// SPDX-License-Identifier: LGPL-2.1-only
// Copyright (C) 2026 Liberux Labs, S. L. <info@liberux.net>

use crate::app::App;
use crate::event_loop::{ AppData, SurfaceFocus };

use crate::input::gesture::{ MoveOutcome, ReleaseEvent };

impl<A: App> AppData<A>
{
	/// Apply the outcome of a motion event. Non-blocking side-effects
	/// only: push messages, call app callbacks, set redraw flags.
	pub( crate ) fn apply_move_outcome
	(
		&mut self,
		focus:   SurfaceFocus,
		outcome: MoveOutcome<A::Message>,
	)
	{
		match outcome
		{
			MoveOutcome::Idle => {}
			MoveOutcome::Drag { pos } =>
			{
				let ( ox, oy ) = self.surface_offset_for( focus );
				self.app.on_drag_move( pos.x + ox, pos.y + oy );
				self.dirty_caches();
				self.surface_mut( focus ).request_redraw();
				self.main.request_redraw();
				for ss in self.overlays.values_mut()
				{
					ss.request_redraw();
				}
			}
			MoveOutcome::Slider { msg } =>
			{
				if let Some( m ) = msg
				{
					self.pending_msgs.push( m );
				}
				self.surface_mut( focus ).request_redraw();
			}
			MoveOutcome::Scroll =>
			{
				self.surface_mut( focus ).request_redraw();
			}
			MoveOutcome::Swipe { up, down, horizontal } =>
			{
				if let Some( v ) = up         { self.app.on_swipe_progress( v ); }
				if let Some( v ) = down       { self.app.on_swipe_down_progress( v ); }
				if let Some( v ) = horizontal { self.app.on_swipe_horizontal_progress( v ); }
				// Swipe-progress callbacks mutate app state outside
				// `update`, so the cached view tree is stale — unless the
				// motion only slides a subsurface over a static main
				// surface, in which case the per-frame subsurface reconcile
				// carries the move and a main re-raster is wasted work.
				if !self.app.subsurface_motion_only()
				{
					self.dirty_caches();
					self.surface_mut( focus ).request_redraw();
					for ss in self.overlays.values_mut()
					{
						ss.request_redraw();
					}
				}
			}
		}
	}

	/// Apply the ordered list of events from a release. A single
	/// release can emit more than one event (e.g. horizontal
	/// fall-through followed by a vertical commit or fall-through), so
	/// we walk the list and run each event's side-effects in order.
	pub( crate ) fn apply_release_events
	(
		&mut self,
		focus:  SurfaceFocus,
		events: Vec<ReleaseEvent<A::Message>>,
	)
	{
		for event in events
		{
			self.apply_release_event( focus, event );
		}
	}

	fn apply_release_event
	(
		&mut self,
		focus: SurfaceFocus,
		event: ReleaseEvent<A::Message>,
	)
	{
		match event
		{
			ReleaseEvent::Drop { pos } =>
			{
				let ( ox, oy ) = self.surface_offset_for( focus );
				if let Some( msg ) = self.app.on_drop( pos.x + ox, pos.y + oy )
				{
					self.pending_msgs.push( msg );
				}
				self.clear_long_press_drag();
				self.dirty_caches();
				self.main.request_redraw();
				self.main.frame_pending = false;
				for ss in self.overlays.values_mut()
				{
					ss.request_redraw();
				}
			}
			ReleaseEvent::SwipeLeft =>
			{
				if let Some( msg ) = self.app.on_swipe_left()
				{
					self.pending_msgs.push( msg );
				}
				// When the app handles the release internally (settle
				// animation, state-only mutation) it returns no
				// Message, so the update-driven redraw never fires.
				// Kick the main surface here so `is_animating()` has a
				// frame to latch onto.
				self.dirty_caches();
				self.main.request_redraw();
				self.main.frame_pending = false;
			}
			ReleaseEvent::SwipeRight =>
			{
				if let Some( msg ) = self.app.on_swipe_right()
				{
					self.pending_msgs.push( msg );
				}
				self.dirty_caches();
				self.main.request_redraw();
				self.main.frame_pending = false;
			}
			ReleaseEvent::SwipeUp =>
			{
				if let Some( msg ) = self.app.on_swipe_up()
				{
					self.pending_msgs.push( msg );
				}
				self.dirty_caches();
				self.main.request_redraw();
				self.main.frame_pending = false;
				for ss in self.overlays.values_mut()
				{
					ss.request_redraw();
					ss.frame_pending = false;
				}
			}
			ReleaseEvent::SwipeDown =>
			{
				if let Some( msg ) = self.app.on_swipe_down()
				{
					self.pending_msgs.push( msg );
				}
				self.dirty_caches();
				self.main.request_redraw();
				self.main.frame_pending = false;
				for ss in self.overlays.values_mut()
				{
					ss.request_redraw();
					ss.frame_pending = false;
				}
			}
			ReleaseEvent::HorizontalFellThrough =>
			{
				// Below threshold: pulse horizontal 0 so a
				// vertical-dominant gesture that drifted laterally
				// does not leave the app stuck on a stale horizontal
				// progress.
				self.app.on_swipe_horizontal_progress( 0.0 );
				self.dirty_caches();
				self.main.request_redraw();
				self.main.frame_pending = false;
			}
			ReleaseEvent::VerticalFellThrough =>
			{
				self.app.on_swipe_progress( 0.0 );
				self.app.on_swipe_down_progress( 0.0 );
				self.dirty_caches();
			}
			ReleaseEvent::PushMsg( msg ) =>
			{
				self.pending_msgs.push( msg );
			}
			ReleaseEvent::EmptyRelease =>
			{
				match focus
				{
					SurfaceFocus::Main =>
					{
						if let Some( msg ) = self.app.on_tap()
						{
							self.pending_msgs.push( msg );
						}
					}
					SurfaceFocus::Overlay( id ) =>
					{
						if let Some( msg ) = self.overlay_dismiss_msg( id )
						{
							self.pending_msgs.push( msg );
						}
					}
				}
			}
		}
	}
}