gen_changelog

#!/bin/bash -e

parse_newstyle() {
    while IFS= read -r line; do
        if printf '%s' "$line" | \
            grep -qE '^[A-z0-9\.]+-\d+ \(\d{4}-\d{2}-\d{2}\)'; then
            version=$(printf '%s' "$line" | cut -d' ' -f1)
            logline=''
        elif printf '%s' "$line" | grep -qE '^\t[A-z]+'; then
            logline=$(printf '%s\n%s\n' "$logline" "$line")
            releases["$version"]="$logline"
        fi
    done < "${pkgdir}/${changelog}"
}

parse_oldstyle() {
    while IFS= read -r line; do
        if printf '%s' "$line" | \
                grep -qE '^\d{4}-\d{2}-\d{2}'; then
            date=$(printf '%s' "$line" | grep -oE '^\d{4}-\d{2}-\d{2}')
            if [ -n "$entry" ]; then
                # Print the previous entry and clear state
                printf '%s\n\n' "$entry"
                entry=''
                logline=''
            fi
        elif printf '%s' "$line" | \
                grep -qE '^\t\* .*-\d+ :$'; then
            version=$(printf '%s' "$line" | grep -oE '\t\* .*-\d+' | cut -d' ' -f2)
        elif printf '%s' "$line" | grep -qE '^\t[A-z]+'; then
            logline=$(printf '%s\n%s\n' "$logline" "$line")
            entry=$(printf '%s (%s)\n%s\n' "$version" "$date" "$logline")
        fi
    done < "${pkgdir}/${changelog}"
    # Print the last entry
    [ -n "$entry" ] && printf '%s\n' "$entry"
}

set -o pipefail

pkgdir='.'
[ -n "$1" ] && pkgdir="$1"
if [ ! -d "$pkgdir" ]; then
    printf 'Missing directory: %s\n' "$pkgdir"
    exit 1
fi

# shellcheck disable=SC1091
. "${pkgdir}/PKGBUILD"

[ -n "$changelog" ] || changelog='ChangeLog'
[ -e "${pkgdir}/${changelog}" ] || touch "${pkgdir}/${changelog}"

if head -n1 "${pkgdir}/${changelog}" | \
   grep -qE '^\d{4}-\d{2}-\d{2}.*<[A-z\d._%+-]+@[A-z\d.-]+\.[A-z]{2,}>$'; then
   content=$(parse_oldstyle)
   printf '%s\n' "$content" >"${pkgdir}/${changelog}"
fi

declare -A releases
parse_newstyle

# shellcheck disable=SC2154
this_version="${pkgver}-${pkgrel}"
if [ ${releases[$this_version]+x} ]; then
    printf 'An entry for version %s already exists in the ChangeLog\n' "$this_version"
    exit 1
fi

printf 'Enter a change description for %s (press ctrl-d when done):\n' "$this_version"
input=$(cat)
wrapped_input=$(printf '%s' "$input" | fold -s -w 72 | sed -e 's/^[ \t]*//' -e 's@^@\t@')

tmpfile=$(mktemp)
entry=$(printf '%s (%s)\n\n%s\n\n' "$this_version" "$(date +%Y-%m-%d)" "$wrapped_input")

printf '%s\n\n' "$entry" >"$tmpfile"
cat "${pkgdir}/${changelog}" >>"$tmpfile"
mv "$tmpfile" "${pkgdir}/${changelog}"

# shellcheck disable=SC2154
printf '\nAdded the following entry to the ChangeLog for %s:\n\n%s\n\n' "$pkgname" "$entry"