#!/usr/bin/env python

from datetime import datetime

from os.path import abspath, commonprefix, exists, join, split

from os import makedirs

from vCalendar import iterwrite

STORE_DIR = "/var/lib/imip-agent/store"

PUBLISH_DIR = "/var/www/imip-agent"

def check_dir(base, dir):

    return commonprefix([base, abspath(dir)]) == base

def make_calendar(fragment, method=None):

    return ("VCALENDAR", {},

            (method and [("METHOD", {}, method)] or []) +

            [("VERSION", {}, "2.0")] +

            fragment

           )

def to_stream(out, fragment, encoding="utf-8"):

    iterwrite(out, encoding=encoding).append(fragment)

class FileBase:

    "Basic filesystem operations."

    def __init__(self, store_dir=STORE_DIR):

        self.store_dir = store_dir

        if not exists(self.store_dir):

            makedirs(self.store_dir)

    def get_file_object(self, base, *parts):

        pathname = join(base, *parts)

        return check_dir(base, pathname) and pathname or None

    def get_object_for_user(self, user, uid):

        dir = self.get_file_object(self.store_dir, user)

        if not dir:

            return False

        filename = self.get_file_object(dir, uid)

        if not filename:

            return False

        if not exists(dir):

            makedirs(dir)

        return filename

class FileStore(FileBase):

    "A file store of tabular free/busy data and objects."

    def get_event(self, user, uid):

        "Get the event for the given 'user' with the given 'uid'."

        filename = self.get_object_for_user(user, uid)

        if not filename or not exists(filename):

            return None

        return exists(filename) and open(filename) or None

    def set_event(self, user, uid, node):

        "Set an event for 'user' having the given 'uid' and 'node'."

        filename = self.get_object_for_user(user, uid)

        if not filename:

            return False

        f = open(filename, "w")

        try:

            to_stream(f, node)

        finally:

            f.close()

        return True

    def get_freebusy(self, user):

        "Get free/busy details for the given 'user'."

        filename = self.get_object_for_user(user, "freebusy")

        if not filename or not exists(filename):

            return None

        f = open(filename)

        try:

            l = []

            for line in f.readlines():

                l.append(tuple(line.strip().split("\t")))

            return l

        finally:

            f.close()

    def set_freebusy(self, user, freebusy):

        "For the given 'user', set 'freebusy' details."

        filename = self.get_object_for_user(user, "freebusy")

        if not filename:

            return False

        f = open(filename, "w")

        try:

            for item in freebusy:

                f.write("\t".join(item) + "\n")

        finally:

            f.close()

        return True

class FilePublisher(FileBase):

    "A publisher of objects."

    def __init__(self, store_dir=PUBLISH_DIR):

        FileBase.__init__(self, store_dir)

    def set_freebusy(self, user, freebusy):

        "For the given 'user', set 'freebusy' details."

        filename = self.get_object_for_user(user, "freebusy")

        if not filename:

            return False

        record = []

        rwrite = record.append

        rwrite(("ORGANIZER", {}, user))

        rwrite(("UID", {}, user))

        rwrite(("DTSTAMP", {}, datetime.utcnow().strftime("%Y%m%dT%H%M%SZ")))

        for start, end, uid in freebusy:

            rwrite(("FREEBUSY", {"FBTYPE" : "BUSY"}, "/".join([start, end])))

        f = open(filename, "w")

        try:

            to_stream(f, make_calendar([("VFREEBUSY", {}, record)], "PUBLISH"))

        finally:

            f.close()

        return True

# vim: tabstop=4 expandtab shiftwidth=4