#!/bin/sh

# vm is a command line tool to  manage and operate virtual machines.

vm_version='vm-0.1'

# TODO:
# - DONE: fetch, build and install vftool in .vm/vftool
# - DONE: setup a config file per VM
# - DONE: creation of hdd image
# - DONE: delete a VM
# - DONE: import iso, kernel, initrd from existing vm
# - when no vm is specified, apply command to last one
# - script install from CDROM iso:
#	- patch alpine setup-disk
#	- setup system, including static IP address
# 	- setup user account from host
# 	- setup ssh from host
# 	- time synchronization from host
#

unset CDPATH
export LC_ALL=C IFS=' 	
'

add() {
	usage 'add [Options] name' 'Add a new VM' && return
	while getopts :c:i:k:p:s: opt; do
		case $opt in
		[cikps]) eval "$opt=$OPTARG";;
		*) Opth=1 add "$1"; exit ;;
		esac
	done
	shift $((OPTIND - 1))

	[ -d "$dir/$1" ] && die "vm $1 already exists in $dir/$1"
	init_alpine || die "could not init alpine iso"
	[ "$1" = 'alpine-iso' ] && return
	mkdir -p "$dir/$1" && cd "$dir/$1" || die "add $1 failed"
	hdd=${p-$1.raw}
	[ -f "$hdd" ] || dd if=/dev/zero of="$hdd" bs=1 count=0 seek="${s-32g}" 2>/dev/null
	echo "hdd=\"$hdd\"" > config
	[ "$c" ] && {
		[ -d "../$c" ] || die "invalid directory: $dir/$c"
		iso=$(getconf "$c" iso)
		cp "../$c/vmlinux" "../$c/initrd" .
		[ "$iso" ] && echo "iso=\"../$c/$iso\"" >> config
		cat <<- EOT >> config
			kernel=${k-vmlinux}
			initrd=initrd
			cpu=1
			ram=512
			arg="console=hvc0"
		EOT
	}
}

console() {
	usage 'console name' 'Attach a console to a VM' && return
	[ "$1" ] || die 'console: name is missing'
	cd "$dir/$1" || die "console $1 failed"
	[ -f vftool.pid ] || die "vm $1 is not active"
	screen -r "$1"
}

del() {
	usage 'del name' 'Delete a VM' && return
	case $1 in ''|*/*|.*) die "invalid VM name: $1" ;; esac
	[ -d "$dir/$1" ] || die "$dir/$1 not found"
	[ -f "$dir/$1/vftool.pid" ] && die "vm $1 is still active, stop it first"
	rm -rf "${dir:?}/$1"
}

die() { [ "$1" ] && echo "$0: $*" >&2; exit 1; }

edit() {
	usage 'edit name' 'Edit a VM configuration' && return
	[ -f "$dir/$1/config" ] || die "$dir/$1/config not found"
	${EDITOR-vi} "$dir/$1/config"
}

finalize() {
	tty=$(vftool_tty)
	printf 'root\nuname -a\n' >> "$tty"
}

getconf() { awk -F '=' -v k="$2" '$1 == k {print $2}' "$dir/$1/config"; }

help() {
	usage 'help' 'Print this help text' && return
        echo "$vm_version - Manage virtual machines"
		echo "Usage: vm command [options] [args]"
		echo "Commands:"
        Opth=1; for c in $Cmdlist; do $c; done
}

info() {
	usage 'info name' 'Print informations on a VM' && return
	echo 'not implemented yet'
}

# CAUTION: be careful to preserve tabs in the following Makefile template string.

alpine_makefile='# Generated by "vm". DO NOT EDIT.
# Check https://alpinelinux.org/downloads for possible upgrades
iso_url = https://dl-cdn.alpinelinux.org/alpine/latest-stable/releases/aarch64/alpine-virt-3.21.3-aarch64.iso
iso = $(notdir $(iso_url))
isoinfo ?= /opt/homebrew/bin/isoinfo

all: initrd vmlinux config

initrd: $(iso) $(isoinfo)
	isoinfo -i $(iso) -J -x /boot/initramfs-virt > $@

vmlinux: $(iso) $(isoinfo)
	isoinfo -i $(iso) -J -x /boot/vmlinuz-virt | gunzip > $@

config: $(iso)
	@echo "iso=$(iso)" >config
	@echo "initrd=initrd" >>config
	@echo "kernel=vmlinux" >>config
	@echo "cpu=1" >> config
	@echo "ram=512" >> config
	@echo "arg=\"console=hvc0\"" >> config

