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

use crate::{keys::Key, Display, Event, KeymapKey, ModifierType};
use glib::translate::*;
use glib::IsA;
use std::{mem, ptr};

pub trait DisplayExtManual: 'static {
    /// Translates the contents of a `GdkEventKey` into a keyval, effective group,
    /// and level.
    ///
    /// Modifiers that affected the translation and are thus unavailable for
    /// application use are returned in `consumed_modifiers`.
    ///
    /// The `effective_group` is the group that was actually used for the
    /// translation; some keys such as Enter are not affected by the active
    /// keyboard group. The `level` is derived from `state`.
    ///
    /// `consumed_modifiers` gives modifiers that should be masked out
    /// from `state` when comparing this key press to a keyboard shortcut.
    /// For instance, on a US keyboard, the `plus` symbol is shifted, so
    /// when comparing a key press to a ``<Control>`plus` accelerator ``<Shift>``
    /// should be masked out.
    ///
    /// This function should rarely be needed, since `GdkEventKey` already
    /// contains the translated keyval. It is exported for the benefit of
    /// virtualized test environments.
    /// ## `keycode`
    /// a keycode
    /// ## `state`
    /// a modifier state
    /// ## `group`
    /// active keyboard group
    ///
    /// # Returns
    ///
    /// [`true`] if there was a keyval bound to keycode/state/group.
    ///
    /// ## `keyval`
    /// return location for keyval
    ///
    /// ## `effective_group`
    /// return location for effective group
    ///
    /// ## `level`
    /// return location for level
    ///
    /// ## `consumed`
    /// return location for modifiers that were used
    ///  to determine the group or level
    #[doc(alias = "gdk_display_translate_key")]
    fn translate_key(
        &self,
        keycode: u32,
        state: ModifierType,
        group: i32,
    ) -> Option<(Key, i32, i32, ModifierType)>;

    /// Retrieves a desktop-wide setting such as double-click time
    /// for the `self`.
    /// ## `name`
    /// the name of the setting
    /// ## `value`
    /// location to store the value of the setting
    ///
    /// # Returns
    ///
    /// [`true`] if the setting existed and a value was stored
    ///  in `value`, [`false`] otherwise
    #[doc(alias = "gdk_display_get_setting")]
    fn get_setting(&self, name: &str) -> Option<glib::Value>;

    /// Obtains a list of keycode/group/level combinations that will
    /// generate `keyval`.
    ///
    /// Groups and levels are two kinds of keyboard mode; in general, the level
    /// determines whether the top or bottom symbol on a key is used, and the
    /// group determines whether the left or right symbol is used.
    ///
    /// On US keyboards, the shift key changes the keyboard level, and there
    /// are no groups. A group switch key might convert a keyboard between
    /// Hebrew to English modes, for example.
    ///
    /// `GdkEventKey` contains a `group` field that indicates the active
    /// keyboard group. The level is computed from the modifier mask.
    ///
    /// The returned array should be freed with `g_free()`.
    /// ## `keyval`
    /// a keyval, such as `GDK_KEY_a`, `GDK_KEY_Up`, `GDK_KEY_Return`, etc.
    ///
    /// # Returns
    ///
    /// [`true`] if keys were found and returned
    ///
    /// ## `keys`
    /// return location
    ///  for an array of [`KeymapKey`][crate::KeymapKey]
    #[doc(alias = "gdk_display_map_keyval")]
    fn map_keyval(&self, keyval: Key) -> Option<Vec<KeymapKey>>;

    /// Returns the keyvals bound to `keycode`.
    ///
    /// The Nth [`KeymapKey`][crate::KeymapKey] in `keys` is bound to the Nth keyval in `keyvals`.
    ///
    /// When a keycode is pressed by the user, the keyval from
    /// this list of entries is selected by considering the effective
    /// keyboard group and level.
    ///
    /// Free the returned arrays with `g_free()`.
    /// ## `keycode`
    /// a keycode
    ///
    /// # Returns
    ///
    /// [`true`] if there were any entries
    ///
    /// ## `keys`
    /// return
    ///  location for array of [`KeymapKey`][crate::KeymapKey]
    ///
    /// ## `keyvals`
    /// return
    ///  location for array of keyvals
    #[doc(alias = "gdk_display_map_keycode")]
    fn map_keycode(&self, keycode: u32) -> Option<Vec<(KeymapKey, Key)>>;

