"""
Provides access to stored idle configuration information.
"""
# Throughout this module there is an emphasis on returning useable 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. 

import os
import sys
from ConfigParser import ConfigParser, NoOptionError, NoSectionError

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
        ConfigParser.__init__(self,defaults=cfgDefaults)
    
    def Get(self, section, option, type=None, default=None):
        """
        Get an option value for given section/option or return default.
        If type is specified, return as type.
        """
        if type=='bool': 
            getVal=self.getboolean
        elif type=='int': 
            getVal=self.getint
        else: 
            getVal=self.get
        if self.has_option(section,option):
            #return getVal(section, option, raw, vars, default)
            return getVal(section, option)
        else:
            return default

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

    def Load(self):
        """ 
        Load the configuration file from disk 
        """
        self.read(self.file)
        
class IdleUserConfParser(IdleConfParser):
    """
    IdleConfigParser specialised for user configuration handling.
    """

    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):
        """
        Remove empty sections and then return 1 if parser has no sections
        left, else return 0.
        """
        self.RemoveEmptySections()
        if self.sections():
            return 0
        else:
            return 1
    
    def RemoveOption(self,section,option):
        """
        If section/option exists, remove it.
        Returns 1 if option was removed, 0 otherwise.
        """
        if self.has_section(section):
            return self.remove_option(section,option)
    
    def SetOption(self,section,option,value):
        """
        Sets option to value, adding section if required.
        Returns 1 if option was added or changed, otherwise 0.
        """
        if self.has_option(section,option):
            if self.get(section,option)==value:
                return 0
            else:
                self.set(section,option,value)
                return 1
        else:
            if not self.has_section(section):
                self.add_section(section)
            self.set(section,option,value)
            return 1
     
    def Save(self):
        """
        If config isn't empty, write file to disk. If config is empty,
        remove the file from disk if it exists.
        """
        if not self.IsEmpty():
            cfgFile=open(self.file,'w')
            self.write(cfgFile)
        else:
            if os.path.exists(self.file):
                os.remove(self.file)    

class IdleConf:
    """
    holds config parsers for all idle config files:
    default config files
        (idle install dir)/config-main.def
        (idle install dir)/config-extensions.def
        (idle install dir)/config-highlight.def
        (idle install dir)/config-keys.def
    user config  files
        (user home dir)/.idlerc/config-main.cfg
        (user home dir)/.idlerc/config-extensions.cfg
        (user home dir)/.idlerc/config-highlight.cfg
        (user home dir)/.idlerc/config-keys.cfg
    """
    def __init__(self):
        self.defaultCfg={}
        self.userCfg={}
        self.cfg={}
        self.CreateConfigHandlers()
        self.LoadCfgFiles()
        #self.LoadCfg()
            
    def CreateConfigHandlers(self):
        """
        set up a dictionary of config parsers for default and user 
        configurations respectively
        """
        #build idle install path
        if __name__ != '__main__': # we were imported
            idleDir=os.path.dirname(__file__)
        else: # we were exec'ed (for testing only)
            idleDir=os.path.abspath(sys.path[0])
        userDir=self.GetUserCfgDir()
        configTypes=('main','extensions','highlight','keys')
        defCfgFiles={}
        usrCfgFiles={}
        for cfgType in configTypes: #build config file names
            defCfgFiles[cfgType]=os.path.join(idleDir,'config-'+cfgType+'.def')                    
            usrCfgFiles[cfgType]=os.path.join(userDir,'config-'+cfgType+'.cfg')                    
        for cfgType in configTypes: #create config parsers
            self.defaultCfg[cfgType]=IdleConfParser(defCfgFiles[cfgType])
            self.userCfg[cfgType]=IdleUserConfParser(usrCfgFiles[cfgType])
    
    def GetUserCfgDir(self):
        """
        Creates (if required) and returns a filesystem directory for storing 
        user config files.
        """
        cfgDir='.idlerc'
        userDir=os.path.expanduser('~')
        if userDir != '~': #'HOME' exists as a key in os.environ
            if not os.path.exists(userDir):
                warn=('\n Warning: HOME environment variable points to\n '+
                        userDir+'\n but the path does not exist.\n')
                sys.stderr.write(warn)
                userDir='~'
        if userDir=='~': #we still don't have a home directory
            #traditionally idle has defaulted to os.getcwd(), is this adeqate?
            userDir = os.getcwd() #hack for no real homedir
        userDir=os.path.join(userDir,cfgDir)    
        if not os.path.exists(userDir):
            try: #make the config dir if it doesn't exist yet 
                os.mkdir(userDir)
            except IOError:
                warn=('\n Warning: unable to create user config directory\n '+
                        userDir+'\n')
                sys.stderr.write(warn)
        return userDir
    
