use std::cmp::max;
use std::collections::VecDeque;
use std::io::{Read, Write};
use std::os::unix::io::AsRawFd;
use std::sync::mpsc::{channel, Sender};
use std::sync::{Arc, Mutex};
use std::time::Instant;

use nix::poll::{poll, PollFd, PollFlags};
use os_pipe::pipe;

use chrono::Local;

use smithay_client_toolkit::keyboard::{
    keysyms, map_keyboard_auto_with_repeat, Event as KbEvent, KeyRepeatKind, KeyState,
};
use smithay_client_toolkit::utils::DoubleMemPool;

use wayland_client::protocol::{wl_compositor, wl_pointer, wl_shm, wl_surface};
use wayland_client::{Display, EventQueue, GlobalEvent, GlobalManager, NewProxy};
use wayland_protocols::wlr::unstable::layer_shell::v1::client::{
    zwlr_layer_shell_v1, zwlr_layer_surface_v1,
};

mod backlight;
mod battery;
mod buffer;
mod calendar;
mod clock;
mod color;
mod draw;
mod launcher;
mod module;
mod sound;

use crate::backlight::Backlight;
use crate::battery::UpowerBattery;
use crate::buffer::Buffer;
use crate::calendar::Calendar;
use crate::clock::Clock;
use crate::color::Color;
use crate::launcher::Launcher;
use crate::module::{Input, Module};
use crate::sound::PulseAudio;

enum Cmd {
    Exit,
    Draw,
    MouseInput { pos: (u32, u32), input: Input },
    KeyboardInput { input: Input },
}

struct App {
    pools: DoubleMemPool,
    display: Display,
    event_queue: EventQueue,
    surface: wl_surface::WlSurface,
    cmd_queue: Arc<Mutex<VecDeque<Cmd>>>,
    dimensions: (u32, u32),
    modules: Vec<Module>,
}

impl App {
    fn redraw(&mut self, force: bool) -> Result<(), ::std::io::Error> {
        let time = Local::now();

        let pool = match self.pools.pool() {
            Some(pool) => pool,
            None => return Ok(()),
        };

        let (buf_x, buf_y) = self.dimensions;

        let bg = Color::new(0.0, 0.0, 0.0, 0.9);

        // resize the pool if relevant

        pool.resize((4 * buf_x * buf_y) as usize)
            .expect("Failed to resize the memory pool.");

        let mmap = pool.mmap();
        let mut buf = Buffer::new(mmap, self.dimensions);
        let mut damage = vec![];

        {
            let mut margin_buf = buf.subdimensions((20, 20, buf_x - 40, buf_y - 40))?;
            for module in self.modules.iter() {
                if module.update(&time, force)? {
                    let mut b = &mut margin_buf.subdimensions(module.get_bounds())?;
                    let mut d = module.draw(&mut b, &bg, &time)?;
                    damage.append(&mut d);
                }
            }
        }

        mmap.flush().unwrap();

        if damage.len() == 0 {
            // Nothing to do
            return Ok(());
        }

        // get a buffer and attach it
        let new_buffer = pool.buffer(
            0,
            buf_x as i32,
            buf_y as i32,
            4 * buf_x as i32,
            wl_shm::Format::Argb8888,
        );
        self.surface.attach(Some(&new_buffer), 0, 0);
        for d in damage {
            self.surface.damage(d.0, d.1, d.2, d.3);
        }
        self.surface.commit();
        Ok(())
    }

    fn cmd_queue(&self) -> Arc<Mutex<VecDeque<Cmd>>> {
        self.cmd_queue.clone()
    }

    fn flush_display(&mut self) {
        self.display.flush().expect("unable to flush display");
    }

    fn event_queue(&mut self) -> &mut EventQueue {
        &mut self.event_queue
    }

    fn wipe(&mut self) {
        let pool = match self.pools.pool() {
            Some(pool) => pool,
            None => return,
        };
        pool.resize((4 * self.dimensions.0 * self.dimensions.1) as usize)
            .expect("Failed to resize the memory pool.");
        let mmap = pool.mmap();
        let mut buf = Buffer::new(mmap, self.dimensions);
        let bg = Color::new(0.0, 0.0, 0.0, 0.9);
        buf.memset(&bg);
    }

    fn get_module(&self, pos: (u32, u32)) -> Option<&Module> {
        for m in self.modules.iter() {
            if m.intersect(pos) {
                return Some(&m);
            }
        }
        None
    }

    fn new(tx: Sender<bool>) -> App {
        //
        // Set up modules
        //
        let (mod_tx, mod_rx) = channel();
        std::thread::spawn(move || {
            let mut modules = vec![
                Module::new(Box::new(Clock::new(tx.clone())), (0, 0, 720, 320)),
                Module::new(Box::new(Calendar::new()), (0, 368, 1280, 344)),
            ];

            if let Ok(m) = Launcher::new() {
                modules.push(Module::new(Box::new(m), (0, 768, 1280, 32)));
            }

