"""idlelib.config -- Manage IDLE configuration information.

The comments at the beginning of config-main.def describe the
configuration files and the design implemented to update user
configuration information.  In particular, user configuration choices
which duplicate the defaults will be removed from the user's
configuration files, and if a user file becomes empty, it will be
deleted.

The configuration database maps options to values.  Conceptually, the
database keys are tuples (config-type, section, item).  As implemented,
there are  separate dicts for default and user values.  Each has
config-type keys 'main', 'extensions', 'highlight', and 'keys'.  The
value for each key is a ConfigParser instance that maps section and item
to values.  For 'main' and 'extensions', user values override
default values.  For 'highlight' and 'keys', user sections augment the
default sections (and must, therefore, have distinct names).

Throughout this module there is an emphasis on returning usable defaults
when a problem occurs in returning a requested configuration value back to
idle. This is to allow IDLE to continue to function in spite of errors in
the retrieval of config information. When a default is returned instead of
a requested config value, a message is printed to stderr to aid in
configuration problem notification and resolution.
"""
# TODOs added Oct 2014, tjr

from configparser import ConfigParser
import os
import sys

from tkinter.font import Font
import idlelib

class InvalidConfigType(Exception): pass
class InvalidConfigSet(Exception): pass
class InvalidTheme(Exception): pass

class IdleConfParser(ConfigParser):
    """
    A ConfigParser specialised for idle configuration file handling
    """
    def __init__(self, cfgFile, cfgDefaults=None):
        """
        cfgFile - string, fully specified configuration file name
        """
        self.file = cfgFile  # This is currently '' when testing.
        ConfigParser.__init__(self, defaults=cfgDefaults, strict=False)

    def Get(self, section, option, type=None, default=None, raw=False):
        """
        Get an option value for given section/option or return default.
        If type is specified, return as type.
        """
        # TODO Use default as fallback, at least if not None
        # Should also print Warning(file, section, option).
        # Currently may raise ValueError
        if not self.has_option(section, option):
            return default
        if type == 'bool':
            return self.getboolean(section, option)
        elif type == 'int':
            return self.getint(section, option)
        else:
            return self.get(section, option, raw=raw)

    def GetOptionList(self, section):
        "Return a list of options for given section, else []."
        if self.has_section(section):
            return self.options(section)
        else:  #return a default value
            return []

    def Load(self):
        "Load the configuration file from disk."
        if self.file:
            self.read(self.file)

class IdleUserConfParser(IdleConfParser):
    """
    IdleConfigParser specialised for user configuration handling.
    """

    def SetOption(self, section, option, value):
        """Return True if option is added or changed to value, else False.

        Add section if required.  False means option already had value.
        """
        if self.has_option(section, option):
            if self.get(section, option) == value:
                return False
            else:
                self.set(section, option, value)
                return True
        else:
            if not self.has_section(section):
                self.add_section(section)
            self.set(section, option, value)
            return True

    def RemoveOption(self, section, option):
        """Return True if option is removed from section, else False.

        False if either section does not exist or did not have option.
        """
        if self.has_section(section):
            return self.remove_option(section, option)
        return False

    def AddSection(self, section):
        "If section doesn't exist, add it."
        if not self.has_section(section):
            self.add_section(section)

    def RemoveEmptySections(self):
        "Remove any sections that have no options."
        for section in self.sections():
            if not self.GetOptionList(section):
                self.remove_section(section)

    def IsEmpty(self):
        "Return True if no sections after removing empty sections."
        self.RemoveEmptySections()
        return not self.sections()

    def Save(self):
        """Update user configuration file.

        If self not empty after removing empty sections, write the file
        to disk. Otherwise, remove the file from disk if it exists.
        """
        fname = self.file
        if fname and fname[0] != '#':
            if not self.IsEmpty():
                try:
                    cfgFile = open(fname, 'w')
                except OSError:
                    os.unlink(fname)
                    cfgFile = open(fname, 'w')
                with cfgFile:
                    self.write(cfgFile)
            elif os.path.exists(self.file):
                os.remove(self.file)

class IdleConf:
    """Hold config parsers for all idle config files in singleton instance.