    def GetOption(self, configType, section, option, default=None, type=None):
        """
        Get an option value for given config type and given general 
        configuration section/option or return a default. If type is specified,
        return as type. Firstly the user configuration is checked, with a 
        fallback to the default configuration, and a final 'catch all' 
        fallback to a useable passed-in default if the option isn't present in 
        either the user or the default configuration.
        configType must be one of ('main','extensions','highlight','keys')
        If a default is returned a warning is printed to stderr.
        """
        if self.userCfg[configType].has_option(section,option):
            return self.userCfg[configType].Get(section, option, type=type)
        elif self.defaultCfg[configType].has_option(section,option):
            return self.defaultCfg[configType].Get(section, option, type=type)
        else:
            warning=('\n Warning: configHandler.py - IdleConf.GetOption -\n'+
                       ' problem retrieving configration option '+`option`+'\n'+
                       ' from section '+`section`+'.\n'+
                       ' returning default value: '+`default`+'\n')
            sys.stderr.write(warning)
            return default
    
    def GetSectionList(self, configSet, configType):
        """
        Get a list of sections from either the user or default config for 
        the given config type.
        configSet must be either 'user' or 'default' 
        configType must be one of ('main','extensions','highlight','keys')
        """
        if not (configType in ('main','extensions','highlight','keys')):
            raise 'Invalid configType specified'
        if configSet == 'user':
            cfgParser=self.userCfg[configType]
        elif configSet == 'default':
            cfgParser=self.defaultCfg[configType]
        else:
            raise 'Invalid configSet specified'
        return cfgParser.sections()
    
    def GetHighlight(self, theme, element, fgBg=None):
        """
        return individual highlighting theme elements.
        fgBg - string ('fg'or'bg') or None, if None return a dictionary
        containing fg and bg colours (appropriate for passing to Tkinter in, 
        e.g., a tag_config call), otherwise fg or bg colour only as specified. 
        """
        #get some fallback defaults
        defaultFg=self.GetOption('highlight', theme, 'normal' + "-foreground",
            default='#000000')
        defaultBg=self.GetOption('highlight', theme, 'normal' + "-background",
            default='#ffffff')
        #try for requested element colours
        fore = self.GetOption('highlight', theme, element + "-foreground")
        back = None
        if element == 'cursor': #there is no config value for cursor bg
            back = None
        else:    
            back = self.GetOption('highlight', theme, element + "-background")
        #fall back if required
        if not fore: fore=defaultFg
        if not back: back=defaultBg
        highlight={"foreground": fore,"background": back}
        if not fgBg: #return dict of both colours
            return highlight
        else: #return specified colour only
            if fgBg == 'fg':
                return highlight["foreground"]
            if fgBg == 'bg':
                return highlight["background"]
            else:    
                raise 'Invalid fgBg specified'
            
    def GetThemeDict(self,type,themeName):
        """
        type - string, 'default' or 'user' theme type
        themeName - string, theme name
        Returns a dictionary which holds {option:value} for each element
        in the specified theme. Values are loaded over a set of ultimate last
        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 'Invalid theme type specified'
        #foreground and background values are provded for each theme element
        #(apart from cursor) even though all these values are not yet used
        #by idle, to allow for their use in the future. Default values are
        #generally black and white.
        theme={ 'normal-foreground':'#000000', 
                'normal-background':'#ffffff', 
                'keyword-foreground':'#000000', 
                'keyword-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', 
                #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.keys():
            colour=cfgParser.Get(type,themeName,element,default=theme[element])        
            theme[element]=colour
        return theme
        
    def CurrentTheme(self):
        """
        Returns the name of the currently active theme        
        """
        return self.GetOption('main','Theme','name',default='')
        
    def CurrentKeys(self):
        """
        Returns the name of the currently active theme        
        """
        return self.GetOption('main','Keys','name',default='')
    
