#!/usr/bin/env python

###
# Copyright (c) 2002, Jeremiah Fincher
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###

"""
Silently listens to a channel, building an SQL database of Markov Chains for
later hijinks.  To read more about Markov Chains, check out
<http://www.cs.bell-labs.com/cm/cs/pearls/sec153.html>.  When the database is
large enough, you can have it make fun little random messages from it.
"""

import plugins

import os.path

import sqlite

import debug
import ircmsgs
import ircutils
import privmsgs
import callbacks


def configure(onStart, afterConnect, advanced):
    # This will be called by setup.py to configure this module.  onStart and
    # afterConnect are both lists.  Append to onStart the commands you would
    # like to be run when the bot is started; append to afterConnect the
    # commands you would like to be run when the bot has finished connecting.
    from questions import expect, anything, something, yn
    onStart.append('load Markov')

class Markov(plugins.ChannelDBHandler, callbacks.Privmsg):
    def __init__(self):
        plugins.ChannelDBHandler.__init__(self)
        callbacks.Privmsg.__init__(self)

    def makeDb(self, filename):
        if os.path.exists(filename):
            return sqlite.connect(filename)
        db = sqlite.connect(filename)
        cursor = db.cursor()
        cursor.execute("""CREATE TABLE pairs (
                          id INTEGER PRIMARY KEY,
                          first TEXT,
                          second TEXT,
                          is_first BOOLEAN,
                          UNIQUE (first, second) ON CONFLICT IGNORE
                          )""")
        cursor.execute("""CREATE TABLE follows (
                          id INTEGER PRIMARY KEY,
                          pair_id INTEGER,
                          word TEXT
                          )""")
        cursor.execute("""CREATE INDEX follows_pair_id ON follows (pair_id)""")
        db.commit()
        return db

    def doPrivmsg(self, irc, msg):
        if not ircutils.isChannel(msg.args[0]):
            return callbacks.Privmsg.doPrivmsg(self, irc, msg)
        channel = msg.args[0]
        db = self.getDb(channel)
        cursor = db.cursor()
        if ircmsgs.isAction(msg):
            words = ircmsgs.unAction(msg).split()
        else:
            words = msg.args[1].split()
        isFirst = True
        for (first, second, follower) in window(words, 3):
            if isFirst:
                cursor.execute("""INSERT OR REPLACE
                                  INTO pairs VALUES (NULL, %s, %s, 1)""",
                               first, second)
                isFirst = False
            else:
                cursor.execute("INSERT INTO pairs VALUES (NULL, %s, %s, 0)",
                               first, second)
            cursor.execute("""SELECT id FROM pairs
                              WHERE first=%s AND second=%s""", first, second)
            id = int(cursor.fetchone()[0])
            cursor.execute("""INSERT INTO follows VALUES (NULL, %s, %s)""",
                           id, follower)
        if not isFirst: # i.e., if the loop iterated at all.
            cursor.execute("""INSERT INTO pairs VALUES (NULL, %s, %s, 0)""",
                           second, follower)
            cursor.execute("""SELECT id FROM pairs
                              WHERE first=%s AND second=%s""", second,follower)
            id = int(cursor.fetchone()[0])
            cursor.execute("INSERT INTO follows VALUES (NULL, %s, NULL)", id)
        db.commit()
        return callbacks.Privmsg.doPrivmsg(self, irc, msg)

    _maxMarkovLength = 80
    _minMarkovLength = 7
    def markov(self, irc, msg, args):
        """[<channel>]

        Returns a randomly-generated Markov Chain generated sentence from the
        data kept on <channel> (which is only necessary if not sent in the
        channel itself).
        """
        channel = privmsgs.getChannel(msg, args)
        db = self.getDb(channel)
        cursor = db.cursor()
        words = []
        cursor.execute("""SELECT id, first, second FROM pairs
                          WHERE is_first=1
                          ORDER BY random()
                          LIMIT 1""")
        if cursor.rowcount == 0:
            irc.error(msg, 'I have no records for that channel.')
            return
        (id, first, second) = cursor.fetchone()
        id = int(id)
        words.append(first)
        words.append(second)
        sql = """SELECT follows.word FROM pairs, follows
                 WHERE pairs.first=%s AND
                       pairs.second=%s AND
                       pairs.id=follows.pair_id
                 ORDER BY random()
                 LIMIT 1"""
        while len(words) < self._maxMarkovLength:
            cursor.execute(sql, words[-2], words[-1])
            results = cursor.fetchone()
            if not results:
                break
            word = results[0]
            if word is None:
                break
            words.append(word)
        if len(words) < self._minMarkovLength:
            self.markov(irc, msg, args)
        else:
            irc.reply(msg, ' '.join(words))

    def markovpairs(self, irc, msg, args):
        """[<channel>]

        Returns the number of Markov's chain links in the database for
        <channel>.
        """
        channel = privmsgs.getChannel(msg, args)
        db = self.getDb(channel)
        cursor = db.cursor()
        cursor.execute("""SELECT COUNT(*) FROM pairs""")
        n = cursor.fetchone()[0]
        s = 'There are %s pairs in my Markov database for %s' % (n, channel)
        irc.reply(msg, s)

    def markovfirsts(self, irc, msg, args):
        """[<channel>]

        Returns the number of Markov's first links in the database for
        <channel>.
        """
        channel = privmsgs.getChannel(msg, args)
        db = self.getDb(channel)
        cursor = db.cursor()
        cursor.execute("""SELECT COUNT(*) FROM pairs WHERE is_first=1""")
        n = cursor.fetchone()[0]
        s = 'There are %s first pairs in my Markov database for %s'%(n,channel)
        irc.reply(msg, s)

    def markovfollows(self, irc, msg, args):
        """[<channel>]

        Returns the number of Markov's third links in the database for
        <channel>.
        """
        channel = privmsgs.getChannel(msg, args)
        db = self.getDb(channel)
        cursor = db.cursor()
        cursor.execute("""SELECT COUNT(*) FROM follows""")
        n = cursor.fetchone()[0]
        s = 'There are %s follows in my Markov database for %s' % (n, channel)
        irc.reply(msg, s)

    def markovlasts(self, irc, msg, args):
        """[<channel>]

        Returns the number of Markov's last links in the database for
        <channel>.
        """
        channel = privmsgs.getChannel(msg, args)
        db = self.getDb(channel)
        cursor = db.cursor()
        cursor.execute("""SELECT COUNT(*) FROM follows WHERE word ISNULL""")
        n = cursor.fetchone()[0]
        s = 'There are %s lasts in my Markov database for %s' % (n, channel)
        irc.reply(msg, s)


Class = Markov

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