// Take a look at the license at the top of the repository in the LICENSE file.

use crate::prelude::*;
use crate::{Dialog, DialogFlags, ResponseType, Widget, Window};
use glib::object::Cast;
use glib::translate::*;
use glib::{IsA, ObjectExt};
use std::cell::{Cell, RefCell};
use std::future::Future;
use std::pin::Pin;
use std::ptr;
use std::rc::Rc;

impl Dialog {
    /// Creates a new [`Dialog`][crate::Dialog] with the given title and transient parent.
    ///
    /// The @flags argument can be used to make the dialog modal, have it
    /// destroyed along with its transient parent, or make it use a headerbar.
    ///
    /// Button text/response ID pairs should be listed in pairs, with a [`None`]
    /// pointer ending the list. Button text can be arbitrary text. A response
    /// ID can be any positive number, or one of the values in the
    /// [`ResponseType`][crate::ResponseType] enumeration. If the user clicks one of these
    /// buttons, [`Dialog`][crate::Dialog] will emit the `signal::Dialog::response` signal
    /// with the corresponding response ID.
    ///
    /// If a [`Dialog`][crate::Dialog] receives a delete event, it will emit ::response with a
    /// response ID of [`ResponseType::DeleteEvent`][crate::ResponseType::DeleteEvent].
    ///
    /// However, destroying a dialog does not emit the ::response signal;
    /// so be careful relying on ::response when using the
    /// [`DialogFlags::DESTROY_WITH_PARENT`][crate::DialogFlags::DESTROY_WITH_PARENT] flag.
    ///
    /// Here’s a simple example:
    /// **⚠️ The following code is in c ⚠️**
    ///
    /// ```c
    /// GtkWindow *main_app_window; // Window the dialog should show up on
    /// GtkWidget *dialog;
    /// GtkDialogFlags flags = GTK_DIALOG_MODAL | GTK_DIALOG_DESTROY_WITH_PARENT;
    /// dialog = gtk_dialog_new_with_buttons ("My dialog",
    ///                                       main_app_window,
    ///                                       flags,
    ///                                       _("_OK"),
    ///                                       GTK_RESPONSE_ACCEPT,
    ///                                       _("_Cancel"),
    ///                                       GTK_RESPONSE_REJECT,
    ///                                       NULL);
    /// ```
    /// ## `title`
    /// Title of the dialog
    /// ## `parent`
    /// Transient parent of the dialog
    /// ## `flags`
    /// from [`DialogFlags`][crate::DialogFlags]
    /// ## `first_button_text`
    /// text to go in first button
    ///
    /// # Returns
    ///
    /// a new [`Dialog`][crate::Dialog]
    #[doc(alias = "gtk_dialog_new_with_buttons")]
    #[doc(alias = "new_with_buttons")]
    pub fn with_buttons<T: IsA<Window>>(
        title: Option<&str>,
        parent: Option<&T>,
        flags: DialogFlags,
        buttons: &[(&str, ResponseType)],
    ) -> Self {
        assert_initialized_main_thread!();
        let ret: Self = unsafe {
            Widget::from_glib_none(ffi::gtk_dialog_new_with_buttons(
                title.to_glib_none().0,
                parent.map(|p| p.as_ref()).to_glib_none().0,
                flags.into_glib(),
                ptr::null_mut(),
            ))
            .unsafe_cast()
        };

        ret.add_buttons(buttons);
        ret
    }
}

// rustdoc-stripper-ignore-next
/// Trait containing manually implemented methods of [`Dialog`](crate::Dialog).
pub trait DialogExtManual: 'static {
    /// Adds multiple buttons.
    ///
    /// This is the same as calling [`DialogExt::add_button()`][crate::prelude::DialogExt::add_button()]
    /// repeatedly. The variable argument list should be [`None`]-terminated
    /// as with [`Dialog::with_buttons()`][crate::Dialog::with_buttons()]. Each button must have both
    /// text and response ID.
    /// ## `first_button_text`
    /// button text
    #[doc(alias = "gtk_dialog_add_buttons")]
    fn add_buttons(&self, buttons: &[(&str, ResponseType)]);

