/* 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::comment::Comment;
use dom::bindings::codegen::DocumentBinding;
use dom::bindings::utils::{DOMString, ErrorResult, Fallible};
use dom::bindings::utils::{Reflectable, Reflector, DerivedWrapper};
use dom::bindings::utils::{is_valid_element_name, InvalidCharacter, Traceable, null_str_as_empty, null_str_as_word_null};
use dom::documentfragment::DocumentFragment;
use dom::element::{Element};
use dom::element::{HTMLHtmlElementTypeId, HTMLHeadElementTypeId, HTMLTitleElementTypeId};
use dom::event::Event;
use dom::htmlcollection::HTMLCollection;
use dom::htmldocument::HTMLDocument;
use dom::htmlelement::HTMLElement;
use dom::htmlhtmlelement::HTMLHtmlElement;
use dom::node::{AbstractNode, ScriptView, Node, ElementNodeTypeId};
use dom::text::Text;
use dom::window::Window;
use dom::windowproxy::WindowProxy;
use dom::htmltitleelement::HTMLTitleElement;
use html::hubbub_html_parser::build_element_from_tag;
use js::jsapi::{JSObject, JSContext, JSVal};
use js::jsapi::{JSTRACE_OBJECT, JSTracer, JS_CallTracer};
use js::glue::RUST_OBJECT_TO_JSVAL;
use servo_util::tree::{TreeNodeRef, ElementLike};

use std::hashmap::HashMap;

use std::cast;
use std::ptr;
use std::str::eq_slice;
use std::libc;
use std::ascii::StrAsciiExt;
use std::unstable::raw::Box;

pub trait ReflectableDocument {
    fn init_reflector(@mut self, cx: *JSContext);
}

#[deriving(Eq)]
pub struct AbstractDocument {
    document: *mut Box<Document>
}

impl AbstractDocument {
    pub fn as_abstract<T: ReflectableDocument>(cx: *JSContext, doc: @mut T) -> AbstractDocument {
        doc.init_reflector(cx);
        AbstractDocument {
            document: unsafe { cast::transmute(doc) }
        }
    }

    pub fn document<'a>(&'a self) -> &'a Document {
        unsafe {
            &(*self.document).data
        }
    }

    pub fn mut_document<'a>(&'a self) -> &'a mut Document {
        unsafe {
            &mut (*self.document).data
        }
    }

    unsafe fn transmute<T, R>(&self, f: &fn(&T) -> R) -> R {
        let box: *Box<T> = cast::transmute(self.document);
        f(&(*box).data)
    }

    unsafe fn transmute_mut<T, R>(&self, f: &fn(&mut T) -> R) -> R {
        let box: *mut Box<T> = cast::transmute(self.document);
        f(&mut (*box).data)
    }

    pub fn with_html<R>(&self, callback: &fn(&HTMLDocument) -> R) -> R {
        match self.document().doctype {
            HTML => unsafe { self.transmute(callback) },
            _ => fail!("attempt to downcast a non-HTMLDocument to HTMLDocument")
        }
    }

    pub fn from_box<T>(ptr: *mut Box<T>) -> AbstractDocument {
        AbstractDocument {
            document: ptr as *mut Box<Document>
        }
    }

    pub fn set_root(&self, root: AbstractNode<ScriptView>) {
        assert!(do root.traverse_preorder().all |node| {
            node.node().owner_doc() == *self
        });

        let document = self.mut_document();
        document.root = Some(root);
        // Register elements having "id" attribute to the owner doc.
        document.register_nodes_with_id(&root);
        document.content_changed();
    }
}

pub enum DocumentType {
    HTML,
    SVG,
    XML
}

pub struct Document {
    priv root: Option<AbstractNode<ScriptView>>,
    reflector_: Reflector,
    window: @mut Window,
    doctype: DocumentType,
    title: ~str,
    idmap: HashMap<~str, AbstractNode<ScriptView>>
}

impl Document {
    #[fixed_stack_segment]
    pub fn new(window: @mut Window, doctype: DocumentType) -> Document {
        Document {
            root: None,
            reflector_: Reflector::new(),
            window: window,
            doctype: doctype,
            title: ~"",
            idmap: HashMap::new()
        }
    }

    pub fn Constructor(owner: @mut Window) -> Fallible<AbstractDocument> {
        let cx = owner.get_cx();

        let document = AbstractDocument::as_abstract(cx, @mut Document::new(owner, XML));

        let root = @HTMLHtmlElement {
            htmlelement: HTMLElement::new(HTMLHtmlElementTypeId, ~"html", document)
        };
        let root = unsafe { Node::as_abstract_node(cx, root) };
        document.set_root(root);

