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

package atspi

/*
#include "adapter_native.h"
*/
import "C"

import (
	"context"
	"errors"
	"fmt"
	"time"
)

func (adapter *Adapter) captureDesktop(ctx context.Context, reviewFocus ObjectID, document, documentText bool) (*AccessibleTree, error) {
	if document {
		root, err := adapter.nativeDocumentRoot(ctx, reviewFocus)
		adapter.treeMutex.Lock()
		previousTree := adapter.documentTree
		adapter.treeMutex.Unlock()
		if (errors.Is(err, ErrObjectNotFound) || errors.Is(err, ErrStaleObject)) && previousTree != nil && len(adapter.nativeFocus) != 0 {
			// Dynamic pages can remove the browse cursor without sending a new
			// focus event. Recover only from the newest retained native focus in
			// the same document. A chrome or other-tab focus is not a fallback.
			currentRoot, rootErr := previousTree.Root()
			for i := len(adapter.nativeFocus) - 1; rootErr == nil && i >= 0; i-- {
				latest := adapter.nativeFocus[i]
				if latest.id.BusName != reviewFocus.BusName {
					break
				}
				C.atspi_accessible_clear_cache_single(latest.source)
				states := C.atspi_accessible_get_state_set(latest.source)
				if states == nil {
					continue
				}
				dead := C.atspi_state_set_contains(states, C.ATSPI_STATE_DEFUNCT) != 0
				C.g_object_unref(C.gpointer(states))
				if dead {
					continue
				}
				// A removed browse target can retain a non-defunct proxy after
				// Chromium has dropped its accessible object. Its role is then
				// invalid; try the preceding real focus instead.
				if C.atspi_accessible_get_role(latest.source, nil) == C.ATSPI_ROLE_INVALID {
					continue
				}
				candidate, candidateErr := adapter.nativeDocumentRoot(ctx, latest.id)
				if candidateErr != nil {
					break
				}
				if nativeObjectID(candidate) == currentRoot.ID() {
					root, err = candidate, nil
				} else {
					C.g_object_unref(C.gpointer(candidate))
				}
				break
			}
		}
		if err != nil {
			return nil, err
		}
		cache := nativeTreeCache{}
		if !documentText && previousTree != nil {
			cache.nodes = previousTree.nativeRefresh(nativeObjectID(root))
			cache.sources = adapter.nativeDocument
		}
		// Retain this bounded capture for narrow OCR geometry queries too.
		retained := make(map[ObjectID]*C.AtspiAccessible)
		rootID, nodes, err := captureNativeTree(ctx, root, "", true, documentText, adapter.captureSound.Load(), retained, cache)
		var tree *AccessibleTree
		if err == nil {
			tree, err = adapter.installCapturedTree(rootID, nodes, true, documentText)
		}
		if err != nil {
			for _, source := range retained {
				C.g_object_unref(C.gpointer(source))
			}
			return nil, err
		}
		adapter.clearNativeDocument()
		adapter.nativeDocument = retained
		return tree, nil
	}
	var rootSource *C.AtspiAccessible
	if reviewFocus.Valid() {
		// A flat-review command only needs its owning window. Starting from
		// the desktop walks every window in the browser process, including
		// unrelated tabs and detached windows, before selecting this one.
		for _, item := range adapter.nativeFocus {
			if item.id == reviewFocus {
				rootSource = C.cthulhu_window_ancestor(item.source)
				break
			}
		}
	}
	if rootSource == nil {
		rootSource = C.atspi_get_desktop(0)
	}
	if rootSource == nil {
		return nil, errors.New("capture AT-SPI review window: root is unavailable")
	}
	retained := make(map[ObjectID]*C.AtspiAccessible)
	cache := nativeTreeCache{}
	if reviewFocus.BusName != "" {
		if adapter.nativeReviewBus == reviewFocus.BusName {
			adapter.treeMutex.Lock()
			previousTree := adapter.tree
			adapter.treeMutex.Unlock()
			if previousTree != nil {
				cache.nodes = previousTree.nativeRefresh(nativeObjectID(rootSource))
				cache.sources = adapter.nativeReview
			}
		}
	}
	root, nodes, err := captureNativeTree(ctx, rootSource, reviewFocus.BusName, document, documentText, adapter.captureSound.Load(), retained, cache)
	if err != nil {
		for _, source := range retained {
			C.g_object_unref(C.gpointer(source))
		}
		return nil, err
	}
	tree, err := adapter.installCapturedTree(root, nodes, document, documentText)
	if err != nil {
		for _, source := range retained {
			C.g_object_unref(C.gpointer(source))
		}
		return nil, err
	}
	adapter.clearNativeReview()
	adapter.nativeReview = retained
	adapter.nativeReviewBus = reviewFocus.BusName
	return tree, nil
}

