// Cthulhu screen reader.
// Copyright (c) 2026 Storm Dragon
// Authors: Storm Dragon, Angus Kola
// SPDX-License-Identifier: GPL-3.0-or-later

package app

import (
	"slices"

	"git.stormux.org/storm/cthulhu/internal/atspi"
	"git.stormux.org/storm/cthulhu/internal/braille"
	"git.stormux.org/storm/cthulhu/internal/config"
	"git.stormux.org/storm/cthulhu/internal/input"
	"git.stormux.org/storm/cthulhu/internal/presentation"
	"git.stormux.org/storm/cthulhu/internal/review"
)

func (handler *accessibilityEventHandler) acceptFocusedEvent(event atspi.Event, activity input.Activity) bool {
	state := handler.state
	logger := handler.logger
	objectReview := handler.objectReview
	browser := handler.browser
	brailleOutput := handler.brailleOutput
	live := handler.live
	// Compare with the owned focus snapshot, not the last speech request:
	// a state/value update can intervene between two toolkit focus events.
	// Still refresh review and braille below before suppressing presentation.
	duplicateFocus := (event.Type == atspi.FocusEvent || event.Type == atspi.FocusedStateEvent && event.Detail1 != 0) &&
		event.Source.Role != "terminal" && !presentsReusedRow(event.Source) &&
		!(state.pendingPromptWindow.Valid() && event.Window == state.pendingPromptWindow) &&
		state.focusedID.Valid() && event.Source.ID() == state.focusedID &&
		event.Source.ID() == state.current.ID() &&
		presentation.FocusTextWithOptions(event.Source, state.presentationOptions) == presentation.FocusTextWithOptions(state.current, state.presentationOptions) &&
		slices.Equal(presentation.SoundCues(event.Source, state.presentationOptions), presentation.SoundCues(state.current, state.presentationOptions))
	if isFocusEvent(event.Type) {
		focusID := event.Source.ID()
		if isFocusGainEvent(event) {
			state.focusCaretID = focusID
			state.focusCaretSequence = activity.Sequence
		} else {
			state.focusCaretID = atspi.ObjectID{}
		}
		if focusID != state.managedContainerID && focusID != state.managedDescendantID {
			state.managedContainerID = atspi.ObjectID{}
			state.managedDescendantID = atspi.ObjectID{}
		}
		// GTK table focus is normalized to its selected cell by the native
		// adapter. Retain the captured table owner before the first arrow
		// move, even when no container focus event reached this loop.
		if event.Source.Role == "table cell" && event.Source.GUITable {
			tableID := atspi.NewObjectID(event.Source.BusName, event.Source.TablePath)
			if tableID.Valid() {
				state.managedContainerID = tableID
				state.managedDescendantID = focusID
			}
		}
		state.focusedID = focusID
		state.selection.reset(event.Source)
		if objectReview != nil {
			objectReview.SyncFocus(event.Source.ID())
		}
	} else if isManagedDescendantEvent(event.Type) {
		containerID := atspi.NewObjectID(event.Source.BusName, event.OriginPath)
		descendantID := event.Source.ID()
		if event.Source.Defunct || event.Source.Role == "invalid" || descendantID.Path == "" {
			logger.Debug("skipped invalid managed descendant", "type", event.Type)
			return true
		}
		if state.focusedID.Path == "" ||
			(containerID != state.focusedID && descendantID != state.focusedID && containerID != state.managedContainerID) {
			logger.Debug("skipped managed descendant outside focused object", "type", event.Type, "role", event.Source.Role)
			return true
		}
		if containerID == state.managedContainerID && descendantID == state.managedDescendantID &&
			(!presentsReusedRow(event.Source) || sameManagedDescendant(event.Source, state.current)) {
			logger.Debug("skipped unchanged managed descendant", "type", event.Type, "role", event.Source.Role)
