/* 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 std::cell::Cell;
use std::sync::Arc;

use dom_struct::dom_struct;
use euclid::default::Size2D;
use html5ever::{LocalName, Prefix, local_name, ns};
use js::rust::HandleObject;
use layout_api::{HTMLMediaData, MediaMetadata};
use net_traits::image_cache::{
    ImageCache, ImageCacheResult, ImageLoadListener, ImageOrMetadataAvailable, ImageResponse,
    PendingImageId,
};
use net_traits::request::{CredentialsMode, Destination, RequestBuilder, RequestId};
use net_traits::{
    CoreResourceThread, FetchMetadata, FetchResponseMsg, NetworkError, ResourceFetchTiming,
};
use pixels::{Snapshot, SnapshotAlphaMode, SnapshotPixelFormat};
use servo_media::player::video::VideoFrame;
use servo_url::ServoUrl;
use style::attr::{AttrValue, LengthOrPercentageOrAuto};

use crate::document_loader::{LoadBlocker, LoadType};
use crate::dom::attr::Attr;
use crate::dom::bindings::cell::DomRefCell;
use crate::dom::bindings::codegen::Bindings::HTMLVideoElementBinding::HTMLVideoElementMethods;
use crate::dom::bindings::inheritance::Castable;
use crate::dom::bindings::refcounted::Trusted;
use crate::dom::bindings::reflector::DomGlobal;
use crate::dom::bindings::root::{DomRoot, LayoutDom};
use crate::dom::bindings::str::DOMString;
use crate::dom::csp::{GlobalCspReporting, Violation};
use crate::dom::document::Document;
use crate::dom::element::{AttributeMutation, Element, LayoutElementHelpers};
use crate::dom::globalscope::GlobalScope;
use crate::dom::html::htmlmediaelement::{HTMLMediaElement, NetworkState, ReadyState};
use crate::dom::node::{Node, NodeDamage, NodeTraits};
use crate::dom::performance::performanceresourcetiming::InitiatorType;
use crate::dom::virtualmethods::VirtualMethods;
use crate::fetch::{FetchCanceller, RequestWithGlobalScope};
use crate::network_listener::{self, FetchResponseListener, ResourceTimingListener};
use crate::script_runtime::CanGc;

#[dom_struct]
pub(crate) struct HTMLVideoElement {
    htmlmediaelement: HTMLMediaElement,
    /// <https://html.spec.whatwg.org/multipage/#dom-video-videowidth>
    video_width: Cell<Option<u32>>,
    /// <https://html.spec.whatwg.org/multipage/#dom-video-videoheight>
    video_height: Cell<Option<u32>>,
    /// Incremented whenever tasks associated with this element are cancelled.
    generation_id: Cell<u32>,
    /// Load event blocker. Will block the load event while the poster frame
    /// is being fetched.
    load_blocker: DomRefCell<Option<LoadBlocker>>,
    /// A copy of the last frame
    #[ignore_malloc_size_of = "VideoFrame"]
    #[no_trace]
    last_frame: DomRefCell<Option<VideoFrame>>,
}

impl HTMLVideoElement {
    fn new_inherited(
        local_name: LocalName,
        prefix: Option<Prefix>,
        document: &Document,
    ) -> HTMLVideoElement {
        HTMLVideoElement {
            htmlmediaelement: HTMLMediaElement::new_inherited(local_name, prefix, document),
            video_width: Cell::new(None),
            video_height: Cell::new(None),
            generation_id: Cell::new(0),
            load_blocker: Default::default(),
            last_frame: Default::default(),
        }
    }

    pub(crate) fn new(
        local_name: LocalName,
        prefix: Option<Prefix>,
        document: &Document,
        proto: Option<HandleObject>,
        can_gc: CanGc,
    ) -> DomRoot<HTMLVideoElement> {
        Node::reflect_node_with_proto(
            Box::new(HTMLVideoElement::new_inherited(
                local_name, prefix, document,
            )),
            document,
            proto,
            can_gc,
        )
    }

    pub(crate) fn get_video_width(&self) -> Option<u32> {
        self.video_width.get()
    }

    pub(crate) fn get_video_height(&self) -> Option<u32> {
        self.video_height.get()
    }

    pub(crate) fn set_natural_dimensions(&self, width: Option<u32>, height: Option<u32>) -> bool {
        if self.video_width.get() == width && self.video_height.get() == height {
            return false;
        }

        self.video_width.set(width);
        self.video_height.set(height);

        self.upcast::<Node>().dirty(NodeDamage::Other);
        true
    }

    /// Gets the copy of the video frame at the current playback position,
    /// if that is available, or else (e.g. when the video is seeking or buffering)
    /// its previous appearance, if any.
    pub(crate) fn get_current_frame_data(&self) -> Option<Snapshot> {
        let frame = self.htmlmediaelement.get_current_frame();
        if frame.is_some() {
            *self.last_frame.borrow_mut() = frame;
        }

        match self.last_frame.borrow().as_ref() {
            Some(frame) => {
                let size = Size2D::new(frame.get_width() as u32, frame.get_height() as u32);
                if !frame.is_gl_texture() {
                    let alpha_mode = SnapshotAlphaMode::Transparent {
                        premultiplied: false,
                    };

