ribir 0.2.0-alpha.6

use crate::clipboard::Clipboard;
use crate::register_platform_app_events_handlers;
use crate::winit_shell_wnd::{new_id, WinitShellWnd};
use ribir_core::{prelude::*, timer::Timer, window::WindowId};
use std::rc::Rc;
use std::{convert::Infallible, sync::Once};
use winit::event::ElementState;
use winit::platform::run_on_demand::EventLoopExtRunOnDemand;
use winit::{
  event::{Event, Ime, KeyEvent, StartCause, WindowEvent},
  event_loop::{ControlFlow, EventLoop, EventLoopBuilder, EventLoopProxy},
  keyboard::KeyCode,
};

pub struct App {
  event_loop: EventLoop<AppEvent>,
  active_wnd: Option<WindowId>,
  events_stream: MutRefItemSubject<'static, AppEvent, Infallible>,
}

#[derive(Debug, Clone, PartialEq, Eq, Hash)]
pub struct HotkeyEvent {
  pub key_code: Option<KeyCode>,
  pub modifiers: Option<ModifiersState>,
}

pub enum AppEvent {
  /// The event is sent when any future is waked to poll.
  FuturesWake,
  /// The event is sent when the application is be required to open a url. For
  /// example, it's launched from browser with a url.
  OpenUrl(String),
  /// The event is get global hotkey, it will receive the hotkey event.
  Hotkey(HotkeyEvent),
  /// The event is sent when the application window focus changed.
  WndFocusChanged(WindowId, bool),
  /// The custom event, you can send any data with this event.
  Custom(Box<dyn Any + Send>),
}

/// A sender to send event to the application event loop from which the
/// `EventSender` was created.
#[derive(Clone)]
pub struct EventSender(EventLoopProxy<AppEvent>);

#[derive(Clone)]
pub struct EventWaker(EventLoopProxy<AppEvent>);

impl App {
  /// Start an application with the `root` widget, this will use the default
  /// theme to create an application and use the `root` widget to create a
  /// window, then run the application.
  #[track_caller]
  pub fn run(root: impl WidgetBuilder) {
    Self::new_window(root, None);
    App::exec()
  }

  /// create a new window with the `root` widget and return the window id.
  #[track_caller]
  pub fn new_window(root: impl WidgetBuilder, size: Option<Size>) -> Rc<Window> {
    let app = unsafe { App::shared_mut() };
    let shell_wnd = WinitShellWnd::new(size, &app.event_loop);
    let wnd = AppCtx::new_window(Box::new(shell_wnd), root);

    if app.active_wnd.is_none() {
      app.active_wnd = Some(wnd.id());
    }
    wnd
  }

  /// Get a event sender of the application event loop, you can use this to send
  /// event.
  pub fn event_sender() -> EventSender {
    let proxy = App::shared().event_loop.create_proxy();
    EventSender(proxy)
  }

  pub fn events_stream() -> MutRefItemSubject<'static, AppEvent, Infallible> {
    App::shared().events_stream.clone()
  }

  pub fn active_window() -> Rc<Window> {
    App::shared()
      .active_wnd
      .and_then(AppCtx::get_window)
      .expect("application at least have one window before use.")
  }

  /// set the window with `id` to be the active window, and the active window.
  #[track_caller]
  pub fn set_active_window(id: WindowId) {
    let app = unsafe { App::shared_mut() };
    app.active_wnd = Some(id);
    // todo: set the window to be the top window, but we not really support
    // multi window fully, implement this later.
    if let Some(wnd) = AppCtx::get_window(id) {
      let mut shell = wnd.shell_wnd().borrow_mut();
      if shell.is_minimized() {
        shell.set_minimized(false);
      }
      shell.focus_window();
    };
  }

  /// run the application, this will start the event loop and block the current
  /// thread until the application exit.
  #[track_caller]
  pub fn exec() {
    Self::active_window().draw_frame();

    let event_loop = &mut unsafe { App::shared_mut() }.event_loop;

