#! /bin/bash
#

set -e
set -u

ProgName="$0"
KVer=''

ERROR=0
WGET=$(which wget)

if [[ -z $WGET ]]; then
	echo "missing wget"
	ERROR=1
fi

if (( ERROR )); then
	exit 1
fi

function Md5Compare ()
{
	if [[ $(cat $2 | cut -d' ' -f1) \
			!= $(md5sum $1 | cut -d' ' -f1) ]]; then
		echo "Bad md5 detected on $1"
		exit 1
	fi
}

function GetDownloadPath()
{
	local v1=$(echo $KVer | cut -d'.' -f1)
	local v2=$(echo $KVer | cut -d'.' -f2)
	local v3=$(echo $KVer | cut -d'.' -f3)
	local v4=$(echo $KVer | cut -d'.' -f4)
	local path="kernel/$v1/$v1.$v2"

	if (( $v1 == 2 )); then
		if [[ -z $v3 ]]; then
			path="$path/$v1.$v2"
		else
			path="$path/$v1.$v2.$v3"
			if [[ -z $v4 ]]; then
				path="$path/$v1.$v2.$v3"
			else
				path="$path/$v1.$v2.$v3.$v4"
			fi
		fi
	else
		if [[ -z $v3 ]]; then
			path="$path/$v1.$v2"
		else
			path="$path/$v1.$v2.$v3"
		fi
	fi
	echo $path
}

function Download()
{
	echo "Downloading files"
	local path=$(GetDownloadPath)
	local f=''

	for f in Modules.tar.gz Modules.tar.gz.md5 uImage uImage.md5 System.map; do
		if [[ ! -f d2plug-$KVer-$f ]]; then
			local sites="http://www.xilka.com/sheeva"
			local s=''
			for s in $sites; do
				if $WGET -c $s/$path/d2plug-$KVer-$f && [[ -f d2plug-$KVer-$f ]]; then
					break
				fi
			done
			if [[ ! -f d2plug-$KVer-$f ]]; then
				echo "Unable to retrieve d2plug-$KVer-$f"
				exit 1
			fi
		fi
	done
	Md5Compare d2plug-$KVer-Modules.tar.gz d2plug-$KVer-Modules.tar.gz.md5
	Md5Compare d2plug-$KVer-uImage d2plug-$KVer-uImage.md5
}

function ExtractModules()
{
	local v1=$(echo $KVer | cut -d'.' -f1)
	local v2=$(echo $KVer | cut -d'.' -f2)
	local v3=$(echo $KVer | cut -d'.' -f3)
	local depmodVer=$KVer
	[[ ! -z $v3 ]] || depmodVer="$v1.$v2.0"
	local extractDir='/'
	[[ ! -L '/lib' ]] || extractDir=$(dirname $(readlink '/lib'))
	[[ -d $extractDir ]] || extractDir="/$extractDir"

	echo "Extracting modules"
	tar x -C $extractDir --overwrite -zf d2plug-$KVer-Modules.tar.gz
	[[ -d /boot ]] || mkdir /boot
	cp d2plug-$KVer-System.map /boot/
	depmod -eF /boot/d2plug-$KVer-System.map $depmodVer-dove-5.4.2
}

function RootKernel()
{
	echo "Writing kernel to /boot"
	[[ -d /boot ]] || mkdir /boot
	cp d2plug-$KVer-uImage /boot/
	echo "****************************************************************"
	echo " create a link from /boot/d2plug-$KVer-uImage to /boot/uImage"
	echo "****************************************************************"
}

function Usage()
{
	echo "Use  $ProgName VERSION to write kernel to /boot"
	echo
	echo "    where VERSION is something like 2.6.32.55"
}

if (( $# < 1 )) || [[ $1 == "--help" ]]; then
	Usage
	exit 1
fi

KVer="$1"

Download
ExtractModules
RootKernel