from datetime import datetime
from flask import current_app, request
from flask_login import current_user
from socket import gaierror
from werkzeug.utils import secure_filename
from .. import db, socketio
from ..decorators import socketio_login_required
from ..events.socketio import sessions as socketio_sessions
from ..models import Corpus
import cqi
import math
import os
import shutil


'''
' A dictionary containing lists of, with corpus ids associated, Socket.IO
' session ids (sid). {<corpus_id>: [<sid>, ...], ...}
'''
corpus_analysis_sessions = {}
'''
' A dictionary containing Socket.IO session id - CQi client pairs.
' {<sid>: CQiClient, ...}
'''
corpus_analysis_clients = {}


@socketio.on('corpus_analysis_init')
@socketio_login_required
def init_corpus_analysis(corpus_id):
    corpus = Corpus.query.get(corpus_id)
    if corpus is None:
        response = {'code': 404, 'desc': None, 'msg': 'Not Found'}
        socketio.emit('corpus_analysis_init', response, room=request.sid)
        return
    if not (corpus.creator == current_user or current_user.is_administrator()):
        response = {'code': 403, 'desc': None, 'msg': 'Forbidden'}
        socketio.emit('corpus_analysis_init', response, room=request.sid)
        return
    if corpus.status not in ['prepared', 'start analysis', 'analysing']:
        response = {'code': 424, 'desc': None, 'msg': 'Failed Dependency'}
        socketio.emit('corpus_analysis_init', response, room=request.sid)
        return
    if corpus.status == 'prepared':
        corpus.status = 'start analysis'
        db.session.commit()
    socketio.start_background_task(corpus_analysis_session_handler,
                                   current_app._get_current_object(),
                                   corpus_id, current_user.id, request.sid)


def corpus_analysis_session_handler(app, corpus_id, user_id, session_id):
    with app.app_context():
        ''' Setup analysis session '''
        corpus = Corpus.query.get(corpus_id)
        retry_counter = 15
        while corpus.status != 'analysing':
            db.session.refresh(corpus)
            retry_counter -= 1
            if retry_counter == 0:
                response = {'code': 408, 'desc': None, 'msg': 'Request Timeout'}  # noqa
                socketio.emit('corpus_analysis_init', response, room=request.sid)  # noqa
                corpus.status = 'stop analysis'
                db.session.commit()
                return
            socketio.sleep(3)
        client = cqi.CQiClient('cqpserver_{}'.format(corpus_id))
        try:
            connect_status = client.connect()
            payload = {'code': connect_status, 'msg': cqi.api.specification.lookup[connect_status]}  # noqa
        except cqi.errors.CQiException as e:
            handle_cqi_exception('corpus_analysis_init', e, session_id)
            corpus.status = 'stop analysis'
            db.session.commit()
            return
        except gaierror:
            response = {'code': 500, 'desc': None, 'msg': 'Internal Server Error'}  # noqa
            socketio.emit('corpus_analysis_init', response, room=session_id)
            corpus.status = 'stop analysis'
            db.session.commit()
            return
        corpus_analysis_clients[session_id] = client
        if corpus_id in corpus_analysis_sessions:
            corpus_analysis_sessions[corpus_id].append(session_id)
        else:
            corpus_analysis_sessions[corpus_id] = [session_id]
        client.status = 'ready'
        response = {'code': 200, 'desc': None, 'msg': 'OK', 'payload': payload}
        socketio.emit('corpus_analysis_init', response, room=session_id)
        ''' Observe analysis session '''
        while session_id in socketio_sessions:
            socketio.sleep(3)
        ''' Teardown analysis session '''
        if client.status == 'running':
            client.status = 'abort'
            while client.status != 'ready':
                socketio.sleep(0.3)
        try:
            client.disconnect()
        except cqi.errors.CQiException:
            pass
        corpus_analysis_clients.pop(session_id, None)
        corpus_analysis_sessions[corpus_id].remove(session_id)
        if not corpus_analysis_sessions[corpus_id]:
            corpus_analysis_sessions.pop(corpus_id, None)
            corpus.status = 'stop analysis'
            db.session.commit()


