epicyon/theme.py

__filename__ = "theme.py"
__author__ = "Bob Mottram"
__license__ = "AGPL3+"
__version__ = "1.2.0"
__maintainer__ = "Bob Mottram"
__email__ = "bob@libreserver.org"
__status__ = "Production"
__module_group__ = "Web Interface"

import os
from utils import isAccountDir
from utils import loadJson
from utils import saveJson
from utils import getImageExtensions
from utils import copytree
from utils import acctDir
from utils import dangerousSVG
from utils import localActorUrl
from shutil import copyfile
from shutil import make_archive
from shutil import unpack_archive
from shutil import rmtree
from content import dangerousCSS


def importTheme(base_dir: str, filename: str) -> bool:
    """Imports a theme
    """
    if not os.path.isfile(filename):
        return False
    tempThemeDir = base_dir + '/imports/files'
    if os.path.isdir(tempThemeDir):
        rmtree(tempThemeDir, ignore_errors=False, onerror=None)
    os.mkdir(tempThemeDir)
    unpack_archive(filename, tempThemeDir, 'zip')
    essentialThemeFiles = ('name.txt', 'theme.json')
    for themeFile in essentialThemeFiles:
        if not os.path.isfile(tempThemeDir + '/' + themeFile):
            print('WARN: ' + themeFile +
                  ' missing from imported theme')
            return False
    newThemeName = None
    with open(tempThemeDir + '/name.txt', 'r') as fp:
        newThemeName = fp.read().replace('\n', '').replace('\r', '')
        if len(newThemeName) > 20:
            print('WARN: Imported theme name is too long')
            return False
        if len(newThemeName) < 2:
            print('WARN: Imported theme name is too short')
            return False
        newThemeName = newThemeName.lower()
        forbiddenChars = (
            ' ', ';', '/', '\\', '?', '!', '#', '@',
            ':', '%', '&', '"', '+', '<', '>', '$'
        )
        for ch in forbiddenChars:
            if ch in newThemeName:
                print('WARN: theme name contains forbidden character')
                return False
    if not newThemeName:
        return False

    # if the theme name in the default themes list?
    defaultThemesFilename = base_dir + '/defaultthemes.txt'
    if os.path.isfile(defaultThemesFilename):
        if newThemeName.title() + '\n' in open(defaultThemesFilename).read():
            newThemeName = newThemeName + '2'

    themeDir = base_dir + '/theme/' + newThemeName
    if not os.path.isdir(themeDir):
        os.mkdir(themeDir)
    copytree(tempThemeDir, themeDir)
    if os.path.isdir(tempThemeDir):
        rmtree(tempThemeDir, ignore_errors=False, onerror=None)
    if scanThemesForScripts(themeDir):
        rmtree(themeDir, ignore_errors=False, onerror=None)
        return False
    return os.path.isfile(themeDir + '/theme.json')


def exportTheme(base_dir: str, theme: str) -> bool:
    """Exports a theme as a zip file
    """
    themeDir = base_dir + '/theme/' + theme
    if not os.path.isfile(themeDir + '/theme.json'):
        return False
    if not os.path.isdir(base_dir + '/exports'):
        os.mkdir(base_dir + '/exports')
    exportFilename = base_dir + '/exports/' + theme + '.zip'
    if os.path.isfile(exportFilename):
        try:
            os.remove(exportFilename)
        except OSError:
            print('EX: exportTheme unable to delete ' + str(exportFilename))
    try:
        make_archive(base_dir + '/exports/' + theme, 'zip', themeDir)
    except BaseException:
        print('EX: exportTheme unable to archive ' +
              base_dir + '/exports/' + str(theme))
        pass
    return os.path.isfile(exportFilename)


def _getThemeFiles() -> []:
    """Gets the list of theme style sheets
    """
    return ('epicyon.css', 'login.css', 'follow.css',
            'suspended.css', 'calendar.css', 'blog.css',
            'options.css', 'search.css', 'links.css',
            'welcome.css', 'graph.css')


