package main

import (
	"flag"
	"fmt"
	"os"

	"github.com/Knetic/govaluate"
)

var exp string = ""
var ver string = ""
var vsn bool = false

func init() {
	flag.BoolVar(&vsn, "v", false, "Show Program Version")
	flag.StringVar(&exp, "e", "", "Evaluable Expression")
	flag.Parse()
}

func main() {
	if vsn {
		_ShowVersion()
		os.Exit(0)
	}

	if exp == "" {
		flag.Usage()
		os.Exit(1)
	}

	expression, err := govaluate.NewEvaluableExpression(exp)
	if err != nil {
		fmt.Printf("[ERR]  %v\r\n", err)
		os.Exit(1)
	}
	result, err := expression.Evaluate(nil)
	if err != nil {
		fmt.Printf("[ERR]  %v\r\n", err)
		os.Exit(1)
	}
	fmt.Printf("Result=%v\r\n", result)
}

func _ShowVersion() {
	fmt.Printf("%s\r\nAuthor: %s\r\nVersion: %s\r\n", os.Args[0], "TE / Vayne Tan", ver)
}