#!/bin/sh

# 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.


# coy [exponent]
# coy [exponent] [years]
# coy [amount] [exponent] [years]
#
# Compound Over Years does what it says, by showing a TSV table. It accepts
# 1, 2, or 3 arguments for the parameters: the default amount is 1.0, while
# the default year-span is 10.


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

awk '
BEGIN {
    quantity = 1.0
    exponent = 1.0
    years = 10

    switch (ARGC) {
        case 2:
            exponent = ARGV[1] + 0.0
            break;

        case 3:
            exponent = ARGV[1] + 0.0
            years = ARGV[2] + 0
            break;

        case 4:
            quantity = ARGV[1] + 0.0
            exponent = ARGV[2] + 0.0
            years = ARGV[3] + 0
            break;

        default:
            msg = "\x1b[31monly 1, 2, or 3 arguments are supported\x1b[0m\n"
            print msg > "/dev/stderr"
            exit 1
    }

    print "year\tquantity"
    for (k = 1.0; y <= years; y++) {
        printf "%d\t%.4f\n", y, quantity * k
        k *= exponent
    }
    exit
}
' "$@"