def isNewsThemeName(base_dir: str, theme_name: str) -> bool:
    """Returns true if the given theme is a news instance
    """
    themeDir = base_dir + '/theme/' + theme_name
    if os.path.isfile(themeDir + '/is_news_instance'):
        return True
    return False


def getThemesList(base_dir: str) -> []:
    """Returns the list of available themes
    Note that these should be capitalized, since they're
    also used to create the web interface dropdown list
    and to lookup function names
    """
    themes = []
    for subdir, dirs, files in os.walk(base_dir + '/theme'):
        for theme_name in dirs:
            if '~' not in theme_name and \
               theme_name != 'icons' and theme_name != 'fonts':
                themes.append(theme_name.title())
        break
    themes.sort()
    print('Themes available: ' + str(themes))
    return themes


def _copyThemeHelpFiles(base_dir: str, theme_name: str,
                        system_language: str) -> None:
    """Copies any theme specific help files from the welcome subdirectory
    """
    if not system_language:
        system_language = 'en'
    themeDir = base_dir + '/theme/' + theme_name + '/welcome'
    if not os.path.isdir(themeDir):
        themeDir = base_dir + '/defaultwelcome'
    for subdir, dirs, files in os.walk(themeDir):
        for helpMarkdownFile in files:
            if not helpMarkdownFile.endswith('_' + system_language + '.md'):
                continue
            destHelpMarkdownFile = \
                helpMarkdownFile.replace('_' + system_language + '.md', '.md')
            if destHelpMarkdownFile == 'profile.md' or \
               destHelpMarkdownFile == 'final.md':
                destHelpMarkdownFile = 'welcome_' + destHelpMarkdownFile
            if os.path.isdir(base_dir + '/accounts'):
                copyfile(themeDir + '/' + helpMarkdownFile,
                         base_dir + '/accounts/' + destHelpMarkdownFile)
        break


def _setThemeInConfig(base_dir: str, name: str) -> bool:
    """Sets the theme with the given name within config.json
    """
    configFilename = base_dir + '/config.json'
    if not os.path.isfile(configFilename):
        return False
    configJson = loadJson(configFilename, 0)
    if not configJson:
        return False
    configJson['theme'] = name
    return saveJson(configJson, configFilename)


def _setNewswirePublishAsIcon(base_dir: str, useIcon: bool) -> bool:
    """Shows the newswire publish action as an icon or a button
    """
    configFilename = base_dir + '/config.json'
    if not os.path.isfile(configFilename):
        return False
    configJson = loadJson(configFilename, 0)
    if not configJson:
        return False
    configJson['show_publish_as_icon'] = useIcon
    return saveJson(configJson, configFilename)


def _setIconsAsButtons(base_dir: str, useButtons: bool) -> bool:
    """Whether to show icons in the header (inbox, outbox, etc)
    as buttons
    """
    configFilename = base_dir + '/config.json'
    if not os.path.isfile(configFilename):
        return False
    configJson = loadJson(configFilename, 0)
    if not configJson:
        return False
    configJson['icons_as_buttons'] = useButtons
    return saveJson(configJson, configFilename)


def _setRssIconAtTop(base_dir: str, atTop: bool) -> bool:
    """Whether to show RSS icon at the top of the timeline
    """
    configFilename = base_dir + '/config.json'
    if not os.path.isfile(configFilename):
        return False
    configJson = loadJson(configFilename, 0)
    if not configJson:
        return False
    configJson['rss_icon_at_top'] = atTop
    return saveJson(configJson, configFilename)


def _setPublishButtonAtTop(base_dir: str, atTop: bool) -> bool:
    """Whether to show the publish button above the title image
    in the newswire column
    """
    configFilename = base_dir + '/config.json'
    if not os.path.isfile(configFilename):
        return False
    configJson = loadJson(configFilename, 0)
    if not configJson:
        return False
    configJson['publish_button_at_top'] = atTop
    return saveJson(configJson, configFilename)


