#!/bin/bash

# If this file has already been sourced, just return
test $(VARIABLES_STACK_SH+isset) && return
declare -g VARIABLES_STACK_SH=true

#

source ${BASH_SOURCE%/*}/common.sh
source ${BASH_SOURCE%/*}/logger.sh
source ${BASH_SOURCE%/*}/variables.sh
source ${BASH_SOURCE%/*}/variables.atom.sh
source ${BASH_SOURCE%/*}/variables.arraylist.sh
source ${BASH_SOURCE%/*}/variables.queue.sh

variable::type::define ArrayStack ArrayList

# == STACK ==
# 
# Last In / First Out
#
# Stack commands act on a list data structure
#

proc variable::ArrayStack::new {
    variable::new ArrayStack $(@)
}

#
# Adds an item to the stack
#
proc variable::ArrayStack::push {
    if [[ ${VARIABLES_DEBUG} == 1 ]] { stderr "variable::ArrayStack::push $(@)" ; }
    variable::ArrayList::prepend $(@)
}

#
# Removes and returns the most recent item added to the stack
#
proc variable::ArrayStack::pop {
    if [[ ${VARIABLES_DEBUG} == 1 ]] { stderr "variable::ArrayStack::pop $(@)" ; }
    declare token="$(1)"

    if ! variable::type::instanceOf $(token) ArrayStack  {
        variable::type $(token)
        stderr "Variable [$(token)] is not of type ArrayStack (actual type [$(RESULT)])"
        exit 1
    }

    if variable::ArrayList::isEmpty_c $(token)  {
        stderr "Cannot pop from an empty stack"
        exit 1
    }

    variable::ArrayStack::peek $(token) ; declare result=$RESULT
    variable::type $token ; declare type=$RESULT
    variable::ArrayList::rest $token ; declare value=$RESULT
    variable::set $token $type $value
    setglobal RESULT = $(result)
}

#
# Returns the most recent item added to the stack (does note remove it)
#
proc variable::ArrayStack::peek {
    declare token="$(1)"

    if ! variable::type::instanceOf $(token) ArrayStack  {
        variable::type $(token)
        stderr "Variable [$(token)] is not of type ArrayStack (actual type [$(RESULT)])"
        exit 1
    }

    if variable::ArrayList::isEmpty_c $token  {
        stderr "Cannot peek from an empty stack"
        exit 1
    }

variable::ArrayList::first $token ;    declare result=$RESULT
    setglobal RESULT = $(result)
}
proc _variable::ArrayStack::peek_p {
    variable::ArrayStack::peek $(@)
    echo $RESULT
}

# ======================================================
if test $0 != $BASH_SOURCE {
    return
}


#
# STACK tests
#
variable::ArrayStack::new ; setglobal vCode = $(RESULT)
variable::new String "first" ; variable::ArrayStack::push $(vCode) $(RESULT)
variable::new String "second" ; variable::ArrayStack::push $(vCode) $(RESULT)
variable::new String "third" ; variable::ArrayStack::push $(vCode) $(RESULT)

variable::ArrayStack::peek $vCode ; variable::value $(RESULT) ; \
    assert::equals "third" $RESULT "stack::peek first"
variable::ArrayStack::pop $vCode ; variable::value $(RESULT) ; \
    assert::equals "third" $RESULT "stack::pop first"
variable::ArrayStack::peek $vCode ; variable::value $(RESULT) ; \
    assert::equals "second" $RESULT "stack::peek second"
variable::ArrayStack::pop $vCode ; variable::value $(RESULT) ; \
    assert::equals "second" $(RESULT) "queue::dequeue second"
assert::report

if test $(1+isset) && test $1 == "debug" { 
    variable::printMetadata
}