@socketio.on('corpus_analysis_meta_data')
@socketio_login_required
def corpus_analysis_get_meta_data(corpus_id):
    # get meta data from db
    db_corpus = Corpus.query.get(corpus_id)
    metadata = {}
    metadata['corpus_name'] = db_corpus.title
    metadata['corpus_description'] = db_corpus.description
    metadata['corpus_creation_date'] = db_corpus.creation_date.isoformat()
    metadata['corpus_last_edited_date'] = \
        db_corpus.last_edited_date.isoformat()
    client = corpus_analysis_clients.get(request.sid)
    if client is None:
        response = {'code': 424, 'desc': None, 'msg': 'Failed Dependency'}
        socketio.emit('corpus_analysis_meta_data', response, room=request.sid)
        return
    # check if client is busy or not
    if client.status == 'running':
        client.status = 'abort'
        while client.status != 'ready':
            socketio.sleep(0.3)
    # get meta data from corpus in cqp server
    client.status = 'running'
    try:
        cwb_corpus = client.corpora.get('CORPUS')
        metadata['corpus_properties'] = cwb_corpus.attrs['properties']
        metadata['corpus_size_tokens'] = cwb_corpus.attrs['size']

        text_attr = cwb_corpus.structural_attributes.get('text')
        struct_attrs = cwb_corpus.structural_attributes.list(
            filters={'part_of': text_attr})
        text_ids = range(0, (text_attr.attrs['size']))
        texts_metadata = {}
        for text_id in text_ids:
            texts_metadata[text_id] = {}
            for struct_attr in struct_attrs:
                texts_metadata[text_id][struct_attr.attrs['name'][(len(text_attr.attrs['name']) + 1):]] = struct_attr.values_by_ids(list(range(struct_attr.attrs['size'])))[text_id]  # noqa
        metadata['corpus_all_texts'] = texts_metadata
        metadata['corpus_analysis_date'] = datetime.utcnow().isoformat()
        metadata['corpus_cqi_py_protocol_version'] = client.api.version
        metadata['corpus_cqi_py_package_version'] = cqi.__version__
        # TODO: make this dynamically
        metadata['corpus_cqpserver_version'] = 'CQPserver v3.4.22'

        # write some metadata to the db
        db_corpus.current_nr_of_tokens = metadata['corpus_size_tokens']
        db.session.commit()

        # emit data
        payload = metadata
        response = {'code': 200, 'desc': None, 'msg': 'OK', 'payload': payload}
        socketio.emit('corpus_analysis_meta_data', response, room=request.sid)
    except cqi.errors.CQiException as e:
        payload = {'code': e.code, 'desc': e.description, 'msg': e.name}
        response = {'code': 500, 'desc': None, 'msg': 'Internal Server Error',
                    'payload': payload}
        socketio.emit('corpus_analysis_meta_data', response, room=request.sid)
    client.status = 'ready'


@socketio.on('corpus_analysis_query')
@socketio_login_required
def corpus_analysis_query(query):
    client = corpus_analysis_clients.get(request.sid)
    if client is None:
        response = {'code': 424, 'desc': None, 'msg': 'Failed Dependency'}
        socketio.emit('corpus_analysis_query', response, room=request.sid)
        return
    if client.status == 'running':
        client.status = 'abort'
        while client.status != 'ready':
            socketio.sleep(0.3)
    client.status = 'running'
    try:
        corpus = client.corpora.get('CORPUS')
        query_status = corpus.query(query)
        results = corpus.subcorpora.get('Results')
    except cqi.errors.CQiException as e:
        client.status = 'ready'
        handle_cqi_exception('corpus_analysis_query', e, request.sid)
        return
    payload = {'status': query_status,
               'msg': cqi.api.specification.lookup[query_status],
               'match_count': results.attrs['size']}
    response = {'code': 200, 'desc': None, 'msg': 'OK', 'payload': payload}
    socketio.emit('corpus_analysis_query', response, room=request.sid)
    chunk_size = 100
    chunk_start = 0
    context = 50
    progress = 0
    while chunk_start <= results.attrs['size']:
        if client.status == 'abort':
            break
        try:
            chunk = results.export(context=context, cutoff=chunk_size, offset=chunk_start)  # noqa
        except cqi.errors.CQiException as e:
            handle_cqi_exception('corpus_analysis_query', e, request.sid)
            break
        if (results.attrs['size'] == 0):
            progress = 100
        else:
            progress = ((chunk_start + chunk_size) / results.attrs['size']) * 100  # noqa
            progress = min(100, int(math.ceil(progress)))
        payload = {'chunk': chunk, 'progress': progress}
        response = {'code': 200, 'desc': None, 'msg': 'OK', 'payload': payload}
        socketio.emit('corpus_analysis_query_results', response, room=request.sid)  # noqa
        chunk_start += chunk_size
    client.status = 'ready'


