from flask import Flask
from flask import request
import re

app = Flask(__name__)


@app.route("/")
def index():
    with open("index.html", "r") as f:
        return f.read()


@app.route("/gen", methods=['GET'])
def content_generator():
    len_param = request.args.get('len')
    total_size = -1
    if re.match(r"^[0-9]+$", len_param):
        total_size = int(len_param)
    elif re.match(r"^[0-9]+k$", len_param):
        total_size = int(len_param[0:-1]) * 1024
    elif re.match(r"^[0-9]+m$", len_param):
        total_size = int(len_param[0:-1]) * 1024 * 1024

    if total_size <= 0:
        return "Invalid payload size", 400

    generated_segment = bytearray()
    for i in range(0, 256):
        generated_segment.append(i)

    res = bytearray()
    while len(res) < total_size:
        remain = total_size - len(res)
        if remain >= len(generated_segment):
            res += generated_segment
        else:
            res += generated_segment[0:remain]

    return bytes(res)