"""
    Full-text searching of logs
"""

import datetime, calendar, pytz

import HyperEstraier as hype

import log_line

class LogSearchIndex (object) :
    """
        An index on the logs for a group of channels.

        This uses Hyper Estraier to handle searching, whereby each log line is a document (yes, I have a powerful server).

        These log documents have the following attributes:
            @uri        - channel/date/line
            @channel    - channel id
            @type       - the LogType id
            @timestamp  - UTC timestamp
            @source     - nickname

        Each document then has a single line of data, which is the log message itself
    """

    def __init__ (self, path, mode='r') :
        """
            Open the database, with the given mode:
                r       - read-only
                w       - read-write, create if not exists
                a       - read-write, do not create
                *       - read-write, truncate and create new
        """
        
        # mapping of { mode -> flags }
        mode_to_flag = {
            'r':    hype.Database.DBREADER,
            'w':    hype.Database.DBREADER | hype.Database.DBWRITER | hype.Database.DBCREAT,
            'a':    hype.Database.DBREADER | hype.Database.DBWRITER | hype.Database.DBCREAT,
            '*':    hype.Database.DBREADER | hype.Database.DBWRITER | hype.Database.DBCREAT | hype.Database.DBTRUNC,
        }

        # look up flags
        flags = mode_to_flag[mode]
        
        # make instance
        self.db = hype.Database()
        
        # open
        if not self.db.open(path, flags) :
            raise Exception("Index open failed: %s, mode=%s, flags=%#06x: %s" % (path, mode, flags, self.db.err_msg(self.db.error())))

    def insert (self, channel, lines) :
        """
            Adds a sequence of LogLines from the given LogChannel to the index
        """
        
        # validate the LogChannel
        assert channel.name
        
        # iterate
        for line in lines :
            # validate the LogLine
            assert line.offset
            assert line.timestamp

            # create new document
            doc = hype.Document()

            # line date
            date = line.timestamp.date()

            # convert to UTC timestamp
            utc_timestamp = calendar.timegm(line.timestamp.utctimetuple())

            # ensure that it's not 1900
            assert date.year != 1900

            # add URI
            doc.add_attr('@uri',        "%s/%s/%d" % (channel.id, date.strftime('%Y-%m-%d'), line.offset))

            # add channel id
            doc.add_attr('@channel',    channel.id)

            # add type
            doc.add_attr('@type',       str(line.type))

            # add UTC timestamp
            doc.add_attr('@timestamp',  str(utc_timestamp))

            # add source attribute?
            if line.source :
                doc.add_attr('@source', str(line.source))
            
            # add data text
            doc.add_text(line.data.encode('utf8'))

            # put
            # XXX: what does this flag mean?
            if not self.db.put_doc(doc, hype.Database.PDCLEAN) :
                raise Exeception("Index put_doc failed")
    
    def search_cond (self, cond) :
        """
            Search using a raw hype.Condition
        """

        # execute search, unused 'flags' arg stays zero
        results = self.db.search(cond, 0)

        # iterate over the document IDs
        for doc_id in results :
            # load document, this throws an exception...
            # option constants are hype.Database.GDNOATTR/GDNOTEXT
            doc = self.db.get_doc(doc_id, 0)

            # load the attributes/text
            channel_id  = doc.attr('@channel')
            type        = int(doc.attr('@type'))
            timestamp   = datetime.datetime.fromtimestamp(int(doc.attr('@timestamp')), pytz.utc)
            source      = doc.attr('@source')
            data        = doc.cat_texts().decode('utf8')

            # build+yield to (channel_id, LogLine) tuple
            yield (channel_id, log_line.LogLine(None, type, timestamp, source, data))

    def search_simple (self, channel, query) :
        """
            Search for lines from the given channel for the given simple query
        """

        # build condition
        cond = hype.Condition()

        # simplified phrase
        cond.set_options(hype.Condition.SIMPLE)

        # add channel attribute
        cond.add_attr("@channel STREQ %s" % (channel.id, ))

        # add phrase
        cond.set_phrase(query)

        # set order
        cond.set_order("@timestamp NUMA")

        # search with cond
        for channel_id, line in self.search_cond(cond) :
            assert channel_id == channel.id

            yield line