#!/usr/bin/env bash
set -x

# make-chroot.sh
# This script will download an Arch Linux rootfs to a reMarkable 2,
# update the packages, and enter the chroot.  Running it subsequently
# will just enter the existing chroot.

PREFIX="/home/root"
CHROOT_PATH="$PREFIX/arch-chroot"
ROOTFS_URL="http://archlinuxarm.org/os/ArchLinuxARM-armv7-latest.tar.gz"
# (reMarkable wget can't do https)

function mount_bind {
    mount -o bind "$CHROOT_PATH" "$CHROOT_PATH"
    mount -o bind /dev "$CHROOT_PATH/dev"
    mount -o bind /dev/pts "$CHROOT_PATH/dev/pts"
    mount -o bind /proc "$CHROOT_PATH/proc"
    mount -o bind /run "$CHROOT_PATH/run"
    mount -o bind /sys "$CHROOT_PATH/sys"
}

# Install rootfs to the desired chroot path
if [[ ! -e "$CHROOT_PATH" ]]
then
    ROOTFS_FILE="$PREFIX/$(basename "$ROOTFS_URL")"
    wget -cO "$ROOTFS_FILE" "$ROOTFS_URL"
    mkdir -p "$CHROOT_PATH"
    tar xpf "$ROOTFS_FILE" -C "$CHROOT_PATH"/
    rm "$ROOTFS_FILE"
    mkdir -p "$CHROOT_PATH/home/root"
    echo "nameserver 1.1.1.1" >> "$CHROOT_PATH/etc/resolv.conf"
    mount_bind
    chroot "$CHROOT_PATH" /usr/bin/pacman-key --init
    chroot "$CHROOT_PATH" /usr/bin/pacman-key --populate archlinuxarm
    chroot "$CHROOT_PATH" /usr/bin/pacman -Syu --noconfirm
    chroot "$CHROOT_PATH" /usr/bin/pacman -S --noconfirm \
	   xorg-server-xvfb x11vnc
fi

# Start X11 and VNC servers, then drop into chroot Bash
mount_bind
chroot "$CHROOT_PATH" /usr/bin/killall Xvfb x11vnc
chroot "$CHROOT_PATH" /usr/bin/Xvfb :0 -screen 0 1404x1872x16 &
chroot "$CHROOT_PATH" /usr/bin/x11vnc -listen 127.0.0.1 -display :0 &
chroot "$CHROOT_PATH" /bin/bash