#!/usr/bin/env bash

# yadm - Yet Another Dotfiles Manager
# Copyright (C) 2015-2019 Tim Byrne and Martin Zuther

# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.


YADM_DIRECTORY=$(dirname $YADM_HOOK_REPO)
YADM_CHECKSUMS=$YADM_DIRECTORY/files.checksums


# check whether file with checksums exists
if [ -f $YADM_CHECKSUMS ]; then
    # check if "shasum" exists
    if command -v shasum > /dev/null; then
        # check if "shasum" supports SHA-512/256 algorithm
        echo -n | shasum --algorithm 512256 2>&1 1> /dev/null

        if [ $? -ne 0 ]; then
            echo
            echo "WARNING: \"shasum\" does not support SHA-512/256.  Checksums were not verified."
            exit $YADM_HOOK_EXIT
        fi

        # check encrypted files for differences and capture output
        YADM_CHECKSUM_OUTPUT=$(shasum --algorithm 512256 --check $YADM_CHECKSUMS 2> /dev/null)
        ERROR_CODE=$?
        
        # some checksums do not match
        if [ $ERROR_CODE -ne 0 ]; then
            echo
            echo "Some SHA-512/256 sums do not match:"
            
            # set output color to red
            echo -e "\033[0;31m"
            
            # display mismatching files
            while IFS= read -r line; do
                echo $line | grep -iv "\sok$" | sed 's/^/        / ; s/: FAILED$//'
            done <<< "$YADM_CHECKSUM_OUTPUT"
            
            # reset output color
            echo -e "\033[0m"
            echo "Consider running either \"yadm encrypt\" or \"yadm decrypt\"."
            
            # signal error
            exit $ERROR_CODE
        fi
    else
        echo
        echo "WARNING: command \"shasum\" not found.  Checksums were not verified."
        exit $YADM_HOOK_EXIT
    fi
fi

# return exit status of the yadm command
exit $YADM_HOOK_EXIT