#!/usr/bin/env python3
# -*- coding: utf-8  -*-
#
#  redfam.py
#
#  Copyright 2015 GOLDERWEB – Jonathan Golder <jonathan@golderweb.de>
#
#  This program is free software; you can redistribute it and/or modify
#  it under the terms of the GNU General Public License as published by
#  the Free Software Foundation; either version 3 of the License, or
#  (at your option) any later version.
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
#
#  You should have received a copy of the GNU General Public License
#  along with this program; if not, write to the Free Software
#  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
#  MA 02110-1301, USA.
#
#
"""
Provides classes for working with RedFams
"""

import hashlib
import locale
import re
from datetime import datetime

import mwparserfromhell as mwparser  # noqa
import pywikibot  # noqa
from pywikibot.tools import deprecated  # noqa

import jogobot
from lib.mysqlred import MysqlRedFam


class RedFam:
    """
    Basic class for RedFams, containing the basic data structure
    """

    def __init__( self, articlesList, beginning, ending=None, red_page_id=None,
                  status=0, fam_hash=None, heading=None ):
        """
        Generates a new RedFam object

        @param    articlesList    list        List of articles
        @param    beginning       datetime    Beginning date
        @param    ending          datetime    Ending date
        @param    red_page_id     int         MW pageid of containing RedPage
        @param    status          int         Status of RedFam
        @param    fam_hash        str         SHA1 hash of articlesList
        @param    heading         str         Original heading of RedFam (Link)
        """

        # Database interface
        self._mysql = MysqlRedFam( fam_hash )

        # Initial attribute values
        self._articlesList = articlesList
        self._beginning = beginning
        self._ending = ending
        self._red_page_id = red_page_id
        self._status = status
        self._fam_hash = fam_hash
        self._heading = heading

        # Calculates the sha1 hash over self._articlesList to
        # rediscover known redundance families
        self.calc_fam_hash()

    def __repr__( self ):
        """
        Returns repression str of RedFam object

        @returns    str     repr() string
        """

        __repr = "RedFam( " + \
                 "articlesList=" + repr( self._articlesList ) + \
                 ", heading=" + repr( self._heading ) + \
                 ", beginning=" + repr( self._beginning ) + \
                 ", ending=" + repr( self._ending ) + \
                 ", red_page_id=" + repr( self._red_page_id ) + \
                 ", status=" + repr( self._status ) + \
                 ", fam_hash=" + repr( self._fam_hash ) + \
                 " )"

        return __repr

    def calc_fam_hash( self ):
        """
        Calculates the SHA-1 hash for the articlesList of redundance family.
        Since we don't need security SHA-1 is just fine.

        @returns    str    String with the hexadecimal hash digest
        """

        h = hashlib.sha1()
        h.update( str( self._articlesList[:8] ).encode('utf-8') )

        if self._fam_hash and h.hexdigest() != self._fam_hash:
            raise RedFamHashError( self._fam_hash, h.hexdigest() )

        elif self._fam_hash:
            return
        else:
            self._fam_hash = h.hexdigest()

    def changed( self ):
        """
        Checks wether anything has changed and maybe triggers db update
        """

        # On archived red_fams do not delete possibly existing ending
        if( not self._ending and self._status > 1 and
            self._mysql.data[ 'ending' ] ):

                self._ending = self._mysql.data[ 'ending' ]

        # Since status change means something has changed, update database
        if( self._status != self._mysql.data[ 'status' ] or
            self._beginning != self._mysql.data[ 'beginning' ] or
            self._ending != self._mysql.data[ 'ending' ] or
            self._red_page_id != self._mysql.data[ 'red_page_id' ] or
            self._heading != self._mysql.data[ 'heading' ]):

                self._mysql.update_fam( self._red_page_id, self._heading,
                                        self._beginning, self._ending,
                                        self._status )

