#!/usr/bin/env python
# License: GPL v3 Copyright: 2018, Kovid Goyal <kovid at kovidgoyal.net>

import os
import shutil
import sys
from functools import lru_cache
from itertools import count

from qt.core import (
    QT_VERSION,
    QApplication,
    QByteArray,
    QEvent,
    QFontDatabase,
    QFontInfo,
    QHBoxLayout,
    QLocale,
    QMimeData,
    QPalette,
    QSize,
    Qt,
    QTimer,
    QUrl,
    QWidget,
    pyqtSignal,
    sip,
)
from qt.webengine import (
    QWebEnginePage,
    QWebEngineProfile,
    QWebEngineScript,
    QWebEngineSettings,
    QWebEngineUrlRequestJob,
    QWebEngineUrlSchemeHandler,
    QWebEngineView,
)

from calibre import as_unicode, prints
from calibre.constants import DEBUG, FAKE_HOST, FAKE_PROTOCOL, __version__, in_develop_mode, is_running_from_develop, ismacos, iswindows
from calibre.ebooks.metadata.book.base import field_metadata
from calibre.ebooks.oeb.polish.utils import guess_type
from calibre.gui2 import choose_images, config, error_dialog, safe_open_url
from calibre.gui2.viewer import link_prefix_for_location_links, performance_monitor, url_for_book_in_library
from calibre.gui2.viewer.config import get_session_pref, load_viewer_profiles, save_viewer_profile, viewer_config_dir, vprefs
from calibre.gui2.viewer.tts import TTS
from calibre.gui2.webengine import RestartingWebEngineView
from calibre.srv.code import get_translations_data
from calibre.utils.filenames import make_long_path_useable
from calibre.utils.localization import _, localize_user_manual_link
from calibre.utils.resources import get_path as P
from calibre.utils.serialize import json_loads
from calibre.utils.shared_file import share_open
from calibre.utils.webengine import Bridge, create_script, from_js, insert_scripts, secure_webengine, send_reply, setup_profile, to_js
from polyglot.builtins import as_bytes

SANDBOX_HOST = FAKE_HOST.rpartition('.')[0] + '.sandbox'


# Override network access to load data from the book {{{

def set_book_path(path, pathtoebook):
    set_book_path.pathtoebook = pathtoebook
    set_book_path.path = os.path.abspath(path)
    set_book_path.metadata = get_data('calibre-book-metadata.json')[0]
    set_book_path.manifest, set_book_path.manifest_mime = get_data('calibre-book-manifest.json')
    set_book_path.parsed_metadata = json_loads(set_book_path.metadata)
    set_book_path.parsed_manifest = json_loads(set_book_path.manifest)


def get_manifest():
    return getattr(set_book_path, 'parsed_manifest', None)


def get_path_for_name(name):
    bdir = getattr(set_book_path, 'path', None)
    if bdir is None:
        return
    path = os.path.abspath(os.path.join(bdir, name))
    if path.startswith(bdir):
        return path


def get_data(name):
    path = get_path_for_name(name)
    if path is None:
        return None, None
    try:
        with share_open(path, 'rb') as f:
            return f.read(), guess_type(name)
    except OSError as err:
        prints(f'Failed to read from book file: {name} with error: {as_unicode(err)}')
    return None, None


@lru_cache(maxsize=4)
def background_image(encoded_fname=''):
    if not encoded_fname:
        img_path = os.path.join(viewer_config_dir, 'bg-image.data')
        try:
            with open(img_path, 'rb') as f:
                data = f.read()
            mt, data = data.split(b'|', 1)
            mt = mt.decode()
            return mt, data
        except FileNotFoundError:
            return 'image/jpeg', b''
    fname = bytes.fromhex(encoded_fname).decode()
    img_path = os.path.join(viewer_config_dir, 'background-images', fname)
    mt = guess_type(fname)[0] or 'image/jpeg'
    try:
        with open(make_long_path_useable(img_path), 'rb') as f:
            return mt, f.read()
    except FileNotFoundError:
        if fname.startswith(('https://', 'http://')):
            from calibre import browser
            br = browser()
            try:
                with br.open(fname) as src:
                    data = src.read()
            except Exception:
                return mt, b''
            with open(make_long_path_useable(img_path), 'wb') as dest:
                dest.write(data)
            return mt, data
        return mt, b''