    Default config files, self.defaultCfg --
        for config_type in self.config_types:
            (idle install dir)/config-{config-type}.def

    User config files, self.userCfg --
        for config_type in self.config_types:
        (user home dir)/.idlerc/config-{config-type}.cfg
    """
    def __init__(self, _utest=False):
        self.config_types = ('main', 'highlight', 'keys', 'extensions')
        self.defaultCfg = {}
        self.userCfg = {}
        self.cfg = {}  # TODO use to select userCfg vs defaultCfg
        # self.blink_off_time = <first editor text>['insertofftime']
        # See https:/bugs.python.org/issue4630, msg356516.

        if not _utest:
            self.CreateConfigHandlers()
            self.LoadCfgFiles()

    def CreateConfigHandlers(self):
        "Populate default and user config parser dictionaries."
        idledir = os.path.dirname(__file__)
        self.userdir = userdir = '' if idlelib.testing else self.GetUserCfgDir()
        for cfg_type in self.config_types:
            self.defaultCfg[cfg_type] = IdleConfParser(
                os.path.join(idledir, f'config-{cfg_type}.def'))
            self.userCfg[cfg_type] = IdleUserConfParser(
                os.path.join(userdir or '#', f'config-{cfg_type}.cfg'))

    def GetUserCfgDir(self):
        """Return a filesystem directory for storing user config files.

        Creates it if required.
        """
        cfgDir = '.idlerc'
        userDir = os.path.expanduser('~')
        if userDir != '~': # expanduser() found user home dir
            if not os.path.exists(userDir):
                if not idlelib.testing:
                    warn = ('\n Warning: os.path.expanduser("~") points to\n ' +
                            userDir + ',\n but the path does not exist.')
                    try:
                        print(warn, file=sys.stderr)
                    except OSError:
                        pass
                userDir = '~'
        if userDir == "~": # still no path to home!
            # traditionally IDLE has defaulted to os.getcwd(), is this adequate?
            userDir = os.getcwd()
        userDir = os.path.join(userDir, cfgDir)
        if not os.path.exists(userDir):
            try:
                os.mkdir(userDir)
            except OSError:
                if not idlelib.testing:
                    warn = ('\n Warning: unable to create user config directory\n' +
                            userDir + '\n Check path and permissions.\n Exiting!\n')
                    try:
                        print(warn, file=sys.stderr)
                    except OSError:
                        pass
                raise SystemExit
        # TODO continue without userDIr instead of exit
        return userDir

    def GetOption(self, configType, section, option, default=None, type=None,
                  warn_on_default=True, raw=False):
        """Return a value for configType section option, or default.

        If type is not None, return a value of that type.  Also pass raw
        to the config parser.  First try to return a valid value
        (including type) from a user configuration. If that fails, try
        the default configuration. If that fails, return default, with a
        default of None.

        Warn if either user or default configurations have an invalid value.
        Warn if default is returned and warn_on_default is True.
        """
        try:
            if self.userCfg[configType].has_option(section, option):
                return self.userCfg[configType].Get(section, option,
                                                    type=type, raw=raw)
        except ValueError:
            warning = ('\n Warning: config.py - IdleConf.GetOption -\n'
                       ' invalid %r value for configuration option %r\n'
                       ' from section %r: %r' %
                       (type, option, section,
                       self.userCfg[configType].Get(section, option, raw=raw)))
            _warn(warning, configType, section, option)
        try:
            if self.defaultCfg[configType].has_option(section,option):
                return self.defaultCfg[configType].Get(
                        section, option, type=type, raw=raw)
        except ValueError:
            pass
        #returning default, print warning
        if warn_on_default:
            warning = ('\n Warning: config.py - IdleConf.GetOption -\n'
                       ' problem retrieving configuration option %r\n'
                       ' from section %r.\n'
                       ' returning default value: %r' %
                       (option, section, default))
            _warn(warning, configType, section, option)
        return default

    def SetOption(self, configType, section, option, value):
        """Set section option to value in user config file."""
        self.userCfg[configType].SetOption(section, option, value)

    def GetSectionList(self, configSet, configType):
        """Return sections for configSet configType configuration.

        configSet must be either 'user' or 'default'
        configType must be in self.config_types.
        """
        if not (configType in self.config_types):
            raise InvalidConfigType('Invalid configType specified')
        if configSet == 'user':
            cfgParser = self.userCfg[configType]
        elif configSet == 'default':
            cfgParser=self.defaultCfg[configType]
        else:
            raise InvalidConfigSet('Invalid configSet specified')
        return cfgParser.sections()

    def GetHighlight(self, theme, element):
        """Return dict of theme element highlight colors.