    @classmethod
    def flush_db_cache( cls ):
        """
        Calls flush method of Mysql Interface class
        """
        MysqlRedFam.flush()


class RedFamParser( RedFam ):
    """
    Provides an interface to RedFam for adding/updating redundance families
    while parsig redundance pages
    """

    # Define the timestamp format
    __timestamp_format = jogobot.config['redundances']['timestamp_format']

    # Define section heading re.pattern
    __sectionhead_pat = re.compile( r"^(.*\[\[.+\]\].*\[\[.+\]\].*)" )

    # Define timestamp re.pattern
    __timestamp_pat = re.compile( jogobot.config['redundances']
                                  ['timestamp_regex'] )

    # Textpattern for recognisation of done-notices
    __done_notice = ":<small>Archivierung dieses Abschnittes \
                     wurde gewünscht von:"
    __done_notice2 = "{{Erledigt|"

    def __init__( self, heading, red_page, red_page_archive,
                  beginning, ending=None ):
        """
        Creates a RedFam object based on data collected while parsing red_pages
        combined with possibly former known data from db

        @param    red_fam_heading     str         Wikitext heading of section
        @param    red_page            page        Pywikibot.page object
        @param    red_page_archive    bool        Is red_page an archive
        @param    beginning           datetime    Timestamp of beginning
                                      str         as strptime parseable string
        @param    ending              datetime    Timestamp of ending
                                      str         strptime parseable string
        """

        # Set object attributes:
        self._red_page_id = red_page._pageid
        self._red_page_archive = red_page_archive
        self._fam_hash = None

        # Method self.add_beginning sets self._beginning directly
        self.add_beginning( beginning )

        # Method self.add_ending sets self._ending directly
        if( ending ):
            self.add_ending( ending )
        else:
            # If no ending was provided set to None
            self._ending = None

        self._status = None

        # Parse the provided heading of redundance section
        # to set self._articlesList
        self.heading_parser( heading )

        # Calculates the sha1 hash over self._articlesList to
        # rediscover known redundance families

        self.calc_fam_hash()

        # Open database connection, ask for data if existing,
        # otherwise create entry
        self.__handle_db()

        # Check status changes
        self.status()

        # Triggers db update if anything changed
        self.changed()

    def __handle_db( self ):
        """
        Handles opening of db connection
        """

        # We need a connection to our mysqldb
        self._mysql = MysqlRedFam( )
        self._mysql.get_fam( self._fam_hash )

        if not self._mysql.data:
            self._mysql.add_fam( self._articlesList, self._heading,
                                 self._red_page_id, self._beginning,
                                 self._ending )

    def heading_parser( self, heading ):
        """
        Parses given red_fam_heading string and saves articles list

        @param  heading  Heading of RedFam-Section
        @type  heading  wikicode or mwparser-parseable
        """

        # Save heading as string
        self._heading = str( heading )

        # Parse string heading with mwparse again everytime
        # In some cases the given wikicode is broken due to syntax errors
        # (Task FS#77)
        heading = mwparser.parse( self._heading )

        # Save destinations of wikilinks in headings
        self._articlesList = [ str( link.title ) for link
                               in heading.ifilter_wikilinks() ]

        # Catch sections with more then 8 articles, print error
        if len( self._articlesList ) > 8:
            # For repression in output we need to know the fam hash
            self.calc_fam_hash()

            jogobot.output(
                ( "\03{{lightred}}" +
                  "Maximum number of articles in red_fam exceeded, " +
                  "maximum number is 8, {number:d} were given \n {repress}"
                  ).format( datetime=datetime.now().strftime(
                      "%Y-%m-%d %H:%M:%S" ), number=len( self._articlesList ),
                    repress=repr( self ) ),
                "WARNING" )

            # Only save the first 8 articles
            self._articlesList = self._articlesList[:8]

    def add_beginning( self, beginning ):
        """
        Adds the beginning date of a redundance diskussion to the object

        @param      datetime    datetime    Beginning date
        """

        self._beginning = self.__datetime( beginning )

    def add_ending( self, ending ):
        """
        Adds the ending date of a redundance diskussion to the object.