@lru_cache(maxsize=2)
def get_mathjax_dir():
    return P('mathjax', allow_user_override=False)


def handle_mathjax_request(rq, name):
    mathjax_dir = get_mathjax_dir()
    path = os.path.abspath(os.path.join(mathjax_dir, '..', name))
    if path.startswith(mathjax_dir):
        mt = guess_type(name)
        try:
            with open(path, 'rb') as f:
                raw = f.read()
        except OSError as err:
            prints(f'Failed to get mathjax file: {name} with error: {err}', file=sys.stderr)
            rq.fail(QWebEngineUrlRequestJob.Error.RequestFailed)
            return
        if name.endswith('/startup.js'):
            raw = P('pdf-mathjax-loader.js', data=True, allow_user_override=False) + raw
        send_reply(rq, mt, raw)
    else:
        prints(f'Failed to get mathjax file: {name} outside mathjax directory', file=sys.stderr)
        rq.fail(QWebEngineUrlRequestJob.Error.RequestFailed)


class UrlSchemeHandler(QWebEngineUrlSchemeHandler):

    def __init__(self, parent=None):
        QWebEngineUrlSchemeHandler.__init__(self, parent)
        self.allowed_hosts = (FAKE_HOST, SANDBOX_HOST)

    def requestStarted(self, rq):
        if bytes(rq.requestMethod()) != b'GET':
            return self.fail_request(rq, QWebEngineUrlRequestJob.Error.RequestDenied)
        url = rq.requestUrl()
        host = url.host()
        if host not in self.allowed_hosts or url.scheme() != FAKE_PROTOCOL:
            return self.fail_request(rq)
        name = url.path()[1:]
        if host == SANDBOX_HOST and name.partition('/')[0] not in ('book', 'mathjax'):
            return self.fail_request(rq)
        if name.startswith('book/'):
            name = name.partition('/')[2]
            if name in ('__index__', '__popup__'):
                send_reply(rq, 'text/html', b'<div>\xa0</div>')
                return
            try:
                data, mime_type = get_data(name)
                if data is None:
                    rq.fail(QWebEngineUrlRequestJob.Error.UrlNotFound)
                    return
                data = as_bytes(data)
                mime_type = {
                    # Prevent warning in console about mimetype of fonts
                    'application/vnd.ms-opentype':'application/x-font-ttf',
                    'application/x-font-truetype':'application/x-font-ttf',
                    'application/font-sfnt': 'application/x-font-ttf',
                }.get(mime_type, mime_type)
                if mime_type == 'text/css':
                    mime_type += '; charset=utf-8'
                send_reply(rq, mime_type, data)
            except Exception:
                import traceback
                traceback.print_exc()
                return self.fail_request(rq, QWebEngineUrlRequestJob.Error.RequestFailed)
        elif name == 'manifest':
            data = b'[' + set_book_path.manifest + b',' + set_book_path.metadata + b']'
            send_reply(rq, set_book_path.manifest_mime, data)
        elif name == 'reader-background':
            mt, data = background_image()
            send_reply(rq, mt, data) if data else rq.fail(QWebEngineUrlRequestJob.Error.UrlNotFound)
        elif name.startswith('reader-background-'):
            encoded_fname = name[len('reader-background-'):]
            mt, data = background_image(encoded_fname)
            send_reply(rq, mt, data) if data else rq.fail(QWebEngineUrlRequestJob.Error.UrlNotFound)
        elif name.startswith('mathjax/'):
            handle_mathjax_request(rq, name)
        elif not name:
            send_reply(rq, 'text/html', viewer_html())
        else:
            return self.fail_request(rq)

    def fail_request(self, rq, fail_code=None):
        if fail_code is None:
            fail_code = QWebEngineUrlRequestJob.Error.UrlNotFound
        rq.fail(fail_code)
        prints(f'Blocking FAKE_PROTOCOL request: {rq.requestUrl().toString()} with code: {fail_code}')