$(iso):
	curl -LO $(iso_url) || { rm -f $@; false; }

$(isoinfo):
	brew install cdrtools
'

init_alpine() {
	mkdir -p "$dir/alpine-iso"  && cd "$dir/alpine-iso" || die 'init alpine failed'
	[ -f 'Makefile' ] || printf '%s' "$alpine_makefile" > Makefile
	make -s all
}

init_vftool() {
	[ -x "$dir/vftool" ] && return
	cd '/tmp' &&
	git clone --depth=1 'https://github.com/evansm7/vftool' &&
	cd 'vftool' &&
	make &&
	cp 'build/vftool' "$dir/vftool"
	rm -rf '/tmp/vftool'
}

log() {
	usage 'log name' 'print logs of a VM' && return
	[ "$1" ] || die "log failed: name missing"
	cd "$dir/$1" || die "log $1 failed"
	cat vftool.log.old vftool.log 2>/dev/null
}

ls() {
	usage 'ls' 'list VMs' && return
	[ -d "$dir" ] && cd "$dir" || return
	for i in */; do
		i=${i%/}
		[ "$i" = '*' ] && continue
		[ -f "$i/vftool.pid" ] && state=active || state=stopped
		printf "%-20s %s\n" "$i" "$state"
	done
}

start() {
	usage 'start [-afs] name' 'Start a VM' && return
	while getopts :afs opt; do
		case $opt in
		(a) a=1 ;;
		(f) f=1 ;;
		(s) s=1 ;;
		(*) Opth=1 start "$1"; exit;;
		esac
	done
	shift $((OPTIND - 1))

	[ "$1" ] || die "start failed: name missing"
	init_vftool
	cd "$dir/$1" || die "start $1 failed"
	[ -f vftool.pid ] && die "Error: process $(cat vftool.pid) is active or $PWD/vftool.pid should be removed"
	start_vm & sleep 2
	! [ "$f" ] || finalize
	! [ "$a" ] || vm console "$1"
	! [ "$s" ] || exec ssh "$1"
}

start_vm() (
        [ -f vftool.log ] && cat vftool.log >> vftool.log.old
	exec 1>vftool.log 2>&1
	. config || die "vm: could not source $PWD/config"
        trap 'rm -f vftool.pid' EXIT

        "$dir/vftool" \
		${kernel+-k "$kernel"} \
		${initrd+-i "$initrd"} \
		${hda+-d "$hda"} \
		${hdb+-d "$hdb"} \
		${hdc+-d "$hdc"} \
		${iso+-c "$iso"} \
		${cpu+-p "$cpu"} \
		${ram+-m "$ram"} \
		-a "${arg-console=hvc0}" \
		>>vftool.log 2>&1 & sleep 1

		[ -f screenlog.0 ] && mv screenlog.0 screenlog.0.old
        echo "$!" >vftool.pid
        screen -L -S "${PWD##*/}" -d -m "$(vftool_tty)"
        wait
)

stop() {
	usage 'stop name' 'Stop a VM' && return
	[ "$1" ] || die 'stop: name missing'
	cd "$dir/$1" || die "stop $1 failed"
	[ -f vftool.pid ] || die "stop: vm $1 is not active"
	kill "$(cat vftool.pid)" || rm -f vftool.pid
}

usage() { [ "$Opth" ] && printf " %-34s %s\n" "$1" "$2"; }

version() {
	usage 'version' 'Print version' && return
	echo "$vm_version"
}

vftool_tty() { grep -om 1 '\/dev\/tty.*' 'vftool.log'; }

# Main starts here.
dir="$HOME/.vm"
Cmdlist='add console del edit info init_alpine init_vftool help ls log start stop version'
[ "$1" ] && C=$1 && shift 1 || { help; exit 1; }
for c in $Cmdlist; do
	case $c in
	("$C")  cmd=$c; break ;;
	("$C"*) [ "$cmd" ] && die "ambiguous command $C" || cmd=$c ;;
	esac
done
[ "$cmd" ] || { help; exit 1; } && $cmd "$@"