package stacks

/* ---------------------------------------------------------------- *
 * IMPORTS
 * ---------------------------------------------------------------- */

import (
	"fmt"
	"strings"
)

/* ---------------------------------------------------------------- *
 * GLOBAL VARIABLES/CONSTANTS
 * ---------------------------------------------------------------- */

//

/* ---------------------------------------------------------------- *
 * TYPE
 * ---------------------------------------------------------------- */

type StackInt struct {
	values []int
}

/* ---------------------------------------------------------------- *
 * METHODS stacks
 * ---------------------------------------------------------------- */

func CREATE() StackInt {
	return StackInt{
		values: []int{},
	}
}

func (S *StackInt) INIT() StackInt {
	return StackInt{
		values: []int{},
	}
}

func (S StackInt) EMPTY() bool {
	return len(S.values) == 0
}

func (S *StackInt) PUSH(x int) {
	S.values = append(S.values, x)
}

func (S *StackInt) TOP() int {
	if S.EMPTY() {
		panic("Cannot pop from empty stack!")
	}
	return S.values[len(S.values)-1]
}

func (S *StackInt) POP() int {
	x := S.TOP()
	S.values = S.values[:(len(S.values) - 1)]
	return x
}

func (S StackInt) String() string {
	if len(S.values) == 0 {
		return "-"
	}
	values := []string{}
	for _, value := range S.values {
		values = append(values, fmt.Sprintf("%v", value))
	}
	return fmt.Sprintf(strings.Join(values, ", "))
}