module html

const null_element = int(-1)

struct Stack {
mut:
    elements []int
    size     int
}

@[inline]
fn is_null(data int) bool {
    return data == null_element
}

@[inline]
fn (stack Stack) is_empty() bool {
    return stack.size <= 0
}

fn (stack Stack) peek() int {
    return if !stack.is_empty() { stack.elements[stack.size - 1] } else { null_element }
}

fn (mut stack Stack) pop() int {
    mut to_return := null_element
    if !stack.is_empty() {
        to_return = stack.elements[stack.size - 1]
        stack.size--
    }
    return to_return
}

fn (mut stack Stack) push(item int) {
    if stack.elements.len > stack.size {
        stack.elements[stack.size] = item
    } else {
        stack.elements << item
    }
    stack.size++
}

struct BTree {
mut:
    all_tags     []Tag
    node_pointer int
    childrens    [][]int
    parents      []int
}

fn (mut btree BTree) add_children(tag Tag) int {
    btree.all_tags << tag
    if btree.all_tags.len > 1 {
        for btree.childrens.len <= btree.node_pointer {
            mut temp_array := btree.childrens.clone()
            temp_array << []int{}
            btree.childrens = temp_array
        }
        btree.childrens[btree.node_pointer] << btree.all_tags.len - 1
        for btree.parents.len < btree.all_tags.len {
            mut temp_array := btree.parents.clone()
            temp_array << 0
            btree.parents = temp_array
        }
        btree.parents[btree.all_tags.len - 1] = btree.node_pointer
    }
    return btree.all_tags.len - 1
}

@[inline]
fn (btree BTree) get_children() []int {
    return btree.childrens[btree.node_pointer]
}

@[inline]
fn (btree BTree) get_parent() int {
    return btree.parents[btree.node_pointer]
}

@[inline]
fn (btree BTree) get_stored() Tag {
    return btree.all_tags[btree.node_pointer]
}

fn (mut btree BTree) move_pointer(to int) {
    if to < btree.all_tags.len {
        btree.node_pointer = to
    }
}