use crate::core::{ElementMaybeSignal, ElementsMaybeSignal};
use crate::utils::IS_IOS;
use crate::{use_event_listener, use_event_listener_with_options};
use default_struct_builder::DefaultBuilder;
use leptos::ev::{blur, click, pointerdown};
use leptos::*;
use std::cell::Cell;
use std::rc::Rc;
use std::sync::RwLock;
use std::time::Duration;
use wasm_bindgen::JsCast;
use web_sys::AddEventListenerOptions;

static IOS_WORKAROUND: RwLock<bool> = RwLock::new(false);

/// Listen for clicks outside of an element.
/// Useful for modals or dropdowns.
///
/// ## Demo
///
/// [Link to Demo](https://github.com/Synphonyte/leptos-use/tree/main/examples/on_click_outside)
///
/// ## Usage
///
/// ```
/// # use leptos::*;
/// # use leptos::ev::resize;
/// # use leptos::html::Div;
/// # use leptos_use::on_click_outside;
/// #
/// # #[component]
/// # fn Demo() -> impl IntoView {
/// let target = create_node_ref::<Div>();
///
/// on_click_outside(target, move |event| { log!("{:?}", event); });
///
/// view! {
///     <div node_ref=target>"Hello World"</div>
///     <div>"Outside element"</div>
/// }
/// # }
/// ```
///
/// > This function uses [Event.composedPath()](https://developer.mozilla.org/en-US/docs/Web/API/Event/composedPath)
/// which is **not** supported by IE 11, Edge 18 and below.
/// If you are targeting these browsers, we recommend you to include
/// [this code snippet](https://gist.github.com/sibbng/13e83b1dd1b733317ce0130ef07d4efd) on your project.
///
/// ## Server-Side Rendering
///
/// Please refer to ["Functions with Target Elements"](https://leptos-use.rs/server_side_rendering.html#functions-with-target-elements)
pub fn on_click_outside<El, T, F>(target: El, handler: F) -> impl FnOnce() + Clone
where
    El: Clone,
    El: Into<ElementMaybeSignal<T, web_sys::EventTarget>>,
    T: Into<web_sys::EventTarget> + Clone + 'static,
    F: FnMut(web_sys::Event) + Clone + 'static,
{
    on_click_outside_with_options::<_, _, _, web_sys::EventTarget>(
        target,
        handler,
        OnClickOutsideOptions::default(),
    )
}

/// Version of `on_click_outside` that takes an `OnClickOutsideOptions`. See `on_click_outside` for more details.
pub fn on_click_outside_with_options<El, T, F, I>(
    target: El,
    handler: F,
    options: OnClickOutsideOptions<I>,
) -> impl FnOnce() + Clone
where
    El: Clone,
    El: Into<ElementMaybeSignal<T, web_sys::EventTarget>>,
    T: Into<web_sys::EventTarget> + Clone + 'static,
    F: FnMut(web_sys::Event) + Clone + 'static,
    I: Into<web_sys::EventTarget> + Clone + 'static,
{
    let OnClickOutsideOptions {
        ignore,
        capture,
        detect_iframes,
    } = options;

    // Fixes: https://github.com/vueuse/vueuse/issues/1520
    // How it works: https://stackoverflow.com/a/39712411
    if *IS_IOS {
        if let Ok(mut ios_workaround) = IOS_WORKAROUND.write() {
            if !*ios_workaround {
                *ios_workaround = true;
                if let Some(body) = document().body() {
                    let children = body.children();
                    for i in 0..children.length() {
                        let _ = children
                            .get_with_index(i)
                            .expect("checked index")
                            .add_event_listener_with_callback(
                                "click",
                                &js_sys::Function::default(),
                            );
                    }
                }
            }
        }
    }

    let should_listen = Rc::new(Cell::new(true));

    let should_ignore = move |event: &web_sys::UiEvent| {
        let ignore = ignore.get_untracked();

        ignore.into_iter().flatten().any(|element| {
            let element: web_sys::EventTarget = element.into();

            event_target::<web_sys::EventTarget>(event) == element
                || event.composed_path().includes(element.as_ref(), 0)
        })
    };

    let target = (target).into();

    let listener = {
        let should_listen = Rc::clone(&should_listen);
        let mut handler = handler.clone();
        let target = target.clone();
        let should_ignore = should_ignore.clone();

        move |event: web_sys::UiEvent| {
            if let Some(el) = target.get_untracked() {
                let el = el.into();

                if el == event_target(&event) || event.composed_path().includes(el.as_ref(), 0) {
                    return;
                }

                if event.detail() == 0 {
                    should_listen.set(!should_ignore(&event));
                }

                if !should_listen.get() {
                    should_listen.set(true);
                    return;
                }

                handler(event.into());
            }
        }
    };

    let remove_click_listener = {
        let mut listener = listener.clone();

        let mut options = AddEventListenerOptions::default();
        options.passive(true).capture(capture);

        use_event_listener_with_options::<_, web_sys::Window, _, _>(
            window(),
            click,
            move |event| listener(event.into()),
            options,
        )
    };

    let remove_pointer_listener = {
        let target = target.clone();
        let should_listen = Rc::clone(&should_listen);

        let mut options = AddEventListenerOptions::default();
        options.passive(true);

        use_event_listener_with_options::<_, web_sys::Window, _, _>(
            window(),
            pointerdown,
            move |event| {
                if let Some(el) = target.get_untracked() {
                    should_listen.set(
                        !event.composed_path().includes(el.into().as_ref(), 0)
                            && !should_ignore(&event),
                    );
                }
            },
            options,
        )
    };

    let remove_blur_listener = if detect_iframes {
        Some(use_event_listener::<_, web_sys::Window, _, _>(
            window(),
            blur,
            move |event| {
                let target = target.clone();
                let mut handler = handler.clone();

                let _ = set_timeout_with_handle(
                    move || {
                        if let Some(el) = target.get_untracked() {
                            if let Some(active_element) = document().active_element() {
                                if active_element.tag_name() == "IFRAME"
                                    && !el
                                        .into()
                                        .unchecked_into::<web_sys::Node>()
                                        .contains(Some(&active_element.into()))
                                {
                                    handler(event.into());
                                }
                            }
                        }
                    },
                    Duration::ZERO,
                );
            },
        ))
    } else {
        None
    };

    move || {
        remove_click_listener();
        remove_pointer_listener();
        if let Some(f) = remove_blur_listener {
            f();
        }
    }
}

/// Options for [`on_click_outside_with_options`].
#[derive(Clone, DefaultBuilder)]
pub struct OnClickOutsideOptions<T>
where
    T: Into<web_sys::EventTarget> + Clone + 'static,
{
    /// List of elementss that should not trigger the callback. Defaults to `[]`.
    ignore: ElementsMaybeSignal<T, web_sys::EventTarget>,

    /// Use capturing phase for internal event listener. Defaults to `true`.
    capture: bool,

    /// Run callback if focus moves to an iframe. Defaults to `false`.
    detect_iframes: bool,
}

impl<T> Default for OnClickOutsideOptions<T>
where
    T: Into<web_sys::EventTarget> + Clone + 'static,
{
    fn default() -> Self {
        Self {
            ignore: Default::default(),
            capture: true,
            detect_iframes: false,
        }
    }
}