import os
import re
import hashlib
import time
from pathlib import Path

from flask import Flask, render_template, request
from flask_dropzone import Dropzone


enabled_filetypes = ['txt', 'csv', 'pdf', 'doc', 'docx', 'xls', 'xlsx', 'ppt', 'pptx']
regex_email = re.compile('^[a-z0-9]+[\._]?[a-z0-9]+[@]\w+[.]\w{2,3}$')
basedir = Path(__file__).resolve().parent
upload_dir = basedir / 'uploads'
if not upload_dir.exists:
    upload_dir.mkdir()

app = Flask(__name__)

app.config.update(
    UPLOADED_PATH = upload_dir,
    MAX_CONTENT_LENGTH = 1000000000  # 1GB
)

dropzone = Dropzone(app)


@app.route('/')
def index():
    return render_template('index.html')


@app.route('/upload', methods=['POST'])
def handle_upload():
    files = request.files
    if len(files) > 20:
        return 'Naložite lahko do 20 datotek hkrati.', 400
    elif len(files) < 1:
        return 'Priložena ni bila nobena datoteka.', 400

    err = check_suffixes(files)
    if err:
        return err, 400

    err = check_form(request.form)
    if err:
        return err, 400

    file_hashes = create_file_hashes(files)

    store_metadata(request.form, file_hashes)
    store_datafiles(files, file_hashes)
    return 'Uspešno ste oddali datotek(e). Št. datotek: {}'.format(len(files))


def check_suffixes(files):
    for key, f in files.items():
        if key.startswith('file'):
            suffix = f.filename.split('.')[-1]
            if suffix not in enabled_filetypes:
                return 'Datoteka "{}" ni pravilnega formata.'.format(f.filename)
    return None


def check_form(form):
    tip = form.get('tip')
    ime = form.get('ime')
    podjetje = form.get('podjetje')
    email = form.get('email')
    telefon = form.get('telefon')

    if tip not in ['enojez', 'prevodi']:
        return 'Napačen tip besedila.'

    if len(ime) > 100:
        return 'Predolgo ime.'

    if len(podjetje) > 100:
        return 'Predolgo ime institucije'

    if len(email) > 100:
        return 'Predolgi email naslov'
    elif not re.search(regex_email, email):
        return 'Email napačnega formata.'

    if len(telefon) > 100:
        return 'Predolga telefonska št.'

    return None


def create_file_hashes(files):
    res = dict()
    for key, f in files.items():
        if key.startswith('file'):
            h = hashlib.md5(f.filename.encode())
            h.update(f.stream.read())
            res[key] = h.hexdigest()
            f.seek(0)
    return res


def store_metadata(form, file_hashes):
    base = app.config['UPLOADED_PATH'] / 'meta'
    if not base.exists():
        base.mkdir()

    tip = form.get('tip')
    ime = form.get('ime')
    podjetje = form.get('podjetje')
    email = form.get('email')
    telefon = form.get('telefon')

    # This hash serves as an identifier for the whole upload.
    metahash = hashlib.md5((tip+ime+podjetje+email+telefon).encode())
    # Include file hashes to avoid metafile name collisions if they have the same form values,
    # but different data files. Sort hashes first so upload order doesn't matter.
    sorted_f_hashes = list(file_hashes.values())
    sorted_f_hashes.sort()
    metahash.update(''.join(sorted_f_hashes).encode())
    metahash = metahash.hexdigest()

    timestamp = int(time.time())
    filename = str(timestamp) + '-' + email + '-' + metahash + '.meta'

    path = base / filename
    with path.open('w') as f:
        f.write('tip=' + tip)
        f.write('\nime=' + ime)
        f.write('\npodjetje=' + podjetje)
        f.write('\nemail=' + email)
        f.write('\ndatoteke=' + str(sorted_f_hashes))


def store_datafiles(files, file_hashes):
    base = app.config['UPLOADED_PATH'] / 'files'
    if not base.exists():
        base.mkdir()

    for key, f in files.items():
        if key.startswith('file'):
            path = base / file_hashes[key]
            if not path.exists():
                path.mkdir()
                f.save(path / f.filename)


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