        The keys are 'foreground' and 'background'.  The values are
        tkinter color strings for configuring backgrounds and tags.
        """
        cfg = ('default' if self.defaultCfg['highlight'].has_section(theme)
               else 'user')
        theme_dict = self.GetThemeDict(cfg, theme)
        fore = theme_dict[element + '-foreground']
        if element == 'cursor':
            element = 'normal'
        back = theme_dict[element + '-background']
        return {"foreground": fore, "background": back}

    def GetThemeDict(self, type, themeName):
        """Return {option:value} dict for elements in themeName.

        type - string, 'default' or 'user' theme type
        themeName - string, theme name
        Values are loaded over ultimate fallback defaults to guarantee
        that all theme elements are present in a newly created theme.
        """
        if type == 'user':
            cfgParser = self.userCfg['highlight']
        elif type == 'default':
            cfgParser = self.defaultCfg['highlight']
        else:
            raise InvalidTheme('Invalid theme type specified')
        # Provide foreground and background colors for each theme
        # element (other than cursor) even though some values are not
        # yet used by idle, to allow for their use in the future.
        # Default values are generally black and white.
        # TODO copy theme from a class attribute.
        theme ={'normal-foreground':'#000000',
                'normal-background':'#ffffff',
                'keyword-foreground':'#000000',
                'keyword-background':'#ffffff',
                'builtin-foreground':'#000000',
                'builtin-background':'#ffffff',
                'comment-foreground':'#000000',
                'comment-background':'#ffffff',
                'string-foreground':'#000000',
                'string-background':'#ffffff',
                'definition-foreground':'#000000',
                'definition-background':'#ffffff',
                'hilite-foreground':'#000000',
                'hilite-background':'gray',
                'break-foreground':'#ffffff',
                'break-background':'#000000',
                'hit-foreground':'#ffffff',
                'hit-background':'#000000',
                'error-foreground':'#ffffff',
                'error-background':'#000000',
                'context-foreground':'#000000',
                'context-background':'#ffffff',
                'linenumber-foreground':'#000000',
                'linenumber-background':'#ffffff',
                #cursor (only foreground can be set)
                'cursor-foreground':'#000000',
                #shell window
                'stdout-foreground':'#000000',
                'stdout-background':'#ffffff',
                'stderr-foreground':'#000000',
                'stderr-background':'#ffffff',
                'console-foreground':'#000000',
                'console-background':'#ffffff',
                }
        for element in theme:
            if not (cfgParser.has_option(themeName, element) or
                    # Skip warning for new elements.
                    element.startswith(('context-', 'linenumber-'))):
                # Print warning that will return a default color
                warning = ('\n Warning: config.IdleConf.GetThemeDict'
                           ' -\n problem retrieving theme element %r'
                           '\n from theme %r.\n'
                           ' returning default color: %r' %
                           (element, themeName, theme[element]))
                _warn(warning, 'highlight', themeName, element)
            theme[element] = cfgParser.Get(
                    themeName, element, default=theme[element])
        return theme

    def CurrentTheme(self):
        "Return the name of the currently active text color theme."
        return self.current_colors_and_keys('Theme')

    def CurrentKeys(self):
        """Return the name of the currently active key set."""
        return self.current_colors_and_keys('Keys')

    def current_colors_and_keys(self, section):
        """Return the currently active name for Theme or Keys section.