    let _ = event_loop.run_on_demand(move |event, loop_handle| {
      match event {
        Event::WindowEvent { event, window_id } => {
          let wnd_id = new_id(window_id);
          let Some(wnd) = AppCtx::get_window(wnd_id) else {
            return;
          };
          match event {
            WindowEvent::CloseRequested => {
              AppCtx::remove_wnd(wnd_id);
              if !AppCtx::has_wnd() {
                loop_handle.exit();
              }
            }
            WindowEvent::RedrawRequested => {
              if let Some(wnd) = AppCtx::get_window(wnd_id) {
                // if this frame is really draw, request another redraw. To make sure the draw
                // always end with a empty draw and emit an extra tick cycle message.
                if wnd.draw_frame() {
                  request_redraw(&wnd);
                }
              }
            }
            WindowEvent::Resized(_) => {
              let size = wnd.shell_wnd().borrow().inner_size();
              wnd.shell_wnd().borrow_mut().on_resize(size);
              request_redraw(&wnd)
            }
            WindowEvent::Focused(focused) => {
              let mut event = AppEvent::WndFocusChanged(wnd_id, focused);
              let app = unsafe { App::shared_mut() };
              app.events_stream.next(&mut event);
            }
            event => {
              App::dispatch_wnd_native_event(&wnd, event);
            }
          }
          wnd.emit_events();
        }
        Event::AboutToWait => {
          let run_count = AppCtx::run_until_stalled();
          if run_count > 0 {
            for wnd in AppCtx::windows().borrow().values() {
              request_redraw(wnd);
            }
          }
          if run_count > 0 {
            loop_handle.set_control_flow(ControlFlow::Poll);
          } else if let Some(t) = Timer::recently_timeout() {
            loop_handle.set_control_flow(ControlFlow::WaitUntil(t));
          } else {
            loop_handle.set_control_flow(ControlFlow::Wait);
          };
        }
        Event::NewEvents(cause) => match cause {
          StartCause::Poll | StartCause::ResumeTimeReached { start: _, requested_resume: _ } => {
            Timer::wake_timeout_futures();
          }
          _ => (),
        },
        Event::UserEvent(mut event) => {
          AppCtx::spawn_local(async move {
            let app = unsafe { App::shared_mut() };
            app.events_stream.next(&mut event);
          })
          .unwrap();
        }
        _ => (),
      }
    });
  }

  fn dispatch_wnd_native_event(wnd: &Window, event: WindowEvent) {
    static mut PRE_EDIT_HANDLE: PreEditHandle = PreEditHandle::new();
    match event {
      WindowEvent::KeyboardInput { event, .. } => {
        let KeyEvent {
          physical_key,
          logical_key,
          text,
          location,
          repeat,
          state,
          ..
        } = event;
        if unsafe { PRE_EDIT_HANDLE.is_in_pre_edit() } {
          return;
        }
        wnd.processes_keyboard_event(physical_key, logical_key, repeat, location, state);
        if state == ElementState::Pressed {
          if let Some(txt) = text {
            wnd.processes_receive_chars(txt.to_string());
          }
        }
      }
      WindowEvent::Ime(ime) => unsafe {
        PRE_EDIT_HANDLE.update(wnd, &ime);
      },
      WindowEvent::MouseInput { state, button, device_id, .. } => {
        if state == ElementState::Pressed {
          unsafe {
            PRE_EDIT_HANDLE.force_exit(wnd);
          }
        }
        wnd.process_mouse_input(device_id, state, button);
      }
      #[allow(deprecated)]
      _ => wnd.processes_native_event(event),
    }
  }

  #[track_caller]
  fn shared() -> &'static App { unsafe { Self::shared_mut() } }

  #[track_caller]
  unsafe fn shared_mut() -> &'static mut App {
    static mut INIT_ONCE: Once = Once::new();
    static mut APP: Option<App> = None;
    INIT_ONCE.call_once(|| {
      let event_loop = EventLoopBuilder::with_user_event().build().unwrap();
      let waker = EventWaker(event_loop.create_proxy());
      let clipboard = Clipboard::new().unwrap();
      unsafe {
        AppCtx::set_clipboard(Box::new(clipboard));
        AppCtx::set_runtime_waker(Box::new(waker));
      }
      register_platform_app_events_handlers();
      APP = Some(App {
        event_loop,
        events_stream: <_>::default(),
        active_wnd: None,
      })
    });
    AppCtx::thread_check();

    APP.as_mut().unwrap()
  }
}

impl EventSender {
  pub fn send(&self, e: AppEvent) {
    if let Err(err) = self.0.send_event(e) {
      log::error!("{}", err.to_string())
    }
  }
}

impl RuntimeWaker for EventWaker {
  fn clone_box(&self) -> Box<dyn RuntimeWaker + Send> { Box::new(self.clone()) }
  fn wake(&self) { let _ = self.0.send_event(AppEvent::FuturesWake); }
}

/// EventWaker only send `RibirEvent::FuturesWake`.
unsafe impl Send for EventWaker {}

pub(crate) fn request_redraw(wnd: &Window) {
  let wnd = wnd.shell_wnd().borrow();
  let shell = wnd.as_any().downcast_ref::<WinitShellWnd>().unwrap();
  shell.winit_wnd.request_redraw();
}

