#!/bin/sh

# The MIT License (MIT)
#
# Copyright © 2025 pacman64
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the “Software”), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.


# avoid [options...] [regular expressions...]
#
# Avoid/ignore lines which match any of the extended-mode regular expressions
# given. When not given any regex, ignore all empty lines by default.
#
# The options are, available both in single and double-dash versions
#
#   -h       show this help message
#   -help    show this help message
#
#   -i       match regexes case-insensitively
#   -ins     match regexes case-insensitively


case "$1" in
    -h|--h|-help|--help)
        # show help message, using the info-comment from this very script
        awk '/^# +avoid /, /^$/ { gsub(/^# ?/, ""); print }' "$0"
        exit 0
    ;;
esac

insensitive=0
case "$1" in
    -i|--i|-ins|--ins)
        insensitive=1
        shift
    ;;
esac

[ "$1" = '--' ] && shift

command='awk'
if [ -e /usr/bin/gawk ]; then
    command='/usr/bin/gawk'
fi
if [ -p /dev/stdout ] || [ -t 1 ]; then
    command="stdbuf -oL ${command}"
fi

${command} -v ci="${insensitive}" '
    BEGIN {
        if (ci && IGNORECASE == "") {
            msg = "this variant of AWK lacks case-insensitive regex-matching"
            print(msg) > "/dev/stderr"
            exit 125
        }
        if (ci) IGNORECASE = 1

        for (i = 1; i < ARGC; i++) {
            re[i] = ARGV[i]
            delete ARGV[i]
        }
    }

    {
        for (i = 1; i < ARGC; i++) if ($0 ~ re[i]) next
        print
        got++
    }

    END { exit(got == 0) }
' "${@:-^\r?$}"