# }}}


def create_profile():
    ans = getattr(create_profile, 'ans', None)
    if ans is None:
        ans = setup_profile(QWebEngineProfile(QApplication.instance()))
        osname = 'windows' if iswindows else ('macos' if ismacos else 'linux')
        # DO NOT change the user agent as it is used to workaround
        # Qt bugs see workaround_qt_bug() in ajax.pyj
        ua = f'calibre-viewer {__version__} {osname}'
        ans.setHttpUserAgent(ua)
        if is_running_from_develop:
            from calibre.utils.rapydscript import compile_viewer
            prints('Compiling viewer code...')
            compile_viewer()
        js = P('viewer.js', data=True, allow_user_override=False)
        translations_json = get_translations_data() or b'null'
        js = js.replace(b'__TRANSLATIONS_DATA__', translations_json, 1)
        if in_develop_mode:
            js = js.replace(b'__IN_DEVELOP_MODE__', b'1')
        insert_scripts(ans, create_script('viewer.js', js))
        url_handler = UrlSchemeHandler(ans)
        ans.installUrlSchemeHandler(QByteArray(FAKE_PROTOCOL.encode('ascii')), url_handler)
        s = ans.settings()
        s.setDefaultTextEncoding('utf-8')
        s.setAttribute(QWebEngineSettings.WebAttribute.LinksIncludedInFocusChain, False)
        create_profile.ans = ans
    return ans


class ViewerBridge(Bridge):

    view_created = from_js(object)
    on_iframe_ready = from_js()
    content_file_changed = from_js(object)
    set_session_data = from_js(object, object)
    set_local_storage = from_js(object, object)
    reload_book = from_js()
    toggle_toc = from_js()
    toggle_bookmarks = from_js()
    toggle_highlights = from_js()
    new_bookmark = from_js(object)
    toggle_inspector = from_js()
    toggle_lookup = from_js(object)
    show_search = from_js(object, object)
    search_result_not_found = from_js(object)
    search_result_discovered = from_js(object)
    find_next = from_js(object)
    update_current_toc_nodes = from_js(object)
    toggle_full_screen = from_js()
    report_cfi = from_js(object, object)
    ask_for_open = from_js(object)
    selection_changed = from_js(object, object)
    autoscroll_state_changed = from_js(object)
    read_aloud_state_changed = from_js(object)
    copy_selection = from_js(object, object)
    view_image = from_js(object)
    copy_image = from_js(object)
    change_background_image = from_js(object)
    overlay_visibility_changed = from_js(object)
    reference_mode_changed = from_js(object)
    show_loading_message = from_js(object)
    show_error = from_js(object, object, object)
    export_shortcut_map = from_js(object)
    print_book = from_js()
    clear_history = from_js()
    reset_interface = from_js()
    quit = from_js()
    customize_toolbar = from_js()
    scrollbar_context_menu = from_js(object, object, object)
    close_prep_finished = from_js(object)
    highlights_changed = from_js(object)
    open_url = from_js(object)
    speak_simple_text = from_js(object)
    tts = from_js(object, object)
    edit_book = from_js(object, object, object)
    show_book_folder = from_js()
    show_help = from_js(object)
    update_reading_rates = from_js(object)
    profile_op = from_js(object, object, object)

    create_view = to_js()
    start_book_load = to_js()
    redraw_tts_bar = to_js()
    goto_toc_node = to_js()
    goto_cfi = to_js()
    full_screen_state_changed = to_js()
    get_current_cfi = to_js()
    show_home_page = to_js()
    background_image_changed = to_js()
    goto_frac = to_js()
    trigger_shortcut = to_js()
    set_system_palette = to_js()
    highlight_action = to_js()
    generic_action = to_js()
    show_search_result = to_js()
    prepare_for_close = to_js()
    repair_after_fullscreen_switch = to_js()
    viewer_font_size_changed = to_js()
    tts_event = to_js()
    profile_response = to_js()


