#!/usr/bin/env bash

set -uo pipefail
IFS=$'\n\t'

# Loops through all text files tracked by Git.
git grep -zIl '' |
while IFS= read -rd '' f; do
    # Ensures that files are UTF-8 formatted.
    recode UTF-8 "$f" 2> /dev/null
    # Ensures that files have LF line endings.
    dos2unix "$f" 2> /dev/null
    # Ensures that files do not contain a BOM.
    sed -i '1s/^\xEF\xBB\xBF//' "$f"
    # Ensures that files end with newline characters.
    tail -c1 < "$f" | read -r _ || echo >> "$f";
    # Remove trailing space characters.
    sed -z -i 's/\x20\x0A/\x0A/g' "$f"
done

git diff > patch.patch
FILESIZE="$(stat -c%s patch.patch)"
MAXSIZE=5

# If no patch has been generated all is OK, clean up, and exit.
if (( FILESIZE < MAXSIZE )); then
    printf "Files in this commit comply with the formatting rules.\n"
    rm -f patch.patch
    exit 0
fi

# A patch has been created, notify the user, clean up, and exit.
printf "\n*** The following differences were found between the code "
printf "and the formatting rules:\n\n"
cat patch.patch
printf "\n*** Aborting, please fix your commit(s) with 'git commit --amend' or 'git rebase -i <hash>'\n"
rm -f patch.patch
exit 1
