#!/bin/bash
# Desc: Checks if arg is a float

#==BEGIN Define script parameters==
#===BEGIN Declare local script functions===
yell() { echo "$0: $*" >&2; } # print script path and all args to stderr
die() { yell "$*"; exit 111; } # same as yell() but non-zero exit status
try() { "$@" || die "cannot $*"; } # runs args as command, reports args if command fails
checkFlt() {
    # Desc: Checks if arg is a float
    # Usage: checkInt arg
    # Input: arg: float
    # Output: - return code 0 (if arg is float)
    #         - return code 1 (if arg is not float)
    # Example: if ! checkInt $arg; then echo "not flt"; fi;
    # Version: 0.0.1
    # Depends: yell(), die(), bash 5.0.3
    # Ref/Attrib: JDB https://stackoverflow.com/a/12643073 float regex
    local returnState

    #===Process Arg===
    if [[ $# -ne 1 ]]; then
	die "ERROR:Invalid number of arguments:$#";
    fi;

    RETEST1='^[+-]?([0-9]+([.][0-9]*)?|[.][0-9]+)$'; # Regular Expression to test
    if [[ ! $1 =~ $RETEST1 ]] ; then
	returnState="false";
    else
	returnState="true";
    fi;

    #===Determine function return code===
    if [ "$returnState" = "true" ]; then
	return 0;
    else
	return 1;
    fi;
} # Checks if arg is integer

#===END Declare local script functions===
#==END Define script parameters==

#==BEGIN test code==
myVar1="4" ; echo "Test 1:Should succeed because int is float without decimal places or decimal.";
(if checkFlt "$myVar1"; then yell "success"; else yell "fail"; fi;) & sleep 1;

myVar1="4.0" ; echo "Test 2:Should succeed because \"4.0\" is a float.";
(if checkFlt "$myVar1"; then yell "success"; else yell "fail"; fi;) & sleep 1;

myVar1=".0" ; echo "Test 3:Should succeed even if float lack whole numbers left of decimal.";
(if checkFlt "$myVar1"; then yell "success"; else yell "fail"; fi;) & sleep 1;

myVar1="4." ; echo "Test 4:Should succeed even if float lacks decimal places right of decimal.";
(if checkFlt "$myVar1"; then yell "success"; else yell "fail"; fi;) & sleep 1;

myVar1="14.0" ; echo "Test 5:Should succeed with multiple whole numbers to left of decimal."
(if checkFlt "$myVar1"; then yell "success"; else yell "fail"; fi;) & sleep 1;

myVar1="." ; echo "Test 6:Should fail because neither whole numbers nor decimal places are present.";
(if checkFlt "$myVar1"; then yell "success"; else yell "fail"; fi;) & sleep 1;

myVar1="4"; myVar2="5"; echo "Test 7:Should fail because multiple numbers are provided.";
(if checkFlt "$myVar1" "$myVar2"; then yell "success"; else yell "fail"; fi;) & sleep 1;

myVar1="4 5"; echo "Test 8:Should fail because multiple numbers are provided.";
(if checkFlt "$myVar1"; then yell "success"; else yell "fail"; fi;) & sleep 1;

myVar1="4.4.4"; echo "Test 9:Should fail because a float should contain only one decimal.";
(if checkFlt "$myVar1"; then yell "success"; else yell "fail"; fi;) & sleep 1;

myVar1="foo"; echo "Test 10:Should fail because floats should only contain numbers and decimal characters."
(if checkFlt "$myVar1"; then yell "success"; else yell "fail"; fi;) & sleep 1;

myVar1="foo"; myVar2="bar"; myVar3="baz"; echo "Test 11: Should fail because multiple arguments provided.";
(if checkFlt "$myVar1" "$myVar2" "$myVar3"; then yell "success"; else yell "fail"; fi;) & sleep 1;
#==END test code==

# Author: Steven Baltakatei Sandoval
# License: GPLv3+