from flask import (
    abort,
    current_app,
    flash,
    Markup,
    redirect,
    render_template,
    request,
    send_from_directory,
    url_for
)
from flask_login import current_user, login_required
from threading import Thread
import os
from app import db, hashids
from app.models import Corpus, CorpusFile, CorpusStatus, CorpusFollowerAssociation, User
from . import bp
from .forms import ChangeCorpusSettingsForm, CreateCorpusFileForm, CreateCorpusForm, UpdateCorpusFileForm


def user_can_read_corpus(user, corpus):
    return corpus.user == user or user.is_administrator() or corpus.is_public


def user_can_update_corpus(user, corpus):
    return corpus.user == user or user.is_administrator()


def user_can_delete_corpus(user, corpus):
    return user_can_update_corpus(user, corpus)


@bp.route('')
@login_required
def corpora():
    query = Corpus.query.filter(
        (Corpus.user_id == current_user.id) | (Corpus.is_public == True)
    )
    corpora = [c.to_json_serializeable() for c in query.all()]
    return render_template('corpora/corpora.html.j2', corpora=corpora, title='Corpora')


@bp.route('/create', methods=['GET', 'POST'])
@login_required
def create_corpus():
    form = CreateCorpusForm()
    if form.validate_on_submit():
        try:
            corpus = Corpus.create(
                title=form.title.data,
                description=form.description.data,
                user=current_user
            )
        except OSError:
            abort(500)
        db.session.commit()
        message = Markup(
            f'Corpus "<a href="{corpus.url}">{corpus.title}</a>" created'
        )
        flash(message, 'corpus')
        return redirect(corpus.url)
    return render_template(
        'corpora/create_corpus.html.j2',
        form=form,
        title='Create corpus'
    )


@bp.route('/<hashid:corpus_id>', methods=['GET', 'POST'])
@login_required
def corpus(corpus_id):
    corpus = Corpus.query.get_or_404(corpus_id)
    if not user_can_read_corpus(current_user, corpus):
        abort(403)
    corpus_settings_form = ChangeCorpusSettingsForm(
        data=corpus.to_json_serializeable(),
        prefix='corpus-settings-form'
    )
    if corpus_settings_form.validate_on_submit():
        corpus.is_public = corpus_settings_form.is_public.data
        db.session.commit()
        flash('Your changes have been saved')
        return redirect(url_for('.corpus', corpus_id=corpus.id))
    return render_template(
        'corpora/corpus.html.j2',
        corpus_settings_form=corpus_settings_form,
        corpus=corpus,
        title='Corpus'
    )



# @bp.route('/<hashid:corpus_id>/update')
# @login_required
# def update_corpus(corpus_id):
#     corpus = Corpus.query.get_or_404(corpus_id)
#     if not user_can_update_corpus(current_user, corpus):
#         abort(403)
#     return render_template(
#         'corpora/update_corpus.html.j2',
#         corpus=corpus,
#         title='Corpus'
#     )


@bp.route('/<hashid:corpus_id>', methods=['DELETE'])
@login_required
def delete_corpus(corpus_id):
    def _delete_corpus(app, corpus_id):
        with app.app_context():
            corpus = Corpus.query.get(corpus_id)
            corpus.delete()
            db.session.commit()

    corpus = Corpus.query.get_or_404(corpus_id)
    if not user_can_delete_corpus(current_user, corpus):
        abort(403)
    thread = Thread(
        target=_delete_corpus,
        args=(current_app._get_current_object(), corpus_id)
    )
    thread.start()
    return {}, 202


@bp.route('/<hashid:corpus_id>/analyse')
@login_required
def analyse_corpus(corpus_id):
    corpus = Corpus.query.get_or_404(corpus_id)
    if not user_can_read_corpus(current_user, corpus):
        abort(403)
    return render_template(
        'corpora/analyse_corpus.html.j2',
        corpus=corpus,
        title=f'Analyse Corpus {corpus.title}'
    )


@bp.route('/<hashid:corpus_id>/build', methods=['POST'])
@login_required
def build_corpus(corpus_id):
    def _build_corpus(app, corpus_id):
        with app.app_context():
            corpus = Corpus.query.get(corpus_id)
            corpus.build()
            db.session.commit()

    corpus = Corpus.query.get_or_404(corpus_id)
    if not user_can_update_corpus(current_user, corpus):
        abort(403)
    # Check if the corpus has corpus files
    if not corpus.files.all():
        response = {'errors': {'message': 'Corpus file(s) required'}}
        return response, 409
    thread = Thread(
        target=_build_corpus,
        args=(current_app._get_current_object(), corpus_id)
    )
    thread.start()
    return {}, 202


@bp.route('/<hashid:corpus_id>/files/create', methods=['GET', 'POST'])
@login_required
def create_corpus_file(corpus_id):
    corpus = Corpus.query.get_or_404(corpus_id)
    if not user_can_update_corpus(current_user, corpus):
        abort(403)
    form = CreateCorpusFileForm()
    if form.is_submitted():
        if not form.validate():
            response = {'errors': form.errors}
            return response, 400
        try:
            corpus_file = CorpusFile.create(
                form.vrt.data,
                address=form.address.data,
                author=form.author.data,
                booktitle=form.booktitle.data,
                chapter=form.chapter.data,
                editor=form.editor.data,
                institution=form.institution.data,
                journal=form.journal.data,
                pages=form.pages.data,
                publisher=form.publisher.data,
                publishing_year=form.publishing_year.data,
                school=form.school.data,
                title=form.title.data,
                mimetype='application/vrt+xml',
                corpus=corpus
            )
        except (AttributeError, OSError):
            abort(500)
        corpus.status = CorpusStatus.UNPREPARED
        db.session.commit()
        message = Markup(
            'Corpus file'
            f'"<a href="{corpus_file.url}">{corpus_file.filename}</a>" added'
        )
        flash(message, category='corpus')
        return {}, 201, {'Location': corpus.url}
    return render_template(
        'corpora/create_corpus_file.html.j2',
        corpus=corpus,
        form=form,
        title='Add corpus file'
    )


