#!/usr/bin/env python

import feedparser
import re
import time
import subprocess
import urllib2
import tempfile
import json

class ConfigParticipant(object):
    def _import_attribute(self, config, key, cast, default):
        if key in config:
            try:
                v = cast(config[key])
            except StandardError as e:
                print "Failed to cast value of %s '%s' to %s: %s" % (key, config[key], cast, e)
                return default
            return v
        else:
            return default

    def _import_list(self, config, key, cast):
        va = self._import_attribute(config, key, list, [])
        va_objs = []
        for v in va:
            try:
                v = cast(v)
            except StandardError as e:
                print "Failed to cast value of %s '%s' to %s: %s" % (key, config[key], cast, e)
                continue
            va_objs.append(v)
        return va_objs

    def _import_data_for_list(self, data, key, obj_list):
        if key not in data:
            return
        try:
            l = list(data[key])
        except TypeError:
            print "Failed to load list for key %s" % key
            return
        for i, v in enumerate(l):
            if i < len(obj_list):
                obj_list[i].import_data(v)
            else:
                print "Too many elements in data - data may be out-of-date"

class App(ConfigParticipant):
    def __init__(self):
        self.feeds = []
        self.config_filename = None
        self.data_filename = None

    def load_config(self, json_filename):
        self.config_filename = json_filename
        try:
            fd = file(self.config_filename)
        except IOError:
            print "No config file"
            return
        self.import_config(json.load(fd))
        fd.close()

    def save_config(self):
        fd = file(self.config_filename, "w")
        json.dump(self.export_data(), fd)
        fd.close()

    def load_data(self, json_filename):
        self.data_filename = json_filename
        try:
            fd = file(json_filename)
        except IOError:
            print "No data file"
            return
        self.import_data(json.load(fd))
        fd.close()

    def save_data(self):
        fd = file(self.data_filename, "w")
        json.dump(self.export_data(), fd)
        fd.close()

    def import_config(self, config):
        self.feeds = self._import_list(config, "feeds", Feed.import_config)

    def export_config(self):
        return {
            "feeds": [f.export_config() for f in self.feeds],
        }

    def import_data(self, data):
        self._import_data_for_list(data, "feeds", self.feeds)

    def export_data(self):
        return {
            "feeds": [f.export_data() for f in self.feeds],
        }

    def setup_env(self):
        opener = urllib2.build_opener(urllib2.HTTPCookieProcessor())
        urllib2.install_opener(opener)

    def get_next_feed(self):
        """Returns a (delay, feed) tuple of time to delay before next feed, and
           next feed to run
        """
        next_expiration = None
        next_feed = None
        for feed in self.feeds:
            expir = feed.poll_delay + feed.last_load
            if next_expiration < expir:
                next_expiration = expir
                next_feed = feed
        delay = next_expiration - int(time.time())
        if delay < 0:
            delay = 0
        return (delay, next_feed)

    def _run_relavent(self, feed):
        found = feed.find_relavant()
        for i in found:
            # download file here instead of relying on transmission since we may
            # have cookies that transmission does not
            f = urllib2.urlopen(i)
            temp = tempfile.NamedTemporaryFile()
            temp.write(f.read())
            f.close()
            temp.flush()
            ret = subprocess.call(["transmission-remote", "localhost", "-a", temp.name])
            temp.close()
            if ret:
                print "Error adding torrent"
        self.save_data()

    def main(self):
        try:
            for feed in self.feeds:
                self._run_relavent(feed)
            while True:
                (delay, feed) = self.get_next_feed()
                time.sleep(delay)
                try:
                    self._run_relavent(feed)
                except urllib2.URLError, e:
                    print e
        except KeyboardInterrupt:
            pass

class Feed(ConfigParticipant):
    def __init__(self):
        self.url = None
        # in seconds
        self.poll_delay = 60 * 60
        # list of Matcher objects
        self.matches = None
        # initialize to Epoch. Should always be integer number of seconds since
        # Epoch
        self.last_load = 0
        # true when the default action (when no matcher matches) should be to
        # count the item as relavant
        self.default_white = False
        self.seen = []

    def _load_feed(self):
        self.last_load = int(time.time())
        f = urllib2.urlopen(self.url)
        d = feedparser.parse(f.read())
        f.close()
        return d

    def find_relavant(self):
        d = self._load_feed()
        found = []
        print "New RSS Items:"
        for i in d['items']:
            if i.link in self.seen:
                continue
            self.seen.append(i.link)
            print " ", i.title
            white = self.default_white
            for m in self.matches:
                if not m.matches(i):
                    continue
                print "    Matched.  White:", m.white
                m.matched_count += 1
                white = m.white
            if white:
                found.append(i.link)
        self.seen = self.seen[-len(d['items']):]
        return found

    @staticmethod
    def import_config(config):
        f = Feed()
        f.url = f._import_attribute(config, "url", str, f.url)
        f.poll_delay = f._import_attribute(config, "poll_delay", int, f.poll_delay)
        f.matches = f._import_list(config, "matches", Matcher.import_config)
        f.default_white = f._import_attribute(config, "default_white", bool, f.default_white)
        return f

    def export_config(self):
        return {
            "url": self.url,
            "poll_delay": self.poll_delay,
            "matches": [m.export_config() for m in self.matches],
            "default_white": self.white,
        }

    def import_data(self, data):
        self.seen = self._import_list(data, "seen", str)
        self._import_data_for_list(data, "matches", self.matches)

    def export_data(self):
        return {
            "seen": self.seen,
            "matches": [m.export_data() for m in self.matches],
        }

class Matcher(ConfigParticipant):
    def __init__(self):
        self.str = None
        self.re = None
        # white marks item to be downloaded, black means don't download
        # similar to white and black lists
        self.white = True
        self.matched_count = 0

    @staticmethod
    def import_config(config):
        m = Matcher()
        m.white = m._import_attribute(config, "white", bool, m.white)
        m.str = m._import_attribute(config, "value", str, m.str)
        m.matched_count = m._import_attribute(config, "matched_count", int, m.matched_count)
        m.re = re.compile(m.str)
        return m

    def export_config(self):
        return {
            "white": self.white,
            "str": self.str,
            "matched_count": self.matched_count,
        }

    def import_data(self, data):
        self.matched_count = self._import_attribute(data, "matched_count", int, self.matched_count)

    def export_data(self):
        return {
            "matched_count": self.matched_count,
        }

    def matches(self, item):
        return self.re.match(item.title)

if __name__ == "__main__":
    app = App()
    app.load_config('.feed-transmission.json')
    app.load_data(".feed-transmission.data")
    app.setup_env()
    app.main()