use crate::{
    config::{Config, WindowCloseBehaviour},
    event_handlers::WindowEventHandlers,
    file_upload::{DesktopFileUploadForm, FileDialogRequest, NativeFileEngine},
    ipc::{IpcMessage, UserWindowEvent},
    query::QueryResult,
    shortcut::ShortcutRegistry,
    webview::WebviewInstance,
};
use dioxus_core::{ElementId, VirtualDom};
use dioxus_html::PlatformEventData;
use std::{
    any::Any,
    cell::{Cell, RefCell},
    collections::HashMap,
    rc::Rc,
    sync::Arc,
};
use tao::{
    event::Event,
    event_loop::{ControlFlow, EventLoop, EventLoopBuilder, EventLoopProxy, EventLoopWindowTarget},
    window::WindowId,
};

/// The single top-level object that manages all the running windows, assets, shortcuts, etc
pub(crate) struct App {
    // move the props into a cell so we can pop it out later to create the first window
    // iOS panics if we create a window before the event loop is started, so we toss them into a cell
    pub(crate) unmounted_dom: Cell<Option<VirtualDom>>,
    pub(crate) cfg: Cell<Option<Config>>,

    // Stuff we need mutable access to
    pub(crate) control_flow: ControlFlow,
    pub(crate) is_visible_before_start: bool,
    pub(crate) window_behavior: WindowCloseBehaviour,
    pub(crate) webviews: HashMap<WindowId, WebviewInstance>,
    pub(crate) float_all: bool,
    pub(crate) show_devtools: bool,

    /// This single blob of state is shared between all the windows so they have access to the runtime state
    ///
    /// This includes stuff like the event handlers, shortcuts, etc as well as ways to modify *other* windows
    pub(crate) shared: Rc<SharedContext>,
}

/// A bundle of state shared between all the windows, providing a way for us to communicate with running webview.
pub(crate) struct SharedContext {
    pub(crate) event_handlers: WindowEventHandlers,
    pub(crate) pending_webviews: RefCell<Vec<WebviewInstance>>,
    pub(crate) shortcut_manager: ShortcutRegistry,
    pub(crate) proxy: EventLoopProxy<UserWindowEvent>,
    pub(crate) target: EventLoopWindowTarget<UserWindowEvent>,
}

impl App {
    pub fn new(cfg: Config, virtual_dom: VirtualDom) -> (EventLoop<UserWindowEvent>, Self) {
        let event_loop = EventLoopBuilder::<UserWindowEvent>::with_user_event().build();

        let app = Self {
            window_behavior: cfg.last_window_close_behavior,
            is_visible_before_start: true,
            webviews: HashMap::new(),
            control_flow: ControlFlow::Wait,
            unmounted_dom: Cell::new(Some(virtual_dom)),
            float_all: !cfg!(debug_assertions),
            show_devtools: false,
            cfg: Cell::new(Some(cfg)),
            shared: Rc::new(SharedContext {
                event_handlers: WindowEventHandlers::default(),
                pending_webviews: Default::default(),
                shortcut_manager: ShortcutRegistry::new(),
                proxy: event_loop.create_proxy(),
                target: event_loop.clone(),
            }),
        };

        // Set the event converter
        dioxus_html::set_event_converter(Box::new(crate::events::SerializedHtmlEventConverter));

        // Wire up the global hotkey handler
        #[cfg(any(target_os = "windows", target_os = "linux", target_os = "macos"))]
        app.set_global_hotkey_handler();

        // Wire up the menubar receiver - this way any component can key into the menubar actions
        #[cfg(any(target_os = "windows", target_os = "linux", target_os = "macos"))]
        app.set_menubar_receiver();

        // Allow hotreloading to work - but only in debug mode
        #[cfg(all(feature = "devtools", debug_assertions))]
        app.connect_hotreload();

        #[cfg(debug_assertions)]
        #[cfg(any(target_os = "windows", target_os = "linux", target_os = "macos"))]
        app.connect_preserve_window_state_handler();

        (event_loop, app)
    }

    pub fn tick(&mut self, window_event: &Event<'_, UserWindowEvent>) {
        self.control_flow = ControlFlow::Wait;
        self.shared
            .event_handlers
            .apply_event(window_event, &self.shared.target);
    }

    #[cfg(any(target_os = "windows", target_os = "linux", target_os = "macos"))]
    pub fn handle_global_hotkey(&self, event: global_hotkey::GlobalHotKeyEvent) {
        self.shared.shortcut_manager.call_handlers(event);
    }