            let mut vert_off = 0;
            if let Ok(m) = UpowerBattery::new(tx.clone()) {
                modules.push(Module::new(Box::new(m), (720, vert_off, 560, 32)));
                vert_off += 32;
            }
            if let Ok(m) = Backlight::new() {
                modules.push(Module::new(Box::new(m), (720, vert_off, 560, 32)));
                vert_off += 32;
            }
            if let Ok(m) = PulseAudio::new(tx.clone()) {
                modules.push(Module::new(Box::new(m), (720, vert_off, 560, 32)));
            }

            mod_tx.send(modules).unwrap();
        });


        let cmd_queue = Arc::new(Mutex::new(VecDeque::new()));

        let (display, mut event_queue) = Display::connect_to_env().unwrap();

        let display_wrapper = display
            .as_ref()
            .make_wrapper(&event_queue.get_token())
            .unwrap()
            .into();

        //
        // Set up global manager
        //
        let manager = GlobalManager::new_with_cb(&display_wrapper, move |event, _| match event {
            GlobalEvent::New {
                id: _,
                interface: _,
                version: _,
            } => {}
            GlobalEvent::Removed {
                id: _,
                interface: _,
            } => {}
        });

        // double sync to retrieve the global list
        // and the globals metadata
        event_queue.sync_roundtrip().unwrap();
        event_queue.sync_roundtrip().unwrap();

        // wl_compositor
        let compositor: wl_compositor::WlCompositor = manager
            .instantiate_range(1, 4, NewProxy::implement_dummy)
            .expect("server didn't advertise `wl_compositor`");

        // wl_shm
        let shm_formats = Arc::new(Mutex::new(Vec::new()));
        let shm_formats2 = shm_formats.clone();
        let shm = manager
            .instantiate_range(1, 1, |shm| {
                shm.implement_closure(
                    move |evt, _| {
                        if let wl_shm::Event::Format { format } = evt {
                            shm_formats2.lock().unwrap().push(format);
                        }
                    },
                    (),
                )
            })
            .expect("server didn't advertise `wl_shm`");

        let pools = DoubleMemPool::new(&shm, || {}).expect("Failed to create a memory pool !");

        //
        // Get our seat
        //
        let seat = manager
            .instantiate_range(1, 6, NewProxy::implement_dummy)
            .unwrap();

        //
        // Keyboard processing
        //
        let kbd_clone = cmd_queue.clone();
        map_keyboard_auto_with_repeat(
            &seat,
            KeyRepeatKind::System,
            move |event: KbEvent, _| match event {
                KbEvent::Key {
                    keysym,
                    utf8,
                    state,
                    ..
                } => match state {
                    KeyState::Pressed => match keysym {
                        keysyms::XKB_KEY_Escape => kbd_clone.lock().unwrap().push_back(Cmd::Exit),
                        v => kbd_clone.lock().unwrap().push_back(Cmd::KeyboardInput {
                            input: Input::Keypress {
                                key: v,
                                interpreted: utf8,
                            },
                        }),
                    },
                    _ => (),
                },
                _ => (),
            },
            |_, _| {},
        )
        .expect("Failed to map keyboard");

        //
        // Prepare shell so that we can create our shell surface
        //
        let shell = if let Ok(layer) = manager.instantiate_exact(
            1,
            |layer: NewProxy<zwlr_layer_shell_v1::ZwlrLayerShellV1>| {
                layer.implement_closure(|_, _| {}, ())
            },
        ) {
            layer
        } else {
            panic!("server didn't advertise `zwlr_layer_shell_v1`");
        };

        let surface = compositor
            .create_surface(NewProxy::implement_dummy)
            .unwrap();

        let shell_surface = shell
            .get_layer_surface(
                &surface,
                None,
                zwlr_layer_shell_v1::Layer::Overlay,
                "".to_string(),
                move |layer| {
                    layer.implement_closure(
                        move |evt, layer| match evt {
                            zwlr_layer_surface_v1::Event::Configure { serial, .. } => layer.ack_configure(serial),
                            _ => unreachable!(),
                        },
                        (),
                    )
                },
            )
            .unwrap();

        //
        // Calculate window dimensions
        //
        let modules = mod_rx.recv().unwrap();

        let mut dimensions = (0, 0);
        for m in modules.iter() {
            let b = m.get_bounds();
            dimensions = (max(dimensions.0, b.0 + b.2), max(dimensions.1, b.1 + b.3));
        }

        // Add padding
        dimensions = (dimensions.0 + 40, dimensions.1 + 40);

        shell_surface.set_keyboard_interactivity(1);
        shell_surface.set_size(dimensions.0, dimensions.1);
        surface.commit();
        event_queue.sync_roundtrip().unwrap();

