#!/bin/bash -lx

set -eE -o pipefail
trap 'echo "$0:$LINENO:error: \"$BASH_COMMAND\" returned $?" >&2' ERR

# note, we could have done machine specific subvols,
# but there were so few files, it just didn't seem
# necessary to have an rw copy on those machines
# which did not have the whole p subvol.

gen_args=()
do_snapshot=false
batch=false
while [[ $1 ]]; do
    case $1 in
        -ob) gen_args+=(--ours -b); batch=true; shift ;;
        -b) gen_args+=(-b); batch=true; shift ;;
        -n) do_snapshot=true; shift ;;
        -h|--help)
            echo "$0: help is head of $BASH_SOURCE:"
            head -n 30 "$BASH_SOURCE"
            exit 0
            ;;
        --) shift; break ;;
        -*) gen_args+=($1) ; shift ;;
        *) host=$1; shift ;;
    esac
done
if [[ ! $host ]]; then
    host=$1
fi

if [[ $host == demohost ]]; then
    do_snapshot=false
fi

# arch and debian don't play nice with unison.
# "connection lost" on unison-gtk, with bignum errs in term,
# and simply freezing on cli, all means compiled under
# different ocaml versions.
# I had the great realization that unison is a self contained
# binary with no special runtime dependencies.
# However, I got a gtk error running the ui version.
# todo: I should test pushing my unison version instead
# of pulling it.
echo "$0: running: gen ${gen_args[@]}"
/p/c/subdir_files/.unison/gen ${gen_args[@]}
if [[ ! $host ]]; then
    echo "$0: error: expected argument for hostname"
    exit 1
fi


# todo: this doesn't deal with if the host is running arch too

# debian uses this path, and has gtk version linked as /usr/bin/unison,
# but I'd rather not push the gtk version
push_path=/usr/bin/unison-latest-stable
if [[ ! -e $push_path ]]; then
    push_path=/usr/bin/unison
fi
# note, i'd prefer to use /usr/local/bin, but it's not in arch's default
# path for root.
rsync -L /usr/bin/unison-latest-stable root@$host:/usr/bin/unison

if $do_snapshot; then
    unison-snapshot
    if ! ssh root@$host "! type unison-snapshot || unison-snapshot"; then
        if [[ ! ${gen_args[@]} ]]; then
            # gen_args are all about syncing with new systems where
            # we could expect the remote snapshot to not be available yet.
            echo "$0: error: failed remote unison-snapshot"
            exit 1
        fi
    fi
fi

if $batch; then
    # todo, figure out what the cli version is called in non-debian distros
    f=unison-latest-stable
else
    f=unison-gtk
    type -t $f &>/dev/null || f=unison-gtk2 # for arch
fi

if s $f  "$host"; then
    if [[ $host == frodo ]]; then
        # only send data to the machine i do full backups to
        p=/p/c/machine_specific/$HOSTNAME/.unison/
        s rsync -rlptgohi $p root@$host:$p
    fi
    p=/p/c/machine_specific/$host/.unison/
    s rsync -rlptgohvi root@$host:$p $p
fi