        Ok(document)
    }
}

impl ReflectableDocument for Document {
    fn init_reflector(@mut self, cx: *JSContext) {
        self.wrap_object_shared(cx, ptr::null()); //XXXjdm a proper scope would be nice
    }
}

impl Reflectable for AbstractDocument {
    fn reflector<'a>(&'a self) -> &'a Reflector {
        self.document().reflector()
    }

    fn mut_reflector<'a>(&'a mut self) -> &'a mut Reflector {
        self.mut_document().mut_reflector()
    }

    fn wrap_object_shared(@mut self, cx: *JSContext, scope: *JSObject) -> *JSObject {
        match self.document().doctype {
            HTML => {
                let doc: @mut HTMLDocument = unsafe { cast::transmute(self.document) };
                doc.wrap_object_shared(cx, scope)
            }
            XML | SVG => {
                fail!("no wrapping for documents that don't exist")
            }
        }
    }

    fn GetParentObject(&self, cx: *JSContext) -> Option<@mut Reflectable> {
        self.document().GetParentObject(cx)
    }
}

impl DerivedWrapper for AbstractDocument {
    #[fixed_stack_segment]
    fn wrap(&mut self, _cx: *JSContext, _scope: *JSObject, vp: *mut JSVal) -> i32 {
        unsafe { *vp = RUST_OBJECT_TO_JSVAL(self.reflector().get_jsobject()) };
        return 1;
    }
}


impl Reflectable for Document {
    fn reflector<'a>(&'a self) -> &'a Reflector {
        &self.reflector_
    }

    fn mut_reflector<'a>(&'a mut self) -> &'a mut Reflector {
        &mut self.reflector_
    }

    fn wrap_object_shared(@mut self, cx: *JSContext, scope: *JSObject) -> *JSObject {
        DocumentBinding::Wrap(cx, scope, self)
    }

    fn GetParentObject(&self, _cx: *JSContext) -> Option<@mut Reflectable> {
        Some(self.window as @mut Reflectable)
    }
}

impl Document {
    pub fn URL(&self) -> DOMString {
        None
    }

    pub fn DocumentURI(&self) -> DOMString {
        None
    }

    pub fn CompatMode(&self) -> DOMString {
        None
    }

    pub fn CharacterSet(&self) -> DOMString {
        None
    }

    pub fn ContentType(&self) -> DOMString {
        None
    }

    pub fn GetDocumentElement(&self) -> Option<AbstractNode<ScriptView>> {
        self.root
    }

    fn get_cx(&self) -> *JSContext {
        self.window.get_cx()
    }

    fn get_scope_and_cx(&self) -> (*JSObject, *JSContext) {
        let win = self.window;
        (win.reflector().get_jsobject(), win.get_cx())
    }

    pub fn GetElementsByTagName(&self, tag: &DOMString) -> @mut HTMLCollection {
        self.createHTMLCollection(|elem| eq_slice(elem.tag_name, null_str_as_empty(tag)))
    }

    pub fn GetElementsByTagNameNS(&self, _ns: &DOMString, _tag: &DOMString) -> @mut HTMLCollection {
        let (scope, cx) = self.get_scope_and_cx();
        HTMLCollection::new(~[], cx, scope)
    }

    pub fn GetElementsByClassName(&self, _class: &DOMString) -> @mut HTMLCollection {
        let (scope, cx) = self.get_scope_and_cx();
        HTMLCollection::new(~[], cx, scope)
    }

    pub fn GetElementById(&self, id: &DOMString) -> Option<AbstractNode<ScriptView>> {
        let key: &~str = &null_str_as_empty(id);
        // TODO: "in tree order, within the context object's tree"
        // http://dom.spec.whatwg.org/#dom-document-getelementbyid.
        self.idmap.find_equiv(key).map(|node| **node)
    }

    pub fn CreateElement(&self, abstract_self: AbstractDocument, local_name: &DOMString) -> Fallible<AbstractNode<ScriptView>> {
        let cx = self.get_cx();
        let local_name = null_str_as_empty(local_name);
        if !is_valid_element_name(local_name) {
            return Err(InvalidCharacter);
        }
        let local_name = local_name.to_ascii_lower();
        Ok(build_element_from_tag(cx, local_name, abstract_self))
    }

