#!/usr/bin/env sh

config_file=.version.json

reverse() {
    if which tac >/dev/null 2>&1; then
        tac
    else
        tail -r
    fi
}

generate_config() {
    sha="$(git rev-parse --short HEAD)"
    (
        echo '{'
        echo '"version": "0.0.0",'
        echo '"sha": "'"$sha"'"'
        echo '}'
    ) | jq . > $config_file
}

get_git_commits() {
    since_hash="$(jq '.sha' < $config_file | tr -d '"')"
    git rev-list "$since_hash..HEAD"
}

get_git_commit_subject() {
    git show -s --format=%s "$1"
}

get_git_commit_body() {
    git show -s --format=%b "$1"
}

get_commit_type() {
    echo "$1" | sed -r -n 's/([a-z]+)(\(?|:?).*/\1/p'
}

get_commit_scope() {
    echo "$1" | sed -r -n 's/[a-z]+\(([^)]+)\).*/\1/p'
}

get_commit_description() {
    echo "$1" | sed -r -n 's/.*:[ ]+(.*)/\1/p'
}

get_commit_footer() {
    with_colon=$(echo "$1" | sed -n '/^[A-Za-z-]\{1,\}: /,//{p;}')
    with_hash=$(echo "$1" | sed -n '/^[A-Za-z-]\{1,\} #/,//{p;}')

    if [ ${#with_colon} -gt ${#with_hash} ]; then
        echo "$with_colon"
    else
        echo "$with_hash"
    fi
}

get_commit_body() {
    pattern=$(get_commit_footer "$1" | head -n 1)
    if [ -n "$pattern" ]; then
        echo "$1" | sed -e "/$pattern/,\$d"
    else
        echo "$1"
    fi
}

is_breaking_change() {
    if echo "$1" | grep -q '!' || echo "$2" | grep -q 'BREAKING[ -]CHANGE: '; then
        echo "yes"
    else
        echo "no"
    fi
}

get_breaking_change() {
    with_colon=$(echo "$1" | sed -n  '/^BREAKING[ -]CHANGE: /,/^[A-Za-z-]\{1,\}: /{ s/BREAKING[ -]CHANGE: \(.*\)/\1/; /^[A-Za-z-]\{1,\}: /!p;}')
    with_hash=$(echo "$1" | sed -n  '/^BREAKING[ -]CHANGE: /,/^[A-Za-z-]\{1,\} #/{ s/BREAKING[ -]CHANGE: \(.*\)/\1/; /^[A-Za-z-]\{1,\} #/!p;}')
    if [ -n "$with_colon" ] && ! echo "$with_colon" | grep -q '[A-Za-z-]\{1,\} #'; then
        echo "$with_colon"
    else
        echo "$with_hash"
    fi
}

generate_changelog_entry() {
    is_patch=0
    is_minor=0
    is_major=0
    for commit in $(get_git_commits); do
        git_subject=$(get_git_commit_subject "$commit")
        git_body=$(get_git_commit_body "$commit")

        type=$(get_commit_type "$git_subject")
        scope=$(get_commit_scope "$git_subject")
        description=$(get_commit_description "$git_subject")
        body=$(get_commit_body "$git_body")
        footer=$(get_commit_footer "$git_body")
        breakingchange=$(get_breaking_change "$footer")
        isbreaking=$(is_breaking_change "$git_subject" "$footer")
        if [ "$isbreaking" = "yes" ] && [ -z "$breakingchange" ]; then
            breakingchange="$body"
        fi

        echo "--------------------------------"
        echo "Subject : $git_subject"
        echo "Body: $git_body"
        echo
        echo "********************************"
        echo
        echo "  - type           : $type"
        echo "  - scope          : $scope"
        echo "  - description    : $description"
        echo "  - body           : $body"
        echo "  - footer         : $footer"
        echo "  - breakingchange : $breakingchange"
        echo "  - isbreaking     : $isbreaking"
        echo
        echo "--------------------------------"
        echo
        echo
    done;
}


init() {
    if [ ! -f "$config_file" ]; then
        echo "Generating a config ... "
        generate_config
        echo "Done"
    else
        echo "Using existing config"
    fi

    generate_changelog_entry
}

init