package main

import (
	"errors"
	"os"
	"reflect"
	"strconv"
	"strings"
)

func getEnv(mask interface{}) Env {
	r := reflect.ValueOf(mask)

	argTypeRV := reflect.New(r.Type())

	for i := 0; i < r.NumField(); i++ {
		v := r.Type().Field(i).Tag.Get("env")
		d := r.Type().Field(i).Tag.Get("default")

		env, ok := os.LookupEnv(v)
		var val string
		if ok {
			val = env
		} else {
			val = d
		}

		switch t := r.Type().Field(i).Type.Name(); t {
		case "string":
			argTypeRV.Elem().Field(i).SetString(val)
		case "bool":
			if strings.EqualFold(val, "true") {
				argTypeRV.Elem().Field(i).SetBool(true)
			} else {
				argTypeRV.Elem().Field(i).SetBool(false)
			}
		case "uint64":
			num, err := strconv.ParseUint(val, 10, 64)
			if err != nil {
				panic(err)
			}
			argTypeRV.Elem().Field(i).SetUint(num)
		default:
			panic(errors.New("Something strange happened: " + t))
		}
	}

	return argTypeRV.Elem().Interface().(Env)
}