        @param      datetime    datetime    Ending date
        """

        self._ending = self.__datetime( ending )

    def __datetime( self, timestamp ):
        """
        Decides wether given timestamp is a parseable string or a
        datetime object and returns a datetime object in both cases

        @param      datetime    timestamp    Datetime object
                    str         timestamp    Parseable string with timestamp

        @returns    datetime                 Datetime object
        """

        # Make sure locale is set to 'de_DE.UTF-8' to prevent problems
        # with wrong month abreviations in strptime
        locale.setlocale(locale.LC_ALL, 'de_DE.UTF-8')

        if( isinstance( timestamp, datetime ) ):
            return timestamp
        else:
            result = datetime.strptime( timestamp,
                                        type( self ).__timestamp_format )
        return result

    def status( self ):
        """
        Handles detection of correct status
        There are three possible stati:
        - 0 Discussion running --> no ending, page is not an archive
        - 1 Discussion over --> ending present, page is not an archive
        - 2 Discussion archived --> ending (normaly) present, page is archive
        - 3 and greater status was set by worker script, do not change it
        """

        # Do not change stati set by worker script etc.
        if not self._mysql.data['status'] > 2:

            # No ending, discussion is running:
            # Sometimes archived discussions also have no detectable ending
            if not self._ending and not self._red_page_archive:
                self._status = 0
            else:
                if not self._red_page_archive:
                    self._status = 1
                else:
                    self._status = 2
        else:

            self._status = self._mysql.data[ 'status' ]

    @classmethod
    def is_section_redfam_cb( cls, heading ):
        """
        Used as callback for wikicode.get_sections in redpage.parse to
        select sections which are redfams
        """
        # Because of strange behavior in some cases, parse heading again
        # (Task FS#77)
        heading = mwparser.parse( str( heading ) )

        # Make sure we have min. two wikilinks in heading to assume a redfam
        if len( heading.filter_wikilinks() ) >= 2:
            return True
        else:
            return False

    @classmethod
    def parser( cls, text, page, isarchive=False ):
        """
        Handles parsing of redfam section

        @param  text  Text of RedFam-Section
        @type  text  wikicode or mwparser-parseable
        """

        # Parse heading with mwparse if needed
        if not isinstance( text, mwparser.wikicode.Wikicode ):
            text = mwparser.parse( text )

        # Extract heading text
        heading = next( text.ifilter_headings() ).title

        # Extract beginnig and maybe ending
        (beginning, ending) = RedFamParser.extract_dates( text, isarchive )

        # Missing beginning (Task: FS#76)
        # Use first day of month of reddisc
        if not beginning:
            match = re.search(
                jogobot.config["redundances"]["reddiscs_onlyinclude_re"],
                page.title() )

            if match:
                beginning = datetime.strptime(
                    "01. {month} {year}".format(
                        month=match.group(1), year=match.group(2)),
                    "%d. %B %Y" )

        # Create the RedFam object
        RedFamParser( heading, page, isarchive, beginning, ending )

    @classmethod
    def extract_dates( cls, text, isarchive=False ):
        """
        Returns tuple of the first and maybe last timestamp of a section.
        Last timestamp is only returned if there is a done notice or param
        *isarchiv* is set to 'True'

        @param  text  Text to search in
        @type  line  Any Type castable to str
        @param  isarchive  If true skip searching done notice (on archivepages)
        @type  isarchive  bool

        @returns  Timestamps, otherwise None
        @returntype  tuple of strs
        """

        # Match all timestamps
        matches = cls.__timestamp_pat.findall( str( text ) )
        if matches:

            # First one is beginning
            # Since some timestamps are broken we need to reconstruct them
            # by regex match groups
            beginning = ( matches[0][0] + ", " + matches[0][1] + ". " +
                          matches[0][2] + ". " + matches[0][3] )