    /// Gets the response id of a widget in the action area
    /// of a dialog.
    /// ## `widget`
    /// a widget in the action area of @self
    ///
    /// # Returns
    ///
    /// the response id of @widget, or [`ResponseType::None`][crate::ResponseType::None]
    ///  if @widget doesn’t have a response id set.
    #[doc(alias = "gtk_dialog_get_response_for_widget")]
    #[doc(alias = "get_response_for_widget")]
    fn response_for_widget<P: IsA<Widget>>(&self, widget: &P) -> ResponseType;

    // rustdoc-stripper-ignore-next
    /// Shows the dialog and returns a `Future` that resolves to the
    /// `ResponseType` on response.
    ///
    /// ```no_run
    /// use gtk4::prelude::*;
    ///
    /// # async fn run() {
    /// let dialog = gtk4::MessageDialog::builder()
    ///    .buttons(gtk4::ButtonsType::OkCancel)
    ///    .text("What is your answer?")
    ///    .build();
    ///
    /// let answer = dialog.run_future().await;
    /// dialog.close();
    /// println!("Answer: {:?}", answer);
    /// # }
    /// ```
    fn run_future<'a>(&'a self) -> Pin<Box<dyn Future<Output = ResponseType> + 'a>>;

    // rustdoc-stripper-ignore-next
    /// Shows the dialog and calls the callback when a response has been received.
    ///
    /// **Important**: this function isn't blocking.
    ///
    /// ```no_run
    /// use gtk4::prelude::*;
    ///
    /// let dialog = gtk4::MessageDialog::builder()
    ///    .buttons(gtk4::ButtonsType::OkCancel)
    ///    .text("What is your answer?")
    ///    .build();
    ///
    /// dialog.run_async(|obj, answer| {
    ///     obj.close();
    ///     println!("Answer: {:?}", answer);
    /// });
    /// ```
    fn run_async<F: FnOnce(&Self, ResponseType) + 'static>(&self, f: F);
}

impl<O: IsA<Dialog>> DialogExtManual for O {
    fn add_buttons(&self, buttons: &[(&str, ResponseType)]) {
        for &(text, id) in buttons {
            O::add_button(self, text, id);
        }
    }

    fn response_for_widget<P: IsA<Widget>>(&self, widget: &P) -> ResponseType {
        unsafe {
            from_glib(ffi::gtk_dialog_get_response_for_widget(
                AsRef::<Dialog>::as_ref(self).to_glib_none().0,
                widget.as_ref().to_glib_none().0,
            ))
        }
    }

    fn run_future<'a>(&'a self) -> Pin<Box<dyn Future<Output = ResponseType> + 'a>> {
        Box::pin(async move {
            let (sender, receiver) = futures_channel::oneshot::channel();

            let sender = Cell::new(Some(sender));

            let response_handler = self.connect_response(move |_, response_type| {
                if let Some(m) = sender.replace(None) {
                    let _result = m.send(response_type);
                }
            });

            self.as_ref().present();

            if let Ok(response) = receiver.await {
                self.disconnect(response_handler);
                response
            } else {
                ResponseType::None
            }
        })
    }

    fn run_async<F: FnOnce(&Self, ResponseType) + 'static>(&self, f: F) {
        let response_handler = Rc::new(RefCell::new(None));
        let response_handler_clone = response_handler.clone();
        let f = RefCell::new(Some(f));
        *response_handler.borrow_mut() = Some(self.connect_response(move |s, response_type| {
            if let Some(handler) = response_handler_clone.borrow_mut().take() {
                s.disconnect(handler);
            }
            (*f.borrow_mut()).take().expect("cannot get callback")(s, response_type);
        }));
        self.as_ref().present();
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate as gtk4;

    #[test]
    async fn dialog_future() {
        let dialog = Dialog::new();
        glib::idle_add_local_once(glib::clone!(@strong dialog => move || {
            dialog.response(ResponseType::Ok);
        }));
        let response = dialog.run_future().await;
        assert_eq!(response, ResponseType::Ok);
    }
}