def _setFullWidthTimelineButtonHeader(base_dir: str, fullWidth: bool) -> bool:
    """Shows the timeline button header containing inbox, outbox,
    calendar, etc as full width
    """
    configFilename = base_dir + '/config.json'
    if not os.path.isfile(configFilename):
        return False
    configJson = loadJson(configFilename, 0)
    if not configJson:
        return False
    configJson['full_width_tl_button_header'] = fullWidth
    return saveJson(configJson, configFilename)


def getTheme(base_dir: str) -> str:
    """Gets the current theme name from config.json
    """
    configFilename = base_dir + '/config.json'
    if os.path.isfile(configFilename):
        configJson = loadJson(configFilename, 0)
        if configJson:
            if configJson.get('theme'):
                return configJson['theme']
    return 'default'


def _removeTheme(base_dir: str):
    """Removes the current theme style sheets
    """
    themeFiles = _getThemeFiles()
    for filename in themeFiles:
        if not os.path.isfile(base_dir + '/' + filename):
            continue
        try:
            os.remove(base_dir + '/' + filename)
        except OSError:
            print('EX: _removeTheme unable to delete ' +
                  base_dir + '/' + filename)


def setCSSparam(css: str, param: str, value: str) -> str:
    """Sets a CSS parameter to a given value
    """
    # is this just a simple string replacement?
    if ';' in param:
        return css.replace(param, value)
    # color replacement
    if param.startswith('rgba('):
        return css.replace(param, value)
    # if the parameter begins with * then don't prepend --
    onceOnly = False
    if param.startswith('*'):
        if param.startswith('**'):
            onceOnly = True
            searchStr = param.replace('**', '') + ':'
        else:
            searchStr = param.replace('*', '') + ':'
    else:
        searchStr = '--' + param + ':'
    if searchStr not in css:
        return css
    if onceOnly:
        s = css.split(searchStr, 1)
    else:
        s = css.split(searchStr)
    newcss = ''
    for sectionStr in s:
        # handle font-family which is a variable
        nextSection = sectionStr
        if ';' in nextSection:
            nextSection = nextSection.split(';')[0] + ';'
        if searchStr == 'font-family:' and "var(--" in nextSection:
            newcss += searchStr + ' ' + sectionStr
            continue

        if not newcss:
            if sectionStr:
                newcss = sectionStr
            else:
                newcss = ' '
        else:
            if ';' in sectionStr:
                newcss += \
                    searchStr + ' ' + value + ';' + sectionStr.split(';', 1)[1]
            else:
                newcss += searchStr + ' ' + sectionStr
    return newcss.strip()


def _setThemeFromDict(base_dir: str, name: str,
                      themeParams: {}, bgParams: {},
                      allow_local_network_access: bool) -> None:
    """Uses a dictionary to set a theme
    """
    if name:
        _setThemeInConfig(base_dir, name)
    themeFiles = _getThemeFiles()
    for filename in themeFiles:
        # check for custom css within the theme directory
        templateFilename = base_dir + '/theme/' + name + '/epicyon-' + filename
        if filename == 'epicyon.css':
            templateFilename = \
                base_dir + '/theme/' + name + '/epicyon-profile.css'

