/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

use dom::attr::{Attr, AttrHelpers};
use dom::bindings::codegen::Bindings::HTMLBaseElementBinding;
use dom::bindings::codegen::InheritTypes::ElementCast;
use dom::bindings::codegen::InheritTypes::HTMLBaseElementDerived;
use dom::bindings::codegen::InheritTypes::HTMLElementCast;
use dom::bindings::js::Root;
use dom::document::{Document, DocumentHelpers};
use dom::element::{ElementTypeId, AttributeHandlers};
use dom::eventtarget::{EventTarget, EventTargetTypeId};
use dom::htmlelement::{HTMLElement, HTMLElementTypeId};
use dom::node::{Node, NodeTypeId, document_from_node};
use dom::virtualmethods::VirtualMethods;
use util::str::DOMString;

use url::{Url, UrlParser};

#[dom_struct]
#[derive(HeapSizeOf)]
pub struct HTMLBaseElement {
    htmlelement: HTMLElement
}

impl HTMLBaseElementDerived for EventTarget {
    fn is_htmlbaseelement(&self) -> bool {
        *self.type_id() ==
            EventTargetTypeId::Node(
                NodeTypeId::Element(ElementTypeId::HTMLElement(HTMLElementTypeId::HTMLBaseElement)))
    }
}

impl HTMLBaseElement {
    fn new_inherited(localName: DOMString, prefix: Option<DOMString>, document: &Document) -> HTMLBaseElement {
        HTMLBaseElement {
            htmlelement: HTMLElement::new_inherited(HTMLElementTypeId::HTMLBaseElement, localName, prefix, document)
        }
    }

    #[allow(unrooted_must_root)]
    pub fn new(localName: DOMString,
               prefix: Option<DOMString>,
               document: &Document) -> Root<HTMLBaseElement> {
        let element = HTMLBaseElement::new_inherited(localName, prefix, document);
        Node::reflect_node(box element, document, HTMLBaseElementBinding::Wrap)
    }

    /// https://html.spec.whatwg.org/multipage/#frozen-base-url
    pub fn frozen_base_url(&self) -> Url {
        let href = ElementCast::from_ref(self).get_attribute(&ns!(""), &atom!("href"))
            .expect("The frozen base url is only defined for base elements \
                     that have a base url.");
        let base = document_from_node(self).fallback_base_url();
        let parsed = UrlParser::new().base_url(&base).parse(&href.value());
        parsed.unwrap_or(base)
    }

    /// Update the cached base element in response to adding or removing an
    /// attribute.
    pub fn add_remove_attr(&self, attr: &Attr) {
        if *attr.local_name() == atom!("href") {
            let document = document_from_node(self);
            document.refresh_base_element();
        }
    }

    /// Update the cached base element in response to binding or unbinding from
    /// a tree.
    pub fn bind_unbind(&self, tree_in_doc: bool) {
        if !tree_in_doc {
            return;
        }

        if ElementCast::from_ref(self).has_attribute(&atom!("href")) {
            let document = document_from_node(self);
            document.refresh_base_element();
        }
    }
}

impl VirtualMethods for HTMLBaseElement {
    fn super_type<'b>(&'b self) -> Option<&'b VirtualMethods> {
        Some(HTMLElementCast::from_ref(self) as &VirtualMethods)
    }

    fn after_set_attr(&self, attr: &Attr) {
        self.super_type().unwrap().after_set_attr(attr);
        self.add_remove_attr(attr);
    }

    fn before_remove_attr(&self, attr: &Attr) {
        self.super_type().unwrap().before_remove_attr(attr);
        self.add_remove_attr(attr);
    }

    fn bind_to_tree(&self, tree_in_doc: bool) {
        self.super_type().unwrap().bind_to_tree(tree_in_doc);
        self.bind_unbind(tree_in_doc);
    }

    fn unbind_from_tree(&self, tree_in_doc: bool) {
        self.super_type().unwrap().unbind_from_tree(tree_in_doc);
        self.bind_unbind(tree_in_doc);
    }
}