            # Last one maybe is ending
            # Done notice format 1
            # Done notice format 2
            # Or on archivepages
            if ( cls.__done_notice in text or
                 cls.__done_notice2 in text or
                 isarchive ):

                ending = ( matches[-1][0] + ", " + matches[-1][1] + ". " +
                           matches[-1][2] + ". " + matches[-1][3] )

            else:
                ending = None
        # Missing dates (Task: FS#76)
        else:
            beginning = None
            ending = None

        return (beginning, ending)


class RedFamWorker( RedFam ):
    """
    Handles working with redundance families stored in database
    where discussion is finished
    """
    def __init__( self, mysql_data ):

        articlesList = []
        for key in sorted( mysql_data.keys() ):
            if 'article' in key and mysql_data[ key ]:
                articlesList.append( mysql_data[ key ] )

        super().__init__( articlesList, mysql_data[ 'beginning' ],
                          mysql_data[ 'ending' ], mysql_data[ 'red_page_id' ],
                          mysql_data[ 'status' ], mysql_data[ 'fam_hash' ],
                          mysql_data[ 'heading' ] )

        self._mysql.data = mysql_data

        # Get related RedPage-Information
        self.redpageid = mysql_data[ 'page_id' ]
        self.redpagetitle = mysql_data[ 'page_title' ]

        # Make sure locale is set to 'de_DE.UTF-8' to prevent problems
        # with wrong month abreviations in strptime
        locale.setlocale(locale.LC_ALL, 'de_DE.UTF-8')

    def update_status( self ):
        """
        Sets status to 3 when worked on
        """

        self._status = 3

    def get_disc_link( self ):
        """
        Constructs and returns the link to Redundancy discussion

        @returns  Link to diskussion
        @rtype  str
        """

        # We need to Replace Links with their linktext
        anchor_code = mwparser.parse( self._mysql.data[ 'heading' ].strip() )
        for link in anchor_code.ifilter_wikilinks():
            if link.text:
                text = link.text
            else:
                text = link.title

            anchor_code.replace( link, text )

        # Whitespace is replaced with underscores
        anchor_code.replace( " ", "_" )

        # We try it with out any more parsing as mw will do while parsing page
        return ( self.redpagetitle + "#" +
                 str(anchor_code).strip() )

    @classmethod
    def list_by_status( cls, status ):
        """
        Lists red_fams stored in db by given status
        """
        mysql = MysqlRedFam()
        for fam in mysql.get_by_status( status ):
            try:
                print( cls( fam ) )
            except RedFamHashError:
                print(fam)
                raise

    @classmethod
    def gen_by_status_and_ending( cls, status, ending ):
        """
        Yield red_fams stored in db by given status which have an ending after
        given one
        """
        mysql = MysqlRedFam()
        for fam in mysql.get_by_status_and_ending( status, ending ):
            try:
                yield cls( fam )
            except RedFamHashError:
                print(fam)
                raise


class RedFamError( Exception ):
    """
    Base class for all Errors of RedFam-Module
    """

    def __init__( self, message=None ):
        """
        Handles Instantiation of RedFamError's
        """
        if not message:
            self.message = "An Error occured while executing a RedFam action"
        else:
            self.message = message

    def __str__( self ):
        """
        Output of error message
        """

        return self.message


class RedFamHashError( RedFamError ):
    """
    Raised when given RedFamHash does not match with calculated
    """

    def __init__( self, givenHash, calculatedHash ):

        message = "Given fam_hash ('{given}') does not match with \
calculated ('{calc}'".format( given=givenHash, calc=calculatedHash )

        super().__init__( message )


class RedFamHeadingError ( RedFamError ):
    """
    Raised when given RedFamHeading does not match __sectionhead_pat Regex
    """
    def __init__( self, heading ):

        message = "Error while trying to parse section heading. Given heading \
'{heading}' does not match RegEx".format( heading=heading )

        super().__init__( message )