        # Ensure that any custom CSS is mostly harmless.
        # If not then just use the defaults
        if dangerousCSS(templateFilename, allow_local_network_access) or \
           not os.path.isfile(templateFilename):
            # use default css
            templateFilename = base_dir + '/epicyon-' + filename
            if filename == 'epicyon.css':
                templateFilename = base_dir + '/epicyon-profile.css'

        if not os.path.isfile(templateFilename):
            continue

        with open(templateFilename, 'r') as cssfile:
            css = cssfile.read()
            for paramName, paramValue in themeParams.items():
                if paramName == 'newswire-publish-icon':
                    if paramValue.lower() == 'true':
                        _setNewswirePublishAsIcon(base_dir, True)
                    else:
                        _setNewswirePublishAsIcon(base_dir, False)
                    continue
                elif paramName == 'full-width-timeline-buttons':
                    if paramValue.lower() == 'true':
                        _setFullWidthTimelineButtonHeader(base_dir, True)
                    else:
                        _setFullWidthTimelineButtonHeader(base_dir, False)
                    continue
                elif paramName == 'icons-as-buttons':
                    if paramValue.lower() == 'true':
                        _setIconsAsButtons(base_dir, True)
                    else:
                        _setIconsAsButtons(base_dir, False)
                    continue
                elif paramName == 'rss-icon-at-top':
                    if paramValue.lower() == 'true':
                        _setRssIconAtTop(base_dir, True)
                    else:
                        _setRssIconAtTop(base_dir, False)
                    continue
                elif paramName == 'publish-button-at-top':
                    if paramValue.lower() == 'true':
                        _setPublishButtonAtTop(base_dir, True)
                    else:
                        _setPublishButtonAtTop(base_dir, False)
                    continue
                css = setCSSparam(css, paramName, paramValue)
            filename = base_dir + '/' + filename
            with open(filename, 'w+') as cssfile:
                cssfile.write(css)

    screenName = (
        'login', 'follow', 'options', 'search', 'welcome'
    )
    for s in screenName:
        if bgParams.get(s):
            _setBackgroundFormat(base_dir, name, s, bgParams[s])


def _setBackgroundFormat(base_dir: str, name: str,
                         backgroundType: str, extension: str) -> None:
    """Sets the background file extension
    """
    if extension == 'jpg':
        return
    cssFilename = base_dir + '/' + backgroundType + '.css'
    if not os.path.isfile(cssFilename):
        return
    with open(cssFilename, 'r') as cssfile:
        css = cssfile.read()
        css = css.replace('background.jpg', 'background.' + extension)
        with open(cssFilename, 'w+') as cssfile2:
            cssfile2.write(css)


def enableGrayscale(base_dir: str) -> None:
    """Enables grayscale for the current theme
    """
    themeFiles = _getThemeFiles()
    for filename in themeFiles:
        templateFilename = base_dir + '/' + filename
        if not os.path.isfile(templateFilename):
            continue
        with open(templateFilename, 'r') as cssfile:
            css = cssfile.read()
            if 'grayscale' not in css:
                css = \
                    css.replace('body, html {',
                                'body, html {\n    filter: grayscale(100%);')
                filename = base_dir + '/' + filename
                with open(filename, 'w+') as cssfile:
                    cssfile.write(css)
    grayscaleFilename = base_dir + '/accounts/.grayscale'
    if not os.path.isfile(grayscaleFilename):
        with open(grayscaleFilename, 'w+') as grayfile:
            grayfile.write(' ')


def disableGrayscale(base_dir: str) -> None:
    """Disables grayscale for the current theme
    """
    themeFiles = _getThemeFiles()
    for filename in themeFiles:
        templateFilename = base_dir + '/' + filename
        if not os.path.isfile(templateFilename):
            continue
        with open(templateFilename, 'r') as cssfile:
            css = cssfile.read()
            if 'grayscale' in css:
                css = \
                    css.replace('\n    filter: grayscale(100%);', '')
                filename = base_dir + '/' + filename
                with open(filename, 'w+') as cssfile:
                    cssfile.write(css)
    grayscaleFilename = base_dir + '/accounts/.grayscale'
    if os.path.isfile(grayscaleFilename):
        try:
            os.remove(grayscaleFilename)
        except OSError:
            print('EX: disableGrayscale unable to delete ' +
                  grayscaleFilename)