    #[cfg(any(target_os = "windows", target_os = "linux", target_os = "macos"))]
    pub fn handle_menu_event(&mut self, event: muda::MenuEvent) {
        match event.id().0.as_str() {
            "dioxus-float-top" => {
                for webview in self.webviews.values() {
                    webview
                        .desktop_context
                        .window
                        .set_always_on_top(self.float_all);
                }
                self.float_all = !self.float_all;
            }
            "dioxus-toggle-dev-tools" => {
                self.show_devtools = !self.show_devtools;
                for webview in self.webviews.values() {
                    let wv = &webview.desktop_context.webview;
                    if self.show_devtools {
                        wv.open_devtools();
                    } else {
                        wv.close_devtools();
                    }
                }
            }
            _ => (),
        }
    }

    #[cfg(all(feature = "devtools", debug_assertions))]
    pub fn connect_hotreload(&self) {
        if let Some(endpoint) = dioxus_cli_config::devserver_ws_endpoint() {
            let proxy = self.shared.proxy.clone();
            dioxus_devtools::connect(endpoint, move |msg| {
                _ = proxy.send_event(UserWindowEvent::HotReloadEvent(msg));
            })
        }
    }

    pub fn handle_new_window(&mut self) {
        for handler in self.shared.pending_webviews.borrow_mut().drain(..) {
            let id = handler.desktop_context.window.id();
            self.webviews.insert(id, handler);
            _ = self.shared.proxy.send_event(UserWindowEvent::Poll(id));
        }
    }

    pub fn handle_close_requested(&mut self, id: WindowId) {
        use WindowCloseBehaviour::*;

        match self.window_behavior {
            LastWindowExitsApp => {
                #[cfg(debug_assertions)]
                self.persist_window_state();

                self.webviews.remove(&id);
                if self.webviews.is_empty() {
                    self.control_flow = ControlFlow::Exit
                }
            }

            LastWindowHides => {
                let Some(webview) = self.webviews.get(&id) else {
                    return;
                };
                hide_app_window(&webview.desktop_context.webview);
            }

            CloseWindow => {
                self.webviews.remove(&id);
            }
        }
    }

    pub fn window_destroyed(&mut self, id: WindowId) {
        self.webviews.remove(&id);

        if matches!(
            self.window_behavior,
            WindowCloseBehaviour::LastWindowExitsApp
        ) && self.webviews.is_empty()
        {
            self.control_flow = ControlFlow::Exit
        }
    }

    pub fn handle_start_cause_init(&mut self) {
        let virtual_dom = self.unmounted_dom.take().unwrap();
        let mut cfg = self.cfg.take().unwrap();

        self.is_visible_before_start = cfg.window.window.visible;
        cfg.window = cfg.window.with_visible(false);

        let webview = WebviewInstance::new(cfg, virtual_dom, self.shared.clone());

        // And then attempt to resume from state
        #[cfg(debug_assertions)]
        self.resume_from_state(&webview);

        let id = webview.desktop_context.window.id();
        self.webviews.insert(id, webview);
    }

    pub fn handle_browser_open(&mut self, msg: IpcMessage) {
        if let Some(temp) = msg.params().as_object() {
            if temp.contains_key("href") {
                let open = webbrowser::open(temp["href"].as_str().unwrap());
                if let Err(e) = open {
                    tracing::error!("Open Browser error: {:?}", e);
                }
            }
        }
    }

    /// The webview is finally loaded
    ///
    /// Let's rebuild it and then start polling it
    pub fn handle_initialize_msg(&mut self, id: WindowId) {
        let view = self.webviews.get_mut(&id).unwrap();

        view.dom
            .rebuild(&mut *view.edits.wry_queue.mutation_state_mut());

        view.edits.wry_queue.send_edits();

        view.desktop_context
            .window
            .set_visible(self.is_visible_before_start);

