#!/bin/sh
# Build Debian root filesystem

OS="$1" # For example "debian"
ARCH="$2" # For example "armhf"
DIST="$3" # For example "buster"

set -ex

case "${OS}-${ARCH}" in
debian-armhf)
	KERNEL=linux-image-armmp
	URL=http://deb.debian.org/debian
	SCRIPT=/usr/share/debootstrap/scripts/sid
	;;
debian-arm64)
	KERNEL=linux-image-arm64
	URL=http://deb.debian.org/debian
	SCRIPT=/usr/share/debootstrap/scripts/sid
	;;
debian-i386)
	KERNEL=linux-image-686
	URL=http://deb.debian.org/debian
	SCRIPT=/usr/share/debootstrap/scripts/sid
	;;
debian-amd64)
	KERNEL=linux-image-amd64
	URL=http://deb.debian.org/debian
	SCRIPT=/usr/share/debootstrap/scripts/sid
	;;
ubuntu-armhf|ubuntu-arm64|ubuntu-amd64)
	KERNEL=linux-image-generic
	URL=http://ports.ubuntu.com/ubuntu-ports
	SCRIPT=/usr/share/debootstrap/scripts/gutsy
	;;
*)
	echo "Can't decide kernel package for \"${ARCH}\""
	exit 1
	;;
esac

# Create fresh empty directory
TMP=$(mktemp -d -p "${PWD}" tmp-XXXXXX)
trap 'rm -rf "${TMP}"' EXIT INT TERM
cd "${TMP}"

# Build a Debian root filesystem (first stage)
debootstrap \
  --arch="${ARCH}" \
  --verbose \
  --variant=minbase \
  --foreign \
  --include=\
netbase,\
net-tools,\
systemd-sysv,\
u-boot-tools,\
initramfs-tools,\
openssh-server \
  "${DIST}" \
  debian \
  "${URL}" \
  "${SCRIPT}"

# Randomly generated root password
PASSWORD=$(pwgen -B -A 6 1)

# Write apt sources config
case "${OS}-${DIST}" in
debian-sid)
	tee debian/tmp/sources.list <<- EOF
deb http://deb.debian.org/debian ${DIST} main
deb-src http://deb.debian.org/debian ${DIST} main
EOF
	;;
debian-bullseye)
	tee debian/tmp/sources.list <<- EOF
deb http://deb.debian.org/debian ${DIST} main
deb-src http://deb.debian.org/debian ${DIST} main
deb http://deb.debian.org/debian ${DIST}-updates main
deb-src http://deb.debian.org/debian ${DIST}-updates main
EOF
	;;
debian-*)
	tee debian/tmp/sources.list <<- EOF
deb http://deb.debian.org/debian ${DIST} main
deb-src http://deb.debian.org/debian ${DIST} main
deb http://deb.debian.org/debian ${DIST}-updates main
deb-src http://deb.debian.org/debian ${DIST}-updates main
deb http://security.debian.org/debian-security ${DIST}/updates main
deb-src http://security.debian.org/debian-security ${DIST}/updates main
EOF
	;;
ubuntu-*)
	tee debian/tmp/sources.list <<- EOF
deb http://ports.ubuntu.com/ubuntu-ports ${DIST} main universe
deb-src http://ports.ubuntu.com/ubuntu-ports ${DIST} main universe
deb http://ports.ubuntu.com/ubuntu-ports ${DIST}-updates main universe
deb-src http://ports.ubuntu.com/ubuntu-ports ${DIST}-updates main universe
deb http://ports.ubuntu.com/ubuntu-ports ${DIST}-security main universe
deb-src http://ports.ubuntu.com/ubuntu-ports ${DIST}-security main universe
EOF
	;;
esac

cp -rv --preserve=mode ../2nd-stage-files/pre-2nd-stage-files/* debian
cp -rv --preserve=mode ../2nd-stage-files/pre-2nd-stage-files-${ARCH}/* debian

# Copy ARM emulation stuff
cp -v /usr/bin/qemu-*-static debian/usr/bin || :

# Build a Debian root filesystem (second stage)
chroot debian /bin/sh -ex <<- EOF
/debootstrap/debootstrap --second-stage
/bin/mv /tmp/sources.list /etc/apt/sources.list
/usr/bin/apt-get update
/usr/bin/apt-get -y --no-install-recommends install ${KERNEL}
/usr/bin/apt-get -y upgrade
/usr/bin/apt-get clean
/bin/rm -rf /var/lib/apt/lists/*
/usr/bin/systemctl enable systemd-networkd.service
/bin/rm -f /var/log/*.log
/bin/echo root:${PASSWORD} | /usr/sbin/chpasswd
/bin/sed -i "s/#*\s*PermitRootLogin .*/PermitRootLogin yes/" /etc/ssh/sshd_config
EOF

# Remove ARM emulation stuff again
rm -v debian/usr/bin/qemu-*-static || :

cp -rv --preserve=mode ../2nd-stage-files/post-2nd-stage-files/* debian

# Set hostname
echo "${OS}" > debian/etc/hostname

# List all files
find debian ! -type d -printf "/%P\n" | sort > files.txt

cp files.txt "${ARTIFACTS_DIR:-/artifacts}/${OS}-${DIST}-${ARCH}-${PASSWORD}.bin.gz.files.txt"

# Make a ext4 filesystem of this and put it into the image
rm -f ext4.img
fallocate -l 1874MiB ext4.img
mkfs.ext4 -d debian ext4.img
pigz ext4.img

cp -v ext4.img.gz "${ARTIFACTS_DIR:-/artifacts}/${OS}-${DIST}-${ARCH}-${PASSWORD}.bin.gz"