                    Some(Snapshot::from_vec(
                        size.cast(),
                        SnapshotPixelFormat::BGRA,
                        alpha_mode,
                        frame.get_data().to_vec(),
                    ))
                } else {
                    // XXX(victor): here we only have the GL texture ID.
                    Some(Snapshot::cleared(size.cast()))
                }
            },
            None => None,
        }
    }

    /// <https://html.spec.whatwg.org/multipage/#poster-frame>
    fn update_poster_frame(&self, poster_url: Option<&str>, can_gc: CanGc) {
        // Step 1. If there is an existing instance of this algorithm running
        // for this video element, abort that instance of this algorithm without
        // changing the poster frame.
        self.generation_id.set(self.generation_id.get() + 1);

        // Step 2. If the poster attribute's value is the empty string or
        // if the attribute is absent, then there is no poster frame; return.
        let Some(poster_url) = poster_url.filter(|poster_url| !poster_url.is_empty()) else {
            self.htmlmediaelement.set_poster_frame(None);
            return;
        };

        // Step 3. Let url be the result of encoding-parsing a URL given
        // the poster attribute's value, relative to the element's node
        // document.
        // Step 4. If url is failure, then return. There is no poster frame.
        let poster_url = match self.owner_document().encoding_parse_a_url(poster_url) {
            Ok(url) => url,
            Err(_) => {
                self.htmlmediaelement.set_poster_frame(None);
                return;
            },
        };

        // We use the image cache for poster frames so we save as much
        // network activity as possible.
        let window = self.owner_window();
        let image_cache = window.image_cache();
        let cache_result = image_cache.get_cached_image_status(
            poster_url.clone(),
            window.origin().immutable().clone(),
            None,
        );

        let id = match cache_result {
            ImageCacheResult::Available(ImageOrMetadataAvailable::ImageAvailable {
                image,
                url,
                ..
            }) => {
                self.process_image_response(ImageResponse::Loaded(image, url), can_gc);
                return;
            },
            ImageCacheResult::Available(ImageOrMetadataAvailable::MetadataAvailable(_, id)) => id,
            ImageCacheResult::ReadyForRequest(id) => {
                self.do_fetch_poster_frame(poster_url, id, can_gc);
                id
            },
            ImageCacheResult::FailedToLoadOrDecode => {
                self.process_image_response(ImageResponse::FailedToLoadOrDecode, can_gc);
                return;
            },
            ImageCacheResult::Pending(id) => id,
        };

        let trusted_node = Trusted::new(self);
        let generation = self.generation_id();
        let callback = window.register_image_cache_listener(id, move |response| {
            let element = trusted_node.root();

            // Ignore any image response for a previous request that has been discarded.
            if generation != element.generation_id() {
                return;
            }
            element.process_image_response(response.response, CanGc::note());
        });

        image_cache.add_listener(ImageLoadListener::new(callback, window.pipeline_id(), id));
    }

    /// <https://html.spec.whatwg.org/multipage/#poster-frame>
    fn do_fetch_poster_frame(&self, poster_url: ServoUrl, id: PendingImageId, can_gc: CanGc) {
        // Step 5. Let request be a new request whose URL is url, client is the element's node
        // document's relevant settings object, destination is "image", initiator type is "video",
        // credentials mode is "include", and whose use-URL-credentials flag is set.
        let document = self.owner_document();
        let global = self.owner_global();
        let request = RequestBuilder::new(
            Some(document.webview_id()),
            poster_url.clone(),
            global.get_referrer(),
        )
        .destination(Destination::Image)
        .credentials_mode(CredentialsMode::Include)
        .use_url_credentials(true)
        .with_global_scope(&global);

