use std::cmp::min;
use std::collections::HashMap;
use std::fmt;
use std::fmt::Write as _;
use std::os::unix::net::UnixStream;
use std::sync::atomic::{AtomicBool, Ordering};
use std::sync::Arc;
use std::time::Duration;

use calloop::EventLoop;
use calloop_wayland_source::WaylandSource;
use single_pixel_buffer::v1::client::wp_single_pixel_buffer_manager_v1::WpSinglePixelBufferManagerV1;
use smithay::reexports::wayland_protocols::wp::single_pixel_buffer;
use smithay::reexports::wayland_protocols::wp::viewporter::client::wp_viewport::WpViewport;
use smithay::reexports::wayland_protocols::wp::viewporter::client::wp_viewporter::WpViewporter;
use smithay::reexports::wayland_protocols::xdg::shell::client::xdg_surface::{self, XdgSurface};
use smithay::reexports::wayland_protocols::xdg::shell::client::xdg_toplevel::{self, XdgToplevel};
use smithay::reexports::wayland_protocols::xdg::shell::client::xdg_wm_base::{self, XdgWmBase};
use wayland_backend::client::Backend;
use wayland_client::globals::Global;
use wayland_client::protocol::wl_buffer::{self, WlBuffer};
use wayland_client::protocol::wl_callback::{self, WlCallback};
use wayland_client::protocol::wl_compositor::WlCompositor;
use wayland_client::protocol::wl_display::WlDisplay;
use wayland_client::protocol::wl_output::{self, WlOutput};
use wayland_client::protocol::wl_registry::{self, WlRegistry};
use wayland_client::protocol::wl_surface::{self, WlSurface};
use wayland_client::{Connection, Dispatch, Proxy as _, QueueHandle};

use crate::utils::id::IdCounter;

pub struct Client {
    pub id: ClientId,
    pub event_loop: EventLoop<'static, State>,
    pub connection: Connection,
    pub qh: QueueHandle<State>,
    pub display: WlDisplay,
    pub state: State,
}

pub struct State {
    pub qh: QueueHandle<State>,

    pub globals: Vec<Global>,
    pub outputs: HashMap<WlOutput, String>,

    pub compositor: Option<WlCompositor>,
    pub xdg_wm_base: Option<XdgWmBase>,
    pub spbm: Option<WpSinglePixelBufferManagerV1>,
    pub viewporter: Option<WpViewporter>,

    pub windows: Vec<Window>,
}

pub struct Window {
    pub qh: QueueHandle<State>,
    pub spbm: WpSinglePixelBufferManagerV1,

    pub surface: WlSurface,
    pub xdg_surface: XdgSurface,
    pub xdg_toplevel: XdgToplevel,
    pub viewport: WpViewport,
    pub pending_configure: Configure,
    pub configures_received: Vec<(u32, Configure)>,
    pub close_requested: bool,

    pub configures_looked_at: usize,
}

#[derive(Debug, Clone, Default)]
pub struct Configure {
    pub size: (i32, i32),
    pub bounds: Option<(i32, i32)>,
    pub states: Vec<xdg_toplevel::State>,
}

#[derive(Default)]
pub struct SyncData {
    pub done: AtomicBool,
}

static CLIENT_ID_COUNTER: IdCounter = IdCounter::new();

#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
pub struct ClientId(u64);

impl ClientId {
    fn next() -> ClientId {
        ClientId(CLIENT_ID_COUNTER.next())
    }
}

impl fmt::Display for Configure {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "size: {} × {}, ", self.size.0, self.size.1)?;
        if let Some(bounds) = self.bounds {
            write!(f, "bounds: {} × {}, ", bounds.0, bounds.1)?;
        } else {
            write!(f, "bounds: none, ")?;
        }
        write!(f, "states: {:?}", self.states)?;
        Ok(())
    }
}

impl Client {
    pub fn new(stream: UnixStream) -> Self {
        let id = ClientId::next();

        let event_loop = EventLoop::try_new().unwrap();
        let backend = Backend::connect(stream).unwrap();
        let connection = Connection::from_backend(backend);
        let queue = connection.new_event_queue();
        let qh = queue.handle();
        WaylandSource::new(connection.clone(), queue)
            .insert(event_loop.handle())
            .unwrap();

        let display = connection.display();
        let _registry = display.get_registry(&qh, ());
        connection.flush().unwrap();

        let state = State {
            qh: qh.clone(),
            globals: Vec::new(),
            outputs: HashMap::new(),
            compositor: None,
            xdg_wm_base: None,
            spbm: None,
            viewporter: None,
            windows: Vec::new(),
        };

