#!/bin/sh

# Wipes and checks out the lammps submodule.
#
# Basically:
#
#     cd lammps
#     rm -rf (dirs that may need wiping)
#     git reset --hard
#
# but with copious amounts of paranoia

fatal() { echo >&2 "FATAL:" "$@"; exit 1; }
error() { echo >&2 "ERROR:" "$@"; }
warning() { echo >&2 "WARNING:" "$@"; }

[ -d .git ] || fatal "You should run this from the repo root"

cd lammps || fatal "Can't find lammps submodule. No action taken."

# submodule .git is easily identified because it is a file, not a directory
[ -f .git ] || fatal "Not 100% sure this is the lammps submodule. No action taken."

cp .git ../lammps.git || fatal "Failed to protect submodule .git. No action taken."

{
    # THE DANGER ZONE
    [ -d src/MAKE ] && # double check our location in case I made a retarded change to the above.
                       # src/MAKE is just an arbitrarily chosen location in the lammps dir which
                       # is unlikely to exist anywhere else.
    rm -rf src lib &&
    [ -f .git ] && # triple check; we DO NOT want to `git reset --hard` the main repository!!
    git reset --hard &&
    mv ../lammps.git .git &&
    true
} || fatal "An unknown error occurred at a bad time! You'll just have to work this one out!"