        // Step 6. Fetch request. This must delay the load event of the element's node document.
        // This delay must be independent from the ones created by HTMLMediaElement during
        // its media load algorithm, otherwise a code like
        // <video poster="poster.png"></video>
        // (which triggers no media load algorithm unless a explicit call to .load() is done)
        // will block the document's load event forever.
        let blocker = &self.load_blocker;
        LoadBlocker::terminate(blocker, can_gc);
        *blocker.borrow_mut() = Some(LoadBlocker::new(
            &self.owner_document(),
            LoadType::Image(poster_url.clone()),
        ));

        let context = PosterFrameFetchContext::new(
            self,
            poster_url,
            id,
            request.id,
            self.global().core_resource_thread(),
        );
        self.owner_document().fetch_background(request, context);
    }

    fn generation_id(&self) -> u32 {
        self.generation_id.get()
    }

    /// <https://html.spec.whatwg.org/multipage/#poster-frame>
    fn process_image_response(&self, response: ImageResponse, can_gc: CanGc) {
        // Step 7. If an image is thus obtained, the poster frame is that image.
        // Otherwise, there is no poster frame.
        match response {
            ImageResponse::Loaded(image, url) => {
                debug!("Loaded poster image for video element: {:?}", url);
                match image.as_raster_image() {
                    Some(image) => self.htmlmediaelement.set_poster_frame(Some(image)),
                    None => warn!("Vector images are not yet supported in video poster"),
                }
                LoadBlocker::terminate(&self.load_blocker, can_gc);
            },
            ImageResponse::MetadataLoaded(..) => {},
            // The image cache may have loaded a placeholder for an invalid poster url
            ImageResponse::FailedToLoadOrDecode => {
                self.htmlmediaelement.set_poster_frame(None);
                // A failed load should unblock the document load.
                LoadBlocker::terminate(&self.load_blocker, can_gc);
            },
        }
    }

    /// <https://html.spec.whatwg.org/multipage/#check-the-usability-of-the-image-argument>
    pub(crate) fn is_usable(&self) -> bool {
        !matches!(
            self.htmlmediaelement.get_ready_state(),
            ReadyState::HaveNothing | ReadyState::HaveMetadata
        )
    }

    pub(crate) fn origin_is_clean(&self) -> bool {
        self.htmlmediaelement.origin_is_clean()
    }

    pub(crate) fn is_network_state_empty(&self) -> bool {
        self.htmlmediaelement.network_state() == NetworkState::Empty
    }
}

impl HTMLVideoElementMethods<crate::DomTypeHolder> for HTMLVideoElement {
    // <https://html.spec.whatwg.org/multipage/#dom-video-width>
    make_dimension_uint_getter!(Width, "width");

    // <https://html.spec.whatwg.org/multipage/#dom-video-width>
    make_dimension_uint_setter!(SetWidth, "width");

    // <https://html.spec.whatwg.org/multipage/#dom-video-height>
    make_dimension_uint_getter!(Height, "height");

    // <https://html.spec.whatwg.org/multipage/#dom-video-height>
    make_dimension_uint_setter!(SetHeight, "height");

    /// <https://html.spec.whatwg.org/multipage/#dom-video-videowidth>
    fn VideoWidth(&self) -> u32 {
        if self.htmlmediaelement.get_ready_state() == ReadyState::HaveNothing {
            return 0;
        }
        self.video_width.get().unwrap_or(0)
    }

    /// <https://html.spec.whatwg.org/multipage/#dom-video-videoheight>
    fn VideoHeight(&self) -> u32 {
        if self.htmlmediaelement.get_ready_state() == ReadyState::HaveNothing {
            return 0;
        }
        self.video_height.get().unwrap_or(0)
    }

    // https://html.spec.whatwg.org/multipage/#dom-video-poster
    make_getter!(Poster, "poster");

    // https://html.spec.whatwg.org/multipage/#dom-video-poster
    make_setter!(SetPoster, "poster");

    // For testing purposes only. This is not an event from
    // https://html.spec.whatwg.org/multipage/#dom-video-poster
    event_handler!(postershown, GetOnpostershown, SetOnpostershown);
}

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

    fn attribute_mutated(&self, attr: &Attr, mutation: AttributeMutation, can_gc: CanGc) {
        self.super_type()
            .unwrap()
            .attribute_mutated(attr, mutation, can_gc);

        if attr.local_name() == &local_name!("poster") {
            if let Some(new_value) = mutation.new_value(attr) {
                self.update_poster_frame(Some(&new_value), CanGc::note())
            } else {
                self.update_poster_frame(None, CanGc::note())
            }
        };
    }

    fn attribute_affects_presentational_hints(&self, attr: &Attr) -> bool {
        match attr.local_name() {
            &local_name!("width") | &local_name!("height") => true,
            _ => self
                .super_type()
                .unwrap()
                .attribute_affects_presentational_hints(attr),
        }
    }

    fn parse_plain_attribute(&self, name: &LocalName, value: DOMString) -> AttrValue {
        match name {
            &local_name!("width") | &local_name!("height") => {
                AttrValue::from_dimension(value.into())
            },
            _ => self
                .super_type()
                .unwrap()
                .parse_plain_attribute(name, value),
        }
    }
}