        _ = self.shared.proxy.send_event(UserWindowEvent::Poll(id));
    }

    /// Todo: maybe we should poll the virtualdom asking if it has any final actions to apply before closing the webview
    ///
    /// Technically you can handle this with the use_window_event hook
    pub fn handle_close_msg(&mut self, id: WindowId) {
        self.webviews.remove(&id);
        if self.webviews.is_empty() {
            self.control_flow = ControlFlow::Exit
        }
    }

    pub fn handle_query_msg(&mut self, msg: IpcMessage, id: WindowId) {
        let Ok(result) = serde_json::from_value::<QueryResult>(msg.params()) else {
            return;
        };

        let Some(view) = self.webviews.get(&id) else {
            return;
        };

        view.desktop_context.query.send(result);
    }

    #[cfg(all(feature = "devtools", debug_assertions))]
    pub fn handle_hot_reload_msg(&mut self, msg: dioxus_devtools::DevserverMsg) {
        use dioxus_devtools::DevserverMsg;

        match msg {
            DevserverMsg::HotReload(hr_msg) => {
                for webview in self.webviews.values_mut() {
                    dioxus_devtools::apply_changes(&webview.dom, &hr_msg);
                    webview.poll_vdom();
                }

                if !hr_msg.assets.is_empty() {
                    for webview in self.webviews.values_mut() {
                        webview.kick_stylsheets();
                    }
                }
            }
            DevserverMsg::FullReloadCommand
            | DevserverMsg::FullReloadStart
            | DevserverMsg::FullReloadFailed => {
                // usually only web gets this message - what are we supposed to do?
                // Maybe we could just binary patch ourselves in place without losing window state?
            }
            DevserverMsg::Shutdown => {
                self.control_flow = ControlFlow::Exit;
            }
        }
    }

    pub fn handle_file_dialog_msg(&mut self, msg: IpcMessage, window: WindowId) {
        let Ok(file_dialog) = serde_json::from_value::<FileDialogRequest>(msg.params()) else {
            return;
        };

        let id = ElementId(file_dialog.target);
        let event_name = &file_dialog.event;
        let event_bubbles = file_dialog.bubbles;
        let files = file_dialog.get_file_event();

        let as_any = Box::new(DesktopFileUploadForm {
            files: Arc::new(NativeFileEngine::new(files)),
        });

        let data = Rc::new(PlatformEventData::new(as_any));

        let view = self.webviews.get_mut(&window).unwrap();

        let event = dioxus_core::Event::new(data as Rc<dyn Any>, event_bubbles);

        let runtime = view.dom.runtime();
        if event_name == "change&input" {
            runtime.handle_event("input", event.clone(), id);
            runtime.handle_event("change", event, id);
        } else {
            runtime.handle_event(event_name, event, id);
        }
    }

    /// Poll the virtualdom until it's pending
    ///
    /// The waker we give it is connected to the event loop, so it will wake up the event loop when it's ready to be polled again
    ///
    /// All IO is done on the tokio runtime we started earlier
    pub fn poll_vdom(&mut self, id: WindowId) {
        let Some(view) = self.webviews.get_mut(&id) else {
            return;
        };

        view.poll_vdom();
    }

    #[cfg(any(target_os = "windows", target_os = "linux", target_os = "macos"))]
    fn set_global_hotkey_handler(&self) {
        let receiver = self.shared.proxy.clone();

        // The event loop becomes the hotkey receiver
        // This means we don't need to poll the receiver on every tick - we just get the events as they come in
        // This is a bit more efficient than the previous implementation, but if someone else sets a handler, the
        // receiver will become inert.
        global_hotkey::GlobalHotKeyEvent::set_event_handler(Some(move |t| {
            // todo: should we unset the event handler when the app shuts down?
            _ = receiver.send_event(UserWindowEvent::GlobalHotKeyEvent(t));
        }));
    }

    #[cfg(any(target_os = "windows", target_os = "linux", target_os = "macos"))]
    fn set_menubar_receiver(&self) {
        let receiver = self.shared.proxy.clone();

        // The event loop becomes the menu receiver
        // This means we don't need to poll the receiver on every tick - we just get the events as they come in
        // This is a bit more efficient than the previous implementation, but if someone else sets a handler, the
        // receiver will become inert.
        muda::MenuEvent::set_event_handler(Some(move |t| {
            // todo: should we unset the event handler when the app shuts down?
            _ = receiver.send_event(UserWindowEvent::MudaMenuEvent(t));
        }));
    }

    /// Do our best to preserve state about the window when the event loop is destroyed
    ///
    /// This will attempt to save the window position, size, and monitor into the environment before
    /// closing. This way, when the app is restarted, it can attempt to restore the window to the same
    /// position and size it was in before, making a better DX.
    pub(crate) fn handle_loop_destroyed(&self) {
        #[cfg(debug_assertions)]
        self.persist_window_state();
    }

