import os

from flask import (
    Blueprint, render_template,
    flash, request, url_for, redirect, abort, g, send_from_directory, current_app)
from werkzeug.utils import secure_filename

from calender.auth import login_required
from calender.db import get_db

bp = Blueprint('calender', __name__)
ALLOWED_EXTENSIONS = {'png', 'jpg', 'jpeg', 'gif'}


@bp.route('/')
def index():
    db = get_db()
    posts = db.execute(
        'SELECT p.id, title, body, created, author_id, username'
        ' FROM post p JOIN user u ON p.author_id = u.id'
        ' ORDER BY created DESC'
    ).fetchall()
    return render_template('calender/index.html', posts=posts)


@bp.route('/create', methods=('GET', 'POST'))
@login_required
def create():
    if request.method == 'POST':
        title = request.form['title']
        body = request.form['body']
        error = None

        if not title:
            error = 'Title is required.'

        if error is not None:
            flash(error)
        else:
            db = get_db()
            db.execute(
                'INSERT INTO post (title, body, author_id)'
                ' VALUES (?, ?, ?)',
                (title, body, g.user['id'])
            )
            db.commit()
            # check if the post request has the file part
            if 'file' not in request.files:
                flash('No file part')
                return redirect(request.url)
            file = request.files['file']
            # if user does not select file, browser also
            # submit an empty part without filename
            if file.filename == '':
                flash('No selected file')
                return redirect(request.url)
            if file and allowed_file(file.filename):
                filename = secure_filename(file.filename)
                file.save(os.path.join(current_app.config['UPLOAD_FOLDER'], filename))
                return redirect(url_for('calender.uploaded_file',
                                        filename=filename))
            return redirect(url_for('calender.index'))

    return render_template('calender/create.html')


def get_post(id, check_author=True):
    post = get_db().execute(
        'SELECT p.id, title, body, created, author_id, username'
        ' FROM post p JOIN user u ON p.author_id = u.id'
        ' WHERE p.id = ?',
        (id,)
    ).fetchone()

    if post is None:
        abort(404, "Post id {0} doesn't exist.".format(id))

    if check_author and post['author_id'] != g.user['id']:
        abort(403)

    return post


@bp.route('/<int:id>/update', methods=('GET', 'POST'))
@login_required
def update(id):
    post = get_post(id)

    if request.method == 'POST':
        title = request.form['title']
        body = request.form['body']
        error = None

        if not title:
            error = 'Title is required.'

        if error is not None:
            flash(error)
        else:
            db = get_db()
            db.execute(
                'UPDATE post SET title = ?, body = ?'
                ' WHERE id = ?',
                (title, body, id)
            )
            db.commit()
            return redirect(url_for('calender.index'))

    return render_template('calender/update.html', post=post)


@bp.route('/<int:id>/delete', methods=('POST',))
@login_required
def delete(id):
    get_post(id)
    db = get_db()
    db.execute('DELETE FROM post WHERE id = ?', (id,))
    db.commit()
    return redirect(url_for('calender.index'))


def allowed_file(filename):
    return '.' in filename and \
           filename.rsplit('.', 1)[1].lower() in ALLOWED_EXTENSIONS


@bp.route('/uploads/<filename>')
def uploaded_file(filename):
    return send_from_directory(current_app.config['UPLOAD_FOLDER'],
                               filename)