@bp.route('/<hashid:corpus_id>/files/<hashid:corpus_file_id>', methods=['GET', 'POST'])
@login_required
def corpus_file(corpus_id, corpus_file_id):
    corpus_file = CorpusFile.query.filter_by(corpus_id = corpus_id, id=corpus_file_id).first_or_404()
    if not (corpus_file.corpus.user == current_user or current_user.is_administrator()):
        abort(403)
    form = UpdateCorpusFileForm(data=corpus_file.to_json_serializeable())
    if form.validate_on_submit():
        form.populate_obj(corpus_file)
        if db.session.is_modified(corpus_file):
            corpus_file.corpus.status = CorpusStatus.UNPREPARED
            db.session.commit()
            message = Markup(f'Corpus file "<a href="{corpus_file.url}">{corpus_file.filename}</a>" updated')
            flash(message, category='corpus')
        return redirect(corpus_file.corpus.url)
    return render_template(
        'corpora/corpus_file.html.j2',
        corpus=corpus_file.corpus,
        corpus_file=corpus_file,
        form=form,
        title='Edit corpus file'
    )


@bp.route('/<hashid:corpus_id>/files/<hashid:corpus_file_id>', methods=['DELETE'])
@login_required
def delete_corpus_file(corpus_id, corpus_file_id):
    def _delete_corpus_file(app, corpus_file_id):
        with app.app_context():
            corpus_file = CorpusFile.query.get(corpus_file_id)
            corpus_file.delete()
            db.session.commit()

    corpus_file = CorpusFile.query.filter_by(corpus_id = corpus_id, id=corpus_file_id).first_or_404()
    if not (corpus_file.corpus.user == current_user or current_user.is_administrator()):
        abort(403)
    thread = Thread(
        target=_delete_corpus_file,
        args=(current_app._get_current_object(), corpus_file_id)
    )
    thread.start()
    return {}, 202


@bp.route('/<hashid:corpus_id>/files/<hashid:corpus_file_id>/download')
@login_required
def download_corpus_file(corpus_id, corpus_file_id):
    corpus_file = CorpusFile.query.filter_by(corpus_id = corpus_id, id=corpus_file_id).first_or_404()
    if not (corpus_file.corpus.user == current_user or current_user.is_administrator()):
        abort(403)
    return send_from_directory(
        os.path.dirname(corpus_file.path),
        os.path.basename(corpus_file.path),
        as_attachment=True,
        attachment_filename=corpus_file.filename,
        mimetype=corpus_file.mimetype
    )


@bp.route('/import', methods=['GET', 'POST'])
@login_required
def import_corpus():
    abort(503)


@bp.route('/<hashid:corpus_id>/export')
@login_required
def export_corpus(corpus_id):
    abort(503)

@bp.route('/<hashid:corpus_id>/follow')
@login_required
# TODO: Wenn Query Paramter genutzt wird, prüfen, ob user_id ungleich current_user.id ist und dann gucken, ob es ein Admin ist.
# Sonst 403.
def follow_corpus(corpus_id):
    corpus = Corpus.query.get_or_404(corpus_id)
    user_hashid = request.args.get('user_id')
    if user_hashid is None:
        user = current_user
    else:
        if not current_user.is_administrator():
            abort(403)
        else:
            user_id = hashids.decode(user_hashid)
            user = User.query.get_or_404(user_id)
    if not user.is_following_corpus(corpus):
        user.follow_corpus(corpus)
    db.session.commit()
    return {}, 202

@bp.route('/<hashid:corpus_id>/unfollow')
@login_required
def unfollow_corpus(corpus_id):
    corpus = Corpus.query.get_or_404(corpus_id)
    user_hashid = request.args.get('user_id')
    if user_hashid is None:
        user = current_user
    else:
        if not current_user.is_administrator():
            abort(403)
        else:
            user_id = hashids.decode(user_hashid)
            user = User.query.get_or_404(user_id)
    if user.is_following_corpus(corpus):
        user.unfollow_corpus(corpus)
    db.session.commit()
    return {}, 202

@bp.route('/add_permission/<hashid:corpus_id>/<hashid:user_id>/<int:permission>')
def add_permission(corpus_id, user_id, permission):
    a = CorpusFollowerAssociation.query.filter_by(followed_corpus_id=corpus_id, following_user_id=user_id).first_or_404()
    a.add_permission(permission)
    db.session.commit()
    return 'ok'


@bp.route('/remove_permission/<hashid:corpus_id>/<hashid:user_id>/<int:permission>')
def remove_permission(corpus_id, user_id, permission):
    a = CorpusFollowerAssociation.query.filter_by(followed_corpus_id=corpus_id, following_user_id=user_id).first_or_404()
    a.remove_permission(permission)
    db.session.commit()
    return 'ok'