#!/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.


# sawk [awk expression...] [filenames...]
#
# Summarize via AWK calculates simple numeric statistics from the AWK
# expression given, using each input line as a data source. Welford's
# algorithm is used for improved accuracy.


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

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

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

awk '
    BEGIN {
        numeric = ints = pos = zero = neg = 0

        inf = "+inf" + 0

        min = inf
        max = -inf
        sum = 0
        mean = 0
        prod = 1
    }

    FNR == 1 { FS = /\t/ ? "\t" : " "; $0 = $0 }
    { low = lower = tolower($0) }

    {
        v = '"${code}"'
        if (v !~ /^ *(0|[0-9]+|[0-9]*\.[0-9]+) *$/) next
        v = v + 0

        numeric++
        ints += v % 1 == 0
        if (v > 0) pos++
        else if (v < 0) neg++
        else if (v == 0) zero++

        min = min < v ? min : v
        max = max > v ? max : v
        sum += v
        prod *= v
        lnSum += v <= 0 ? -inf : log(v)

        # advance welford`s algorithm
        d1 = v - mean
        mean += d1 / numeric
        d2 = v - mean
        meanSq += d1 * d2
    }

    END {
        sum = mean * numeric
        if (numeric == 0) lnSum = -inf

        # separate name-value pairs using tabs, and prepare a
        # pipeable command which ignores all-zero decimals
        OFS = "\t"

        print "numeric", numeric
        if (numeric > 0) {
            print "min", sprintf("%f", min)
            print "max", sprintf("%f", max)
            print "sum", sprintf("%f", sum)
            print "mean", sprintf("%f", mean)
            print "geomean", (zero == 0 && neg == 0) ?
                sprintf("%f", exp(lnSum / numeric)) :
                ""
            print "sd", sprintf("%f", sqrt(meanSq / numeric))
            print "product", sprintf("%g", prod)
        } else {
            print "min", ""
            print "max", ""
            print "sum", ""
            print "mean", ""
            print "geomean", ""
            print "sd", ""
            print "product", ""
        }
        print "integer", ints
        print "positive", pos
        print "zero", zero
        print "negative", neg
    }
' "$@" | sed -E 's-([0-9]+)\.0+$-\1-g; s-([0-9]+\.[0-9]*[1-9])0+$-\1-g'