/* 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 euclid::size::TypedSize2D;
use gecko_bindings::bindings::RawServoStyleSet;
use gecko_bindings::sugar::ownership::{HasBoxFFI, HasFFI, HasSimpleFFI};
use num_cpus;
use std::cmp;
use std::collections::HashMap;
use std::env;
use std::sync::mpsc::{channel, Receiver, Sender};
use std::sync::{Arc, RwLock};
use style::animation::Animation;
use style::context::SharedStyleContext;
use style::dom::OpaqueNode;
use style::media_queries::{Device, MediaType};
use style::parallel::WorkQueueData;
use style::selector_matching::Stylist;
use style::stylesheets::Stylesheet;
use style::thread_state;
use style::workqueue::WorkQueue;
use style_traits::ViewportPx;

pub struct PerDocumentStyleData {
    /// Rule processor.
    pub stylist: Arc<Stylist>,

    /// List of stylesheets, mirrored from Gecko.
    pub stylesheets: Vec<Arc<Stylesheet>>,

    /// Whether the stylesheets list above has changed since the last restyle.
    pub stylesheets_changed: bool,

    // FIXME(bholley): Hook these up to something.
    pub new_animations_sender: Sender<Animation>,
    pub new_animations_receiver: Receiver<Animation>,
    pub running_animations: Arc<RwLock<HashMap<OpaqueNode, Vec<Animation>>>>,
    pub expired_animations: Arc<RwLock<HashMap<OpaqueNode, Vec<Animation>>>>,

    // FIXME(bholley): This shouldn't be per-document.
    pub work_queue: Option<WorkQueue<SharedStyleContext, WorkQueueData>>,

    pub num_threads: usize,
}

lazy_static! {
    pub static ref NUM_THREADS: usize = {
        match env::var("STYLO_THREADS").map(|s| s.parse::<usize>().expect("invalid STYLO_THREADS")) {
            Ok(num) => num,
            _ => cmp::max(num_cpus::get() * 3 / 4, 1),
        }
    };
}

impl PerDocumentStyleData {
    pub fn new() -> PerDocumentStyleData {
        // FIXME(bholley): Real window size.
        let window_size: TypedSize2D<f32, ViewportPx> = TypedSize2D::new(800.0, 600.0);
        let device = Device::new(MediaType::Screen, window_size);

        let (new_anims_sender, new_anims_receiver) = channel();

        PerDocumentStyleData {
            stylist: Arc::new(Stylist::new(device)),
            stylesheets: vec![],
            stylesheets_changed: true,
            new_animations_sender: new_anims_sender,
            new_animations_receiver: new_anims_receiver,
            running_animations: Arc::new(RwLock::new(HashMap::new())),
            expired_animations: Arc::new(RwLock::new(HashMap::new())),
            work_queue: if *NUM_THREADS <= 1 {
                None
            } else {
                WorkQueue::new("StyleWorker", thread_state::LAYOUT, *NUM_THREADS).ok()
            },
            num_threads: *NUM_THREADS,
        }
    }

    pub fn flush_stylesheets(&mut self) {
        // The stylist wants to be flushed if either the stylesheets change or the
        // device dimensions change. When we add support for media queries, we'll
        // need to detect the latter case and trigger a flush as well.
        if self.stylesheets_changed {
            let _ = Arc::get_mut(&mut self.stylist).unwrap()
                                                   .update(&self.stylesheets, None, true);
            self.stylesheets_changed = false;
        }
    }
}

unsafe impl HasFFI for PerDocumentStyleData {
    type FFIType = RawServoStyleSet;
}
unsafe impl HasSimpleFFI for PerDocumentStyleData {}
unsafe impl HasBoxFFI for PerDocumentStyleData {}

impl Drop for PerDocumentStyleData {
    fn drop(&mut self) {
        if let Some(ref mut queue) = self.work_queue {
            queue.shutdown();
        }
    }
}