#!/usr/bin/awk -f

# The MIT License (MIT)
#
# Copyright © 2020-2025 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.


# imatch [regular expressions...]
#
# Only keep lines which case-insensitively match any of the regexes given.
# When not given any regex, match non-empty lines by default.


BEGIN {
    if (IGNORECASE == "") {
        msg = "this variant of AWK lacks case-insensitive regex-matching"
        printf("\x1b[31m%s\x1b[0m\n", msg) > "/dev/stderr"
        exit 125
    }
    IGNORECASE = 1

    if (ARGC < 2) {
        ARGC = 2
        ARGV[1] = "[^\r]"
    }

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

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

END {
    exit(got == 0)
}