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

package atspi

/*
#include <atspi/atspi.h>
*/
import "C"

import "context"

// Capture only single-character embedded children. Chromium's ordinary text
// descendants share their parent's offset domain and need no extra ranges.
// Require every child to occupy one placeholder, avoiding duplicate text from
// containers which also expose their plain text through static children.
// All handles stay on the GLib owner and are released before returning.
func nativeTextChildren(ctx context.Context, source *C.AtspiAccessible, count int, children []ObjectID) []TextChild {
	if count <= 0 || len(children) == 0 {
		return nil
	}
	hypertext := C.atspi_accessible_get_hypertext_iface(source)
	if hypertext == nil {
		return nil
	}
	defer C.g_object_unref(C.gpointer(hypertext))
	links := int(C.atspi_hypertext_get_n_links(hypertext, nil))
	if links <= 0 || links != len(children) {
		return nil
	}
	text := C.atspi_accessible_get_text_iface(source)
	if text == nil {
		return nil
	}
	defer C.g_object_unref(C.gpointer(text))
	known := make(map[ObjectID]bool, len(children))
	for _, child := range children {
		known[child] = true
	}
	var result []TextChild
	previous := -1
	for index := 0; index < links; index++ {
		if ctx.Err() != nil {
			return nil
		}
		link := C.atspi_hypertext_get_link(hypertext, C.gint(index), nil)
		if link == nil {
			return nil
		}
		start := int(C.atspi_hyperlink_get_start_index(link, nil))
		end := int(C.atspi_hyperlink_get_end_index(link, nil))
		child := C.atspi_hyperlink_get_object(link, 0, nil)
		var id ObjectID
		if child != nil {
			id = nativeObjectID(child)
			C.g_object_unref(C.gpointer(child))
		}
		C.g_object_unref(C.gpointer(link))
		if start <= previous || end != start+1 || start < 0 || end > count || !known[id] {
			return nil
		}
		value := C.atspi_text_get_text(text, C.gint(start), C.gint(end), nil)
		placeholder := value != nil && C.GoString(value) == "\ufffc"
		if value != nil {
			C.g_free(C.gpointer(value))
		}
		if !placeholder {
			return nil
		}
		delete(known, id)
		result = append(result, TextChild{Offset: start, Child: id})
		previous = start
	}
	return result
}