#!/usr/bin/env bash

 # Generate a minimal filesystem for archlinux and load it into the local
 # docker as "archlinux"
 # requires root
 set -e
 

 hash pacstrap &>/dev/null || {

 	echo "Could not find pacstrap. Run pacman -S arch-install-scripts"
 	exit 1

 }

 hash expect &>/dev/null || {

 	echo "Could not find expect. Run pacman -S expect"
 	exit 1

 }
 

 export LANG="C.UTF-8"
 

 ROOTFS=$(mktemp -d ${TMPDIR:-/var/tmp}/rootfs-archlinux-XXXXXXXXXX)

 chmod 755 $ROOTFS

 # packages to ignore for space savings

 PKGIGNORE=(
     cryptsetup
     device-mapper
     dhcpcd
     iproute2
     jfsutils
     linux
     lvm2
     man-db
     man-pages
     mdadm
     nano
     netctl
     openresolv
     pciutils
     pcmciautils
     reiserfsprogs
     s-nail
     systemd-sysvcompat
     usbutils
     vi
     xfsprogs
 )
 IFS=','
 PKGIGNORE="${PKGIGNORE[*]}"
 unset IFS

 case "$(uname -m)" in
 	armv*)
 		if pacman -Q archlinuxarm-keyring >/dev/null 2>&1; then
 			pacman-key --init
 			pacman-key --populate archlinuxarm
 		else
 			echo "Could not find archlinuxarm-keyring. Please, install it and run pacman-key --populate archlinuxarm"
 			exit 1
 		fi
 		PACMAN_CONF='./mkimage-archarm-pacman.conf'
 		PACMAN_MIRRORLIST='Server = http://mirror.archlinuxarm.org/$arch/$repo'
 		PACMAN_EXTRA_PKGS='archlinuxarm-keyring'
 		EXPECT_TIMEOUT=120
 		ARCH_KEYRING=archlinuxarm
 		DOCKER_IMAGE_NAME=archlinuxarm
 		;;
 	*)
 		PACMAN_CONF='./mkimage-arch-pacman.conf'
 		PACMAN_MIRRORLIST='Server = https://mirrors.kernel.org/archlinux/$repo/os/$arch'
 		PACMAN_EXTRA_PKGS=''
 		EXPECT_TIMEOUT=60
 		ARCH_KEYRING=archlinux
 		DOCKER_IMAGE_NAME=archlinux
 		;;
 esac
 
 export PACMAN_MIRRORLIST
 

 expect <<EOF

 	set send_slow {1 .1}
 	proc send {ignore arg} {
 		sleep .1
 		exp_send -s -- \$arg
 	}

 	set timeout $EXPECT_TIMEOUT

 	spawn pacstrap -C $PACMAN_CONF -c -d -G -i $ROOTFS base haveged $PACMAN_EXTRA_PKGS --ignore $PKGIGNORE

 	expect {
 		-exact "anyway? \[Y/n\] " { send -- "n\r"; exp_continue }
 		-exact "(default=all): " { send -- "\r"; exp_continue }
 		-exact "installation? \[Y/n\]" { send -- "y\r"; exp_continue }
 	}

 EOF

 arch-chroot $ROOTFS /bin/sh -c 'rm -r /usr/share/man/*'

 arch-chroot $ROOTFS /bin/sh -c "haveged -w 1024; pacman-key --init; pkill haveged; pacman -Rs --noconfirm haveged; pacman-key --populate $ARCH_KEYRING; pkill gpg-agent"

 arch-chroot $ROOTFS /bin/sh -c "ln -s /usr/share/zoneinfo/UTC /etc/localtime"

 echo 'en_US.UTF-8 UTF-8' > $ROOTFS/etc/locale.gen

 arch-chroot $ROOTFS locale-gen

 arch-chroot $ROOTFS /bin/sh -c 'echo $PACMAN_MIRRORLIST > /etc/pacman.d/mirrorlist'

 
 # udev doesn't work in containers, rebuild /dev

 DEV=$ROOTFS/dev
 rm -rf $DEV
 mkdir -p $DEV
 mknod -m 666 $DEV/null c 1 3
 mknod -m 666 $DEV/zero c 1 5
 mknod -m 666 $DEV/random c 1 8
 mknod -m 666 $DEV/urandom c 1 9
 mkdir -m 755 $DEV/pts
 mkdir -m 1777 $DEV/shm
 mknod -m 666 $DEV/tty c 5 0
 mknod -m 600 $DEV/console c 5 1
 mknod -m 666 $DEV/tty0 c 4 0
 mknod -m 666 $DEV/full c 1 7
 mknod -m 600 $DEV/initctl p
 mknod -m 666 $DEV/ptmx c 5 2

 ln -sf /proc/self/fd $DEV/fd

 tar --numeric-owner --xattrs --acls -C $ROOTFS -c . | docker import - $DOCKER_IMAGE_NAME
 docker run --rm -t $DOCKER_IMAGE_NAME echo Success.

 rm -rf $ROOTFS