    pub fn CreateElementNS(&self, _namespace: &DOMString, _qualified_name: &DOMString) -> Fallible<AbstractNode<ScriptView>> {
        fail!("stub")
    }

    pub fn CreateDocumentFragment(&self, abstract_self: AbstractDocument) -> AbstractNode<ScriptView> {
        let cx = self.get_cx();
        let fragment = @DocumentFragment::new(abstract_self);
        unsafe { Node::as_abstract_node(cx, fragment) }
    }

    pub fn CreateTextNode(&self, abstract_self: AbstractDocument, data: &DOMString) -> AbstractNode<ScriptView> {
        let cx = self.get_cx();
        let text = @Text::new(null_str_as_empty(data), abstract_self);
        unsafe { Node::as_abstract_node(cx, text) }
    }

    pub fn CreateComment(&self, abstract_self: AbstractDocument, data: &DOMString) -> AbstractNode<ScriptView> {
        let cx = self.get_cx();
        let comment = @Comment::new(null_str_as_word_null(data), abstract_self);
        unsafe { Node::as_abstract_node(cx, comment) }
    }

    pub fn CreateEvent(&self, _interface: &DOMString) -> Fallible<@mut Event> {
        fail!("stub")
    }

    pub fn GetInputEncoding(&self) -> DOMString {
        None
    }

    pub fn Referrer(&self) -> DOMString {
        None
    }

    pub fn LastModified(&self) -> DOMString {
        None
    }

    pub fn ReadyState(&self) -> DOMString {
        None
    }

    pub fn Title(&self, _: AbstractDocument) -> DOMString {
        let mut title = ~"";
        match self.doctype {
            SVG => {
                fail!("no SVG document yet")
            },
            _ => {
                match self.GetDocumentElement() {
                    None => {},
                    Some(root) => {
                        for node in root.traverse_preorder() {
                            if node.type_id() != ElementNodeTypeId(HTMLTitleElementTypeId) {
                                loop;
                            }
                            for child in node.children() {
                                if child.is_text() {
                                    do child.with_imm_text() |text| {
                                        let s = text.element.Data();
                                        title = title + null_str_as_empty(&s);
                                    }
                                }
                            }
                            break;
                        }
                    }
                }
            }
        }
        let v: ~[&str] = title.word_iter().collect();
        title = v.connect(" ");
        title = title.trim().to_owned();
        Some(title)
    }

    pub fn SetTitle(&self, abstract_self: AbstractDocument, title: &DOMString) -> ErrorResult {
        match self.doctype {
            SVG => {
                fail!("no SVG document yet")
            },
            _ => {
                let (_scope, cx) = self.get_scope_and_cx();
                match self.GetDocumentElement() {
                    None => {},
                    Some(root) => {
                        for node in root.traverse_preorder() {
                            if node.type_id() != ElementNodeTypeId(HTMLHeadElementTypeId) {
                                loop;
                            }
                            let mut has_title = false;
                            for child in node.children() {
                                if child.type_id() != ElementNodeTypeId(HTMLTitleElementTypeId) {
                                    loop;
                                }
                                has_title = true;
                                for title_child in child.children() {
                                    child.remove_child(title_child);
                                }
                                child.add_child(self.CreateTextNode(abstract_self, title));
                                break;
                            }
                            if !has_title {
                                let new_title = @HTMLTitleElement {
                                    htmlelement: HTMLElement::new(HTMLTitleElementTypeId, ~"title", abstract_self)
                                };
                                let new_title = unsafe { 
                                    Node::as_abstract_node(cx, new_title) 
                                };
                                new_title.add_child(self.CreateTextNode(abstract_self, title));
                                node.add_child(new_title);
                            }
                            break;
                        }
                    }
                }
            }
        }
        Ok(())
    }

    pub fn Dir(&self) -> DOMString {
        None
    }

    pub fn SetDir(&self, _dir: &DOMString) {
    }

    pub fn GetDefaultView(&self) -> Option<@mut WindowProxy> {
        None
    }

    pub fn GetActiveElement(&self) -> Option<AbstractNode<ScriptView>> {
        None
    }

    pub fn HasFocus(&self) -> Fallible<bool> {
        Ok(false)
    }

    pub fn GetCurrentScript(&self) -> Option<AbstractNode<ScriptView>> {
        None
    }

