/* 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 https://mozilla.org/MPL/2.0/. */

use dom_struct::dom_struct;
use html5ever::{LocalName, Prefix, local_name, namespace_url, ns};
use js::rust::HandleObject;
use servo_url::ServoUrl;

use crate::dom::attr::Attr;
use crate::dom::bindings::codegen::Bindings::HTMLBaseElementBinding::HTMLBaseElementMethods;
use crate::dom::bindings::inheritance::Castable;
use crate::dom::bindings::root::DomRoot;
use crate::dom::bindings::str::DOMString;
use crate::dom::document::Document;
use crate::dom::element::{AttributeMutation, Element};
use crate::dom::htmlelement::HTMLElement;
use crate::dom::node::{BindContext, Node, NodeTraits, UnbindContext};
use crate::dom::virtualmethods::VirtualMethods;
use crate::script_runtime::CanGc;

#[dom_struct]
pub(crate) struct HTMLBaseElement {
    htmlelement: HTMLElement,
}

impl HTMLBaseElement {
    fn new_inherited(
        local_name: LocalName,
        prefix: Option<Prefix>,
        document: &Document,
    ) -> HTMLBaseElement {
        HTMLBaseElement {
            htmlelement: HTMLElement::new_inherited(local_name, prefix, document),
        }
    }

    #[cfg_attr(crown, allow(crown::unrooted_must_root))]
    pub(crate) fn new(
        local_name: LocalName,
        prefix: Option<Prefix>,
        document: &Document,
        proto: Option<HandleObject>,
        can_gc: CanGc,
    ) -> DomRoot<HTMLBaseElement> {
        Node::reflect_node_with_proto(
            Box::new(HTMLBaseElement::new_inherited(local_name, prefix, document)),
            document,
            proto,
            can_gc,
        )
    }

    /// <https://html.spec.whatwg.org/multipage/#frozen-base-url>
    pub(crate) fn frozen_base_url(&self) -> ServoUrl {
        let href = self
            .upcast::<Element>()
            .get_attribute(&ns!(), &local_name!("href"))
            .expect(
                "The frozen base url is only defined for base elements \
                 that have a base url.",
            );
        let document = self.owner_document();
        let base = document.fallback_base_url();
        let parsed = base.join(&href.value());
        parsed.unwrap_or(base)
    }

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

        if self.upcast::<Element>().has_attribute(&local_name!("href")) {
            let document = self.owner_document();
            document.refresh_base_element();
        }
    }
}

impl HTMLBaseElementMethods<crate::DomTypeHolder> for HTMLBaseElement {
    // https://html.spec.whatwg.org/multipage/#dom-base-href
    fn Href(&self) -> DOMString {
        // Step 1.
        let document = self.owner_document();

        // Step 2.
        let attr = self
            .upcast::<Element>()
            .get_attribute(&ns!(), &local_name!("href"));
        let value = attr.as_ref().map(|attr| attr.value());
        let url = value.as_ref().map_or("", |value| &**value);

        // Step 3.
        let url_record = document.fallback_base_url().join(url);

        match url_record {
            Err(_) => {
                // Step 4.
                url.into()
            },
            Ok(url_record) => {
                // Step 5.
                url_record.into_string().into()
            },
        }
    }

    // https://html.spec.whatwg.org/multipage/#dom-base-href
    make_setter!(SetHref, "href");
}

impl VirtualMethods for HTMLBaseElement {
    fn super_type(&self) -> Option<&dyn VirtualMethods> {
        Some(self.upcast::<HTMLElement>() as &dyn VirtualMethods)
    }

    fn attribute_mutated(&self, attr: &Attr, mutation: AttributeMutation) {
        self.super_type().unwrap().attribute_mutated(attr, mutation);
        if *attr.local_name() == local_name!("href") {
            self.owner_document().refresh_base_element();
        }
    }

    fn bind_to_tree(&self, context: &BindContext) {
        self.super_type().unwrap().bind_to_tree(context);
        self.bind_unbind(context.tree_is_in_a_document_tree);
    }

    fn unbind_from_tree(&self, context: &UnbindContext) {
        self.super_type().unwrap().unbind_from_tree(context);
        self.bind_unbind(context.tree_is_in_a_document_tree);
    }
}