# -*- coding: utf-8  -*-
#
# Copyright (C) 2009-2012 Ben Kurtovic <ben.kurtovic@verizon.net>
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.

from hashlib import sha256
from os.path import expanduser
from threading import Lock

import oursql

from earwigbot.tasks import Task

class AFCCopyvios(Task):
    """A task to check newly-edited [[WP:AFC]] submissions for copyright
    violations."""
    name = "afc_copyvios"
    number = 1

    def setup(self):
        cfg = self.config.tasks.get(self.name, {})
        self.template = cfg.get("template", "AfC suspected copyvio")
        self.ignore_list = cfg.get("ignoreList", [])
        self.min_confidence = cfg.get("minConfidence", 0.5)
        self.max_queries = cfg.get("maxQueries", 10)
        self.cache_results = cfg.get("cacheResults", False)
        default_summary = "Tagging suspected [[WP:COPYVIO|copyright violation]] of {url}"
        self.summary = self.make_summary(cfg.get("summary", default_summary))

        # Connection data for our SQL database:
        kwargs = cfg.get("sql", {})
        kwargs["read_default_file"] = expanduser("~/.my.cnf")
        self.conn_data = kwargs
        self.db_access_lock = Lock()

    def run(self, **kwargs):
        """Entry point for the bot task.

        Takes a page title in kwargs and checks it for copyvios, adding
        {{self.template}} at the top if a copyvio has been detected. A page is
        only checked once (processed pages are stored by page_id in an SQL
        database).
        """
        if self.shutoff_enabled():
            return
        title = kwargs["page"]
        page = self.bot.wiki.get_site().get_page(title)
        with self.db_access_lock:
            self.conn = oursql.connect(**self.conn_data)
            self.process(page)

    def process(self, page):
        """Detect copyvios in 'page' and add a note if any are found."""
        title = page.title
        if title in self.ignore_list:
            msg = "Skipping page in ignore list: [[{0}]]"
            self.logger.info(msg.format(title))
            return

        pageid = page.pageid
        if self.has_been_processed(pageid):
            msg = "Skipping check on already processed page [[{0}]]"
            self.logger.info(msg.format(title))
            return

        self.logger.info("Checking [[{0}]]".format(title))
        result = page.copyvio_check(self.min_confidence, self.max_queries)
        url = result.url
        confidence = "{0}%".format(round(result.confidence * 100, 2))

        if result.violation:
            content = page.get()
            template = "\{\{{0}|url={1}|confidence={2}\}\}\n"
            template = template.format(self.template, url, confidence)
            newtext = template + content
            if "{url}" in self.summary:
                page.edit(newtext, self.summary.format(url=url))
            else:
                page.edit(newtext, self.summary)
            msg = "Found violation: [[{0}]] -> {1} ({2} confidence)"
            self.logger.warn(msg.format(title, url, confidence))
        else:
            msg = "No violations detected (best: {1} at {2} confidence)"
            self.logger.debug(msg.format(url, confidence))

        self.log_processed(pageid)
        if self.cache_results:
            self.cache_result(page, result)

    def has_been_processed(self, pageid):
        """Returns True if pageid was processed before, otherwise False."""
        query = "SELECT 1 FROM processed WHERE page_id = ?"
        with self.conn.cursor() as cursor:
            cursor.execute(query, (pageid,))
            results = cursor.fetchall()
        if results:
            return True
        return False

    def log_processed(self, pageid):
        """Adds pageid to our database of processed pages.

        Raises an exception if the page has already been processed.
        """
        query = "INSERT INTO processed VALUES (?)"
        with self.conn.cursor() as cursor:
            cursor.execute(query, (pageid,))

    def cache_result(self, page, result):
        """Store the check's result in a cache table temporarily.

        The cache contains the page's ID, a hash of its content, the URL of the
        best match, the time of caching, and the number of queries used. It
        will replace any existing cache entries for that page.

        The cache is intended for EarwigBot's complementary Toolserver web
        interface, in which copyvio checks can be done separately from the bot.
        The cache saves time and money by saving the result of the web search
        but neither the result of the comparison nor any actual text (which
        could violate data retention policy). Cache entries are (intended to
        be) retained for one day; this task does not remove old entries (that
        is handled by the Toolserver component).

        This will only be called if "cache_results" == True in the task's
        config, which is False by default.
        """
        pageid = page.pageid
        hash = sha256(page.get()).hexdigest()
        query1 = "SELECT 1 FROM cache WHERE cache_id = ?"
        query2 = "DELETE FROM cache WHERE cache_id = ?"
        query3 = "INSERT INTO cache VALUES (?, ?, ?, CURRENT_TIMESTAMP, ?, ?)"
        with self.conn.cursor() as cursor:
            cursor.execute(query1, (pageid,))
            if cursor.fetchall():
                cursor.execute(query2, (pageid,))
            cursor.execute(query3, (pageid, hash, result.url, result.queries, 0))