def apply_font_settings(page_or_view):
    s = page_or_view.settings()
    sd = vprefs['session_data']
    fs = sd.get('standalone_font_settings', {})
    if fs.get('serif_family'):
        s.setFontFamily(QWebEngineSettings.FontFamily.SerifFont, fs.get('serif_family'))
    else:
        s.resetFontFamily(QWebEngineSettings.FontFamily.SerifFont)
    if fs.get('sans_family'):
        s.setFontFamily(QWebEngineSettings.FontFamily.SansSerifFont, fs.get('sans_family'))
    else:
        s.resetFontFamily(QWebEngineSettings.FontFamily.SansSerifFont)
    if fs.get('mono_family'):
        s.setFontFamily(QWebEngineSettings.FontFamily.FixedFont, fs.get('mono_family'))
    else:
        s.resetFontFamily(QWebEngineSettings.FontFamily.FixedFont)
    sf = fs.get('standard_font') or 'serif'
    sf = getattr(QWebEngineSettings.FontFamily, {'serif': 'SerifFont', 'sans': 'SansSerifFont', 'mono': 'FixedFont'}[sf])
    s.setFontFamily(QWebEngineSettings.FontFamily.StandardFont, s.fontFamily(sf))
    old_minimum = s.fontSize(QWebEngineSettings.FontSize.MinimumFontSize)
    old_base = s.fontSize(QWebEngineSettings.FontSize.DefaultFontSize)
    old_fixed_base = s.fontSize(QWebEngineSettings.FontSize.DefaultFixedFontSize)
    mfs = fs.get('minimum_font_size')
    if mfs is None:
        s.resetFontSize(QWebEngineSettings.FontSize.MinimumFontSize)
    else:
        s.setFontSize(QWebEngineSettings.FontSize.MinimumFontSize, int(mfs))
    bfs = sd.get('base_font_size')
    if bfs is not None:
        s.setFontSize(QWebEngineSettings.FontSize.DefaultFontSize, int(bfs))
        s.setFontSize(QWebEngineSettings.FontSize.DefaultFixedFontSize, int(bfs * 13 / 16))

    font_size_changed = (old_minimum, old_base, old_fixed_base) != (
            s.fontSize(QWebEngineSettings.FontSize.MinimumFontSize),
            s.fontSize(QWebEngineSettings.FontSize.DefaultFontSize),
            s.fontSize(QWebEngineSettings.FontSize.DefaultFixedFontSize)
    )
    if font_size_changed and hasattr(page_or_view, 'execute_when_ready'):
        page_or_view.execute_when_ready('viewer_font_size_changed')

    return s


class WebPage(QWebEnginePage):

    def __init__(self, parent):
        profile = create_profile()
        QWebEnginePage.__init__(self, profile, parent)
        profile.setParent(self)
        secure_webengine(self, for_viewer=True)
        apply_font_settings(self)
        self.bridge = ViewerBridge(self)
        self.bridge.copy_selection.connect(self.trigger_copy)

    def trigger_copy(self, text, html):
        if text:
            md = QMimeData()
            md.setText(text)
            if html:
                md.setHtml(html)
            QApplication.instance().clipboard().setMimeData(md)

    def javaScriptConsoleMessage(self, level, msg, linenumber, source_id):
        prefix = {
            QWebEnginePage.JavaScriptConsoleMessageLevel.InfoMessageLevel: 'INFO',
            QWebEnginePage.JavaScriptConsoleMessageLevel.WarningMessageLevel: 'WARNING'
        }.get(level, 'ERROR')
        prints(f'{prefix}: {source_id}:{linenumber}: {msg}', file=sys.stderr)
        try:
            sys.stderr.flush()
        except OSError:
            pass

    def acceptNavigationRequest(self, url, req_type, is_main_frame):
        if req_type in (QWebEnginePage.NavigationType.NavigationTypeReload, QWebEnginePage.NavigationType.NavigationTypeBackForward):
            return True
        if url.scheme() in (FAKE_PROTOCOL, 'data'):
            return True
        if url.scheme() in ('http', 'https', 'calibre') and req_type == QWebEnginePage.NavigationType.NavigationTypeLinkClicked:
            if DEBUG:
                prints('Open URL from book:', url.toString())
            safe_open_url(url)
        else:
            prints('Blocking navigation request to:', url.toString(), file=sys.stderr)
        return False

    def go_to_anchor(self, anchor):
        self.bridge.go_to_anchor.emit(anchor or '')

    def runjs(self, src, callback=None):
        if callback is None:
            self.runJavaScript(src, QWebEngineScript.ScriptWorldId.ApplicationWorld)
        else:
            self.runJavaScript(src, QWebEngineScript.ScriptWorldId.ApplicationWorld, callback)


def viewer_html():
    ans = getattr(viewer_html, 'ans', None)
    if ans is None:
        ans = viewer_html.ans = P('viewer.html', data=True, allow_user_override=False)
    return ans


class Inspector(QWidget):

