webapp.py

"""
     This file is part of poster-gen.

    poster-gen 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.

    poster-gen 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 poster-gen. If not, see <https://www.gnu.org/licenses/>.
"""

from flask import Flask, render_template, request, send_file, redirect
from poster_generator import generator
import io
from dotenv import load_dotenv
import os
import re
import requests

load_dotenv()

app = Flask(__name__, instance_relative_config=True)
app.config["SECRET_KEY"]=os.getenv('FLASK_SECRET')


@app.route('/')
def index():
    return render_template('mainpage.html', ns=os.getenv('NAMESPACE'), key=os.getenv("KEY"))


@app.route('/result', methods = ['POST', 'GET'])
def result():
    if request.method == 'POST':
        album_link = request.form["album_input"]
        width = 3300 if 'width' not in request.form or not request.form["width"].isnumeric() else int(request.form["width"])
        height = 5100 if 'height' not in request.form or not request.form["height"].isnumeric() else int(request.form["height"])

        # check that input is not empty
        if album_link == "" or album_link is None:
            return render_template('mainpage.html', warning_notification='Input field cannot be empty', ns=os.getenv('NAMESPACE'), key=os.getenv("KEY"))

        # check values for height and width
        if width < 300 or height < 450:  # width and height have minimum requirements
            return render_template('mainpage.html', warning_notification='Width must be at least 300px and height must be at least 450px', ns=os.getenv('NAMESPACE'), key=os.getenv("KEY"))
        if height < width * 1.25 or height > width * 2:  # height must be between 30% and 100% larger than width
            return render_template('mainpage.html', warning_notification='Height must be between 25% and 100% larger than width', ns=os.getenv('NAMESPACE'), key=os.getenv("KEY"))
        
        # poster options
        options = {}

        # get color theme of poster
        theme = request.form["theme"]
        options['theme'] = theme

        # check if featured artists are to be removed from track
        remove_featured = request.form.get("remove_featured_artists")
        if remove_featured == 'true':
            options['remove_featured_artists'] = True
        else:
            options['remove_featured_artists'] = False

        if re.match(r'https://spotify.link/([a-zA-Z0-9]+)', album_link):
            album_link = requests.get(album_link).url

        patterns = [
            (r'^https://open\.spotify\.com/album/([a-zA-Z0-9]+)', 'albums'),
            (r'^spotify:album:([a-zA-Z0-9]+)', 'albums'),
            (r'^https://open\.spotify\.com/track/([a-zA-Z0-9]+)', 'tracks'),
            (r'^spotify:track:([a-zA-Z0-9]+)', 'tracks')
            ]
    
        if not any(re.match(pattern, album_link) for pattern, _ in patterns):
            return render_template('mainpage.html', warning_notification='Invalid album link', ns=os.getenv('NAMESPACE'), key=os.getenv("KEY"))

        link_type = next(link_type for pattern, link_type in patterns if re.match(pattern, album_link))
        link_id = next(re.match(pattern, album_link).group(1) for pattern, _ in patterns if re.match(pattern, album_link))
    
        # generate poster
        poster, album_name = generator(link_id, (width, height), options, link_type)

        # check that album data was fetched
        if poster is None or album_name is None:
            return render_template('mainpage.html', warning_notification=f'Failed to get album data based on input "{album_link}"', ns=os.getenv('NAMESPACE'), key=os.getenv("KEY"))

        poster_bytes = io.BytesIO()
        poster.save(poster_bytes, "png")
        poster_bytes.seek(0)

        return send_file(
            poster_bytes,
            mimetype='image/png',
            download_name=f"{album_name}_{theme}_poster.jpg",
            as_attachment=True
        )

    else:
        # redirect to home screen if result page is called in browser
        return redirect('/', ns=os.getenv('NAMESPACE'), key=os.getenv("KEY"))


if __name__ == '__main__':
    app.run(debug=True)