#!/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.


# ca [decimals...] [expression]
#
#
# CAlculator is an easier-to-use version of `bc` (basic calculator) where
#
#   - you give the expression as an argument, while `bc` reads it from stdin
#   - you don't need quoting when avoiding parentheses and spaces
#   - you can use either ** or ^ to raise powers
#   - you can use [ and ] or ( and ) interchangeably
#   - the number of decimals is 20 by default
#   - automatically includes the extended bc math library via option -l
#   - there are several extra predefined values and functions


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

# handle optional scale-override parameter
scale=20
if [ $# -eq 2 ]; then
    scale="$1"
    shift
fi

# ensure output is all on 1 line, define several funcs and values, then
# inject the expression given as this script's arguments, transformed
# according to the rules described above
{
BC_LINE_LENGTH=0 bc -l << ENDOFSCRIPT
scale = ${scale};

femto = 0.000000000000001;
pico = 0.000000000001;
nano = 0.000000001;
micro = 0.000001;
milli = 0.001;

kilo = 1000;
mega = 1000 * kilo;
giga = 1000 * mega;
tera = 1000 * giga;
peta = 1000 * tera;
exa =  1000 * peta;
zetta =  1000 * exa;

binkilo = 1024;
binmega = 1024 * binkilo;
bingiga = 1024 * binmega;
bintera = 1024 * bingiga;
binpeta = 1024 * bintera;
binexa = 1024 * binpeta;
binzetta = 1024 * binexa;

kb = 1024;
mb = 1024 * kb;
gb = 1024 * mb;
tb = 1024 * gb;
pb = 1024 * tb;
eb = 1024 * pb;
zb = 1024 * eb;

kib = 1024;
mib = 1024 * kib;
gib = 1024 * mib;
tib = 1024 * gib;
pib = 1024 * tib;
zib = 1024 * pib;

mol = 602214076000000000000000;
mole = 602214076000000000000000;

cup2l = 0.23658824;
floz2l = 0.0295735295625;
floz2ml = 29.5735295625;
ft2m = 0.3048;
gal2l = 3.785411784;
in2cm = 2.54;
lb2kg = 0.45359237;
mi2km = 1.609344;
mpg2kpl = 0.425143707;
nmi2km = 1.852;
oz2g = 28.349523125
psi2pa = 6894.757293168;
ton2kg = 907.18474;
yd2m = 0.9144;

ga2l = gal2l;
nm2km = nmi2km;
tn2kg = ton2kg;

hour = 3600;
day = 24 * hour;
week = 7 * day;

hr = hour;
wk = week;

define ftin(f, i) {
    return (0.3048 * f + 0.0254 * i);
}

define lboz(l, o) {
    return (0.45359237 * l + 0.028349523 * o);
}

define eu() {
    return (e(1));
}

define euler() {
    return (e(1));
}

define pi() {
    return (4*a(1));
}

define tau() {
    return (8*a(1));
}

define deg(x) {
    return (180 * x / pi());
}

define rad(x) {
    return (pi() * x / 180);
}

define abs(x) {
    if (x >= 0) return (x);
    return (-x);
}

define exp(x) {
    return (e(x));
}

define j0(x) {
    return (j(0, x));
}

define j1(x) {
    return (j(1, x));
}

define ln(x) {
    return (l(x));
}

define log(x) {
    return (l(x));
}

define log2(x) {
    return (l(x) / l(2));
}

define log10(x) {
    return (l(x) / l(10));
}

define sin(x) {
    return (s(x));
}

define cos(x) {
    return (c(x));
}

define tan(x) {
    return (s(x) / c(x));
}

define cot(x) {
    return (c(x) / s(x));
}

define atan(x) {
    return (a(x));
}

define sinh(x) {
    return ((e(x) - e(-x)) / 2);
}

define cosh(x) {
    return ((e(x) + e(-x)) / 2);
}

define tanh(x) {
    return ((e(x) - e(-x)) / (e(x) + e(-x)));
}

define coth(x) {
    return ((e(x) + e(-x)) / (e(x) - e(-x)));
}

define hypot(x, y) {
    return (sqrt(x*x + y*y));
}

define sinc(x) {
    if (x == 0) return (1);
    return (s(x) / x);
}

define min(x, y) {
    if (x <= y) return (x);
    return (y);
}

define max(x, y) {
    if (x >= y) return (x);
    return (y);
}

define mod(x, y) {
    auto s, m;
    s = scale;
    scale = 0;
    m = x % y;
    scale = s;
    return (m);
}

define mod1(x) {
    return (mod(x, 1));
}

define modf(x) {
    return (mod(x, 1));
}

define round0(x) {
    auto i;
    i = x - mod(x, 1);
    if (x - i >= 0.5) {
        return (i + 1);
    }
    return (i);
}

define round(x, d) {
    auto k;
    k = 10^d;
    return (round0(x * k) / k);
}

define r(x, d) {
    return (round(x, d));
}

define r0(x) {
    return (round0(x));
}

define fac(x) {
    auto f, i;
    if (x < 0) return (0);
    f = 1;
    for (i = x; i >= 2; i--) { f *= i; }
    return (f);
}

define f(x) {
    return (fac(x));
}

define fact(x) {
    return (fac(x));
}

define factorial(x) {
    return (fac(x));
}

define per(n, k) {
    auto p, i;
    if (n < k) return (0);
    p = 1;
    for (i = n; i >= n - k + 1; i--) { p *= i; }
    return (p);
}

define p(n, k) {
    return (per(n, k));
}

define perm(n, k) {
    return (per(n, k));
}

define com(n, k) {
    if (n < k) return (0);
    return (per(n, k) / fac(k));
}

define comb(n, k) {
    return (com(n, k));
}

define gcd(x, y) {
    return (x * y / lcm(x, y));
}

define lcm(x, y) {
    auto a, b, z;

    /* the LCM is defined only for positive integers */
    # if (mod(x, 1) != 0 || x < 1 || mod(y, 1) != 0 || y < 1) { return 0; }
    # if (mod(x, 1) != 0) return (0);
    if (x < 1) return (0);
    # if (mod(y, 1) != 0) return (0);
    if (y < 1) return (0);

    a = min(x, y);
    b = max(x, y);

    z = b;
    while (mod(z, a) != 0) { z += b; }
    return (z);
}

define sgn(x) {
    if (x > 0) return (1);
    if (x < 0) return (-1);
    return (0);
}

define sign(x) {
    return (sgn(x));
}

define logistic(x) {
    return (1 / (1 + e(-x)));
}

$(echo "$@" | sed 's-^+--g; s-_--g; s-\*\*-^-g; s-\[-(-g; s-\]-)-g')
ENDOFSCRIPT
} |
# ensure the result shows at least a zero before the decimal dot, then
# rid the result of trailing zero decimals and/or trailing decimal dots
sed -E 's-^\.-0.-; s/^-\./-0./; s-(\.[0-9]+[1-9]+)0+$-\1-; s-\.0*$--'