#!/bin/sh

# The MIT License (MIT)
#
# Copyright (c) 2026 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.


# tla [options...] [awk expression...] [files...]
#
# Transform Lines with Awk expression: this is a convenient shortcut, to type
# even less when using AWK.
#
# If a leading `=` (no quotes) is given as an argument, no inputs are read,
# and the expression is evaluated/printed once, quitting right away.
#
# The options are, available both in single and double-dash versions
#
#   -h, -help             show this help message
#   -ins, -insensitive    match regexes case-insensitively; fail if unsupported
#   -tsv                  tab-separated values: split input fields using tabs


case "$1" in
    -h|--h|-help|--help)
        awk '/^# +tla /, /^$/ { gsub(/^# ?/, ""); print }' "$0"
        exit 0
    ;;
esac

tsv=0
buffered=0
case_ins=0
no_input=0
cmd='awk'

while [ $# -gt 0 ]; do
    case "$1" in
        =) no_input=1; shift; continue ;;

        --b|-buffered|--buffered) buffered=1; shift; continue ;;

        -F)
            if [ $# -lt 2 ]; then
                printf "expected value after -F option\n" >&2
                exit 1
            fi
            cmd="${cmd} -F $2"; shift 2; continue
        ;;

        -F*) cmd="${cmd} $1"; shift; continue ;;

        -v)
            shift
            if [ $# -eq 0 ]; then
                printf "expected variable assignment after -v option\n" >&2
                exit 1
            fi
            cmd="${cmd} -v $1"
            shift
            continue
        ;;

        -i|--i|-ins|--ins|-insensitive|--insensitive)
            case_ins=1; shift; continue
        ;;

        -tsv|--tsv) tsv=1; shift; continue ;;

        -) break ;;

        --) shift; break ;;

        -*)
            printf "unsupported option '%s'\n" "$1" >&2
            exit 1
        ;;
    esac

    break
done

flush=''
if [ "${buffered}" -eq 0 ] && { [ -p /dev/stdout ] || [ -t 1 ]; }; then
    flush='fflush()'
fi

expr="${1:-\$0}"
[ $# -gt 0 ] && shift

# show all non-existing files given
failed=0
for arg in "$@"; do
    [ "${arg}" = "-" ] && continue
    [ -e "${arg}" ] && continue
    printf "no file named \"%s\"\n" "${arg}" >&2
    failed=1
done

[ "${failed}" -gt 0 ] && exit 2

ci='
    BEGIN {
        if (IGNORECASE == "") {
            m = "your `awk` command lacks case-insensitive regex-matching"
            print(m) > "/dev/stderr"
            exit 125
        }
        IGNORECASE = 1
    }
'
if [ "${case_ins}" -eq 0 ]; then
    ci=''
fi

if [ "${no_input}" -eq 1 ]; then
    src="${ci}"'
    BEGIN { print ('"${expr}"'); exit }
'
else
    src="${ci}"'
    { print ('"${expr}"'); '"${flush}"' }
'
fi

if [ "${tsv}" -eq 1 ]; then
    ${cmd} -F "\t" -v OFS="\t" "${src}" "$@"
else
    ${cmd} "${src}" "$@"
fi