# -*- coding: utf-8 -*-
# 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, see <http://www.gnu.org/licenses/>.
"""
kallithea.lib.indexers
~~~~~~~~~~~~~~~~~~~~~~

Whoosh indexing module for Kallithea

This file was forked by the Kallithea project in July 2014.
Original author and date, and relevant copyright and licensing information is below:
:created_on: Aug 17, 2010
:author: marcink
:copyright: (c) 2013 RhodeCode GmbH, and others.
:license: GPLv3, see LICENSE.md for more details.
"""

import os
import sys
import logging
from os.path import dirname

# Add location of top level folder to sys.path
sys.path.append(dirname(dirname(dirname(os.path.realpath(__file__)))))

from whoosh.analysis import RegexTokenizer, LowercaseFilter, IDTokenizer
from whoosh.fields import TEXT, ID, STORED, NUMERIC, BOOLEAN, Schema, FieldType, DATETIME
from whoosh.formats import Characters
from whoosh.highlight import highlight as whoosh_highlight, HtmlFormatter, ContextFragmenter
from kallithea.lib.utils2 import LazyProperty

log = logging.getLogger(__name__)

# CUSTOM ANALYZER wordsplit + lowercase filter
ANALYZER = RegexTokenizer(expression=r"\w+") | LowercaseFilter()

# CUSTOM ANALYZER wordsplit + lowercase filter, for emailaddr-like text
#
# This is useful to:
# - avoid removing "stop words" from text
# - search case-insensitively
#
EMAILADDRANALYZER = RegexTokenizer() | LowercaseFilter()

# CUSTOM ANALYZER raw-string + lowercase filter
#
# This is useful to:
# - avoid tokenization
# - avoid removing "stop words" from text
# - search case-insensitively
#
ICASEIDANALYZER = IDTokenizer() | LowercaseFilter()

# CUSTOM ANALYZER raw-string
#
# This is useful to:
# - avoid tokenization
# - avoid removing "stop words" from text
#
IDANALYZER = IDTokenizer()

# CUSTOM ANALYZER wordsplit + lowercase filter, for pathname-like text
#
# This is useful to:
# - avoid removing "stop words" from text
# - search case-insensitively
#
PATHANALYZER = RegexTokenizer() | LowercaseFilter()

# INDEX SCHEMA DEFINITION
SCHEMA = Schema(
    fileid=ID(unique=True),
    owner=TEXT(analyzer=EMAILADDRANALYZER),
    # this field preserves case of repository name for exact matching
    repository_rawname=TEXT(analyzer=IDANALYZER),
    repository=TEXT(stored=True, analyzer=ICASEIDANALYZER),
    path=TEXT(stored=True, analyzer=PATHANALYZER),
    content=FieldType(format=Characters(), analyzer=ANALYZER,
                      scorable=True, stored=True),
    modtime=STORED(),
    extension=TEXT(stored=True, analyzer=PATHANALYZER)
)

IDX_NAME = 'HG_INDEX'
FORMATTER = HtmlFormatter('span', between='\n<span class="break">...</span>\n')
FRAGMENTER = ContextFragmenter(200)

CHGSETS_SCHEMA = Schema(
    raw_id=ID(unique=True, stored=True),
    date=NUMERIC(stored=True),
    last=BOOLEAN(),
    owner=TEXT(analyzer=EMAILADDRANALYZER),
    # this field preserves case of repository name for exact matching
    # and unique-ness in index table
    repository_rawname=ID(unique=True),
    repository=ID(stored=True, analyzer=ICASEIDANALYZER),
    author=TEXT(stored=True, analyzer=EMAILADDRANALYZER),
    message=FieldType(format=Characters(), analyzer=ANALYZER,
                      scorable=True, stored=True),
    parents=TEXT(),
    added=TEXT(analyzer=PATHANALYZER),
    removed=TEXT(analyzer=PATHANALYZER),
    changed=TEXT(analyzer=PATHANALYZER),
)

CHGSET_IDX_NAME = 'CHGSET_INDEX'

# used only to generate queries in journal
JOURNAL_SCHEMA = Schema(
    username=ID(),
    date=DATETIME(),
    action=TEXT(),
    repository=ID(),
    ip=TEXT(),
)


class WhooshResultWrapper(object):
    def __init__(self, search_type, searcher, matcher, highlight_items,
                 repo_location):
        self.search_type = search_type
        self.searcher = searcher
        self.matcher = matcher
        self.highlight_items = highlight_items
        self.fragment_size = 200
        self.repo_location = repo_location

    @LazyProperty
    def doc_ids(self):
        docs_id = []
        while self.matcher.is_active():
            docnum = self.matcher.id()
            chunks = [offsets for offsets in self.get_chunks()]
            docs_id.append([docnum, chunks])
            self.matcher.next()
        return docs_id

    def __str__(self):
        return '<%s at %s>' % (self.__class__.__name__, len(self.doc_ids))

    def __repr__(self):
        return self.__str__()

    def __len__(self):
        return len(self.doc_ids)

    def __iter__(self):
        """
        Allows Iteration over results,and lazy generate content

        *Requires* implementation of ``__getitem__`` method.
        """
        for docid in self.doc_ids:
            yield self.get_full_content(docid)

    def __getitem__(self, key):
        """
        Slicing of resultWrapper
        """
        i, j = key.start, key.stop

        slices = []
        for docid in self.doc_ids[i:j]:
            slices.append(self.get_full_content(docid))
        return slices

    def get_full_content(self, docid):
        res = self.searcher.stored_fields(docid[0])
        log.debug('result: %s', res)
        if self.search_type == 'content':
            full_repo_path = os.path.join(self.repo_location, res['repository'])
            f_path = res['path'].split(full_repo_path)[-1]
            f_path = f_path.lstrip(os.sep)
            content_short = self.get_short_content(res, docid[1])
            res.update({'content_short': content_short,
                        'content_short_hl': self.highlight(content_short),
                        'f_path': f_path
            })
        elif self.search_type == 'path':
            full_repo_path = os.path.join(self.repo_location, res['repository'])
            f_path = res['path'].split(full_repo_path)[-1]
            f_path = f_path.lstrip(os.sep)
            res.update({'f_path': f_path})
        elif self.search_type == 'message':
            res.update({'message_hl': self.highlight(res['message'])})

        log.debug('result: %s', res)

        return res

    def get_short_content(self, res, chunks):

        return ''.join([res['content'][chunk[0]:chunk[1]] for chunk in chunks])

    def get_chunks(self):
        """
        Smart function that implements chunking the content
        but not overlap chunks so it doesn't highlight the same
        close occurrences twice.
        """
        memory = [(0, 0)]
        if self.matcher.supports('positions'):
            for span in self.matcher.spans():
                start = span.startchar or 0
                end = span.endchar or 0
                start_offseted = max(0, start - self.fragment_size)
                end_offseted = end + self.fragment_size

                if start_offseted < memory[-1][1]:
                    start_offseted = memory[-1][1]
                memory.append((start_offseted, end_offseted,))
                yield (start_offseted, end_offseted,)

    def highlight(self, content, top=5):
        if self.search_type not in ['content', 'message']:
            return ''
        hl = whoosh_highlight(
            text=content,
            terms=self.highlight_items,
            analyzer=ANALYZER,
            fragmenter=FRAGMENTER,
            formatter=FORMATTER,
            top=top
        )
        return hl