    def __init__(self, dock_action, parent=None):
        QWidget.__init__(self, parent=parent)
        self.view_to_debug = parent
        self.view = None
        self.layout = QHBoxLayout(self)
        self.layout.setContentsMargins(0, 0, 0, 0)
        self.dock_action = dock_action
        QTimer.singleShot(0, self.connect_to_dock)

    def connect_to_dock(self):
        ac = self.dock_action
        ac.toggled.connect(self.visibility_changed)
        if ac.isChecked():
            self.visibility_changed(True)

    def visibility_changed(self, visible):
        if visible and self.view is None:
            self.view = QWebEngineView(self.view_to_debug)
            setup_profile(self.view.page().profile())
            self.view_to_debug.page().setDevToolsPage(self.view.page())
            self.layout.addWidget(self.view)

    def sizeHint(self):
        return QSize(600, 1200)


def system_colors():
    app = QApplication.instance()
    is_dark_theme = app.is_dark_theme
    pal = app.palette()
    ans = {
        'background': pal.color(QPalette.ColorRole.Base).name(),
        'foreground': pal.color(QPalette.ColorRole.Text).name(),
    }
    if is_dark_theme:
        # only override link colors for dark themes
        # since if the book specifies its own link colors
        # they will likely work well with light themes
        ans['link'] = pal.color(QPalette.ColorRole.Link).name()
    return ans


class WebView(RestartingWebEngineView):

    cfi_changed = pyqtSignal(object)
    reload_book = pyqtSignal()
    toggle_toc = pyqtSignal()
    show_search = pyqtSignal(object, object)
    search_result_not_found = pyqtSignal(object)
    search_result_discovered = pyqtSignal(object)
    find_next = pyqtSignal(object)
    toggle_bookmarks = pyqtSignal()
    toggle_highlights = pyqtSignal()
    new_bookmark = pyqtSignal(object)
    toggle_inspector = pyqtSignal()
    toggle_lookup = pyqtSignal(object)
    update_current_toc_nodes = pyqtSignal(object)
    toggle_full_screen = pyqtSignal()
    ask_for_open = pyqtSignal(object)
    selection_changed = pyqtSignal(object, object)
    autoscroll_state_changed = pyqtSignal(object)
    read_aloud_state_changed = pyqtSignal(object)
    view_image = pyqtSignal(object)
    copy_image = pyqtSignal(object)
    overlay_visibility_changed = pyqtSignal(object)
    reference_mode_changed = pyqtSignal(object)
    show_loading_message = pyqtSignal(object)
    show_error = pyqtSignal(object, object, object)
    print_book = pyqtSignal()
    reset_interface = pyqtSignal()
    quit = pyqtSignal()
    customize_toolbar = pyqtSignal()
    scrollbar_context_menu = pyqtSignal(object, object, object)
    close_prep_finished = pyqtSignal(object)
    highlights_changed = pyqtSignal(object)
    update_reading_rates = pyqtSignal(object)
    edit_book = pyqtSignal(object, object, object)
    shortcuts_changed = pyqtSignal(object)
    paged_mode_changed = pyqtSignal()
    standalone_misc_settings_changed = pyqtSignal(object)
    view_created = pyqtSignal(object)
    content_file_changed = pyqtSignal(str)
    change_toolbar_actions = pyqtSignal(object)