@socketio.on('corpus_analysis_get_match_with_full_context')
@socketio_login_required
def corpus_analysis_get_match_with_full_context(payload):
    type = payload['type']
    data_indexes = payload['data_indexes']
    first_cpos = payload['first_cpos']
    last_cpos = payload['last_cpos']
    client = corpus_analysis_clients.get(request.sid)
    if client is None:
        response = {'code': 424, 'desc': 'No client found for this session',
                    'msg': 'Failed Dependency'}
        socketio.emit('corpus_analysis_get_match_with_full_context', response,
                      room=request.sid)
        return
    if client.status == 'running':
        client.status = 'abort'
        while client.status != 'ready':
            socketio.sleep(0.3)
    client.status = 'running'
    try:
        corpus = client.corpora.get('CORPUS')
        s = corpus.structural_attributes.get('s')
    except cqi.errors.CQiException as e:
        handle_cqi_exception('corpus_analysis_get_match_with_full_context', e, request.sid)  # noqa
        return
    i = 0
    # Send data one match at a time.
    for index, f_cpos, l_cpos in zip(data_indexes, first_cpos, last_cpos):
        if client.status == 'abort':
            break
        i += 1
        matches = []
        cpos_lookup = text_lookup = {}
        try:
            tmp = s.export(f_cpos, l_cpos, context=10)
        except cqi.errors.CQiException as e:
            handle_cqi_exception('corpus_analysis_get_match_with_full_context', e, request.sid)  # noqa
            break
        matches.append(tmp['matches'][0])
        cpos_lookup.update(tmp['cpos_lookup'])
        text_lookup.update(tmp['text_lookup'])
        progress = i / len(data_indexes) * 100
        payload = {'matches': matches, 'progress': progress,
                   'cpos_lookup': cpos_lookup, 'text_lookup': text_lookup}
        response = {'code': 200, 'desc': None, 'msg': 'OK', 'payload': payload,
                    'type': type, 'data_indexes': data_indexes}
        socketio.emit('corpus_analysis_get_match_with_full_context',
                      response, room=request.sid)
    client.status = 'ready'


@socketio.on('export_corpus')
@socketio_login_required
def export_corpus(corpus_id):
    corpus = Corpus.query.get(corpus_id)
    if corpus is None:
        response = {'code': 404, 'msg': 'Not found'}
        socketio.emit('export_corpus', response, room=request.sid)
        return
    if corpus.status != 'prepared':
        response = {'code': 412, 'msg': 'Precondition Failed'}
        socketio.emit('export_corpus', response, room=request.sid)
        return
    # delete old corpus archive if it exists/has been build before
    if corpus.archive_file is not None and os.path.isfile(corpus.archive_file):
        os.remove(corpus.archive_file)
    archive_file_base_name = '[corpus]_' + secure_filename(corpus.title)
    corpus.archive_file = archive_file_base_name + '.zip'
    db.session.commit()
    shutil.make_archive(
        os.path.join(corpus.creator.path, 'corpora', archive_file_base_name),
        'zip',
        corpus.path
    )
    socketio.emit('export_corpus_{}'.format(corpus.id), room=request.sid)


def handle_cqi_exception(event, exception, room):
    response = {'code': 500,
                'desc': None,
                'msg': 'Internal Server Error',
                'payload': {'code': exception.code,
                            'desc': exception.description,
                            'msg': exception.name}}
    socketio.emit(event, response, room=room)