#[derive(Default)]
struct PreEditHandle(Option<String>);

impl PreEditHandle {
  const fn new() -> Self { Self(None) }
  fn update(&mut self, wnd: &Window, pre_edit: &Ime) {
    match pre_edit {
      Ime::Enabled => {}
      Ime::Preedit(txt, cursor) => match txt.is_empty() {
        true => self.exit(wnd),
        false => self.update_pre_edit(wnd, txt, cursor),
      },
      Ime::Commit(value) => {
        self.exit(wnd);
        wnd.processes_receive_chars(value.clone());
      }
      Ime::Disabled => self.exit(wnd),
    }
  }

  fn is_in_pre_edit(&self) -> bool { self.0.is_some() }

  fn force_exit(&mut self, wnd: &Window) {
    if self.is_in_pre_edit() {
      wnd.set_ime_allowed(false);
      wnd.processes_ime_pre_edit(ImePreEdit::End);
      if let Some(s) = self.0.take() {
        wnd.processes_receive_chars(s);
      }
      wnd.set_ime_allowed(true);
    }
  }

  fn exit(&mut self, wnd: &Window) {
    if self.is_in_pre_edit() {
      wnd.processes_ime_pre_edit(ImePreEdit::End);
      self.0.take();
    }
  }

  fn update_pre_edit(&mut self, wnd: &Window, txt: &str, cursor: &Option<(usize, usize)>) {
    if !self.is_in_pre_edit() {
      wnd.processes_ime_pre_edit(ImePreEdit::Begin);
    }

    wnd.processes_ime_pre_edit(ImePreEdit::PreEdit {
      value: txt.to_owned(),
      cursor: *cursor,
    });
    self.0 = Some(txt.to_owned());
  }
}

#[cfg(test)]
mod tests {
  use ribir_core::{
    prelude::*,
    test_helper::{MockBox, TestWindow},
  };
  use std::{cell::RefCell, rc::Rc};
  use winit::event::{Ime, WindowEvent};

  use super::App;
  #[derive(Debug, Default)]
  struct LogImeEvent {
    log: Rc<RefCell<Vec<String>>>,
  }
  impl Compose for LogImeEvent {
    fn compose(this: impl StateWriter<Value = Self>) -> impl WidgetBuilder {
      fn_widget! {
        @MockBox {
          size: INFINITY_SIZE,
          auto_focus: true,
          on_ime_pre_edit: move |e| {
            match &e.pre_edit {
              ImePreEdit::Begin => $this.log.borrow_mut().push("on_ime_pre_edit_begin".to_string()),
              ImePreEdit::PreEdit { value, .. } => $this.log.borrow_mut().push(format!("on_ime_pre_edit_update {value}")),
              ImePreEdit::End => $this.log.borrow_mut().push("on_ime_pre_edit_end".to_string()),
            }
          },
          on_chars: move|e| $this.log.borrow_mut().push(format!("on_chars {}", e.chars)),
          on_tap: move |_| $this.log.borrow_mut().push("on_tap".to_string()),
        }
      }
    }
  }
  #[test]
  fn ime_pre_edit() {
    let w = Stateful::new(LogImeEvent::default());
    let log = w.read().log.clone();

    let w = fn_widget! { @ {w} };
    let mut wnd = TestWindow::new_with_size(w, Size::new(200., 200.));

    wnd.draw_frame();

    App::dispatch_wnd_native_event(&wnd, WindowEvent::Ime(Ime::Enabled));
    App::dispatch_wnd_native_event(
      &wnd,
      WindowEvent::Ime(Ime::Preedit("hello".to_string(), None)),
    );
    App::dispatch_wnd_native_event(&wnd, WindowEvent::Ime(Ime::Disabled));
    wnd.draw_frame();
    assert_eq!(
      &*log.borrow(),
      &[
        "on_ime_pre_edit_begin",
        "on_ime_pre_edit_update hello",
        "on_ime_pre_edit_end"
      ]
    );

    log.borrow_mut().clear();
    App::dispatch_wnd_native_event(
      &wnd,
      WindowEvent::Ime(Ime::Preedit("hello".to_string(), None)),
    );
    App::dispatch_wnd_native_event(&wnd, WindowEvent::Ime(Ime::Commit("hello".to_string())));
    wnd.draw_frame();
    assert_eq!(
      &*log.borrow(),
      &[
        "on_ime_pre_edit_begin",
        "on_ime_pre_edit_update hello",
        "on_ime_pre_edit_end",
        "on_chars hello",
      ]
    );

    log.borrow_mut().clear();
    App::dispatch_wnd_native_event(
      &wnd,
      WindowEvent::Ime(Ime::Preedit("hello".to_string(), None)),
    );
    let device_id = unsafe { winit::event::DeviceId::dummy() };
    App::dispatch_wnd_native_event(
      &wnd,
      WindowEvent::MouseInput {
        state: winit::event::ElementState::Pressed,
        button: winit::event::MouseButton::Left,
        device_id,
      },
    );
    App::dispatch_wnd_native_event(
      &wnd,
      WindowEvent::MouseInput {
        state: winit::event::ElementState::Released,
        button: winit::event::MouseButton::Left,
        device_id,
      },
    );
    wnd.draw_frame();
    assert_eq!(
      &*log.borrow(),
      &[
        "on_ime_pre_edit_begin",
        "on_ime_pre_edit_update hello",
        "on_ime_pre_edit_end",
        "on_chars hello",
        "on_tap",
      ]
    );
  }
}