        idlelib.config-main.def ('default') includes these sections

        [Theme]
        default= 1
        name= IDLE Classic
        name2=

        [Keys]
        default= 1
        name=
        name2=

        Item 'name2', is used for built-in ('default') themes and keys
        added after 2015 Oct 1 and 2016 July 1.  This kludge is needed
        because setting 'name' to a builtin not defined in older IDLEs
        to display multiple error messages or quit.
        See https://bugs.python.org/issue25313.
        When default = True, 'name2' takes precedence over 'name',
        while older IDLEs will just use name.  When default = False,
        'name2' may still be set, but it is ignored.
        """
        cfgname = 'highlight' if section == 'Theme' else 'keys'
        default = self.GetOption('main', section, 'default',
                                 type='bool', default=True)
        name = ''
        if default:
            name = self.GetOption('main', section, 'name2', default='')
        if not name:
            name = self.GetOption('main', section, 'name', default='')
        if name:
            source = self.defaultCfg if default else self.userCfg
            if source[cfgname].has_section(name):
                return name
        return "IDLE Classic" if section == 'Theme' else self.default_keys()

    @staticmethod
    def default_keys():
        if sys.platform[:3] == 'win':
            return 'IDLE Classic Windows'
        elif sys.platform == 'darwin':
            return 'IDLE Classic OSX'
        else:
            return 'IDLE Modern Unix'

    def GetExtensions(self, active_only=True,
                      editor_only=False, shell_only=False):
        """Return extensions in default and user config-extensions files.

        If active_only True, only return active (enabled) extensions
        and optionally only editor or shell extensions.
        If active_only False, return all extensions.
        """
        extns = self.RemoveKeyBindNames(
                self.GetSectionList('default', 'extensions'))
        userExtns = self.RemoveKeyBindNames(
                self.GetSectionList('user', 'extensions'))
        for extn in userExtns:
            if extn not in extns: #user has added own extension
                extns.append(extn)
        for extn in ('AutoComplete','CodeContext',
                     'FormatParagraph','ParenMatch'):
            extns.remove(extn)
            # specific exclusions because we are storing config for mainlined old
            # extensions in config-extensions.def for backward compatibility
        if active_only:
            activeExtns = []
            for extn in extns:
                if self.GetOption('extensions', extn, 'enable', default=True,
                                  type='bool'):
                    #the extension is enabled
                    if editor_only or shell_only:  # TODO both True contradict
                        if editor_only:
                            option = "enable_editor"
                        else:
                            option = "enable_shell"
                        if self.GetOption('extensions', extn,option,
                                          default=True, type='bool',
                                          warn_on_default=False):
                            activeExtns.append(extn)
                    else:
                        activeExtns.append(extn)
            return activeExtns
        else:
            return extns

    def RemoveKeyBindNames(self, extnNameList):
        "Return extnNameList with keybinding section names removed."
        return [n for n in extnNameList if not n.endswith(('_bindings', '_cfgBindings'))]

    def GetExtnNameForEvent(self, virtualEvent):
        """Return the name of the extension binding virtualEvent, or None.

        virtualEvent - string, name of the virtual event to test for,
                       without the enclosing '<< >>'
        """
        extName = None
        vEvent = '<<' + virtualEvent + '>>'
        for extn in self.GetExtensions(active_only=0):
            for event in self.GetExtensionKeys(extn):
                if event == vEvent:
                    extName = extn  # TODO return here?
        return extName

    def GetExtensionKeys(self, extensionName):
        """Return dict: {configurable extensionName event : active keybinding}.

        Events come from default config extension_cfgBindings section.
        Keybindings come from GetCurrentKeySet() active key dict,
        where previously used bindings are disabled.
        """
        keysName = extensionName + '_cfgBindings'
        activeKeys = self.GetCurrentKeySet()
        extKeys = {}
        if self.defaultCfg['extensions'].has_section(keysName):
            eventNames = self.defaultCfg['extensions'].GetOptionList(keysName)
            for eventName in eventNames:
                event = '<<' + eventName + '>>'
                binding = activeKeys[event]
                extKeys[event] = binding
        return extKeys

    def __GetRawExtensionKeys(self,extensionName):
        """Return dict {configurable extensionName event : keybinding list}.

