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

use crate::prelude::*;
use crate::Dialog;
use crate::DialogFlags;
use crate::ResponseType;
use crate::Widget;
use crate::Window;
use glib::translate::*;
use std::cell::Cell;
use std::future::Future;
use std::pin::Pin;
use std::ptr;

impl Dialog {
    /// Creates a new [`Dialog`][crate::Dialog] with title `title` (or [`None`] for the default
    /// title; see [`GtkWindowExt::set_title()`][crate::prelude::GtkWindowExt::set_title()]) and transient parent `parent` (or
    /// [`None`] for none; see [`GtkWindowExt::set_transient_for()`][crate::prelude::GtkWindowExt::set_transient_for()]). The `flags`
    /// argument can be used to make the dialog modal ([`DialogFlags::MODAL`][crate::DialogFlags::MODAL])
    /// and/or to have it destroyed along with its transient parent
    /// ([`DialogFlags::DESTROY_WITH_PARENT`][crate::DialogFlags::DESTROY_WITH_PARENT]). After `flags`, button
    /// text/response ID pairs should be listed, 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 dialog buttons,
    /// [`Dialog`][crate::Dialog] will emit the `signal::Dialog::response` signal with the corresponding
    /// response ID. If a [`Dialog`][crate::Dialog] receives the `signal::Widget::delete-event` signal,
    /// 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. Buttons are from left to right,
    /// so the first button in the list will be the leftmost button in the dialog.
    ///
    /// Here’s a simple example:
    ///
    ///
    /// **⚠️ The following code is in C ⚠️**
    ///
    /// ```C
    ///  GtkWidget *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, or [`None`]
    /// ## `parent`
    /// Transient parent of the dialog, or [`None`]
    /// ## `flags`
    /// from [`DialogFlags`][crate::DialogFlags]
    /// ## `first_button_text`
    /// text to go in first button, or [`None`]
    ///
    /// # Returns
    ///
    /// a new [`Dialog`][crate::Dialog]
    #[doc(alias = "gtk_dialog_new_with_buttons")]
    pub fn with_buttons<T: IsA<Window>>(
        title: Option<&str>,
        parent: Option<&T>,
        flags: DialogFlags,
        buttons: &[(&str, ResponseType)],
    ) -> Dialog {
        assert_initialized_main_thread!();
        let ret: Dialog = 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
    }
}

pub trait DialogExtManual: 'static {
    /// Adds more buttons, same as calling [`DialogExt::add_button()`][crate::prelude::DialogExt::add_button()]
    /// repeatedly. The variable argument list should be [`None`]-terminated
    /// as with `gtk_dialog_new_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)]);

    // rustdoc-stripper-ignore-next
    /// Shows the dialog and returns a `Future` that resolves to the
    /// `ResponseType` on response.
    ///
    /// ```no_run
    /// use gtk::prelude::*;
    ///
    /// # async fn run() {
    /// let dialog = gtk::MessageDialog::builder()
    ///    .buttons(gtk::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>>;
}

impl<O: IsA<Dialog> + IsA<Widget>> DialogExtManual for O {
    fn add_buttons(&self, buttons: &[(&str, ResponseType)]) {
        for &(text, id) in buttons {
            //FIXME: self.add_button don't work on 1.8
            O::add_button(self, text, id);
        }
    }

    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.show();

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