import urllib
import string
import copy

class Stock(object):

    #Maps common stat name to (indexStr, toFindColon)
    dictStatToIndexTuple = {'Price' : ('time_rtq_ticker', False),
                            'Shares Outstanding' : ('>Shares Outstanding', True),
                            'Operating Cash Flow' : ('>Operating Cash Flow (TTM)', True),
                            'Price/Sales' : ('>Price/Sales (ttm)', True),
                            'Price/Earnings (Forward)' : ('>Forward P/E (fye', True),
                            'Price/Book' : ('>Price/Book (mrq)', True),
                            'Enterprise Value/EBITDA' : ('>Enterprise Value/EBITDA (ttm)', True)}

    def __init__(self, name, tag):
        """
        name = a string of the stock's name, to be displayed to user
        tag = a string of the stock's Yahoo! Finance tag
        """
        assert type(name) == str and type(tag) == str
        self.name = name
        self.tag = tag
        self.url = 'http://finance.yahoo.com/q/ks?s=' + tag
        self.statDict = {}
        self.update()

    def update(self):
        """
        Pull and calculate the current stock statistics
        """

        print '=====Types in update function====='

        #Refresh source. Generate error if not connected to internet?
        source = urllib.urlopen(self.url).read() #Need to specify read size to ensure reads all of file?      
        print 'type(source) =', type(source)

        #For each stat pull its value and add it to self.statDict
        for stat in Stock.dictStatToIndexTuple:
            #The paramater used as toFindColon
            print 'type(Stock.dictStatToIndexTuple[stat][1]) =', type(Stock.dictStatToIndexTuple[stat][1]), '\n'
            indexStr = copy.deepcopy(Stock.dictStatToIndexTuple[stat][0])
            toFindColon = copy.deepcopy(Stock.dictStatToIndexTuple[stat][1])
            self.statDict[stat] = self.pullStockDataField(source, indexStr, toFindColon)

    def pullStockDataField(source, indexStr, toFindColon, numOpenTags = 1):
        """
        Given source, a string containing the source code of the
        stock company's Yahoo! Finance Key Statistics page, indexStr,
        a string of characters with which to search the page source for the starting
        index (specifying which data field to pull), and toFindColon, a boolean
        indicating whether or not a displayed colon should be found before displayed
        numbers indicate the value of the data field,
        Returns a float containing the value of the data field.
        """
        
        ##########################
        #Why do the types change?#
        ##########################
        print '=====Types in pullStockDataField function====='
        print 'type(source) =', type(source)
        print 'type(toFindColon) =', type(toFindColon)
        assert type(source) == str and type(indexStr) == str
        assert type(numOpenTags) == int and type(toFindColon) == bool

        #snip...
        
google = Stock('Google', 'GOOG')

>>> 
=====Types in update function=====
type(source) = <type 'str'>
type(Stock.dictStatToIndexTuple[stat][1]) = <type 'bool'> 

=====Types in pullStockDataField function=====
type(source) = <class '__main__.Stock'>
type(toFindColon) = <type 'str'>

Traceback (most recent call last):
  File "C:/Users/Scott Emmons/Desktop/blah.py", line 69, in <module>
    google = Stock('Google', 'GOOG')
  File "C:/Users/Scott Emmons/Desktop/blah.py", line 26, in __init__
    self.update()
  File "C:/Users/Scott Emmons/Desktop/blah.py", line 45, in update
    self.statDict[stat] = self.pullStockDataField(source, indexStr, toFindColon)
  File "C:/Users/Scott Emmons/Desktop/blah.py", line 64, in pullStockDataField
    assert type(source) == str and type(indexStr) == str
AssertionError
>>>

self.statDict[stat] = self.pullStockDataField(source, indexStr, toFindColon)

    def pullStockDataField(source, indexStr, toFindColon, numOpenTags = 1):