        Self {
            id,
            event_loop,
            connection,
            qh,
            display,
            state,
        }
    }

    pub fn dispatch(&mut self) {
        self.event_loop
            .dispatch(Duration::ZERO, &mut self.state)
            .unwrap();
    }

    pub fn send_sync(&self) -> Arc<SyncData> {
        let data = Arc::new(SyncData::default());
        self.display.sync(&self.qh, data.clone());
        self.connection.flush().unwrap();
        data
    }

    pub fn create_window(&mut self) -> &mut Window {
        self.state.create_window()
    }

    pub fn window(&mut self, surface: &WlSurface) -> &mut Window {
        self.state.window(surface)
    }

    pub fn output(&mut self, name: &str) -> WlOutput {
        self.state
            .outputs
            .iter()
            .find(|(_, v)| *v == name)
            .unwrap()
            .0
            .clone()
    }
}

impl State {
    pub fn create_window(&mut self) -> &mut Window {
        let compositor = self.compositor.as_ref().unwrap();
        let xdg_wm_base = self.xdg_wm_base.as_ref().unwrap();
        let viewporter = self.viewporter.as_ref().unwrap();

        let surface = compositor.create_surface(&self.qh, ());
        let xdg_surface = xdg_wm_base.get_xdg_surface(&surface, &self.qh, ());
        let xdg_toplevel = xdg_surface.get_toplevel(&self.qh, ());
        let viewport = viewporter.get_viewport(&surface, &self.qh, ());

        let window = Window {
            qh: self.qh.clone(),
            spbm: self.spbm.clone().unwrap(),

            surface,
            xdg_surface,
            xdg_toplevel,
            viewport,
            pending_configure: Configure::default(),
            configures_received: Vec::new(),
            close_requested: false,

            configures_looked_at: 0,
        };

        self.windows.push(window);
        self.windows.last_mut().unwrap()
    }

    pub fn window(&mut self, surface: &WlSurface) -> &mut Window {
        self.windows
            .iter_mut()
            .find(|w| w.surface == *surface)
            .unwrap()
    }
}

impl Window {
    pub fn commit(&self) {
        self.surface.commit();
    }

    pub fn ack_last(&self) {
        let serial = self.configures_received.last().unwrap().0;
        self.xdg_surface.ack_configure(serial);
    }

    pub fn ack_last_and_commit(&self) {
        self.ack_last();
        self.commit();
    }

    pub fn attach_new_buffer(&self) {
        let buffer = self.spbm.create_u32_rgba_buffer(0, 0, 0, 0, &self.qh, ());
        self.surface.attach(Some(&buffer), 0, 0);
    }

    pub fn set_size(&self, w: u16, h: u16) {
        self.viewport.set_destination(i32::from(w), i32::from(h));
    }

    pub fn set_fullscreen(&self, output: Option<&WlOutput>) {
        self.xdg_toplevel.set_fullscreen(output);
    }

    pub fn unset_fullscreen(&self) {
        self.xdg_toplevel.unset_fullscreen();
    }

    pub fn set_parent(&self, parent: Option<&XdgToplevel>) {
        self.xdg_toplevel.set_parent(parent);
    }

    pub fn set_title(&self, title: &str) {
        self.xdg_toplevel.set_title(title.to_owned());
    }

    pub fn recent_configures(&mut self) -> impl Iterator<Item = &Configure> {
        let start = self.configures_looked_at;
        self.configures_looked_at = self.configures_received.len();
        self.configures_received[start..].iter().map(|(_, c)| c)
    }