        Events come from default config extension_cfgBindings section.
        Keybindings list come from the splitting of GetOption, which
        tries user config before default config.
        """
        keysName = extensionName+'_cfgBindings'
        extKeys = {}
        if self.defaultCfg['extensions'].has_section(keysName):
            eventNames = self.defaultCfg['extensions'].GetOptionList(keysName)
            for eventName in eventNames:
                binding = self.GetOption(
                        'extensions', keysName, eventName, default='').split()
                event = '<<' + eventName + '>>'
                extKeys[event] = binding
        return extKeys

    def GetExtensionBindings(self, extensionName):
        """Return dict {extensionName event : active or defined keybinding}.

        Augment self.GetExtensionKeys(extensionName) with mapping of non-
        configurable events (from default config) to GetOption splits,
        as in self.__GetRawExtensionKeys.
        """
        bindsName = extensionName + '_bindings'
        extBinds = self.GetExtensionKeys(extensionName)
        #add the non-configurable bindings
        if self.defaultCfg['extensions'].has_section(bindsName):
            eventNames = self.defaultCfg['extensions'].GetOptionList(bindsName)
            for eventName in eventNames:
                binding = self.GetOption(
                        'extensions', bindsName, eventName, default='').split()
                event = '<<' + eventName + '>>'
                extBinds[event] = binding

        return extBinds

    def GetKeyBinding(self, keySetName, eventStr):
        """Return the keybinding list for keySetName eventStr.

        keySetName - name of key binding set (config-keys section).
        eventStr - virtual event, including brackets, as in '<<event>>'.
        """
        eventName = eventStr[2:-2] #trim off the angle brackets
        binding = self.GetOption('keys', keySetName, eventName, default='',
                                 warn_on_default=False).split()
        return binding

    def GetCurrentKeySet(self):
        "Return CurrentKeys with 'darwin' modifications."
        result = self.GetKeySet(self.CurrentKeys())

        if sys.platform == "darwin":
            # macOS (OS X) Tk variants do not support the "Alt"
            # keyboard modifier.  Replace it with "Option".
            # TODO (Ned?): the "Option" modifier does not work properly
            #     for Cocoa Tk and XQuartz Tk so we should not use it
            #     in the default 'OSX' keyset.
            for k, v in result.items():
                v2 = [ x.replace('<Alt-', '<Option-') for x in v ]
                if v != v2:
                    result[k] = v2

        return result

    def GetKeySet(self, keySetName):
        """Return event-key dict for keySetName core plus active extensions.

        If a binding defined in an extension is already in use, the
        extension binding is disabled by being set to ''
        """
        keySet = self.GetCoreKeys(keySetName)
        activeExtns = self.GetExtensions(active_only=1)
        for extn in activeExtns:
            extKeys = self.__GetRawExtensionKeys(extn)
            if extKeys: #the extension defines keybindings
                for event in extKeys:
                    if extKeys[event] in keySet.values():
                        #the binding is already in use
                        extKeys[event] = '' #disable this binding
                    keySet[event] = extKeys[event] #add binding
        return keySet

    def IsCoreBinding(self, virtualEvent):
        """Return True if the virtual event is one of the core idle key events.

        virtualEvent - string, name of the virtual event to test for,
                       without the enclosing '<< >>'
        """
        return ('<<'+virtualEvent+'>>') in self.GetCoreKeys()

# TODO make keyBindings a file or class attribute used for test above
# and copied in function below.

    former_extension_events = {  #  Those with user-configurable keys.
        '<<force-open-completions>>', '<<expand-word>>',
        '<<force-open-calltip>>', '<<flash-paren>>', '<<format-paragraph>>',
         '<<run-module>>', '<<check-module>>', '<<zoom-height>>',
         '<<run-custom>>',
         }

    def GetCoreKeys(self, keySetName=None):
        """Return dict of core virtual-key keybindings for keySetName.