struct PosterFrameFetchContext {
    /// Reference to the script thread image cache.
    image_cache: Arc<dyn ImageCache>,
    /// The element that initiated the request.
    elem: Trusted<HTMLVideoElement>,
    /// The cache ID for this request.
    id: PendingImageId,
    /// True if this response is invalid and should be ignored.
    cancelled: bool,
    /// Url for the resource
    url: ServoUrl,
    /// A [`FetchCanceller`] for this request.
    fetch_canceller: FetchCanceller,
}

impl FetchResponseListener for PosterFrameFetchContext {
    fn process_request_body(&mut self, _: RequestId) {}

    fn process_request_eof(&mut self, _: RequestId) {
        self.fetch_canceller.ignore()
    }

    fn process_response(
        &mut self,
        request_id: RequestId,
        metadata: Result<FetchMetadata, NetworkError>,
    ) {
        self.image_cache.notify_pending_response(
            self.id,
            FetchResponseMsg::ProcessResponse(request_id, metadata.clone()),
        );

        let metadata = metadata.ok().map(|meta| match meta {
            FetchMetadata::Unfiltered(m) => m,
            FetchMetadata::Filtered { unsafe_, .. } => unsafe_,
        });

        let status_is_ok = metadata
            .as_ref()
            .map_or(true, |m| m.status.in_range(200..300));

        if !status_is_ok {
            self.cancelled = true;
            self.fetch_canceller.abort();
        }
    }

    fn process_response_chunk(&mut self, request_id: RequestId, payload: Vec<u8>) {
        if self.cancelled {
            // An error was received previously, skip processing the payload.
            return;
        }

        self.image_cache.notify_pending_response(
            self.id,
            FetchResponseMsg::ProcessResponseChunk(request_id, payload.into()),
        );
    }

    fn process_response_eof(
        self,
        request_id: RequestId,
        response: Result<(), NetworkError>,
        timing: ResourceFetchTiming,
    ) {
        self.image_cache.notify_pending_response(
            self.id,
            FetchResponseMsg::ProcessResponseEOF(request_id, response.clone(), timing.clone()),
        );
        network_listener::submit_timing(&self, &response, &timing, CanGc::note());
    }

    fn process_csp_violations(&mut self, _request_id: RequestId, violations: Vec<Violation>) {
        let global = &self.resource_timing_global();
        global.report_csp_violations(violations, None, None);
    }
}

impl ResourceTimingListener for PosterFrameFetchContext {
    fn resource_timing_information(&self) -> (InitiatorType, ServoUrl) {
        let initiator_type = InitiatorType::LocalName(
            self.elem
                .root()
                .upcast::<Element>()
                .local_name()
                .to_string(),
        );
        (initiator_type, self.url.clone())
    }

    fn resource_timing_global(&self) -> DomRoot<GlobalScope> {
        self.elem.root().owner_document().global()
    }
}

impl PosterFrameFetchContext {
    fn new(
        elem: &HTMLVideoElement,
        url: ServoUrl,
        id: PendingImageId,
        request_id: RequestId,
        core_resource_thread: CoreResourceThread,
    ) -> PosterFrameFetchContext {
        let window = elem.owner_window();
        PosterFrameFetchContext {
            image_cache: window.image_cache(),
            elem: Trusted::new(elem),
            id,
            cancelled: false,
            url,
            fetch_canceller: FetchCanceller::new(request_id, false, core_resource_thread),
        }
    }
}

pub(crate) trait LayoutHTMLVideoElementHelpers {
    fn data(self) -> HTMLMediaData;
    fn get_width(self) -> LengthOrPercentageOrAuto;
    fn get_height(self) -> LengthOrPercentageOrAuto;
}

impl LayoutHTMLVideoElementHelpers for LayoutDom<'_, HTMLVideoElement> {
    fn data(self) -> HTMLMediaData {
        let video = self.unsafe_get();

        // Get the current frame being rendered.
        let current_frame = video.htmlmediaelement.get_current_frame_to_present();

        // This value represents the natural width and height of the video.
        // It may exist even if there is no current frame (for example, after the
        // metadata of the video is loaded).
        let metadata = video
            .get_video_width()
            .zip(video.get_video_height())
            .map(|(width, height)| MediaMetadata { width, height });

        HTMLMediaData {
            current_frame,
            metadata,
        }
    }

    fn get_width(self) -> LengthOrPercentageOrAuto {
        self.upcast::<Element>()
            .get_attr_for_layout(&ns!(), &local_name!("width"))
            .map(AttrValue::as_dimension)
            .cloned()
            .unwrap_or(LengthOrPercentageOrAuto::Auto)
    }

    fn get_height(self) -> LengthOrPercentageOrAuto {
        self.upcast::<Element>()
            .get_attr_for_layout(&ns!(), &local_name!("height"))
            .map(AttrValue::as_dimension)
            .cloned()
            .unwrap_or(LengthOrPercentageOrAuto::Auto)
    }
}