def _setCustomFont(base_dir: str):
    """Uses a dictionary to set a theme
    """
    customFontExt = None
    customFontType = None
    fontExtension = {
        'woff': 'woff',
        'woff2': 'woff2',
        'otf': 'opentype',
        'ttf': 'truetype'
    }
    for ext, extType in fontExtension.items():
        filename = base_dir + '/fonts/custom.' + ext
        if os.path.isfile(filename):
            customFontExt = ext
            customFontType = extType
    if not customFontExt:
        return

    themeFiles = _getThemeFiles()
    for filename in themeFiles:
        templateFilename = base_dir + '/' + filename
        if not os.path.isfile(templateFilename):
            continue
        with open(templateFilename, 'r') as cssfile:
            css = cssfile.read()
            css = \
                setCSSparam(css, "*src",
                            "url('./fonts/custom." +
                            customFontExt +
                            "') format('" +
                            customFontType + "')")
            css = setCSSparam(css, "*font-family", "'CustomFont'")
            filename = base_dir + '/' + filename
            with open(filename, 'w+') as cssfile:
                cssfile.write(css)


def setThemeFromDesigner(base_dir: str, theme_name: str, domain: str,
                         themeParams: {},
                         allow_local_network_access: bool,
                         system_language: str):
    customThemeFilename = base_dir + '/accounts/theme.json'
    saveJson(themeParams, customThemeFilename)
    setTheme(base_dir, theme_name, domain,
             allow_local_network_access, system_language)


def resetThemeDesignerSettings(base_dir: str, theme_name: str, domain: str,
                               allow_local_network_access: bool,
                               system_language: str) -> None:
    """Resets the theme designer settings
    """
    customVariablesFile = base_dir + '/accounts/theme.json'
    if os.path.isfile(customVariablesFile):
        try:
            os.remove(customVariablesFile)
        except OSError:
            print('EX: unable to remove theme designer settings on reset')


def _readVariablesFile(base_dir: str, theme_name: str,
                       variablesFile: str,
                       allow_local_network_access: bool) -> None:
    """Reads variables from a file in the theme directory
    """
    themeParams = loadJson(variablesFile, 0)
    if not themeParams:
        return

    # set custom theme parameters
    customVariablesFile = base_dir + '/accounts/theme.json'
    if os.path.isfile(customVariablesFile):
        customThemeParams = loadJson(customVariablesFile, 0)
        if customThemeParams:
            for variableName, value in customThemeParams.items():
                themeParams[variableName] = value

    bgParams = {
        "login": "jpg",
        "follow": "jpg",
        "options": "jpg",
        "search": "jpg"
    }
    _setThemeFromDict(base_dir, theme_name, themeParams, bgParams,
                      allow_local_network_access)


def _setThemeDefault(base_dir: str, allow_local_network_access: bool):
    name = 'default'
    _removeTheme(base_dir)
    _setThemeInConfig(base_dir, name)
    bgParams = {
        "login": "jpg",
        "follow": "jpg",
        "options": "jpg",
        "search": "jpg"
    }
    themeParams = {
        "newswire-publish-icon": True,
        "full-width-timeline-buttons": False,
        "icons-as-buttons": False,
        "rss-icon-at-top": True,
        "publish-button-at-top": False,
        "banner-height": "20vh",
        "banner-height-mobile": "10vh",
        "search-banner-height-mobile": "15vh"
    }
    _setThemeFromDict(base_dir, name, themeParams, bgParams,
                      allow_local_network_access)


def _setThemeFonts(base_dir: str, theme_name: str) -> None:
    """Adds custom theme fonts
    """
    theme_name_lower = theme_name.lower()
    fontsDir = base_dir + '/fonts'
    themeFontsDir = \
        base_dir + '/theme/' + theme_name_lower + '/fonts'
    if not os.path.isdir(themeFontsDir):
        return
    for subdir, dirs, files in os.walk(themeFontsDir):
        for filename in files:
            if filename.endswith('.woff2') or \
               filename.endswith('.woff') or \
               filename.endswith('.ttf') or \
               filename.endswith('.otf'):
                destFilename = fontsDir + '/' + filename
                if os.path.isfile(destFilename):
                    # font already exists in the destination location
                    continue
                copyfile(themeFontsDir + '/' + filename,
                         destFilename)
        break


