"""Alert on changes on websites"""

from random import randint
import urllib.parse
from urllib.parse import urlparse

from hooks import hook
from more import Response

nemubotversion = 3.4

from .atom import Atom
from . import page


def load(DATAS):
    """Register events on watched website"""
    DATAS.setIndex("url", "watch")
    for site in DATAS.getNodes("watch"):
        if site.hasNode("alert"):
            start_watching(site, randint(-30, 30))
        else:
            print("No alert defined for this site: " + site["url"])
            #DATAS.delChild(site)


def del_site(url):
    """Remove a site from watching list

    Argument:
    url -- URL to unwatch
    """

    o = urlparse(url, "http")
    if o.scheme != "" and url in DATAS.index:
        site = DATAS.index[url]
        for a in site.getNodes("alert"):
            if a["channel"] == msg.channel:
                if not (msg.frm == a["nick"] or msg.frm_owner):
                    raise IRCException("you cannot unwatch this URL.")
                site.delChild(a)
                if not site.hasNode("alert"):
                    del_event(site["_evt_id"])
                    DATAS.delChild(site)
                save()
                return Response("I don't watch this URL anymore.",
                                channel=msg.channel, nick=msg.nick)
    raise IRCException("I didn't watch this URL!")


def add_site(url):
    """Add a site to watching list

    Argument:
    url -- URL to watch
    """

    o = urlparse(url, "http")
    if o.netloc == "":
        raise IRCException("sorry, I can't watch this URL :(")

    alert = ModuleState("alert")
    alert["nick"] = msg.nick
    alert["server"] = msg.server
    alert["channel"] = msg.channel
    alert["message"] = "{url} just changed!"

    if url not in DATAS.index:
        watch = ModuleState("watch")
        watch["type"] = diffType
        watch["url"] = url
        watch["time"] = 123
        DATAS.addChild(watch)
        watch.addChild(alert)
        start_watching(watch)
    else:
        DATAS.index[url].addChild(alert)

    save()
    return Response(channel=msg.channel, nick=msg.nick,
                    message="this site is now under my supervision.")


def format_response(site, link='%s', title='%s', categ='%s', content='%s'):
    """Format and send response for given site

    Argument:
    site -- DATAS structure representing a site to watch

    Keyword arguments:
    link -- link to the content
    title -- for ATOM feed: title of the new article
    categ -- for ATOM feed: category of the new article
    content -- content of the page/new article
    """

    for a in site.getNodes("alert"):
        send_response(a["server"],
                      Response(a["message"].format(url=site["url"],
                                                   link=link,
                                                   title=title,
                                                   categ=categ,
                                                   content=content),
                               channel=a["channel"],
                               server=a["server"]))


def alert_change(content, site):
    """Function called when a change is detected on a given site

    Arguments:
    content -- The new content
    site -- DATAS structure representing a site to watch
    """

    if site["type"] == "updown":
        if site["lastcontent"] is None:
            site["lastcontent"] = content is not None

        if (content is not None) != site.getBool("lastcontent"):
            format_response(site, link=site["url"])
            site["lastcontent"] = content is not None
        start_watching(site)
        return

    if content is None:
        start_watching(site)
        return

    if site["type"] == "atom":
        if site["_lastpage"] is None:
            if site["lastcontent"] is None or site["lastcontent"] == "":
                site["lastcontent"] = content
            site["_lastpage"] = Atom(site["lastcontent"])
        try:
            page = Atom(content)
        except:
            print("An error occurs during Atom parsing. Restart event...")
            start_watching(site)
            return
        diff = site["_lastpage"].diff(page)
        if len(diff) > 0:
            site["_lastpage"] = page
            diff.reverse()
            for d in diff:
                site.setIndex("term", "category")
                categories = site.index

                if len(categories) > 0:
                    if d.category is None or d.category not in categories:
                        format_response(site, link=d.link, categ=categories[""]["part"], title=d.title)
                    else:
                        format_response(site, link=d.link, categ=categories[d.category]["part"], title=d.title)
                else:
                    format_response(site, link=d.link, title=urllib.parse.unquote(d.title))
        else:
            start_watching(site)
            return  # Stop here, no changes, so don't save

    else:  # Just looking for any changes
        format_response(site, link=site["url"], content=content)
    site["lastcontent"] = content
    start_watching(site)
    save()


def start_watching(site, offset=0):
    """Launch the event watching given site

    Argument:
    site -- DATAS structure representing a site to watch

    Keyword argument:
    offset -- offset time to delay the launch of the first check
    """

    o = urlparse(site["url"], "http")
    print_debug("Add %s event for site: %s" % (site["type"], o.netloc))

    evt = ModuleEvent(func=lambda url: page.render(url, None),
                      cmp_data=site["lastcontent"],
                      func_data=site["url"], offset=offset,
                      interval=site.getInt("time"),
                      call=alert_change, call_data=site)
    site["_evt_id"] = add_event(evt)