    /// Appends the given event onto the front of the event
    /// queue for `self`.
    ///
    /// This function is only useful in very special situations
    /// and should not be used by applications.
    /// ## `event`
    /// a [`Event`][crate::Event]
    #[doc(alias = "gdk_display_put_event")]
    fn put_event<P: AsRef<Event>>(&self, event: &P);
}

impl<O: IsA<Display>> DisplayExtManual for O {
    fn translate_key(
        &self,
        keycode: u32,
        state: ModifierType,
        group: i32,
    ) -> Option<(Key, i32, i32, ModifierType)> {
        unsafe {
            let mut keyval = mem::MaybeUninit::uninit();
            let mut effective_group = mem::MaybeUninit::uninit();
            let mut level = mem::MaybeUninit::uninit();
            let mut consumed = mem::MaybeUninit::uninit();
            let ret = from_glib(ffi::gdk_display_translate_key(
                self.as_ref().to_glib_none().0,
                keycode,
                state.into_glib(),
                group,
                keyval.as_mut_ptr(),
                effective_group.as_mut_ptr(),
                level.as_mut_ptr(),
                consumed.as_mut_ptr(),
            ));
            if ret {
                let keyval: Key = keyval.assume_init().into();
                let effective_group = effective_group.assume_init();
                let level = level.assume_init();
                let consumed = consumed.assume_init();
                Some((keyval, effective_group, level, from_glib(consumed)))
            } else {
                None
            }
        }
    }

    fn get_setting(&self, name: &str) -> Option<glib::Value> {
        unsafe {
            let mut value = glib::Value::uninitialized();
            let ret = ffi::gdk_display_get_setting(
                self.as_ref().to_glib_none().0,
                name.to_glib_none().0,
                value.to_glib_none_mut().0,
            );
            if from_glib(ret) {
                Some(value)
            } else {
                None
            }
        }
    }

    fn map_keyval(&self, keyval: Key) -> Option<Vec<KeymapKey>> {
        unsafe {
            let mut keys = ptr::null_mut();
            let mut n_keys = mem::MaybeUninit::uninit();
            let ret = from_glib(ffi::gdk_display_map_keyval(
                self.as_ref().to_glib_none().0,
                keyval.into_glib(),
                &mut keys,
                n_keys.as_mut_ptr(),
            ));
            if ret {
                Some(FromGlibContainer::from_glib_full_num(
                    keys,
                    n_keys.assume_init() as usize,
                ))
            } else {
                None
            }
        }
    }

    fn map_keycode(&self, keycode: u32) -> Option<Vec<(KeymapKey, Key)>> {
        unsafe {
            let mut keys = ptr::null_mut();
            let mut keyvals = ptr::null_mut();
            let mut n_entries = mem::MaybeUninit::uninit();
            let ret = from_glib(ffi::gdk_display_map_keycode(
                self.as_ref().to_glib_none().0,
                keycode,
                &mut keys,
                &mut keyvals,
                n_entries.as_mut_ptr(),
            ));
            if ret {
                let n_keys = n_entries.assume_init() as usize;
                let keyvals: Vec<u32> = FromGlibContainer::from_glib_full_num(keyvals, n_keys);
                let keyvals = keyvals.into_iter().map(|k| k.into());
                let keys: Vec<KeymapKey> = FromGlibContainer::from_glib_full_num(keys, n_keys);

                Some(keys.into_iter().zip(keyvals).collect())
            } else {
                None
            }
        }
    }

    fn put_event<P: AsRef<Event>>(&self, event: &P) {
        unsafe {
            ffi::gdk_display_put_event(
                self.as_ref().to_glib_none().0,
                event.as_ref().to_glib_none().0,
            );
        }
    }
}