#! /usr/bin/env bash

set -e
# Arguments 'TO', optional user (can be configured in ~/.ssh/config.d/...), command to run over ssh

# Figure out the IPAddress I need to operate from
# Figure out the interface name to use
# Set the interface to the IP Address if not already setup
# Test with ping
# Connect with SSH

if [ $# -eq 0 ]; then
    printf '%s\n' \
        "${0#/*} <TO> [<FROM>] [<Interface>]" \
        "" \
        "Configure MacOS iface to connect to <TO> address from <FROM> address" \
        "Default <Interface> is en9" \
        "" \
        "FROM and FROM_SN will be autofilled for the following subnets:" \
        "    10.117.10.0/24" \
        "    192.168.[1 or 2].0/24" \
        "" \
        "for other subnets, you'll need to specify a FROM argument and a FROM_SN env variable" \
        ""
    exit 2
fi

TO="${1}"
IFACE="${IFACE:-en9}"
SLEEP="${SLEEP:-3s}"
PINGOK=1
CMDs=("${@:2}")

[ "${#CMDs}" -gt 0 ] || CMDs=( hostname )

_myip() {
    lsip | awk "/${IFACE}/"'{split($3, a, "/"); print a[1];}'
}

_ping() {
    ping -c "${PING_C:-3}" -W 250 "${TO}"
}

_log() {
    printf '%s\n' \
            "${@:2}" \
    >&2
    exit ${1} 
}

if _ping &>/dev/null; then
    printf "Connection detected.\n"
else
    PINGOK=0
    case "${TO}" in
        10.117.10.*)
            FROM=10.117.10.254
            FROM_SN=255.255.255.0
            ;;
        192.168.1.*)
            FROM=192.168.1.254
            FROM_SN=255.255.255.0
            ;;
        192.168.2.*)
            FROM=192.168.2.254
            FROM_SN=255.255.255.0
            ;;
        *)
            FROM=${FROM:?FROM and FROM_SN Must be supplied for unknown IPv4 destination $1}
            FROM_SN${FROM_SN:?FROM and FROM_SN Must be supplied for unknown IPv4 destination $1}
            ;;
    esac

    MYIP=''
    MYIP="$(_myip)"

    if [ "$FROM" == "$MYIP" ]; then
        _log 2 "Already setup with $MYIP, but ping to $TO is failing, you'll need to troubleshoot this."
        exit 2
    fi

    echo "$MYIP detected on $IFACE, Setting up $FROM / $FROM_SN - \`sudo\` might be prompting you for your password"

    sudo ipconfig set "${IFACE}" manual "${FROM}" "${FROM_SN}" \
    && sleep "${SLEEP}" \
    && MYIP="$(_myip)"
fi

if [ $PINGOK -eq 0 ] && _ping &>/dev/null; then
    PINGOK=1
fi

if [ $PINGOK -eq 1 ]; then
    # auto-copy-ssh-id "${TO}"

    ssh-keygen -R "${TO}" || true

    ssh \
        -o PasswordAuthentication=no \
        -o BatchMode=yes \
        -o ConnectTimeout=2 \
        -ttn \
        "${TO}" -- "${CMDs[*]}" \
    || 1>&2 printf '%s\n' \
        "Could not SSH into ${TO}, you might want to run 'pull-vast.id_rsa ${TO}' or 'auto-copy-ssh-id ${TO}'"
else
    _log 2 "Ping faild."
fi

exit