prepare-commit-msg.en

#!/bin/bash
#
# https://github.com/negokaz/git-fancy-message-prefix
#

function templates {
# format:
#
#   prefix:   emoji(code)   description
#
# Full Emoji List: https://unicode.org/emoji/charts/full-emoji-list.html
cat <<EOF
feat:     \U2728    A new feature
fix:      \U1f41e   A bug fix
doc:      \U1f4da   Documentation only changes
style:    \U1f484   Changes that do not affect the meaning of the code\n(white-space, formatting, missing semi-colons, etc)
refactor: \U1f528   A code change that neither fixes a bug nor adds a featur
perf:     \U1f680   A code change that improves performance
test:     \U1f6a8   Adding missing or correcting existing tests
chore:    \U1f477   Changes to the build process or auxiliary tools and libraries\nsuch as documentation generation
merge:    \U1f500
EOF
# "merge:" is a special prefix to create merge commit message.
}

readonly overview_title="Overview (Uncomment one of the following templates)"
readonly  details_title="Details"


readonly COMMIT_MSG_FILE=$1 COMMIT_SOURCE=$2 SHA1=$3

function main {
    case "${COMMIT_SOURCE}" in
        message) # use -m/-F
            local commit_message="$(cat "${COMMIT_MSG_FILE}")"
            local prefix="$(extract_prefix "${commit_message}")"
            add_emoji "${prefix}" "${commit_message}" > "${COMMIT_MSG_FILE}"
            ;;
        template) # use template (ex: -t option)
            : # do nothing
            ;;
        merge) # merge commit
            local commit_message="$(cat "${COMMIT_MSG_FILE}")"
            add_emoji "merge:" "${commit_message}" > "${COMMIT_MSG_FILE}"
            ;;
        squash) # squash commits in a branch with --squash
            : # do nothing
            ;;
        commit) # use -c/-C/--amend
            local commit_message="$(cat "${COMMIT_MSG_FILE}")"
            if is_interactive "${commit_message}"
            then
                apply_template "${commit_message}" > "${COMMIT_MSG_FILE}"
            fi
            ;;
        *) # no option
            local commit_message="$(cat "${COMMIT_MSG_FILE}")"
            create_full_template "${commit_message}" > "${COMMIT_MSG_FILE}"
            ;;
    esac
}

function create_full_template {
    local commit_message="$1"

    echo "# ${overview_title}"
    print_templates
    echo ""
    echo "# ${details_title}"
    echo ""
    echo "${commit_message}"
}

function apply_template {
    local commit_message="$1"

    local prefix="$(extract_prefix_without_emoji "${commit_message}")"
    local template=$(select_template "${prefix}")
    if [[ -z "${template}" ]]
    then
        # invalid prefix
        extract_title "${commit_message}"
        print_templates
    else
        # valid prefix
        local title="$(extract_title_without_prefix "${commit_message}")"
        print_templates "${prefix}" "${title}"
    fi
    echo
    echo "# ${details_title}"
    echo
    extract_details "${commit_message}"
}

function print_templates {
    local apply_prefix="$1" apply_title="$2"

    templates | grep -v '^merge:' | sed -e 's/\\/\\\\/g' \
        | while read prefix emoji description
        do
            local desc_comment="$(
                echo -e "${description}" | awk '
                    NR == 1 {
                        print "#  └ " $0
                    }
                    NR != 1 {
                        print "#    " $0
                    }
                '
            )"
            if [[ "${apply_prefix}" = "${prefix}" ]]
            then
                echo '#=================================================='
                echo "$(emoji_char "${emoji}")${prefix}${apply_title}"
                echo "${desc_comment}"
                echo '#=================================================='
            else
                echo "#$(emoji_char "${emoji}")${prefix} "
                echo "${desc_comment}"
            fi
            
        done
}

function add_emoji {
    local prefix="$1" commit_message="$2"

    local template=$(select_template "${prefix}")
    local emoji=$(emoji_of "${template}")
    
    echo "${emoji}${commit_message}"
}

function select_template {
    templates | awk -v prefix="$1" '$1 == prefix'
}

function decode_emoji {
    perl -CO -pE 's/\\u(\p{Hex}+)/chr(hex($1))/xieg'
}

function emoji_char {
    echo "$1" | decode_emoji
}

function emoji_of {
    local template="$1"
    echo "${template}" | awk '{ print $2 }' | decode_emoji
}

function is_interactive {
    local commit_message="$1"
    # If it is interactive mode, it may contain comment lines ('^#')
    echo "${commit_message}" | grep -E '^#' &> /dev/null
}

function extract_prefix {
    local commit_message="$1"
    extract_title "${commit_message}" | awk '{ print $1 }'
}

function extract_prefix_without_emoji {
    local commit_message="$1"
    extract_prefix "${commit_message}" | sed -E 's/[^a-zA-Z0-9:]//g'
}

function extract_title {
    local commit_message="$1"
    echo "${commit_message}" | head -n 1
}

function extract_title_without_prefix {
    local commit_message="$1"
    extract_title "${commit_message}" | awk '{ $1 = ""; print }'
}

function extract_details {
    local commit_message="$1"
    echo "${commit_message}" | tail -n +3
}

main