def getTextModeBanner(base_dir: str) -> str:
    """Returns the banner used for shell browsers, like Lynx
    """
    text_mode_bannerFilename = base_dir + '/accounts/banner.txt'
    if os.path.isfile(text_mode_bannerFilename):
        with open(text_mode_bannerFilename, 'r') as fp:
            bannerStr = fp.read()
            if bannerStr:
                return bannerStr.replace('\n', '<br>')
    return None


def getTextModeLogo(base_dir: str) -> str:
    """Returns the login screen logo used for shell browsers, like Lynx
    """
    textModeLogoFilename = base_dir + '/accounts/logo.txt'
    if not os.path.isfile(textModeLogoFilename):
        textModeLogoFilename = base_dir + '/img/logo.txt'

    with open(textModeLogoFilename, 'r') as fp:
        logoStr = fp.read()
        if logoStr:
            return logoStr.replace('\n', '<br>')
    return None


def _setTextModeTheme(base_dir: str, name: str) -> None:
    # set the text mode logo which appears on the login screen
    # in browsers such as Lynx
    textModeLogoFilename = \
        base_dir + '/theme/' + name + '/logo.txt'
    if os.path.isfile(textModeLogoFilename):
        try:
            copyfile(textModeLogoFilename,
                     base_dir + '/accounts/logo.txt')
        except OSError:
            print('EX: _setTextModeTheme unable to copy ' +
                  textModeLogoFilename + ' ' +
                  base_dir + '/accounts/logo.txt')
    else:
        try:
            copyfile(base_dir + '/img/logo.txt',
                     base_dir + '/accounts/logo.txt')
        except OSError:
            print('EX: _setTextModeTheme unable to copy ' +
                  base_dir + '/img/logo.txt ' +
                  base_dir + '/accounts/logo.txt')

    # set the text mode banner which appears in browsers such as Lynx
    text_mode_bannerFilename = \
        base_dir + '/theme/' + name + '/banner.txt'
    if os.path.isfile(base_dir + '/accounts/banner.txt'):
        try:
            os.remove(base_dir + '/accounts/banner.txt')
        except OSError:
            print('EX: _setTextModeTheme unable to delete ' +
                  base_dir + '/accounts/banner.txt')
    if os.path.isfile(text_mode_bannerFilename):
        try:
            copyfile(text_mode_bannerFilename,
                     base_dir + '/accounts/banner.txt')
        except OSError:
            print('EX: _setTextModeTheme unable to copy ' +
                  text_mode_bannerFilename + ' ' +
                  base_dir + '/accounts/banner.txt')


def _setThemeImages(base_dir: str, name: str) -> None:
    """Changes the profile background image
    and banner to the defaults
    """
    theme_name_lower = name.lower()

    profileImageFilename = \
        base_dir + '/theme/' + theme_name_lower + '/image.png'
    bannerFilename = \
        base_dir + '/theme/' + theme_name_lower + '/banner.png'
    searchBannerFilename = \
        base_dir + '/theme/' + theme_name_lower + '/search_banner.png'
    leftColImageFilename = \
        base_dir + '/theme/' + theme_name_lower + '/left_col_image.png'
    rightColImageFilename = \
        base_dir + '/theme/' + theme_name_lower + '/right_col_image.png'

