import os
from ConfigParser import RawConfigParser

class Whale:
    """A Whale represents a distribution list.

    On the filesystem, a Whale looks like a directory with three files in it:

        - config
        - to.addrs
        - from.addrs

    Kraken eat Whales for dinner.

    """

    def __init__(self, path):
        """Given a path to a directory, initialize a Whale.
        """

        conf_path = os.path.join(path, 'config')
        send_path = os.path.join(path, 'to.addrs')
        from_path = os.path.join(path, 'from.addrs')

        self.id   = os.path.split(path)[1]
        self.path = path

        cp = RawConfigParser()
        cp.read(conf_path)
        self.global_ = dict(cp.items('global'))
        self.imap = dict(cp.items('imap'))
        self.smtp = dict(cp.items('smtp'))

        mode = self.global_.get('mode')

        if mode not in ('announcements', 'discussion'):
            raise SystemExit("No mode")

        if mode == 'announcements':
            # Only sends to to.addrs. Only from.addrs can post.

            self.mode = 'announcements'
            self.send_to = self.addrs(send_path)
            self.accept_from = self.addrs(from_path)

        elif mode == 'discussion':
            # All list members can post. from.addrs contains aliases.

            self.mode = 'discussion'
            self.send_to = self.addrs(send_path)
            accept_from = []
            for addr in self.addrs(from_path):
                if addr not in self.send_to:
                    accept_from.append(addr)
            self.accept_from = self.send_to + accept_from


    def addrs(self, filename):
        """Given a filename, return a list of email addresses.
        """
        lines = file(filename).read().split(os.linesep)
        return [l.lower() for l in lines if l and not l.startswith('#')]