import email
from email.header import decode_header, make_header
import imaplib

import imapclient

from bureau import Bureau, add_command, add_api


class Message(object):
    """
    This is just a convenience class for holding email message data.
    It could be fancier some day but for now this seems fine.
    """
    pass

class MailRoom(Bureau):
    """
    The Mail Room handles (electronic) post for the other Bureaus of
    the Screenless Office.
    """

    name = "Mail Room"
    prefix = "PO"
    version = 0

    def __init__(self):
        Bureau.__init__(self)
        # TODO: multiple accounts / folders
        if "user" in self.config:
            self.login = self.config["user"]["login"]
            self.password = self.config["user"]["password"]
            self.host = self.config["user"]["host"]
            self.spamfolder = self.config["user"]["spamfolder"]
            self.trashfolder = self.config["user"]["trashfolder"]

            self.imap_ssl = self.config["user"]["ssl"]
            if self.imap_ssl.lower() == "true":
                self.imap_ssl = True
            else:
                self.imap_ssl = False

            self.imapserv = imapclient.IMAPClient(self.host, use_uid=True, ssl=self.imap_ssl)
            self.imapserv.login(self.login, self.password)
            self.imapserv.select_folder("INBOX")
        else:
            print("you need to configure an IMAP account!")
            print("add a [user] section to PO.ini with:")
            print("  login = mylogin")
            print("  password = mypassword")
            print("  host = my.imap.server.address.com")

        # setup db's for mapping short codes to IMAP msg ids (and reversed)
        self.postdb = self.dbenv.open_db(b"postdb")
        self.postdb_rev = self.dbenv.open_db(b"postdb_rev")

    def _connect_imap(self):
        try:
            self.imapserv.select_folder("INBOX")
        except imaplib.error:
            self.imapserv.login(self.login, self.password)

    def get_imap_id(self, msgid):
        """
        take short code and look up the IMAP message id
        """
        with self.dbenv.begin(db=self.postdb) as txn:
            imap_id = txn.get(msgid.encode())
            return int(imap_id)

    @add_command("fax", "Send a Document Camera Image via Email")
    def fax(self, data):
        """
        Takes a photograph using the document camera and sends it in an E-mail.
        """
        photo = self.send("PXphoto.")

    @add_command("r", "Print full email")
    def read(self, data):
        """
        Prints out the full detailed version of an email.
        """
        shortcode, _ = data.split(".")
        imap_id = self.get_imap_id(shortcode)
        self._connect_imap()
        resp = self.imapserv.fetch([imap_id],
                                   ['INTERNALDATE', 'RFC822'])

        internaldate = resp[imap_id][b'INTERNALDATE']
        
        msg_data = resp[imap_id][b'RFC822'].decode('utf-8')
        msg_obj = email.message_from_string(msg_data)
        print("message fields:", msg_obj.keys())

        # format and tidy header data
        msg = Message()
        msg.fromstr = make_header(decode_header(msg_obj['From']))
        msg.tostr = make_header(decode_header(msg_obj['To']))
        msg.subject = make_header(decode_header(msg_obj['Subject']))
        if 'Cc' in msg_obj:
            msg.cc = make_header(decode_header(msg_obj['Cc']))
        else:
            msg.cc = None
        msg.date = internaldate
        msg.shortcode = shortcode
        msg.attachments = []

        # TODO: should use msg_obj.get_body and deal with HTML
        msg.content = ""

        # extract other sub-messages / attachments
        for part in msg_obj.walk():
            # TODO: save interesting attachments to files 
            #       should clean these up on delete
            if part.get_content_type() == "text/plain":
                msg.content = part.get_payload(decode=True).decode("utf-8")

        self.print_full("email.html", msg=msg, shortcode=shortcode)

    @add_command("d", "Delete email")
    def delete(self, data):
        """
        Deletes an email and moves it to the trash folder.
        """
        shortcode, _ = data.split(".")
        imap_id = self.get_imap_id(shortcode)
        self._connect_imap()
        self.imapserv.add_flags(imap_id, [imapclient.SEEN])
        self.imapserv.copy((imap_id), self.trashfolder)
        self.imapserv.delete_messages((imap_id))
        self.imapserv.expunge()

    @add_command("sp", "Mark as spam")
    def mark_spam(self, data):
        """
        Flags an email as spam, mark as read and move it to the configured SPAM
        folder.
        """
        shortcode, _ = data.split(".")
        imap_id = self.get_imap_id(shortcode)
        self._connect_imap()
        self.imapserv.add_flags(imap_id, [imapclient.SEEN])
        self.imapserv.copy((imap_id), self.spamfolder)
        self.imapserv.delete_messages((imap_id))
        self.imapserv.expunge()

    @add_command("re", "Reply with scan")
    def reply_scan(self, data):
        """
        Reply to the sender of a mail with the PDF currently queued in the
        document scanner.
        """
        # look up short code to get IMAP ID
        # extract the sender and title
        # put together the reply
        pass

    @add_api("unread", "Get unread mails")
    def unread(self):
        """
        Polls the currently configured IMAP server and returns a dict
        containing unread emails.
        """
        messages = self.imapserv.sort("ARRIVAL", ["UNSEEN"])
        print("%d unread messages in INBOX" % len(messages))
        return self.imapserv.fetch(messages, ['FLAGS', 'INTERNALDATE',
                                              'ENVELOPE', 'RFC822.SIZE'])


def main():
    mr = MailRoom()
    mr.run()


if __name__ == "__main__":
    main()