    pub fn format_recent_configures(&mut self) -> String {
        let mut buf = String::new();
        for configure in self.recent_configures() {
            if !buf.is_empty() {
                buf.push('\n');
            }
            write!(buf, "{configure}").unwrap();
        }
        buf
    }
}

impl Dispatch<WlCallback, Arc<SyncData>> for State {
    fn event(
        _state: &mut Self,
        _proxy: &WlCallback,
        event: <WlCallback as wayland_client::Proxy>::Event,
        data: &Arc<SyncData>,
        _conn: &Connection,
        _qhandle: &QueueHandle<Self>,
    ) {
        match event {
            wl_callback::Event::Done { .. } => data.done.store(true, Ordering::Relaxed),
            _ => unreachable!(),
        }
    }
}

impl Dispatch<WlRegistry, ()> for State {
    fn event(
        state: &mut Self,
        registry: &WlRegistry,
        event: <WlRegistry as wayland_client::Proxy>::Event,
        _data: &(),
        _conn: &Connection,
        qh: &QueueHandle<Self>,
    ) {
        match event {
            wl_registry::Event::Global {
                name,
                interface,
                version,
            } => {
                if interface == WlCompositor::interface().name {
                    let version = min(version, WlCompositor::interface().version);
                    state.compositor = Some(registry.bind(name, version, qh, ()));
                } else if interface == XdgWmBase::interface().name {
                    let version = min(version, XdgWmBase::interface().version);
                    state.xdg_wm_base = Some(registry.bind(name, version, qh, ()));
                } else if interface == WpSinglePixelBufferManagerV1::interface().name {
                    let version = min(version, WpSinglePixelBufferManagerV1::interface().version);
                    state.spbm = Some(registry.bind(name, version, qh, ()));
                } else if interface == WpViewporter::interface().name {
                    let version = min(version, WpViewporter::interface().version);
                    state.viewporter = Some(registry.bind(name, version, qh, ()));
                } else if interface == WlOutput::interface().name {
                    let version = min(version, WlOutput::interface().version);
                    let output = registry.bind(name, version, qh, ());
                    state.outputs.insert(output, String::new());
                }

                let global = Global {
                    name,
                    interface,
                    version,
                };
                state.globals.push(global);
            }
            wl_registry::Event::GlobalRemove { .. } => (),
            _ => unreachable!(),
        }
    }
}

impl Dispatch<WlOutput, ()> for State {
    fn event(
        state: &mut Self,
        output: &WlOutput,
        event: <WlOutput as wayland_client::Proxy>::Event,
        _data: &(),
        _conn: &Connection,
        _qhandle: &QueueHandle<Self>,
    ) {
        match event {
            wl_output::Event::Geometry { .. } => (),
            wl_output::Event::Mode { .. } => (),
            wl_output::Event::Done => (),
            wl_output::Event::Scale { .. } => (),
            wl_output::Event::Name { name } => {
                *state.outputs.get_mut(output).unwrap() = name;
            }
            wl_output::Event::Description { .. } => (),
            _ => unreachable!(),
        }
    }
}

impl Dispatch<WlCompositor, ()> for State {
    fn event(
        _state: &mut Self,
        _proxy: &WlCompositor,
        _event: <WlCompositor as wayland_client::Proxy>::Event,
        _data: &(),
        _conn: &Connection,
        _qhandle: &QueueHandle<Self>,
    ) {
        unreachable!()
    }
}

impl Dispatch<XdgWmBase, ()> for State {
    fn event(
        _state: &mut Self,
        xdg_wm_base: &XdgWmBase,
        event: <XdgWmBase as wayland_client::Proxy>::Event,
        _data: &(),
        _conn: &Connection,
        _qhandle: &QueueHandle<Self>,
    ) {
        match event {
            xdg_wm_base::Event::Ping { serial } => {
                xdg_wm_base.pong(serial);
            }
            _ => unreachable!(),
        }
    }
}

