PS6

#======================
# Part 1
# Data structure design
#======================

# Problem 1

class NewsStory(object):
    def __init__(self, guid, title, subject, summary, link):
        self.guid = guid
        self.title = title
        self.subject = subject
        self.summary = summary
        self.link = link

    def getGuid(self):
        return self.guid

    def getTitle(self):
        return self.title

    def getSubject(self):
        return self.subject

    def getSummary(self):
        return self.summary

    def getLink(self):
        return self.link

#======================
# Part 2
# Triggers
#======================

class Trigger(object):
    def evaluate(self, story):
        """
        Returns True if an alert should be generated
        for the given news item, or False otherwise.
        """
        raise NotImplementedError

# Whole Word Triggers
# Problems 2-5

class WordTrigger(Trigger):
    def __init__(self, word):
        self.word = word.lower()

    def isWordIn(self, text):
        the_text = text[:]
        the_text = the_text.lower()
        for i in range(0, len(string.punctuation)):
            the_text = string.replace(the_text, string.punctuation[i], ' ')
        the_text = the_text.split(' ')
        return self.word in the_text


class TitleTrigger(WordTrigger):
    def evaluate(self, story):
        """
        Returns True if an alert should be generated
        for the given news item, or False otherwise.
        """
        return self.isWordIn(story.getTitle())


class SubjectTrigger(WordTrigger):
    def evaluate(self, story):
        """
        Returns True if an alert should be generated
        for the given news item, or False otherwise.
        """
        return self.isWordIn(story.getSubject())

class SummaryTrigger(WordTrigger):
    def evaluate(self, story):
        """
        Returns True if an alert should be generated
        for the given news item, or False otherwise.
        """
        return self.isWordIn(story.getSummary())

# Composite Triggers
# Problems 6-8

class NotTrigger(Trigger):
    def __init__(self, T):
        self.T = T

    def evaluate(self, story):
        """
        Returns True if an alert should be generated
        for the given news item, or False otherwise.
        """
        return not self.T.evaluate(story)

class AndTrigger(Trigger):
    def __init__(self, T1, T2):
        self.T1 = T1
        self.T2 = T2

    def evaluate(self, story):
        """
        Returns True if an alert should be generated
        for the given news item, or False otherwise.
        """
        return self.T1.evaluate(story) and self.T2.evaluate(story)

class OrTrigger(Trigger):
    def __init__(self, T1, T2):
        self.T1 = T1
        self.T2 = T2

    def evaluate(self, story):
        """
        Returns True if an alert should be generated
        for the given news item, or False otherwise.
        """
        return self.T1.evaluate(story) or self.T2.evaluate(story)


# Phrase Trigger
# Question 9

class PhraseTrigger(Trigger):
    def __init__(self, phrase):
        self.phrase = phrase
    def evaluate(self, story):
        """
        Returns True if an alert should be generated
        for the given news item, or False otherwise.
        """
        if self.phrase in story.getTitle():
            return True
        elif self.phrase in story.getSubject():
            return True
        elif self.phrase in story.getSummary():
            return True
        return False

#======================
# Part 3
# Filtering
#======================

def filterStories(stories, triggerlist):
    """
    Takes in a list of NewsStory instances.

    Returns: a list of only the stories for which a trigger in triggerlist fires.
    """
    storyList = []
    for story in stories:
        for trigger in triggerlist:
            if trigger.evaluate(story):
                storyList.append(story)
    return storyList

#======================
# Part 4
# User-Specified Triggers
#======================

def makeTrigger(triggerMap, triggerType, params, name):
    """
    Takes in a map of names to trigger instance, the type of trigger to make,
    and the list of parameters to the constructor, and adds a new trigger
    to the trigger map dictionary.

    triggerMap: dictionary with names as keys (strings) and triggers as values
    triggerType: string indicating the type of trigger to make (ex: "TITLE")
    params: list of strings with the inputs to the trigger constructor (ex: ["world"])
    name: a string representing the name of the new trigger (ex: "t1")

    Modifies triggerMap, adding a new key-value pair for this trigger.

    Returns: None
    """
    if triggerType == 'SUMMARY':
        trigger = SummaryTrigger(params[0])
    elif triggerType == 'SUBJECT':
        trigger = SubjectTrigger(params[0])
    elif triggerType == 'TITLE':
        trigger = TitleTrigger(params[0])
    elif triggerType == 'PHRASE':
        phrase = (' ').join(params)
        trigger = PhraseTrigger(phrase)
    elif triggerType == 'AND':
        trigger = AndTrigger(triggerMap[params[0]], triggerMap[params[1]])
    elif triggerType == 'OR':
        trigger = OrTrigger(triggerMap[params[0]], triggerMap[params[1]])
    elif triggerType == 'NOT':
        trigger = NotTrigger(triggerMap[params[0]])
    else:
        return None
    triggerMap[name] = trigger
    return trigger