#!/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.


# realign [filenames...]
#
# Realign all detected columns, right-aligning any detected numbers in any
# column. ANSI style-codes are also kept as given.
#
# The only option available is to show this help message, using any of
# `-h`, `--h`, `-help`, or `--help`, without the quotes.


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

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

command='awk'
if [ -e /usr/bin/gawk ]; then
    command='gawk'
fi

# 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

${command} '
    # always ignore trailing carriage-returns
    { gsub(/\r$/, "") }

    # first non-empty line auto-detects whether input is SSV or TSV
    width == 0 && /\t/ { FS = "\t"; $0 = $0 }

    # first non-empty line auto-detects number of table columns
    width == 0 { width = NF }

    width > 0 {
        nrows++

        for (i = 1; i <= NF; i++) {
            data[nrows][i] = $i

            plain = $i
            gsub(/\x1b\[[0-9;]*[A-Za-z]/, "", plain)
            w = length(plain)
            if (widths[i] < w) widths[i] = w

            # handle non-numbers
            if (!match(plain, /^[+-]?[0-9]+(\.[0-9]+)?$/)) {
                continue
            }

            # see if number has decimals
            if (match(plain, /\./)) {
                dd = w - (RSTART - 1)
                if (dot_decs[i] < dd) dot_decs[i] = dd
            }
        }
    }

    END {
        for (i = 1; i <= nrows; i++) {
            due = 0

            for (j = 1; j <= width; j++) {
                v = data[i][j]

                # put 2-space gaps between columns
                if (1 < j) due += 2

                if (v ~ /^ *$/) {
                    due += widths[j]
                    continue
                }

                plain = v
                gsub(/\x1b\[[0-9;]*[A-Za-z]/, "", plain)
                w = length(plain)

                # handle non-numbers
                if (!match(plain, /^[+-]?[0-9]+(\.[0-9]+)?$/)) {
                    printf "%*s%s", due, "", v
                    due = widths[j] - w
                    continue
                }

                # count `dot-decimals` trail in the number
                dd = match(plain, /\./) ? w - (RSTART - 1) : 0

                rpad = dot_decs[j] - dd
                lpad = widths[j] - (w + rpad) + due

                printf "%*s%s", lpad, "", v
                due = rpad
            }

            # treat extra columns as part of the last one
            last = length(data[i])
            for (j = width + 1; j <= last; j++) printf " %s", data[i][j]

            printf "\n"
        }
    }
' "$@"