impl Dispatch<WlSurface, ()> for State {
    fn event(
        _state: &mut Self,
        _proxy: &WlSurface,
        event: <WlSurface as wayland_client::Proxy>::Event,
        _data: &(),
        _conn: &Connection,
        _qhandle: &QueueHandle<Self>,
    ) {
        match event {
            wl_surface::Event::Enter { .. } => (),
            wl_surface::Event::Leave { .. } => (),
            wl_surface::Event::PreferredBufferScale { .. } => (),
            wl_surface::Event::PreferredBufferTransform { .. } => (),
            _ => unreachable!(),
        }
    }
}

impl Dispatch<XdgSurface, ()> for State {
    fn event(
        state: &mut Self,
        xdg_surface: &XdgSurface,
        event: <XdgSurface as wayland_client::Proxy>::Event,
        _data: &(),
        _conn: &Connection,
        _qhandle: &QueueHandle<Self>,
    ) {
        match event {
            xdg_surface::Event::Configure { serial } => {
                let window = state
                    .windows
                    .iter_mut()
                    .find(|w| w.xdg_surface == *xdg_surface)
                    .unwrap();
                let configure = window.pending_configure.clone();
                window.configures_received.push((serial, configure));
            }
            _ => unreachable!(),
        }
    }
}

impl Dispatch<XdgToplevel, ()> for State {
    fn event(
        state: &mut Self,
        xdg_toplevel: &XdgToplevel,
        event: <XdgToplevel as wayland_client::Proxy>::Event,
        _data: &(),
        _conn: &Connection,
        _qhandle: &QueueHandle<Self>,
    ) {
        let window = state
            .windows
            .iter_mut()
            .find(|w| w.xdg_toplevel == *xdg_toplevel)
            .unwrap();

        match event {
            xdg_toplevel::Event::Configure {
                width,
                height,
                states,
            } => {
                let configure = &mut window.pending_configure;
                configure.size = (width, height);
                configure.states = states
                    .chunks_exact(4)
                    .flat_map(TryInto::<[u8; 4]>::try_into)
                    .map(u32::from_ne_bytes)
                    .flat_map(xdg_toplevel::State::try_from)
                    .collect();
            }
            xdg_toplevel::Event::Close => {
                window.close_requested = true;
            }
            xdg_toplevel::Event::ConfigureBounds { width, height } => {
                window.pending_configure.bounds = Some((width, height));
            }
            xdg_toplevel::Event::WmCapabilities { .. } => (),
            _ => unreachable!(),
        }
    }
}

impl Dispatch<WlBuffer, ()> for State {
    fn event(
        _state: &mut Self,
        _proxy: &WlBuffer,
        event: <WlBuffer as wayland_client::Proxy>::Event,
        _data: &(),
        _conn: &Connection,
        _qhandle: &QueueHandle<Self>,
    ) {
        match event {
            wl_buffer::Event::Release => (),
            _ => unreachable!(),
        }
    }
}

impl Dispatch<WpSinglePixelBufferManagerV1, ()> for State {
    fn event(
        _state: &mut Self,
        _proxy: &WpSinglePixelBufferManagerV1,
        _event: <WpSinglePixelBufferManagerV1 as wayland_client::Proxy>::Event,
        _data: &(),
        _conn: &Connection,
        _qhandle: &QueueHandle<Self>,
    ) {
        unreachable!()
    }
}

impl Dispatch<WpViewporter, ()> for State {
    fn event(
        _state: &mut Self,
        _proxy: &WpViewporter,
        _event: <WpViewporter as wayland_client::Proxy>::Event,
        _data: &(),
        _conn: &Connection,
        _qhandle: &QueueHandle<Self>,
    ) {
        unreachable!()
    }
}

impl Dispatch<WpViewport, ()> for State {
    fn event(
        _state: &mut Self,
        _proxy: &WpViewport,
        _event: <WpViewport as wayland_client::Proxy>::Event,
        _data: &(),
        _conn: &Connection,
        _qhandle: &QueueHandle<Self>,
    ) {
        unreachable!()
    }
}