#!/bin/sh

set -exu

disk_size=4G

dl_alpine() {
	tmpdir="$(mktemp --directory)"
	trap "rm $tmpdir" EXIT
	pushd "$tmpdir"

	# Setup GPG
	wget 'https://alpinelinux.org/keys/ncopa.asc'
	gpg --import ncopa.asc

	wget 'https://dl-cdn.alpinelinux.org/alpine/v3.15/releases/x86_64/alpine-virt-3.15.4-x86_64.iso' 'https://dl-cdn.alpinelinux.org/alpine/v3.15/releases/x86_64/alpine-virt-3.15.4-x86_64.iso.asc'
	gpg --verify alpine-virt-3.15.4-x86_64.iso.asc alpine-virt-3.15.4-x86_64.iso

	# Cleanup
	popd
	mv "$tmpdir/alpine-virt-3.15.4-x86_64.iso" .
	rm "$tmpdir/alpine-virt-3.15.4-x86_64.iso.asc" "$tmpdir/ncopa.asc"
	rmdir "$tmpdir"
	trap - EXIT
}

test -f alpine-virt-3.15.4-x86_64.iso || dl_alpine

# Clean old disk
test -f dummydisk.img && rm dummydisk.img

qemu-img create -f raw dummydisk.img "$disk_size"

# Launch installation
# Basic VM is sufficient
qemu-system-x86_64 -enable-kvm -m 2G -cdrom alpine-virt-3.15.4-x86_64.iso -drive media=disk,format=raw,file=dummydisk.img

# Now the user has to run installation from the VM. See ./alpine_install for details.