use ui;
use ui::widget;
use ui::x11;
use xcb;

use std::sync::Arc;

const CLIENT_MESSAGE: u8 = xcb::CLIENT_MESSAGE | 0x80; // 0x80 flag for client messages

pub struct Tray {
    tx: widget::MessageSender,
    conn: Arc<x11::Connection>,
    window: xcb::Window,
    children: Vec<xcb::Window>,
    timestamp: xcb::Timestamp,
}

impl Tray {
    pub fn new(tx: widget::MessageSender, conn: Arc<x11::Connection>, window: xcb::Window) -> Tray {
        Tray {
            conn: conn,
            tx: tx,
            window: window,
            children: vec![],
            timestamp: 0
        }
    }

    pub fn take_selection(&mut self, timestamp: xcb::Timestamp) -> bool {
        let selection = self.conn.atom(x11::_NET_SYSTEM_TRAY_S0);
        xcb::set_selection_owner(&self.conn, self.window, selection, timestamp);
        let owner = xcb::get_selection_owner(&self.conn, selection).get_reply().unwrap().owner();
        let ok = owner == self.window;
        if ok {
            self.timestamp = timestamp;
            let screen = self.conn.default_screen();

            let client_event = xcb::ClientMessageEvent::new(
                32, // 32 bits (refers to data)
                screen.root,
                self.conn.atom(x11::MANAGER),
                xcb::ClientMessageData::from_data32([timestamp, selection, self.window, 0, 0])
            );
            xcb::send_event(&self.conn, false, screen.root, xcb::EVENT_MASK_STRUCTURE_NOTIFY, &client_event);
            self.conn.flush();
        }
        ok
    }

    pub fn adopt(&mut self, window: xcb::Window) {
        let conn = &self.conn;
        xcb::change_window_attributes(conn, window, &[
            (xcb::CW_EVENT_MASK, xcb::EVENT_MASK_STRUCTURE_NOTIFY)
        ]);
        xcb::reparent_window(conn, window, self.window, 0, 0);
        xcb::map_window(conn, window);
        self.force_size(window, None);
        conn.flush();
        self.children.push(window);
        self.relayout();
    }

    pub fn forget(&mut self, window: xcb::Window) {
        self.children.retain(|child| *child != window);
        self.relayout();
    }

    fn relayout(&self) {
        self.tx.send(widget::Message::Relayout).expect("Failed to send relayout");
    }

    pub fn force_size(&self, window: xcb::Window, dimensions: Option<(u16, u16)>) {
        let conn = &self.conn;
        let dimensions = dimensions.unwrap_or_else(|| {
            let geometry = xcb::get_geometry(conn, window).get_reply().unwrap();
            (geometry.width(), geometry.height())
        });
        if dimensions != (ui::SIZE, ui::SIZE) {
            xcb::configure_window(conn, window, &[
                (xcb::CONFIG_WINDOW_WIDTH as u16, ui::SIZE as u32),
                (xcb::CONFIG_WINDOW_HEIGHT as u16, ui::SIZE as u32)
            ]);
            conn.flush();
        }
    }
}

impl widget::Widget for Tray {
    fn width(&mut self) -> u16 {
        (self.children.len() * 20) as u16
    }

    fn render(&mut self, x: u16) {
        for (index, child) in self.children.iter().enumerate() {
            let window = *child;
            let xpos = x as u32 + index as u32 * 20;
            xcb::configure_window(&self.conn, window, &[
                (xcb::CONFIG_WINDOW_X as u16, xpos)
            ]);
        }
    }

    fn handle_event(&mut self, event: &widget::Message) -> bool {
        match event {
            &widget::Message::XcbEvent(ref event) =>
                match event.response_type() {
                    xcb::PROPERTY_NOTIFY if self.timestamp == 0 => {
                        let event: &xcb::PropertyNotifyEvent = unsafe { xcb::cast_event(&event) };
                        if !self.take_selection(event.time()) {
                            println!("Could not take ownership of tray selection. Maybe another tray is also running?");
                            return true
                        }
                    },
                    CLIENT_MESSAGE => {
                        let event: &xcb::ClientMessageEvent = unsafe { xcb::cast_event(&event) };
                        if event.type_() == self.conn.atom(x11::_NET_SYSTEM_TRAY_OPCODE) {
                            let data = event.data().data32();
                            let opcode = data[1];
                            let window = data[2];
                            if opcode == 0 {
                                self.adopt(window);
                            }
                        }
                    },
                    xcb::REPARENT_NOTIFY => {
                        let event: &xcb::ReparentNotifyEvent = unsafe { xcb::cast_event(&event) };
                        if event.parent() != self.window {
                            self.forget(event.window());
                        }
                    },
                    xcb::DESTROY_NOTIFY => {
                        let event: &xcb::DestroyNotifyEvent = unsafe { xcb::cast_event(&event) };
                        self.forget(event.window());
                    },
                    xcb::CONFIGURE_NOTIFY => {
                        let event: &xcb::ConfigureNotifyEvent = unsafe { xcb::cast_event(&event) };
                        let window = event.window();
                        if window != self.window {
                            self.force_size(window, Some((event.width(), event.height())));
                        }
                    },
                    xcb::SELECTION_CLEAR => {
                        self.finish();
                    },
                    _ => {}
                },
                _ => {}
        }
        false
    }

    fn finish(&mut self) {
        let conn = &self.conn;
        let screen = conn.default_screen();

        for child in self.children.iter() {
            let window = *child;
            xcb::change_window_attributes(conn, window, &[
                (xcb::CW_EVENT_MASK, xcb::EVENT_MASK_NO_EVENT)
            ]);
            xcb::unmap_window(conn, window);
            xcb::reparent_window(conn, window, screen.root, 0, 0);
        }
        xcb::change_window_attributes(conn, self.window, &[
            (xcb::CW_EVENT_MASK, xcb::EVENT_MASK_STRUCTURE_NOTIFY)
        ]);
        xcb::set_selection_owner(conn, xcb::NONE, conn.atom(x11::_NET_SYSTEM_TRAY_S0), self.timestamp);
        conn.flush();
    }
}