        The default keySetName None corresponds to the keyBindings base
        dict. If keySetName is not None, bindings from the config
        file(s) are loaded _over_ these defaults, so if there is a
        problem getting any core binding there will be an 'ultimate last
        resort fallback' to the CUA-ish bindings defined here.
        """
        # TODO: = dict(sorted([(v-event, keys), ...]))?
        keyBindings={
            # vitual-event: list of key events.
            '<<copy>>': ['<Control-c>', '<Control-C>'],
            '<<cut>>': ['<Control-x>', '<Control-X>'],
            '<<paste>>': ['<Control-v>', '<Control-V>'],
            '<<beginning-of-line>>': ['<Control-a>', '<Home>'],
            '<<center-insert>>': ['<Control-l>'],
            '<<close-all-windows>>': ['<Control-q>'],
            '<<close-window>>': ['<Alt-F4>'],
            '<<do-nothing>>': ['<Control-x>'],
            '<<end-of-file>>': ['<Control-d>'],
            '<<python-docs>>': ['<F1>'],
            '<<python-context-help>>': ['<Shift-F1>'],
            '<<history-next>>': ['<Alt-n>'],
            '<<history-previous>>': ['<Alt-p>'],
            '<<interrupt-execution>>': ['<Control-c>'],
            '<<view-restart>>': ['<F6>'],
            '<<restart-shell>>': ['<Control-F6>'],
            '<<open-class-browser>>': ['<Alt-c>'],
            '<<open-module>>': ['<Alt-m>'],
            '<<open-new-window>>': ['<Control-n>'],
            '<<open-window-from-file>>': ['<Control-o>'],
            '<<plain-newline-and-indent>>': ['<Control-j>'],
            '<<print-window>>': ['<Control-p>'],
            '<<redo>>': ['<Control-y>'],
            '<<remove-selection>>': ['<Escape>'],
            '<<save-copy-of-window-as-file>>': ['<Alt-Shift-S>'],
            '<<save-window-as-file>>': ['<Alt-s>'],
            '<<save-window>>': ['<Control-s>'],
            '<<select-all>>': ['<Alt-a>'],
            '<<toggle-auto-coloring>>': ['<Control-slash>'],
            '<<undo>>': ['<Control-z>'],
            '<<find-again>>': ['<Control-g>', '<F3>'],
            '<<find-in-files>>': ['<Alt-F3>'],
            '<<find-selection>>': ['<Control-F3>'],
            '<<find>>': ['<Control-f>'],
            '<<replace>>': ['<Control-h>'],
            '<<goto-line>>': ['<Alt-g>'],
            '<<smart-backspace>>': ['<Key-BackSpace>'],
            '<<newline-and-indent>>': ['<Key-Return>', '<Key-KP_Enter>'],
            '<<smart-indent>>': ['<Key-Tab>'],
            '<<indent-region>>': ['<Control-Key-bracketright>'],
            '<<dedent-region>>': ['<Control-Key-bracketleft>'],
            '<<comment-region>>': ['<Alt-Key-3>'],
            '<<uncomment-region>>': ['<Alt-Key-4>'],
            '<<tabify-region>>': ['<Alt-Key-5>'],
            '<<untabify-region>>': ['<Alt-Key-6>'],
            '<<toggle-tabs>>': ['<Alt-Key-t>'],
            '<<change-indentwidth>>': ['<Alt-Key-u>'],
            '<<del-word-left>>': ['<Control-Key-BackSpace>'],
            '<<del-word-right>>': ['<Control-Key-Delete>'],
            '<<force-open-completions>>': ['<Control-Key-space>'],
            '<<expand-word>>': ['<Alt-Key-slash>'],
            '<<force-open-calltip>>': ['<Control-Key-backslash>'],
            '<<flash-paren>>': ['<Control-Key-0>'],
            '<<format-paragraph>>': ['<Alt-Key-q>'],
            '<<run-module>>': ['<Key-F5>'],
            '<<run-custom>>': ['<Shift-Key-F5>'],
            '<<check-module>>': ['<Alt-Key-x>'],
            '<<zoom-height>>': ['<Alt-Key-2>'],
            }