// Remember a bounded set of event sources so document capture can start at
// native focus, without rediscovering it through cached browser chrome. All
// references are used and released on the GLib thread, including at shutdown.
func (adapter *Adapter) rememberNativeFocus(source *C.AtspiAccessible, id ObjectID) {
	if !id.Valid() {
		return
	}
	for i, item := range adapter.nativeFocus {
		if item.id == id {
			C.g_object_unref(C.gpointer(item.source))
			adapter.nativeFocus = append(adapter.nativeFocus[:i], adapter.nativeFocus[i+1:]...)
			break
		}
	}
	if len(adapter.nativeFocus) == 16 {
		C.g_object_unref(C.gpointer(adapter.nativeFocus[0].source))
		adapter.nativeFocus = adapter.nativeFocus[1:]
	}
	owned := (*C.AtspiAccessible)(C.g_object_ref(C.gpointer(source)))
	adapter.nativeFocus = append(adapter.nativeFocus, nativeFocusReference{id, owned})
}

// Keep an exact document-to-frame association across Chromium tab switches.
// Some returned tabs temporarily lose their AT-SPI parent chain, although
// their document identity and the already correlated frame remain live.
func (adapter *Adapter) rememberDocumentWindow(document ObjectID, window *C.AtspiAccessible) {
	if !document.Valid() || window == nil {
		return
	}
	if adapter.documentWindows == nil {
		adapter.documentWindows = make(map[ObjectID]nativeDocumentWindow)
	}
	if old, ok := adapter.documentWindows[document]; ok {
		C.g_object_unref(C.gpointer(old.source))
	} else {
		if len(adapter.documentWindowIDs) == 32 {
			oldest := adapter.documentWindowIDs[0]
			C.g_object_unref(C.gpointer(adapter.documentWindows[oldest].source))
			delete(adapter.documentWindows, oldest)
			adapter.documentWindowIDs = adapter.documentWindowIDs[1:]
		}
		adapter.documentWindowIDs = append(adapter.documentWindowIDs, document)
	}
	adapter.documentWindows[document] = nativeDocumentWindow{
		id: nativeObjectID(window), source: (*C.AtspiAccessible)(C.g_object_ref(C.gpointer(window))),
	}
}

func (adapter *Adapter) forgetDocumentWindow(document ObjectID) {
	known, ok := adapter.documentWindows[document]
	if !ok {
		return
	}
	C.g_object_unref(C.gpointer(known.source))
	delete(adapter.documentWindows, document)
	for i, id := range adapter.documentWindowIDs {
		if id == document {
			adapter.documentWindowIDs = append(adapter.documentWindowIDs[:i], adapter.documentWindowIDs[i+1:]...)
			break
		}
	}
	if adapter.activeDocument == document {
		adapter.activeDocument = ObjectID{}
	}
}

func (adapter *Adapter) forgetWindowDocuments(window ObjectID) {
	for _, id := range append([]ObjectID(nil), adapter.documentWindowIDs...) {
		if adapter.documentWindows[id].id == window {
			adapter.forgetDocumentWindow(id)
		}
	}
	if adapter.selectedTabWindow == window {
		adapter.selectedTabWindow = ObjectID{}
	}
}

func (adapter *Adapter) detachedDocumentWindow(source *C.AtspiAccessible, eventType string, detail int) (*C.AtspiAccessible, ObjectID) {
	if adapter.selectedTabWindow == (ObjectID{}) && !adapter.activeDocument.Valid() {
		return nil, ObjectID{}
	}
	var document *C.AtspiAccessible
	if _, known := adapter.documentWindows[nativeObjectID(source)]; known {
		document = (*C.AtspiAccessible)(C.g_object_ref(C.gpointer(source)))
	} else {
		document = C.cthulhu_document_ancestor(source)
	}
	if document == nil {
		return nil, ObjectID{}
	}
	id := nativeObjectID(document)
	states := C.atspi_accessible_get_state_set(document)
	showing := states != nil && C.atspi_state_set_contains(states, C.ATSPI_STATE_SHOWING) != 0 &&
		C.atspi_state_set_contains(states, C.ATSPI_STATE_VISIBLE) != 0 &&
		C.atspi_state_set_contains(states, C.ATSPI_STATE_DEFUNCT) == 0
	if states != nil {
		C.g_object_unref(C.gpointer(states))
	}
	C.g_object_unref(C.gpointer(document))
	known, ok := adapter.documentWindows[id]
	if !showing || !ok || !restoredDocumentWindowAllowed(id, adapter.activeDocument,
		adapter.selectedTabWindow, known.id, eventType, detail) {
		return nil, ObjectID{}
	}
	frameStates := C.atspi_accessible_get_state_set(known.source)
	frameActive := frameStates != nil && C.atspi_state_set_contains(frameStates, C.ATSPI_STATE_ACTIVE) != 0 &&
		C.atspi_state_set_contains(frameStates, C.ATSPI_STATE_SHOWING) != 0 &&
		C.atspi_state_set_contains(frameStates, C.ATSPI_STATE_DEFUNCT) == 0
	if frameStates != nil {
		C.g_object_unref(C.gpointer(frameStates))
	}
	if !frameActive {
		return nil, ObjectID{}
	}
	return (*C.AtspiAccessible)(C.g_object_ref(C.gpointer(known.source))), id
}

func restoredDocumentWindowAllowed(document, active, selectedWindow, knownWindow ObjectID, eventType string, detail int) bool {
	if !document.Valid() || !knownWindow.Valid() {
		return false
	}
	if eventType == FocusedStateEvent && detail == 0 {
		return false
	}
	if document == active {
		return true
	}
	return selectedWindow == knownWindow && eventType == FocusedStateEvent && detail != 0
}