    #[cfg(debug_assertions)]
    fn persist_window_state(&self) {
        if let Some(webview) = self.webviews.values().next() {
            let window = &webview.desktop_context.window;

            let monitor = window.current_monitor().unwrap();
            let position = window.outer_position().unwrap();
            let size = window.outer_size();

            let x = position.x;
            let y = position.y;

            // This is to work around a bug in how tao handles inner_size on macOS
            // We *want* to use inner_size, but that's currently broken, so we use outer_size instead and then an adjustment
            //
            // https://github.com/tauri-apps/tao/issues/889
            let adjustment = match window.is_decorated() {
                true if cfg!(target_os = "macos") => 56,
                _ => 0,
            };

            let state = PreservedWindowState {
                x,
                y,
                width: size.width.max(200),
                height: size.height.saturating_sub(adjustment).max(200),
                monitor: monitor.name().unwrap().to_string(),
            };

            // Yes... I know... we're loading a file that might not be ours... but it's a debug feature
            if let Ok(state) = serde_json::to_string(&state) {
                _ = std::fs::write(restore_file(), state);
            }
        }
    }

    // Write this to the target dir so we can pick back up
    #[cfg(debug_assertions)]
    fn resume_from_state(&mut self, webview: &WebviewInstance) {
        if let Ok(state) = std::fs::read_to_string(restore_file()) {
            if let Ok(state) = serde_json::from_str::<PreservedWindowState>(&state) {
                let window = &webview.desktop_context.window;
                let position = (state.x, state.y);
                let size = (state.width, state.height);
                window.set_outer_position(tao::dpi::PhysicalPosition::new(position.0, position.1));
                window.set_inner_size(tao::dpi::PhysicalSize::new(size.0, size.1));
            }
        }
    }

    /// Wire up a receiver to sigkill that lets us preserve the window state
    /// Whenever sigkill is sent, we shut down the app and save the window state
    #[cfg(debug_assertions)]
    fn connect_preserve_window_state_handler(&self) {
        // TODO: make this work on windows
        #[cfg(unix)]
        {
            // Wire up the trap
            let target = self.shared.proxy.clone();
            std::thread::spawn(move || {
                use signal_hook::consts::{SIGINT, SIGTERM};
                let sigkill = signal_hook::iterator::Signals::new([SIGTERM, SIGINT]);
                if let Ok(mut sigkill) = sigkill {
                    for _ in sigkill.forever() {
                        if target.send_event(UserWindowEvent::Shutdown).is_err() {
                            std::process::exit(0);
                        }

                        // give it a moment for the event to be processed
                        std::thread::sleep(std::time::Duration::from_secs(1));
                    }
                }
            });
        }
    }
}

#[derive(Debug, serde::Serialize, serde::Deserialize)]
struct PreservedWindowState {
    x: i32,
    y: i32,
    width: u32,
    height: u32,
    monitor: String,
}

/// Different hide implementations per platform
#[allow(unused)]
pub fn hide_app_window(window: &wry::WebView) {
    #[cfg(target_os = "windows")]
    {
        use tao::platform::windows::WindowExtWindows;
        window.set_visible(false);
    }

    #[cfg(target_os = "linux")]
    {
        use tao::platform::unix::WindowExtUnix;
        window.set_visible(false);
    }

    #[cfg(target_os = "macos")]
    {
        // window.set_visible(false); has the wrong behaviour on macOS
        // It will hide the window but not show it again when the user switches
        // back to the app. `NSApplication::hide:` has the correct behaviour
        use objc::runtime::Object;
        use objc::{msg_send, sel, sel_impl};
        objc::rc::autoreleasepool(|| unsafe {
            let app: *mut Object = msg_send![objc::class!(NSApplication), sharedApplication];
            let nil = std::ptr::null_mut::<Object>();
            let _: () = msg_send![app, hide: nil];
        });
    }
}

/// Return the location of a tempfile with our window state in it such that we can restore it later
#[cfg(debug_assertions)]
fn restore_file() -> std::path::PathBuf {
    /// Get the name of the program or default to "dioxus" so we can hash it
    fn get_prog_name_or_default() -> Option<String> {
        Some(
            std::env::current_exe()
                .ok()?
                .file_name()?
                .to_str()?
                .to_string(),
        )
    }

    let name = get_prog_name_or_default().unwrap_or_else(|| "dioxus".to_string());
    let hashed_id = name.chars().map(|c| c as usize).sum::<usize>();
    let mut path = std::env::temp_dir();
    path.push(format!("{}-window-state.json", hashed_id));
    path
}