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#![allow(expl_impl_clone_on_copy)]

use super::{NodeRef, NodeId};

impl<'a, T: 'a> NodeRef<'a, T> {
    /// Returns the value of this node.
    pub fn value(&self) -> &'a T {
        &self.node.value
    }

    /// Returns the ID of this node.
    pub fn id(&self) -> NodeId<T> {
        self.tree.node_id(self.index)
    }

    /// Returns a reference to this node's parent.
    pub fn parent(&self) -> Option<NodeRef<'a, T>> {
        self.node.parent.map(|i| self.tree.get_unchecked(i))
    }

    /// Returns a reference to this node's previous sibling.
    pub fn prev_sibling(&self) -> Option<NodeRef<'a, T>> {
        self.node.prev_sibling.map(|i| self.tree.get_unchecked(i))
    }

    /// Returns a reference to this node's next sibling.
    pub fn next_sibling(&self) -> Option<NodeRef<'a, T>> {
        self.node.next_sibling.map(|i| self.tree.get_unchecked(i))
    }

    /// Returns a reference to this node's first child.
    pub fn first_child(&self) -> Option<NodeRef<'a, T>> {
        self.node.children.map(|(i, _)| self.tree.get_unchecked(i))
    }

    /// Returns a reference to this node's last child.
    pub fn last_child(&self) -> Option<NodeRef<'a, T>> {
        self.node.children.map(|(_, i)| self.tree.get_unchecked(i))
    }

    /// Returns true if this node has siblings.
    pub fn has_siblings(&self) -> bool {
        self.node.prev_sibling.is_some() || self.node.next_sibling.is_some()
    }

    /// Returns true if this node has children.
    pub fn has_children(&self) -> bool {
        self.node.children.is_some()
    }
}

impl<'a, T: 'a> Copy for NodeRef<'a, T> { }
impl<'a, T: 'a> Clone for NodeRef<'a, T> {
    fn clone(&self) -> Self { *self }
}

impl<'a, T: 'a> Eq for NodeRef<'a, T> { }
impl<'a, T: 'a> PartialEq for NodeRef<'a, T> {
    #[allow(trivial_casts)]
    fn eq(&self, other: &Self) -> bool {
        self.tree as *const _ == other.tree as *const _
            && self.node as *const _ == other.node as *const _
            && self.index == other.index
    }
}