    def GetExtensions(self, activeOnly=1):
        """
        Gets a list of all idle extensions declared in the config files.
        activeOnly - boolean, if true only return active (enabled) 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) 
        if activeOnly:
            activeExtns=[]
            for extn in extns:
                if self.GetOption('extensions',extn,'enable',default=1,
                    type='bool'):
                    #the extension is enabled
                    activeExtns.append(extn)
            return activeExtns
        else:
            return extns        

    def RemoveKeyBindNames(self,extnNameList):
        #get rid of keybinding section names
        names=extnNameList
        kbNameIndicies=[]
        for name in names:
            if name.endswith('_bindings') or name.endswith('_cfgBindings'): 
                    kbNameIndicies.append(names.index(name))
        kbNameIndicies.sort()
        kbNameIndicies.reverse()
        for index in kbNameIndicies: #delete each keybinding section name    
            del(names[index])
        return names
        
    def GetExtnNameForEvent(self,virtualEvent):
        """
        Returns the name of the extension that virtualEvent is bound in, or
        None if not bound in any extension.
        virtualEvent - string, name of the virtual event to test for, without
                       the enclosing '<< >>'
        """
        extName=None
        vEvent='<<'+virtualEvent+'>>'
        for extn in self.GetExtensions(activeOnly=0):
            for event in self.GetExtensionKeys(extn).keys():
                if event == vEvent:
                    extName=extn
                    print extName
        return extName
    
    def GetExtensionKeys(self,extensionName):
        """
        returns a dictionary of the configurable keybindings for a particular
        extension,as they exist in the dictionary returned by GetCurrentKeySet;
        that is, 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):
        """
        returns a dictionary of the configurable keybindings for a particular
        extension, as defined in the configuration files, or an empty dictionary
        if no bindings are found
        """
        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):
        """
        Returns a dictionary of all the event bindings for a particular
        extension. The configurable keybindings are returned as they exist in
        the dictionary returned by GetCurrentKeySet; that is, where re-used 
        keybindings are disabled.
        """
        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):
        """
        returns the keybinding for a specific event.
        keySetName - string, name of key binding set
        eventStr - string, the virtual event we want the binding for, 
                   represented as a string, eg. '<<event>>'
        """
        eventName=eventStr[2:-2] #trim off the angle brackets
        binding=self.GetOption('keys',keySetName,eventName,default='').split()
        return binding

    def GetCurrentKeySet(self):
        return self.GetKeySet(self.CurrentKeys())
    
    def GetKeySet(self,keySetName):
        """
        Returns a dictionary of: all requested core keybindings, plus the 
        keybindings for all currently active extensions. If a binding defined
        in an extension is already in use, that binding is disabled.
        """
        keySet=self.GetCoreKeys(keySetName)
        activeExtns=self.GetExtensions(activeOnly=1)
        for extn in activeExtns:
            extKeys=self.__GetRawExtensionKeys(extn)
            if extKeys: #the extension defines keybindings
                for event in extKeys.keys():
                    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):
        """
        returns true if the virtual event is bound in the core idle keybindings.
        virtualEvent - string, name of the virtual event to test for, without
                       the enclosing '<< >>'
        """
        return ('<<'+virtualEvent+'>>') in self.GetCoreKeys().keys()
    
    def GetCoreKeys(self, keySetName=None):
        """
        returns the requested set of core keybindings, with fallbacks if
        required.
        Keybindings loaded 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.
        """
        keyBindings={
            '<<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>'],
            '<<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>'],
            '<<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>'],
            '<<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>'] }
        
        if keySetName:
            for event in keyBindings.keys():
                binding=self.GetKeyBinding(keySetName,event)
                if binding: #otherwise will keep default
                    keyBindings[event]=binding
            
        return keyBindings

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

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

idleConf=IdleConf()

### module test
if __name__ == '__main__':
    def dumpCfg(cfg):
        print '\n',cfg,'\n'
        for key in cfg.keys():
            sections=cfg[key].sections()
            print key
            print sections
            for section in sections:
                options=cfg[key].options(section)
                print section    
                print options
                for option in options:
                    print option, '=', cfg[key].Get(section,option)
    dumpCfg(idleConf.defaultCfg)
    dumpCfg(idleConf.userCfg)
    print idleConf.userCfg['main'].Get('Theme','name')
    #print idleConf.userCfg['highlight'].GetDefHighlight('Foo','normal')