        //
        // Cursor processing
        //
        let pointer_clone = cmd_queue.clone();
        seat.get_pointer(move |ptr| {
            let mut pos: (u32, u32) = (0, 0);
            let mut vert_scroll: f64 = 0.0;
            let mut horiz_scroll: f64 = 0.0;
            let mut btn: u32 = 0;
            let mut btn_clicked = false;
            ptr.implement_closure(
                move |evt, _| match evt {
                    wl_pointer::Event::Enter {
                        surface_x,
                        surface_y,
                        ..
                    } => {
                        pos = (surface_x as u32, surface_y as u32);
                    }
                    wl_pointer::Event::Leave { .. } => {
                        pos = (0, 0);
                    }
                    wl_pointer::Event::Motion {
                        surface_x,
                        surface_y,
                        ..
                    } => {
                        pos = (surface_x as u32, surface_y as u32);
                    }
                    wl_pointer::Event::Axis {
                        axis,
                        value,
                        ..
                    } => {
                        if axis == wl_pointer::Axis::VerticalScroll {
                            vert_scroll += value;
                        }
                    }
                    wl_pointer::Event::Button {
                        button,
                        state,
                        ..
                    } => match state {
                        wl_pointer::ButtonState::Released => {
                            btn = button;
                            btn_clicked = true;
                        }
                        _ => {}
                    },
                    wl_pointer::Event::Frame => {
                        if pos.0 < 20 || pos.1 < 20 {
                            // Ignore stuff outside our margins
                            return;
                        }
                        let pos = (pos.0 - 20, pos.1 - 20);
                        if vert_scroll != 0.0 || horiz_scroll != 0.0 {
                            pointer_clone.lock().unwrap().push_back(Cmd::MouseInput {
                                pos: pos,
                                input: Input::Scroll {
                                    pos: pos,
                                    x: horiz_scroll,
                                    y: vert_scroll,
                                },
                            });
                            vert_scroll = 0.0;
                            horiz_scroll = 0.0;
                        }
                        if btn_clicked {
                            pointer_clone.lock().unwrap().push_back(Cmd::MouseInput {
                                pos: pos,
                                input: Input::Click {
                                    pos: pos,
                                    button: btn,
                                },
                            });
                            btn_clicked = false;
                        }
                    }
                    _ => {}
                },
                (),
            )
        })
        .unwrap();

        display.flush().unwrap();

        App {
            surface: surface,
            display: display,
            event_queue: event_queue,
            cmd_queue: cmd_queue,
            pools: pools,
            dimensions: dimensions,
            modules: modules,
        }
    }
}

fn main() {
    let (mut rx_pipe, mut tx_pipe) = pipe().unwrap();
    let (tx_draw, rx_draw) = channel();

    let mut app = App::new(tx_draw);
    app.wipe();

    let worker_queue = app.cmd_queue();
    std::thread::spawn(move || loop {
        rx_draw.recv().unwrap();
        worker_queue.lock().unwrap().push_back(Cmd::Draw);
        tx_pipe.write_all(&[0x1]).unwrap();
    });

    let mut fds = [
        PollFd::new(app.event_queue().get_connection_fd(), PollFlags::POLLIN),
        PollFd::new(rx_pipe.as_raw_fd(), PollFlags::POLLIN),
    ];

    app.cmd_queue().lock().unwrap().push_back(Cmd::Draw);

    let q = app.cmd_queue();
    loop {
        let cmd = q.lock().unwrap().pop_front();
        match cmd {
            Some(cmd) => match cmd {
                Cmd::Draw => {
                    app.redraw(false).expect("Failed to draw");
                    app.flush_display();
                }
                Cmd::MouseInput { pos, input } => {
                    if let Some(m) = app.get_module(pos) {
                        let bounds = m.get_bounds();
                        let input = input.offset((bounds.0, bounds.1));
                        m.input(input);
                        q.lock().unwrap().push_back(Cmd::Draw);
                    }
                }
                Cmd::KeyboardInput { input } => {
                    for m in app.modules.iter() {
                        m.input(input.clone());
                    }
                    q.lock().unwrap().push_back(Cmd::Draw);
                }
                Cmd::Exit => {
                    std::process::exit(0);
                }
            },
            None => {
                app.flush_display();

                poll(&mut fds, -1).unwrap();

                if fds[0].revents().unwrap().contains(PollFlags::POLLIN) {
                    if let Some(guard) = app.event_queue().prepare_read() {
                        if let Err(e) = guard.read_events() {
                            if e.kind() != ::std::io::ErrorKind::WouldBlock {
                                eprintln!(
                                    "Error while trying to read from the wayland socket: {:?}",
                                    e
                                );
                            }
                        }
                    }

                    app.event_queue()
                        .dispatch_pending()
                        .expect("Failed to dispatch all messages.");
                }

                if fds[1].revents().unwrap().contains(PollFlags::POLLIN) {
                    let mut v: Vec<u8> = vec![0x00];
                    rx_pipe.read_exact(&mut v).unwrap();
                }
            }
        }
    }
}