        if keySetName:
            if not (self.userCfg['keys'].has_section(keySetName) or
                    self.defaultCfg['keys'].has_section(keySetName)):
                warning = (
                    '\n Warning: config.py - IdleConf.GetCoreKeys -\n'
                    ' key set %r is not defined, using default bindings.' %
                    (keySetName,)
                )
                _warn(warning, 'keys', keySetName)
            else:
                for event in keyBindings:
                    binding = self.GetKeyBinding(keySetName, event)
                    if binding:
                        keyBindings[event] = binding
                    # Otherwise return default in keyBindings.
                    elif event not in self.former_extension_events:
                        warning = (
                            '\n Warning: config.py - IdleConf.GetCoreKeys -\n'
                            ' problem retrieving key binding for event %r\n'
                            ' from key set %r.\n'
                            ' returning default value: %r' %
                            (event, keySetName, keyBindings[event])
                        )
                        _warn(warning, 'keys', keySetName, event)
        return keyBindings

    def GetExtraHelpSourceList(self, configSet):
        """Return list of extra help sources from a given configSet.

        Valid configSets are 'user' or 'default'.  Return a list of tuples of
        the form (menu_item , path_to_help_file , option), or return the empty
        list.  'option' is the sequence number of the help resource.  'option'
        values determine the position of the menu items on the Help menu,
        therefore the returned list must be sorted by 'option'.

        """
        helpSources = []
        if configSet == 'user':
            cfgParser = self.userCfg['main']
        elif configSet == 'default':
            cfgParser = self.defaultCfg['main']
        else:
            raise InvalidConfigSet('Invalid configSet specified')
        options=cfgParser.GetOptionList('HelpFiles')
        for option in options:
            value=cfgParser.Get('HelpFiles', option, default=';')
            if value.find(';') == -1: #malformed config entry with no ';'
                menuItem = '' #make these empty
                helpPath = '' #so value won't be added to list
            else: #config entry contains ';' as expected
                value=value.split(';')
                menuItem=value[0].strip()
                helpPath=value[1].strip()
            if menuItem and helpPath: #neither are empty strings
                helpSources.append( (menuItem,helpPath,option) )
        helpSources.sort(key=lambda x: x[2])
        return helpSources

    def GetAllExtraHelpSourcesList(self):
        """Return a list of the details of all additional help sources.

        Tuples in the list are those of GetExtraHelpSourceList.
        """
        allHelpSources = (self.GetExtraHelpSourceList('default') +
                self.GetExtraHelpSourceList('user') )
        return allHelpSources

    def GetFont(self, root, configType, section):
        """Retrieve a font from configuration (font, font-size, font-bold)
        Intercept the special value 'TkFixedFont' and substitute
        the actual font, factoring in some tweaks if needed for
        appearance sakes.

        The 'root' parameter can normally be any valid Tkinter widget.

        Return a tuple (family, size, weight) suitable for passing
        to tkinter.Font
        """
        family = self.GetOption(configType, section, 'font', default='courier')
        size = self.GetOption(configType, section, 'font-size', type='int',
                              default='10')
        bold = self.GetOption(configType, section, 'font-bold', default=0,
                              type='bool')
        if (family == 'TkFixedFont'):
            f = Font(name='TkFixedFont', exists=True, root=root)
            actualFont = Font.actual(f)
            family = actualFont['family']
            size = actualFont['size']
            if size <= 0:
                size = 10  # if font in pixels, ignore actual size
            bold = actualFont['weight'] == 'bold'
        return (family, size, 'bold' if bold else 'normal')

    def LoadCfgFiles(self):
        "Load all configuration files."
        for key in self.defaultCfg:
            self.defaultCfg[key].Load()
            self.userCfg[key].Load() #same keys

    def SaveUserCfgFiles(self):
        "Write all loaded user configuration files to disk."
        for key in self.userCfg:
            self.userCfg[key].Save()


idleConf = IdleConf()

_warned = set()
def _warn(msg, *key):
    key = (msg,) + key
    if key not in _warned:
        try:
            print(msg, file=sys.stderr)
        except OSError:
            pass
        _warned.add(key)


class ConfigChanges(dict):
    """Manage a user's proposed configuration option changes.