    pub fn ReleaseCapture(&self) {
    }

    pub fn MozFullScreenEnabled(&self) -> bool {
        false
    }

    pub fn GetMozFullScreenElement(&self) -> Fallible<Option<AbstractNode<ScriptView>>> {
        Ok(None)
    }

    pub fn GetMozPointerLockElement(&self) -> Option<AbstractNode<ScriptView>> {
        None
    }

    pub fn MozExitPointerLock(&self) {
    }

    pub fn Hidden(&self) -> bool {
        false
    }

    pub fn MozHidden(&self) -> bool {
        self.Hidden()
    }

    pub fn VisibilityState(&self) -> DocumentBinding::VisibilityState {
        DocumentBinding::VisibilityStateValues::Visible
    }

    pub fn MozVisibilityState(&self) -> DocumentBinding::VisibilityState {
        self.VisibilityState()
    }

    pub fn GetSelectedStyleSheetSet(&self) -> DOMString {
        None
    }

    pub fn SetSelectedStyleSheetSet(&self, _sheet: &DOMString) {
    }

    pub fn GetLastStyleSheetSet(&self) -> DOMString {
        None
    }

    pub fn GetPreferredStyleSheetSet(&self) -> DOMString {
        None
    }

    pub fn EnableStyleSheetsForSet(&self, _name: &DOMString) {
    }

    pub fn ElementFromPoint(&self, _x: f32, _y: f32) -> Option<AbstractNode<ScriptView>> {
        None
    }

    pub fn QuerySelector(&self, _selectors: &DOMString) -> Fallible<Option<AbstractNode<ScriptView>>> {
        Ok(None)
    }

    pub fn GetElementsByName(&self, name: &DOMString) -> @mut HTMLCollection {
        self.createHTMLCollection(|elem|
            elem.get_attr("name").is_some() && eq_slice(elem.get_attr("name").unwrap(), null_str_as_empty(name)))
    }

    pub fn createHTMLCollection(&self, callback: &fn(elem: &Element) -> bool) -> @mut HTMLCollection {
        let mut elements = ~[];
        match self.GetDocumentElement() {
            None => {},
            Some(root) => {
                for child in root.traverse_preorder() {
                    if child.is_element() {
                        do child.with_imm_element |elem| {
                            if callback(elem) {
                                elements.push(child);
                            }
                        }
                    }
                }
            }
        }
        let (scope, cx) = self.get_scope_and_cx();
        HTMLCollection::new(elements, cx, scope)
    }

    pub fn content_changed(&self) {
        self.window.content_changed();
    }

    pub fn wait_until_safe_to_modify_dom(&self) {
        self.window.wait_until_safe_to_modify_dom();
    }

    pub fn register_nodes_with_id(&mut self, root: &AbstractNode<ScriptView>) {
        foreach_ided_elements(root, |id: &~str, abstract_node: &AbstractNode<ScriptView>| {
            // TODO: "in tree order, within the context object's tree"
            // http://dom.spec.whatwg.org/#dom-document-getelementbyid.
            self.idmap.find_or_insert(id.clone(), *abstract_node);
        });
    }

    pub fn unregister_nodes_with_id(&mut self, root: &AbstractNode<ScriptView>) {
        foreach_ided_elements(root, |id: &~str, _| {
            // TODO: "in tree order, within the context object's tree"
            // http://dom.spec.whatwg.org/#dom-document-getelementbyid.
            self.idmap.pop(id);
        });
    }
}

#[inline(always)]
fn foreach_ided_elements(root: &AbstractNode<ScriptView>,
                         callback: &fn(&~str, &AbstractNode<ScriptView>)) {
    for node in root.traverse_preorder() {
        if !node.is_element() {
            loop;
        }

        do node.with_imm_element |element| {
            match element.get_attr("id") {
                Some(id) => {
                    callback(&id.to_str(), &node);
                }
                None => ()
            }
        }
    }
}

impl Traceable for Document {
    #[fixed_stack_segment]
    fn trace(&self, tracer: *mut JSTracer) {
        match self.root {
            None => {},
            Some(root) => {
                unsafe {
                    (*tracer).debugPrinter = ptr::null();
                    (*tracer).debugPrintIndex = -1;
                    do "root".to_c_str().with_ref |name| {
                        (*tracer).debugPrintArg = name as *libc::c_void;
                        debug!("tracing root node");
                        JS_CallTracer(tracer as *JSTracer,
                                      root.reflector().get_jsobject(),
                                      JSTRACE_OBJECT as u32);
                    }
                }
            }
        }
    }
}