# -*- coding: utf-8  -*-

from datetime import datetime, timedelta
from gzip import GzipFile
from json import loads
from os.path import expanduser
from StringIO import StringIO
from urllib import quote
from urllib2 import URLError

from earwigbot.bot import Bot
from oursql import connect

__all__ = ["calculate_tif"]

SITE_DB = "enwiki_p"

def _get_db(bot):
    args = bot.config.wiki["_tifSQL"]
    args["read_default_file"] = expanduser("~/.my.cnf")
    args["autoping"] = True
    args["autoreconnect"] = True
    return connect(**args)

def _count_transclusions(cursor, title, ns):
    query = """SELECT COUNT(*)
        FROM {0}.templatelinks
        WHERE tl_title = ? AND tl_namespace = ? AND tl_from_namespace = 0"""
    cursor.execute(query.format(SITE_DB), (title, ns))
    return cursor.fetchall()[0][0]

def _count_views(cursor, title, ns):
    query = """SELECT SUM(cache_views), MIN(cache_time)
        FROM {0}.templatelinks
        INNER JOIN cache ON tl_from = cache_id
        WHERE tl_title = ? AND tl_namespace = ? AND tl_from_namespace = 0"""
    cursor.execute(query.format(SITE_DB), (title, ns))
    return cursor.fetchall()[0]

def _get_avg_views(site, article):
    url = ("https://wikimedia.org/api/rest_v1/metrics/pageviews/per-article/"
           "{0}.{1}/all-access/user/{2}/daily/{3}/{4}")
    days = 30
    slug = quote(article, safe="")
    start = (datetime.utcnow() - timedelta(days=days)).strftime("%Y%m%d")
    end = datetime.utcnow().strftime("%Y%m%d")
    query = url.format(site.lang, site.project, slug, start, end)

    try:
        response = site._opener.open(query)  # We're terrible
    except URLError:
        return None

    result = response.read()
    if response.headers.get("Content-Encoding") == "gzip":
        stream = StringIO(result)
        gzipper = GzipFile(fileobj=stream)
        result = gzipper.read()

    try:
        res = loads(result)
    except ValueError:
        return None

    if "items" not in res:
        return None
    total_views = sum(item["views"] for item in res["items"])
    return total_views / (float(days) * 24 * 60)

def _update_views(cursor, site, title, ns):
    cache_life = "7 DAY"
    query1 = """DELETE FROM cache
        WHERE cache_time < DATE_SUB(NOW(), INTERVAL {0})"""
    query2 = """SELECT tl_from, page_title
        FROM {0}.templatelinks
        LEFT JOIN {0}.page ON tl_from = page_id
        LEFT JOIN cache ON tl_from = cache_id
        WHERE tl_title = ? AND tl_namespace = ? AND tl_from_namespace = 0
            AND cache_id IS NULL"""
    query3 = """INSERT INTO cache (cache_id, cache_views, cache_time)
            VALUES (?, ?, NOW()) ON DUPLICATE KEY
            UPDATE cache_views = ?, cache_time = NOW()"""

    cursor.execute(query1.format(cache_life))
    cursor.execute(query2.format(SITE_DB), (title, ns))
    while True:
        titles = cursor.fetchmany(1024)
        if not titles:
            break

        viewcounts = [(pageid, _get_avg_views(site, name))
                      for (pageid, name) in titles]
        parambatch = [(i, v, v) for (i, v) in viewcounts if v is not None]
        cursor.executemany(query3, parambatch)

def _compute_stats(db, page):
    title = page.title.split(":", 1)[-1].replace(" ", "_")
    title = title[0].upper() + title[1:]

    with db.cursor() as cursor:
        transclusions = _count_transclusions(cursor, title, page.namespace)
        _update_views(cursor, page.site, title, page.namespace)
        tif, cache_time = _count_views(cursor, title, page.namespace)
    return tif, transclusions, cache_time

def _format_time(cache_time):
    formatter = lambda n, w: "{0} {1}{2}".format(n, w, "" if n == 1 else "s")
    diff = datetime.utcnow() - cache_time
    total_seconds = diff.days * 86400 + diff.seconds
    if total_seconds > 86400:
        return formatter(total_seconds / 86400, "day")
    if total_seconds > 3600:
        return formatter(total_seconds / 3600, "hour")
    if total_seconds > 60:
        return formatter(total_seconds / 60, "minute")
    return formatter(total_seconds, "second")

def _get_protection(page):
    edit = [prot for prot in page.protection if prot["type"] == "edit"]
    return edit[0] if edit else None

def calculate_tif(title):
    bot = Bot(".earwigbot")
    db = _get_db(bot)
    site = bot.wiki.get_site()
    page = site.get_page(title)
    result = {"title": title, "page": page}

    if page.exists != page.PAGE_EXISTS:
        result["error"] = "no page"
        return result

    tif, transclusions, cache_time = _compute_stats(db, page)

    result["tif"] = tif
    result["transclusions"] = transclusions
    result["protection"] = _get_protection(page)
    if cache_time:
        result["cache_time"] = cache_time.strftime("%b %d, %Y %H:%M:%S UTC")
        result["cache_age"] = _format_time(cache_time)
    return result