import re, httpx
from typing import Union

HEADERS = {
    'User-Agent': 'Mozilla/5.0 (X11; Linux x86_64; rv:121.0) Gecko/20100101 Firefox/121.0',
    'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,*/*;q=0.8',
    'Accept-Language': 'en-US,en;q=0.5',
    'Accept-Encoding': 'gzip, deflate, br',
    'DNT': '1',
    'Sec-GPC': '1',
    'Connection': 'keep-alive',
    'Upgrade-Insecure-Requests': '1',
    'Sec-Fetch-Dest': 'document',
    'Sec-Fetch-Mode': 'navigate',
    'Sec-Fetch-Site': 'none',
    'Sec-Fetch-User': '?1',
    'Pragma': 'no-cache',
    'Cache-Control': 'no-cache',
}

async def _get_cookies(client):
    # Make a request to https://www.coles.com.au/ as if we were a normal browser, then return the cookies
    response = await client.get('https://www.coles.com.au/', headers=HEADERS, follow_redirects=True)
    return dict(response.cookies)

def _get_package_size(size: str) -> Union[int, str]:
    if size:
        match = re.match(r'(\d+)(.*)', size)
        if match:
            return int(match.group(1)), match.group(2)

    return 1, 'items'

def _get_client():
    return httpx.AsyncClient()

last_cookies = None
async def _request_url(url: str) -> dict:
    global last_cookies

    async with _get_client() as client:
        if last_cookies:
            cookies = last_cookies
        else:
            cookies = await _get_cookies(client)
            last_cookies = cookies

        try:
            response = await client.get(url, headers=HEADERS, follow_redirects=True, cookies=cookies)
            response.raise_for_status()
            return response.json()
        except httpx.NetworkError as ne:
            print(ne)
            last_cookies = None
            return None

def _get_product_details_url(product_id) -> str:
    # https://www.coles.com.au/_next/data/20240926.02_v4.18.0/en/product/cadbury-favourites-boxed-chocolate-340g-3571992.json?slug=cadbury-favourites-boxed-chocolate-340g-3571992
    # https://www.coles.com.au/_next/data/20240926.02_v4.18.0/en/product/coles-blueberries-170g-3571948.json?slug=coles-blueberries-170g-3571948
    return f'https://www.coles.com.au/_next/data/20240926.02_v4.18.0/en/product/{product_id}.json'

def get_product_id(url: str) -> str:
    # https://www.coles.com.au/product/cadbury-favourites-boxed-chocolate-340g-3571992
    regex = r'https://www.coles.com.au/product/([^/]+)/?.*'
    match = re.match(regex, url)
    if match:
        return match.group(1)
    return None

async def scrape(product_id: str) -> Union[dict, dict]:
    details_url = _get_product_details_url(product_id)
    raw_data = await _request_url(details_url)
    
    product = raw_data['pageProps']['product']

    quantity, unit = _get_package_size(product['size'])

    img_prefix = 'https://shop.coles.com.au'
    images = product['images'][0]
    product_data = {
        'name': product['name'], 
        'quantity': quantity, 
        'unit': unit, 
        'img_small': (img_prefix + images['thumb']['path']) if images else None,
        'img_large': (img_prefix + images['full']['path']) if images else None,
    }

    return product_data, raw_data