    def __init__(self, parent=None):
        self._host_widget = None
        self.callback_id_counter = count()
        self.callback_map = {}
        self.current_cfi = self.current_content_file = None
        RestartingWebEngineView.__init__(self, parent)
        self.tts = TTS(self)
        self.tts.settings_changed.connect(self.tts_settings_changed)
        self.tts.event_received.connect(self.tts_event_received)
        self.tts.configured.connect(self.redraw_tts_bar)
        self.dead_renderer_error_shown = False
        self.render_process_failed.connect(self.render_process_died)
        w = self.screen().availableSize().width()
        QApplication.instance().palette_changed.connect(self.palette_changed)
        self.show_home_page_on_ready = True
        self._size_hint = QSize(int(w/3), int(w/2))
        self._page = WebPage(self)
        self._page.linkHovered.connect(self.link_hovered)
        self.view_is_ready = False
        self.bridge.bridge_ready.connect(self.on_bridge_ready)
        self.bridge.on_iframe_ready.connect(self.on_iframe_ready)
        self.bridge.view_created.connect(self.on_view_created)
        self.bridge.content_file_changed.connect(self.on_content_file_changed)
        self.bridge.set_session_data.connect(self.set_session_data)
        self.bridge.set_local_storage.connect(self.set_local_storage)
        self.bridge.reload_book.connect(self.reload_book)
        self.bridge.toggle_toc.connect(self.toggle_toc)
        self.bridge.show_search.connect(self.show_search)
        self.bridge.search_result_not_found.connect(self.search_result_not_found)
        self.bridge.search_result_discovered.connect(self.search_result_discovered)
        self.bridge.find_next.connect(self.find_next)
        self.bridge.toggle_bookmarks.connect(self.toggle_bookmarks)
        self.bridge.toggle_highlights.connect(self.toggle_highlights)
        self.bridge.new_bookmark.connect(self.new_bookmark)
        self.bridge.toggle_inspector.connect(self.toggle_inspector)
        self.bridge.toggle_lookup.connect(self.toggle_lookup)
        self.bridge.quit.connect(self.quit)
        self.bridge.update_current_toc_nodes.connect(self.update_current_toc_nodes)
        self.bridge.toggle_full_screen.connect(self.toggle_full_screen)
        self.bridge.ask_for_open.connect(self.ask_for_open)
        self.bridge.selection_changed.connect(self.selection_changed)
        self.bridge.autoscroll_state_changed.connect(self.autoscroll_state_changed)
        self.bridge.read_aloud_state_changed.connect(self.read_aloud_state_changed)
        self.bridge.view_image.connect(self.view_image)
        self.bridge.copy_image.connect(self.copy_image)
        self.bridge.overlay_visibility_changed.connect(self.overlay_visibility_changed)
        self.bridge.reference_mode_changed.connect(self.reference_mode_changed)
        self.bridge.show_loading_message.connect(self.show_loading_message)
        self.bridge.show_error.connect(self.show_error)
        self.bridge.print_book.connect(self.print_book)
        self.bridge.clear_history.connect(self.clear_history)
        self.bridge.reset_interface.connect(self.reset_interface)
        self.bridge.quit.connect(self.quit)
        self.bridge.customize_toolbar.connect(self.customize_toolbar)
        self.bridge.scrollbar_context_menu.connect(self.scrollbar_context_menu)
        self.bridge.close_prep_finished.connect(self.close_prep_finished)
        self.bridge.highlights_changed.connect(self.highlights_changed)
        self.bridge.update_reading_rates.connect(self.update_reading_rates)
        self.bridge.profile_op.connect(self.profile_op)
        self.bridge.edit_book.connect(self.edit_book)
        self.bridge.show_book_folder.connect(self.show_book_folder)
        self.bridge.show_help.connect(self.show_help)
        self.bridge.open_url.connect(safe_open_url)
        self.bridge.speak_simple_text.connect(self.tts.speak_simple_text)
        self.bridge.tts.connect(self.tts.action)
        self.bridge.export_shortcut_map.connect(self.set_shortcut_map)
        self.shortcut_map = {}
        self.bridge.report_cfi.connect(self.call_callback)
        self.bridge.change_background_image.connect(self.change_background_image)
        self.pending_bridge_ready_actions = {}
        self.setPage(self._page)
        self.setAcceptDrops(False)
        self.setUrl(QUrl(f'{FAKE_PROTOCOL}://{FAKE_HOST}/'))
        self.urlChanged.connect(self.url_changed)
        if parent is not None:
            self.inspector = Inspector(parent.inspector_dock.toggleViewAction(), self)
            parent.inspector_dock.setWidget(self.inspector)

    def profile_op(self, which, profile_name, settings):
        if which == 'all-profiles':
            vp = load_viewer_profiles('viewer:')
            self.execute_when_ready('profile_response', 'all-profiles', vp)
        elif which == 'save-profile':
            save_viewer_profile(profile_name, settings, 'viewer:')
            self.execute_when_ready('profile_response', 'save-profile', profile_name)
        elif which == 'apply-profile':
            self.execute_when_ready('profile_response', 'apply-profile', settings)
        elif which == 'request-save':
            self.execute_when_ready('profile_response', 'request-save', profile_name)
        elif which == 'apply-profile-to-viewer-ui':
            toolbar_actions = None
            s = settings.get('__standalone_extra_settings__', {})
            toolbar_actions = s.get('toolbar-actions', None)
            self.change_toolbar_actions.emit(toolbar_actions)

