Upload new File

"""Authentication routes"""
# pylint: disable=invalid-name

import os
import io
import base64
from urllib.parse import urlparse

from PIL import Image
from flask import Blueprint, render_template, session, redirect, url_for, \
    request, flash, current_app, abort, send_from_directory

from app import db
from app.models import Tile

tiles_bp = Blueprint('tiles', __name__)


def valid_tile(z, x, y):
    """Returns true if the tile coordinates are valid"""
    # check z in [0, 14]
    if z < 0 or z > 14:
        return False
    # check x in [0, 2^zoom[
    if x < 0  or x >= 2**z:
        return False
    # check y in [0, 2^zoom[
    if y < 0 or y >= 2 ** z:
        return False
    return True


@tiles_bp.route('/tiles/upload')
def upload():
    """Render an upload form"""
    return '''
    <!doctype html>
    <title>Upload new File</title>
    <h1>Upload new File</h1>
    <form action="/tiles/1/0/1" method=post enctype=multipart/form-data>
      <input type=file name=file>
      <input type=submit value=Upload>
    </form>
    '''


@tiles_bp.route('/tiles/<int:z>/<int:x>/<int:y>', methods=['GET'])
def get_tile(z, x, y):
    """Serves a tile"""
    if not valid_tile(z, x, y):
        return abort(404)
    folder = current_app.config['UPLOAD_FOLDER']
    filename = f'{z}-{x}-{y}.png'

    if not os.path.isfile(os.path.join(folder, filename)):
        return send_from_directory('static', 'missing.png')

    return send_from_directory('../' + folder, filename)


@tiles_bp.route('/tiles/<int:z>/<int:x>/<int:y>', methods=['POST'])
def create_tile(z, x, y):
    if not valid_tile(z, x, y):
        return abort(404)

    image_bytes = None
    # try to read file from request.files (byte-stream)
    if 'file' in request.files:
        image_bytes = request.files['file'].stream
    # try to read file from form (base64 encoded dataURL)
    if image_bytes is None and ('file' in request.form):
        parsed_url = urlparse(request.form['file'])
        head, data = parsed_url.path.split(',', 1)
        image_bytes = io.BytesIO(base64.b64decode(data))

    if image_bytes is None:
        flash('No file part')
        return redirect(url_for('index'))

    try:
        image = Image.open(image_bytes)
        image = image.resize((256, 256))
    except OSError:
        flash('cannot read image')
        return redirect(url_for('index'))

    folder = current_app.config['UPLOAD_FOLDER']
    filename = f'{z}-{x}-{y}.png'
    image.save(os.path.join(folder, filename))

    flash('Uploaded tile successfully')
    return redirect(url_for('index'))