from xml.etree.ElementTree import ElementTree
import util.Strings as Strings
classArgsMem = {}
CONFIG_PATH = 'config/'
def loadParamRequirementDict(className):
    if not className in classArgsMem: #WOO CACHING
        classArgsMem[className] = fileToDict(CONFIG_PATH + className) 
    return classArgsMem[className]
def loadConfigFile(fileName): #TODO: error handling etc.
    #try:
        fileName = CONFIG_PATH + fileName
        if '.params' in fileName:
            return fileToDict(fileName)
        if '.xml' in fileName:
            config = ElementTree()
            config.parse(fileName)
            return config
    #except:
        return None
def compositeXMLTrees(parentTree, overridingTree):
    #type checking -- convert ElementTrees to their root elements
    parentItems = parentTree.getchildren()
    overrideItems = overridingTree.getchildren()
    #first, lets figure out what tags we have in the override tree:
    tagCollection = [el.tag for el in overrideItems] #we can speed this up with a dict if necessary
    overrideRoot = overridingTree.getroot()
    for item in parentItems:
        if not item.tag in tagCollection: #no override 
            overrideRoot.insert(-1, item) #insert the new item at the end
        else:
            #do we merge or replace?
            intersectingElements = findElementsByTag(item.tag, overrideItems)
            if len(intersectingItems) > 1:
                print 'ABUSE!'
            interEl = intersectingElements[0]
            mode = 'Replace'
            if Strings.OVERRIDE_BEHAVIOR in interEl.attrib:
                mode = interEl.attrib[Strings.OVERRIDE_BEHAVIOR] 
            if mode != 'Replace' and mode != 'Merge':
                print 'Bad Mode.  Replacing'
                mode = 'Replace'
            if mode = 'Replace':
                pass #we don't need to do anything
            if mode = 'Merge': 
                pass #TODO: code this

def findElementsByTag(tag, eList):
    return [el for el in eList if el.tag == tag]
def fileToDict(fileName):
    fileText = ''
    try:
        print 'File Read'
        with open(fileName) as f:
            for line in f:
                fileText += line.rstrip('\n').lstrip('\t') + ' ' 
    except IOError:
        return {}
    if fileText == '':
        return {}
    return eval(fileText)
#parses arguments into python objects if possible, otherwise leaves as strings
def generateArgDict(parentNode, recurse=False):
    args = {}
    for arg in parentNode.getchildren():
        key = arg.tag
        if arg.getchildren() != []:
            value = generateArgDict(arg, True)
        else:
            #convert into python if possible, otherwise don't
            try:
                value = eval(arg.text)
            except (NameError,SyntaxError):
                value = str(arg.text)
        if key in args: #build of lists of like-elements
            if type(args[key]) != type([]):
                args[key] = [args[key]]
            args[key].append(value)
        else:
            args[key]=value
    #if we should be a list but we aren't:
    if len(args.keys()) == 1 and recurse:
        return args[args.keys()[0]]
    return args