    _setTextModeTheme(base_dir, theme_name_lower)

    backgroundNames = ('login', 'shares', 'delete', 'follow',
                       'options', 'block', 'search', 'calendar',
                       'welcome')
    extensions = getImageExtensions()

    for subdir, dirs, files in os.walk(base_dir + '/accounts'):
        for acct in dirs:
            if not isAccountDir(acct):
                continue
            accountDir = os.path.join(base_dir + '/accounts', acct)

            for backgroundType in backgroundNames:
                for ext in extensions:
                    if theme_name_lower == 'default':
                        backgroundImageFilename = \
                            base_dir + '/theme/default/' + \
                            backgroundType + '_background.' + ext
                    else:
                        backgroundImageFilename = \
                            base_dir + '/theme/' + theme_name_lower + '/' + \
                            backgroundType + '_background' + '.' + ext

                    if os.path.isfile(backgroundImageFilename):
                        try:
                            copyfile(backgroundImageFilename,
                                     base_dir + '/accounts/' +
                                     backgroundType + '-background.' + ext)
                            continue
                        except OSError:
                            print('EX: _setThemeImages unable to copy ' +
                                  backgroundImageFilename)
                    # background image was not found
                    # so remove any existing file
                    if os.path.isfile(base_dir + '/accounts/' +
                                      backgroundType + '-background.' + ext):
                        try:
                            os.remove(base_dir + '/accounts/' +
                                      backgroundType + '-background.' + ext)
                        except OSError:
                            print('EX: _setThemeImages unable to delete ' +
                                  base_dir + '/accounts/' +
                                  backgroundType + '-background.' + ext)

            if os.path.isfile(profileImageFilename) and \
               os.path.isfile(bannerFilename):
                try:
                    copyfile(profileImageFilename,
                             accountDir + '/image.png')
                except OSError:
                    print('EX: _setThemeImages unable to copy ' +
                          profileImageFilename)

                try:
                    copyfile(bannerFilename,
                             accountDir + '/banner.png')
                except OSError:
                    print('EX: _setThemeImages unable to copy ' +
                          bannerFilename)

                try:
                    if os.path.isfile(searchBannerFilename):
                        copyfile(searchBannerFilename,
                                 accountDir + '/search_banner.png')
                except OSError:
                    print('EX: _setThemeImages unable to copy ' +
                          searchBannerFilename)

                try:
                    if os.path.isfile(leftColImageFilename):
                        copyfile(leftColImageFilename,
                                 accountDir + '/left_col_image.png')
                    elif os.path.isfile(accountDir +
                                        '/left_col_image.png'):
                        try:
                            os.remove(accountDir + '/left_col_image.png')
                        except OSError:
                            print('EX: _setThemeImages unable to delete ' +
                                  accountDir + '/left_col_image.png')
                except OSError:
                    print('EX: _setThemeImages unable to copy ' +
                          leftColImageFilename)

                try:
                    if os.path.isfile(rightColImageFilename):
                        copyfile(rightColImageFilename,
                                 accountDir + '/right_col_image.png')
                    else:
                        if os.path.isfile(accountDir +
                                          '/right_col_image.png'):
                            try:
                                os.remove(accountDir + '/right_col_image.png')
                            except OSError:
                                print('EX: _setThemeImages unable to delete ' +
                                      accountDir + '/right_col_image.png')
                except OSError:
                    print('EX: _setThemeImages unable to copy ' +
                          rightColImageFilename)
        break


def setNewsAvatar(base_dir: str, name: str,
                  http_prefix: str,
                  domain: str, domain_full: str) -> None:
    """Sets the avatar for the news account
    """
    nickname = 'news'
    newFilename = base_dir + '/theme/' + name + '/icons/avatar_news.png'
    if not os.path.isfile(newFilename):
        newFilename = base_dir + '/theme/default/icons/avatar_news.png'
    if not os.path.isfile(newFilename):
        return
    avatarFilename = \
        localActorUrl(http_prefix, domain_full, nickname) + '.png'
    avatarFilename = avatarFilename.replace('/', '-')
    filename = base_dir + '/cache/avatars/' + avatarFilename