// Called only by the GLib owner at load completion. Chromium can finish an
// earlier load after the user has returned to chrome. Window activation alone
// cannot distinguish that from a load which should acquire document focus.
func (adapter *Adapter) focusedChrome(document ObjectID) ObjectID {
	ctx, cancel := context.WithTimeout(context.Background(), 100*time.Millisecond)
	defer cancel()
	for i := len(adapter.nativeFocus) - 1; i >= 0 && ctx.Err() == nil; i-- {
		item := adapter.nativeFocus[i]
		if item.id.BusName != document.BusName || item.id == document {
			continue
		}
		C.atspi_accessible_clear_cache_single(item.source)
		states := C.atspi_accessible_get_state_set(item.source)
		if states == nil {
			continue
		}
		focused := C.atspi_state_set_contains(states, C.ATSPI_STATE_FOCUSED) != 0
		C.g_object_unref(C.gpointer(states))
		if !focused {
			continue
		}
		root, err := adapter.nativeDocumentRoot(ctx, item.id)
		if root != nil {
			C.g_object_unref(C.gpointer(root))
		}
		if errors.Is(err, ErrNotInDocument) {
			return item.id
		}
	}
	return ObjectID{}
}

// Return an owned reference to the outermost document containing focus.
// Parent traversal is bounded and never scans other windows or tabs.
func (adapter *Adapter) nativeDocumentRoot(ctx context.Context, focus ObjectID) (*C.AtspiAccessible, error) {
	var source *C.AtspiAccessible
	for _, item := range adapter.nativeFocus {
		if item.id == focus {
			source = (*C.AtspiAccessible)(C.g_object_ref(C.gpointer(item.source)))
			break
		}
	}
	if source == nil {
		return nil, fmt.Errorf("%w: document focus bus %q path %q", ErrObjectNotFound, focus.BusName, focus.Path)
	}
	C.atspi_accessible_clear_cache_single(source)
	states := C.atspi_accessible_get_state_set(source)
	if states != nil {
		dead := C.atspi_state_set_contains(states, C.ATSPI_STATE_DEFUNCT) != 0
		C.g_object_unref(C.gpointer(states))
		if dead {
			C.g_object_unref(C.gpointer(source))
			return nil, ErrStaleObject
		}
	}
	var document *C.AtspiAccessible
	defer func() {
		if source != nil {
			C.g_object_unref(C.gpointer(source))
		}
		if document != nil {
			C.g_object_unref(C.gpointer(document))
		}
	}()
	seen := make(map[ObjectID]bool)
	for depth := 0; source != nil; depth++ {
		if err := ctx.Err(); err != nil {
			return nil, err
		}
		id := nativeObjectID(source)
		if depth >= 256 || seen[id] {
			return nil, ErrInvalidTree
		}
		seen[id] = true
		C.atspi_accessible_clear_cache_single(source)
		var nativeErr *C.GError
		role := C.atspi_accessible_get_role(source, &nativeErr)
		if nativeErr != nil {
			err := nativeError("query document ancestor role", nativeErr)
			C.g_error_free(nativeErr)
			return nil, err
		}
		if role == C.ATSPI_ROLE_DOCUMENT_WEB || role == C.ATSPI_ROLE_DOCUMENT_FRAME || role == C.ATSPI_ROLE_EMBEDDED {
			if document != nil {
				C.g_object_unref(C.gpointer(document))
			}
			document = (*C.AtspiAccessible)(C.g_object_ref(C.gpointer(source)))
		}
		if role == C.ATSPI_ROLE_APPLICATION {
			break
		}
		parent := C.atspi_accessible_get_parent(source, &nativeErr)
		if nativeErr != nil {
			if parent != nil {
				C.g_object_unref(C.gpointer(parent))
			}
			err := nativeError("query document ancestor", nativeErr)
			C.g_error_free(nativeErr)
			return nil, err
		}
		C.g_object_unref(C.gpointer(source))
		source = parent
	}
	if document == nil {
		return nil, ErrNotInDocument
	}
	root := document
	document = nil
	return root, nil
}

// geometryFromNative runs only during owned-tree capture on the GLib thread.
// All interface/state/rectangle references are released here; only scalar
// values cross the boundary. Unsupported or failed component queries leave
// bounds unknown, while cancellation aborts capture.