#!/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.


# uawk [options...] [awk expression...] [filenames...]
#
#
# Unique via AWK avoids lines duplicating the AWK expression given, by
# emitting only the first line which gives the expression each of its
# unique results.
#
# When not given any expression, whole lines are used: this effectively
# makes it a line deduplicator which keeps lines in their original order,
# unlike `uniq`, which requires sorted lines to avoid repetitions.
#
# The handy case-insensitive shortcut options may cause this tool to fail,
# if the main AWK tool installed doesn't support the special IGNORECASE
# variable.
#
# The AWK options available only in single-dash versions are
#
#   -F fs               use `fs` for the field separator (the `FS` variable)
#   -V                  show the AWK version installed
#   -v var=val          set a variable to a given value
#
# The other 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                  split fields using tabs, same as using -F "\t"


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

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

tsv=0
case_insensitive=0

while [ $# -gt 0 ]; do
    arg="$1"

    if [ "${arg}" = "--" ]; then
        shift
        break
    fi

    case "${arg}" in
        -F)
            shift
            if [ $# -eq 0 ]; then
                printf "expected value after -F option\n" >&2
                exit 1
            fi
            command="${command} -F $1"
            shift
            continue
        ;;

        -F*)
            command="${command} ${arg}"
            shift
            continue
        ;;

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

        -ins|--ins|-insensitive|--insensitive)
            case_insensitive=1
            shift
            continue
        ;;

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

        -*)
            command="${command} ${arg}"
            shift
            continue
        ;;
    esac

    break
done

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

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

if [ "${failed}" -gt 0 ]; then
    exit 2
fi

ci='
    BEGIN {
        if (IGNORECASE == "") {
            m = "your `awk` command lacks case-insensitive regex-matching"
            printf("\x1b[38;2;204;0;0m%s\x1b[0m\n", m) > "/dev/stderr"
            exit 125
        }
        IGNORECASE = 1
    }
'
if [ "${case_insensitive}" -eq 0 ]; then
    ci=''
fi

src="${ci}"'
    BEGIN { for (i = 1; i < ARGC; i++) if (files[ARGV[i]]++) delete ARGV[i] }
    FNR == 1 { FS = /\t/ ? "\t" : " "; $0 = $0 }
    !c['"${code}"']++
'

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