    if os.path.isfile(filename):
        try:
            os.remove(filename)
        except OSError:
            print('EX: setNewsAvatar unable to delete ' + filename)
    if os.path.isdir(base_dir + '/cache/avatars'):
        copyfile(newFilename, filename)
    accountDir = acctDir(base_dir, nickname, domain)
    copyfile(newFilename, accountDir + '/avatar.png')


def _setClearCacheFlag(base_dir: str) -> None:
    """Sets a flag which can be used by an external system
    (eg. a script in a cron job) to clear the browser cache
    """
    if not os.path.isdir(base_dir + '/accounts'):
        return
    flagFilename = base_dir + '/accounts/.clear_cache'
    with open(flagFilename, 'w+') as flagFile:
        flagFile.write('\n')


def setTheme(base_dir: str, name: str, domain: str,
             allow_local_network_access: bool, system_language: str) -> bool:
    """Sets the theme with the given name as the current theme
    """
    result = False

    prevThemeName = getTheme(base_dir)

    # if the theme has changed then remove any custom settings
    if prevThemeName != name:
        resetThemeDesignerSettings(base_dir, name, domain,
                                   allow_local_network_access,
                                   system_language)

    _removeTheme(base_dir)

    themes = getThemesList(base_dir)
    for theme_name in themes:
        theme_name_lower = theme_name.lower()
        if name == theme_name_lower:
            allow_access = allow_local_network_access
            try:
                globals()['setTheme' + theme_name](base_dir, allow_access)
            except BaseException:
                print('EX: setTheme unable to set theme ' + theme_name)

            if prevThemeName:
                if prevThemeName.lower() != theme_name_lower:
                    # change the banner and profile image
                    # to the default for the theme
                    _setThemeImages(base_dir, name)
                    _setThemeFonts(base_dir, name)
            result = True

    if not result:
        # default
        _setThemeDefault(base_dir, allow_local_network_access)
        result = True

    variablesFile = base_dir + '/theme/' + name + '/theme.json'
    if os.path.isfile(variablesFile):
        _readVariablesFile(base_dir, name, variablesFile,
                           allow_local_network_access)

    _setCustomFont(base_dir)

    # set the news avatar
    newsAvatarThemeFilename = \
        base_dir + '/theme/' + name + '/icons/avatar_news.png'
    if os.path.isdir(base_dir + '/accounts/news@' + domain):
        if os.path.isfile(newsAvatarThemeFilename):
            newsAvatarFilename = \
                base_dir + '/accounts/news@' + domain + '/avatar.png'
            copyfile(newsAvatarThemeFilename, newsAvatarFilename)

    grayscaleFilename = base_dir + '/accounts/.grayscale'
    if os.path.isfile(grayscaleFilename):
        enableGrayscale(base_dir)
    else:
        disableGrayscale(base_dir)

    _copyThemeHelpFiles(base_dir, name, system_language)
    _setThemeInConfig(base_dir, name)
    _setClearCacheFlag(base_dir)
    return result


def updateDefaultThemesList(base_dir: str) -> None:
    """Recreates the list of default themes
    """
    theme_names = getThemesList(base_dir)
    defaultThemesFilename = base_dir + '/defaultthemes.txt'
    with open(defaultThemesFilename, 'w+') as defaultThemesFile:
        for name in theme_names:
            defaultThemesFile.write(name + '\n')


def scanThemesForScripts(base_dir: str) -> bool:
    """Scans the theme directory for any svg files containing scripts
    """
    for subdir, dirs, files in os.walk(base_dir + '/theme'):
        for f in files:
            if not f.endswith('.svg'):
                continue
            svgFilename = os.path.join(subdir, f)
            content = ''
            with open(svgFilename, 'r') as fp:
                content = fp.read()
            svgDangerous = dangerousSVG(content, False)
            if svgDangerous:
                print('svg file contains script: ' + svgFilename)
                return True
        # deliberately no break - should resursively scan
    return False