			return true
		}
		state.managedContainerID = containerID
		state.managedDescendantID = descendantID
		if event.Type == atspi.SelectionChangedEvent && sameSelectionItem(event.Source, state.current) {
			logger.Debug("skipped selection already presented by focus", "role", event.Source.Role)
			return true
		}
	} else if (isStateChangeEvent(event.Type) || isValueChangeEvent(event.Type)) &&
		(state.focusedID.Path == "" || event.Source.ID() != state.focusedID) {
		logger.Debug("skipped event outside focused object", "type", event.Type, "role", event.Source.Role)
		return true
	}
	if event.Type == atspi.SelectedStateEvent && sameSelectionItem(event.Source, state.current) {
		logger.Debug("skipped selected state already presented by focus", "role", event.Source.Role)
		return true
	}
	if isFocusEvent(event.Type) || isManagedDescendantEvent(event.Type) ||
		event.Type == atspi.AccessibleNameEvent && presentsReusedRow(event.Source) &&
			event.Source.ID() == state.managedDescendantID ||
		(event.Source.Path != "" && event.Source.ID() == state.focusedID) {
		state.current = event.Source
	}
	if isTextChangeEvent(event.Type) {
		if !speaksTextChanges(event.Source) && !event.Source.LiveRegion {
			logger.Debug("skipped text change outside editable content", "type", event.Type, "role", event.Source.Role)
			return true
		}
		if !event.Source.LiveRegion {
			state.suppressNextCaretPath = event.Source.Path
		}
	}
	if event.Type == atspi.CaretEvent && browser != nil && browser.ready && !event.Source.Editable {
		state.current = event.Source
	}
	if brailleOutput != nil && (isFocusGainEvent(event) ||
		isManagedDescendantEvent(event.Type) || event.Type == atspi.CaretEvent ||
		event.Type == atspi.AccessibleNameEvent &&
			(event.Source.ID() == state.focusedID || presentsReusedRow(event.Source)) ||
		event.Type == atspi.TextSelectionChangedEvent && event.Source.TextCaretKnown ||
		isStateChangeEvent(event.Type) || isValueChangeEvent(event.Type) ||
		isTextChangeEvent(event.Type) && speaksTextChanges(event.Source)) &&
		event.Source.ID() == state.current.ID() {
		source := event.Source
		if (isStateChangeEvent(event.Type) || isValueChangeEvent(event.Type)) &&
			!source.TextCaretKnown && source.ID() == state.brailleSnapshot.ID() {
			source.TextCaretKnown = state.brailleSnapshot.TextCaretKnown
			source.BrailleLine = state.brailleSnapshot.BrailleLine
			source.BrailleLineStart = state.brailleSnapshot.BrailleLineStart
			source.BrailleCaret = state.brailleSnapshot.BrailleCaret
		}
		if len(source.BrailleContext) == 0 && source.ID() == state.brailleSnapshot.ID() {
			source.BrailleContext = state.brailleSnapshot.BrailleContext
		}
		state.brailleSnapshot = source
		brailleOptions := config.DefaultSettings().Braille
		textAttributes := config.DefaultTextAttributes()
		if live != nil {
			settings := live.Load()
			brailleOptions, textAttributes = settings.Braille, settings.TextAttributes
		}
		frame := brailleFocusFrameWithOptions(source, brailleOptions, textAttributes)
		if browser != nil && browser.ready && browser.mode == review.BrowseMode && !source.Editable &&
			objectReview != nil && browser.document.Valid() && source.Role != "password text" {
			focus := objectReview.Focus()
			frame.Document = &braille.DocumentRoute{Epoch: objectReview.DocumentEpoch(), FocusBus: focus.BusName, FocusPath: focus.Path,
				DocumentBus: browser.document.BusName, DocumentPath: browser.document.Path}
		}
		brailleOutput.EnqueueFrame(frame)
	}
	if duplicateFocus {
		logger.Debug("skipped unchanged accessible focus", "type", event.Type, "role", event.Source.Role)
	}
	return duplicateFocus
}