
			G_ACTION=doUsage
		fi

		[[ -z $G_ACTION ]] && G_ACTION=doShowComponent
		return
	fi

	# yes we do - make a note of it too

	G_PHPVERSION="$1"
	[[ -z $G_ACTION ]] && G_ACTION=doSetComponent
	shift

	# we're done for now
}

# ------------------------------------------------------------------------
# main() - it all happens here

main ()
{
	parseArgs "$@"
	$G_ACTION $G_COMPONENT $G_PHPVERSION

	exit $G_EXITSTATUS
}

main "$@"