    def link_hovered(self, url):
        if url == 'javascript:void(0)':
            url = ''
        self.generic_action('show-status-message', {'text': url})

    def shutdown(self):
        self.tts.shutdown()

    def set_shortcut_map(self, smap):
        self.shortcut_map = smap
        self.shortcuts_changed.emit(smap)

    def url_changed(self, url):
        if url.hasFragment():
            frag = url.fragment(QUrl.ComponentFormattingOption.FullyDecoded)
            if frag and frag.startswith('bookpos='):
                cfi = frag[len('bookpos='):]
                if cfi:
                    self.current_cfi = cfi
                    self.cfi_changed.emit(cfi)

    @property
    def host_widget(self):
        ans = self._host_widget
        if ans is not None and not sip.isdeleted(ans):
            return ans

    def render_process_died(self):
        if self.dead_renderer_error_shown:
            return
        self.dead_renderer_error_shown = True
        error_dialog(self, _('Render process crashed'), _(
            'The Qt WebEngine Render process has crashed.'
            ' You should try restarting the viewer.'), show=True)

    def event(self, event):
        if event.type() == QEvent.Type.ChildPolished:
            child = event.child()
            if 'HostView' in child.metaObject().className():
                self._host_widget = child
                self._host_widget.setFocus(Qt.FocusReason.OtherFocusReason)
        return QWebEngineView.event(self, event)

    def sizeHint(self):
        return self._size_hint

    def refresh(self):
        self.pageAction(QWebEnginePage.WebAction.ReloadAndBypassCache).trigger()

    @property
    def bridge(self):
        return self._page.bridge

    def on_bridge_ready(self):
        f = QApplication.instance().font()
        fi = QFontInfo(f)
        family = f.family()
        if family in ('.AppleSystemUIFont', 'MS Shell Dlg 2'):
            family = 'system-ui'
        ui_data = {
            'all_font_families': QFontDatabase.families(),
            'ui_font_family': family,
            'ui_font_sz': f'{fi.pointSizeF()}pt',
            'show_home_page_on_ready': self.show_home_page_on_ready,
            'system_colors': system_colors(),
            'QT_VERSION': QT_VERSION,
            'short_time_fmt': QLocale.system().timeFormat(QLocale.FormatType.ShortFormat),
            'use_roman_numerals_for_series_number': config['use_roman_numerals_for_series_number'],
        }
        self.bridge.create_view(
            vprefs['session_data'], vprefs['local_storage'], field_metadata.all_metadata(), ui_data)
        performance_monitor('bridge ready')
        for func, args in self.pending_bridge_ready_actions.items():
            getattr(self.bridge, func)(*args)

    def on_iframe_ready(self):
        performance_monitor('iframe ready')

    def on_view_created(self, data):
        self.view_created.emit(data)
        self.view_is_ready = True

    def on_content_file_changed(self, data):
        self.current_content_file = data
        self.content_file_changed.emit(self.current_content_file)

    def start_book_load(self, initial_position=None, highlights=None, current_book_data=None, reading_rates=None):
        key = (set_book_path.path,)
        book_url = link_prefix_for_location_links(add_open_at=False)
        book_in_library_url = url_for_book_in_library()
        self.execute_when_ready(
            'start_book_load', key, initial_position, set_book_path.pathtoebook, highlights or [], book_url,
            reading_rates, book_in_library_url)

    def execute_when_ready(self, action, *args):
        if self.bridge.ready:
            getattr(self.bridge, action)(*args)
        else:
            self.pending_bridge_ready_actions[action] = args

    def goto_toc_node(self, node_id):
        self.execute_when_ready('goto_toc_node', node_id)

    def goto_cfi(self, cfi, add_to_history=False):
        self.execute_when_ready('goto_cfi', cfi, bool(add_to_history))

    def notify_full_screen_state_change(self, in_fullscreen_mode):
        self.execute_when_ready('full_screen_state_changed', in_fullscreen_mode)

    def set_session_data(self, key, val):
        fonts_changed = paged_mode_changed = standalone_misc_settings_changed = update_vprefs = False
        sd = vprefs['session_data']

