#!/bin/bash -e
# taken from: https://raw.githubusercontent.com/andrewseidl/githook-clang-format/master/clang-format.hook
# - with just added check for cpp file & check for proper version of clang-format
# - with use of clang-format diff.py - for changed chunk changes only
# might be worth to consider: https://github.com/Sarcasm/run-clang-format


L_GIT_DIR=$(git rev-parse --show-toplevel)
source $L_GIT_DIR/config/format-config.sh

# if autoformatting was disabled by user - then ignore this commit hook
if [[ $DISABLE_AUTO_FORMATTING ]]; then
    [[ $VERBOSE ]] && echo "auto formatting is disabled"
    exit 0
fi

# check if clang-format in path is in proper version, version is 3rd column in `clang-format --version`
CVER=$( [[ $(which clang-format) ]] && echo $(clang-format --version | cut -d ' ' -f 3 | cut -d '.' -f 1) || echo "0")
# check for either clang-format or clang-format-9
if [[ $CVER -lt 9 && ! $(which clang-format-9) ]]; then
    cat << EOF > 1
Either install:
    clang-format in at least version 9 and set as default"
    or
    clang-format-9

    Your clang format version in path used:
        $(clang-format --version):
        $(clang-format-9 --version)
    git commit aborted"
EOF
    exit 1
fi

get_clang_format_script() {
    local declare searchpaths=(
        $(which "clang-format-diff.py")                                 # clang-format-diff in path
        "/usr/share/clang/clang-format-9/clang-format-diff.py"          # clang-format-diff location for clang format 9 Ubuntu/Debian 18.04
        "/usr/share/clang/clang-format-${CVER}/clang-format-diff.py"    # clang-format-diff location on Ubuntu/Debian
        "/usr/share/clang/clang-format-diff.py"                         # clang-format_diff location on Arch last resort
    )
    local tool=""
    for el in ${searchpaths[@]}; do
        if [[ -f ${el} ]]; then
            tool=${el}
            break
        fi
    done
    if [[ ${tool} == "" ]]; then
        echo clang-format-diff not found in path and: ${sarchpaths[@]} >2
    fi
    echo "${tool}"
}

L_CLANG_DIFF_TOOL=$(get_clang_format_script)
if ! [[ $L_CLANG_DIFF_TOOL ]] || [[ $L_CLANG_DIFF_TOOL == "" ]]; then
    exit 1
fi

format_file() {
  file="${1}"
  if [ -f $file ]; then
    [[ $VERBOSE ]] && echo "Format: ${1} diff"
    git diff -U0 --no-color --cached ${1} | ${L_CLANG_DIFF_TOOL} -style file -p1 -i
    git add ${1}
  fi
}

check_file() {
  file="${1}"
  last_commit="${2}"
  if [ -f $file ]; then
    [[ $VERBOSE ]] && echo -en "Checking: \e[33m${file}\e[0m :\t"
    if [[ -z ${last_commit} ]]; then
        OUT=$(git diff -U0 --no-color --cached ${file} | ${L_CLANG_DIFF_TOOL} -style file -p1 )
    else
        OUT=$(git diff -U0 --no-color remotes/origin/master...HEAD ${file} | ${L_CLANG_DIFF_TOOL} -style file -p1 )
    fi
    if [ -z "$OUT" ]; then
        [[ ${VERBOSE} ]] && echo "OK"
        return 0
    else
        [[ ${VERBOSE} ]] && echo "error"
        return 1
    fi
  fi
}

# bash function using above config function
shouldnt_ignore() {
    # change full name path to path relative to root git dir
    local fname=${1/"$L_GIT_DIR"/"./"}
    for el in ${ignore_paths[@]}; do
        if [[ ./${fname}  =~ ^${el}.* ]]; then
            [[ $VERBOSE ]] && echo "Ignore: ${fname} formatting due to: $el match!"
            return 1
        fi
    done
    return 0
}

case "${1}" in
  --about )
    echo "Runs clang-format on source files"
    FILES=''
    LAST=""
    ;;
  --last)
    FILES=$(git diff --name-only remotes/origin/master...HEAD)
    LAST="True"
    ;;
  * )
    FILES=$(git diff-index --cached --name-only HEAD)
    ;;
esac

EXIT_CODE=0
error_files=()
for file in ${FILES}; do
    if [[ ${file} =~ ^.*\.(cpp|hpp|c|h|cxx|gcc|cc)$ ]] && shouldnt_ignore ${file}; then
        check_file "${file}" ${LAST}
        RESULT=$?
        if [[ ${RESULT} -eq 1 ]]; then
            error_files+=(${file})
            EXIT_CODE=1
        fi
    fi
done

if [[ ${EXIT_CODE} -eq 1 ]]; then
    echo -e "before commit please run:\n\t git clang-format\n "
    echo -e "Files containing style errors:"
    I=0
    while [[ ${I} -lt ${#error_files[@]} ]]; do
        echo -e "\t${error_files[${I}]}"
        I=$(( ${I} + 1 ))
    done
    exit 1
else
    exit 0
fi