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

#include "adapter_native.h"
#include <string.h>

AtspiTextRange *cthulhu_text_get_string_at_offset(AtspiText *text, gint offset,
                                                AtspiTextGranularity unit, GError **error) {
    if (unit != ATSPI_TEXT_GRANULARITY_LINE || offset < 0) {
        return atspi_text_get_string_at_offset(text, offset, unit, error);
    }

    // Chromium can retain layout boundaries past truncated hypertext. In a
    // captured crash, LINE at the final U+2026 (140 of 141 characters) tried
    // to take a substring starting at 146 and aborted the entire browser.
    // Checking returned boundaries is too late: use bounded GetText for an
    // ellipsis before invoking the provider's boundary calculation.
    GError *probeError = NULL;
    guint character = atspi_text_get_character_at_offset(text, offset, &probeError);
    if (probeError != NULL) {
        g_propagate_error(error, probeError);
        return NULL;
    }
    if (character != 0x2026) {
        return atspi_text_get_string_at_offset(text, offset, unit, error);
    }
    gint count = atspi_text_get_character_count(text, &probeError);
    if (probeError != NULL) {
        g_propagate_error(error, probeError);
        return NULL;
    }
    if (count <= 0 || offset != count - 1) {
        return atspi_text_get_string_at_offset(text, offset, unit, error);
    }

    gint start = MAX(0, offset - 4095);
    gchar *content = atspi_text_get_text(text, start, offset + 1, error);
    if (content == NULL) return NULL;
    if (!g_utf8_validate(content, -1, NULL) ||
        g_utf8_strlen(content, -1) != offset + 1 - start ||
        !g_str_has_suffix(content, "\342\200\246")) {
        g_free(content);
        return NULL;
    }

    // Preserve explicit line breaks. A provider's visual wrapping is unsafe
    // at this character; retain the bounded logical line and native offsets.
    gchar *line = strrchr(content, '\n');
    line = line != NULL ? line + 1 : content;
    AtspiTextRange *range = g_new0(AtspiTextRange, 1);
    range->start_offset = start + g_utf8_pointer_to_offset(content, line);
    range->end_offset = offset + 1;
    range->content = g_strdup(line);
    g_free(content);
    return range;
}