        def change(key, val):
            nonlocal fonts_changed, paged_mode_changed, standalone_misc_settings_changed, update_vprefs
            changed = sd.get(key) != val
            if changed:
                update_vprefs = True
                if val is None:
                    sd.pop(key, None)
                else:
                    sd[key] = val
                if key in ('standalone_font_settings', 'base_font_size'):
                    fonts_changed = True
                elif key == 'read_mode':
                    paged_mode_changed = True
                elif key == 'standalone_misc_settings':
                    standalone_misc_settings_changed = True

        if isinstance(key, dict):
            for k, val in key.items():
                change(k, val)
        elif key == '*' and val is None:
            vprefs['session_data'] = {}
            fonts_changed = paged_mode_changed = standalone_misc_settings_changed = update_vprefs = True
        elif key != '*':
            change(key, val)
        if update_vprefs:
            vprefs['session_data'] = sd
        if fonts_changed:
            apply_font_settings(self)
        if paged_mode_changed:
            self.paged_mode_changed.emit()
        if standalone_misc_settings_changed:
            self.standalone_misc_settings_changed.emit(val)

    def set_local_storage(self, key, val):
        if key == '*' and val is None:
            vprefs['local_storage'] = {}
        elif key != '*':
            sd = vprefs['local_storage']
            sd[key] = val
            vprefs['local_storage'] = sd

    def do_callback(self, func_name, callback):
        cid = str(next(self.callback_id_counter))
        self.callback_map[cid] = callback
        self.execute_when_ready('get_current_cfi', cid)

    def call_callback(self, request_id, data):
        callback = self.callback_map.pop(request_id, None)
        if callback is not None:
            callback(data)

    def get_current_cfi(self, callback):
        self.do_callback('get_current_cfi', callback)

    def show_home_page(self):
        self.execute_when_ready('show_home_page')

    def redraw_tts_bar(self):
        self.execute_when_ready('redraw_tts_bar', get_session_pref('tts_bar_position', 'float', None))

    def change_background_image(self, img_id):
        files = choose_images(self, 'viewer-background-image', _('Choose background image'), formats=['png', 'gif', 'jpg', 'jpeg', 'webp'])
        if files:
            img = files[0]
            d = os.path.join(viewer_config_dir, 'background-images')
            os.makedirs(d, exist_ok=True)
            fname = os.path.basename(img)
            shutil.copyfile(img, os.path.join(d, fname))
            background_image.ans = None
            encoded = fname.encode().hex()
            self.execute_when_ready('background_image_changed', img_id, f'{FAKE_PROTOCOL}://{FAKE_HOST}/reader-background-{encoded}')

    def goto_frac(self, frac):
        self.execute_when_ready('goto_frac', frac)

    def clear_history(self):
        self._page.history().clear()

    def clear_caches(self):
        self._page.profile().clearHttpCache()

    def trigger_shortcut(self, which):
        if which:
            self.execute_when_ready('trigger_shortcut', which)

    def show_search_result(self, sr):
        self.execute_when_ready('show_search_result', sr)

    def palette_changed(self):
        self.execute_when_ready('set_system_palette', system_colors())

    def prepare_for_close(self):
        self.execute_when_ready('prepare_for_close')

    def highlight_action(self, uuid, which):
        self.execute_when_ready('highlight_action', uuid, which)
        self.setFocus(Qt.FocusReason.OtherFocusReason)

    def generic_action(self, which, data):
        self.execute_when_ready('generic_action', which, data)

    def tts_event_received(self, which, data):
        self.execute_when_ready('tts_event', which, data)

    def tts_settings_changed(self, ui_settings):
        self.execute_when_ready('tts_event', 'configured', ui_settings)

    def show_book_folder(self):
        path = os.path.dirname(os.path.abspath(set_book_path.pathtoebook))
        safe_open_url(QUrl.fromLocalFile(path))

    def show_help(self, which):
        if which == 'viewer':
            safe_open_url(localize_user_manual_link('https://manual.calibre-ebook.com/viewer.html'))

    def repair_after_fullscreen_switch(self):
        self.execute_when_ready('repair_after_fullscreen_switch')

    def remove_recently_opened(self, path=''):
        self.generic_action('remove-recently-opened', {'path': path})