    Names used across multiple methods:
        page -- one of the 4 top-level dicts representing a
                .idlerc/config-x.cfg file.
        config_type -- name of a page.
        section -- a section within a page/file.
        option -- name of an option within a section.
        value -- value for the option.

    Methods
        add_option: Add option and value to changes.
        save_option: Save option and value to config parser.
        save_all: Save all the changes to the config parser and file.
        delete_section: If section exists,
                        delete from changes, userCfg, and file.
        clear: Clear all changes by clearing each page.
    """
    def __init__(self):
        "Create a page for each configuration file"
        self.pages = []  # List of unhashable dicts.
        for config_type in idleConf.config_types:
            self[config_type] = {}
            self.pages.append(self[config_type])

    def add_option(self, config_type, section, item, value):
        "Add item/value pair for config_type and section."
        page = self[config_type]
        value = str(value)  # Make sure we use a string.
        if section not in page:
            page[section] = {}
        page[section][item] = value

    @staticmethod
    def save_option(config_type, section, item, value):
        """Return True if the configuration value was added or changed.

        Helper for save_all.
        """
        if idleConf.defaultCfg[config_type].has_option(section, item):
            if idleConf.defaultCfg[config_type].Get(section, item) == value:
                # The setting equals a default setting, remove it from user cfg.
                return idleConf.userCfg[config_type].RemoveOption(section, item)
        # If we got here, set the option.
        return idleConf.userCfg[config_type].SetOption(section, item, value)

    def save_all(self):
        """Save configuration changes to the user config file.

        Clear self in preparation for additional changes.
        Return changed for testing.
        """
        idleConf.userCfg['main'].Save()

        changed = False
        for config_type in self:
            cfg_type_changed = False
            page = self[config_type]
            for section in page:
                if section == 'HelpFiles':  # Remove it for replacement.
                    idleConf.userCfg['main'].remove_section('HelpFiles')
                    cfg_type_changed = True
                for item, value in page[section].items():
                    if self.save_option(config_type, section, item, value):
                        cfg_type_changed = True
            if cfg_type_changed:
                idleConf.userCfg[config_type].Save()
                changed = True
        for config_type in ['keys', 'highlight']:
            # Save these even if unchanged!
            idleConf.userCfg[config_type].Save()
        self.clear()
        # ConfigDialog caller must add the following call
        # self.save_all_changed_extensions()  # Uses a different mechanism.
        return changed

    def delete_section(self, config_type, section):
        """Delete a section from self, userCfg, and file.

        Used to delete custom themes and keysets.
        """
        if section in self[config_type]:
            del self[config_type][section]
        configpage = idleConf.userCfg[config_type]
        configpage.remove_section(section)
        configpage.Save()

    def clear(self):
        """Clear all 4 pages.

        Called in save_all after saving to idleConf.
        XXX Mark window *title* when there are changes; unmark here.
        """
        for page in self.pages:
            page.clear()


# TODO Revise test output, write expanded unittest
def _dump():  # htest # (not really, but ignore in coverage)
    from zlib import crc32
    line, crc = 0, 0

    def sprint(obj):
        nonlocal line, crc
        txt = str(obj)
        line += 1
        crc = crc32(txt.encode(encoding='utf-8'), crc)
        print(txt)
        #print('***', line, crc, '***')  # Uncomment for diagnosis.

    def dumpCfg(cfg):
        print('\n', cfg, '\n')  # Cfg has variable '0xnnnnnnnn' address.
        for key in sorted(cfg):
            sections = cfg[key].sections()
            sprint(key)
            sprint(sections)
            for section in sections:
                options = cfg[key].options(section)
                sprint(section)
                sprint(options)
                for option in options:
                    sprint(option + ' = ' + cfg[key].Get(section, option))

    dumpCfg(idleConf.defaultCfg)
    dumpCfg(idleConf.userCfg)
    print('\nlines = ', line, ', crc = ', crc, sep='')


if __name__ == '__main__':
    from unittest import main
    main('idlelib.idle_test.test_config', verbosity=2, exit=False)

    _dump()
    # Run revised _dump() (700+ lines) as htest?  More sorting.
    # Perhaps as window with tabs for textviews, making it config viewer.