import csv

from datetime import datetime
from dataclasses import dataclass

from tqdm import tqdm
from bs4 import BeautifulSoup
from bs4.element import Tag, NavigableString
import requests

BASE_URL = "https://auctions.yahoo.co.jp/"

KEYWORDS = [
  "keyword1",
  "keyword2",
  "keyword3",
]


@dataclass
class Advertisement:
  title: str
  url: str
  current_price: int
  fixed_price: int | None
  bids: int
  time_since_posted: str
  shipping_fee: int | str |  None


def crawl_search_index_for_keyword(keyword: str) -> list[Advertisement]:
    response = requests.get(f"{BASE_URL}/search/search", {
        "p": keyword
    });
    soup = BeautifulSoup(response.text, "html.parser")

    try:
      number_of_results = soup.find(class_='Tab__subText').text.removesuffix('件').replace(',', '')
      number_of_pages_to_scrape = (int(number_of_results) // 100) + 1
    except:
      print(soup.prettify())
      print('Failed to scrape page')
      print('See website contents above')
      exit(1)

    result = []
    progress_bar = tqdm(range(number_of_pages_to_scrape), leave=False)
    progress_bar.set_description(f"Scraping {number_of_results} items for '{keyword}'...")
    for page in progress_bar:
        response = requests.get(f"{BASE_URL}/search/search", {
            "p": keyword,
            "b": page * 100 + 1,
        });
        soup = BeautifulSoup(response.text, "html.parser")
        for item in soup.find(class_='Products__items'):
          if isinstance(item, NavigableString):
            continue
          advertisement_data = extract_advertisement_data(item)
          if advertisement_data is not None:
            result.append(advertisement_data)

    return result


# Advertisementの一つのHTML要素から、Advertisementのデータを取得
def extract_advertisement_data(ad: Tag) -> Advertisement | None:
  title = (
    ad
      .find(class_='Product__title')
      .text
      .replace('\n', '')
      .strip()
  )

  url = (
    ad
      .find(class_='Product__title')
      .find('a')
      ['href']
  )

  current_price = int(
    ad
      .find(class_='Product__price')
      .find(string="現在")
      .parent
      .find_next_sibling()
      .text
      .removesuffix('円')
      .replace(',', '')
      .strip()
  )

  all_prices = ad.find_all(class_='Product__price')
  if len(all_prices) > 1 and (fixed_price := all_prices[1].find(string="即決")) is not None:
    fixed_price = int(
      fixed_price
        .parent
        .find_next_sibling()
        .text
        .removesuffix('円')
        .replace(',', '')
        .strip()
    )
  else:
    fixed_price = None

  bids = int(
    ad
      .find(class_='Product__bid')
      .text
      .strip()
  )

  time_since_posted = (
    ad
      .find(class_='Product__time')
      .text
      .strip()
  )

  # 'Product__postage'のHTML要素があれば、送料を取得
  if (shipping_fee := ad.find(class_='Product__postage')) is not None:
    shipping_text = shipping_fee.text.strip()

    if shipping_text.startswith('＋送料'):
      shipping_fee = int(
        shipping_fee
          .text
          .strip()
          .removeprefix('＋送料')
          .removesuffix('〜')
          .removesuffix('円')
          .replace(',', '')
      )

    elif shipping_text == '送料未定':
      shipping_fee = 'undecided'

    elif shipping_text == '送料は商品ページ参照':
      shipping_fee = 'refer to product page'

    # 写真のうえの’送料無料’の文字列を取得
    elif shipping_text == '' and ad.find(class_='Product__icon--freeShipping') is not None:
      shipping_fee = "free"

    else:
      shipping_fee = shipping_text

  return Advertisement(
    title,
    url,
    current_price,
    fixed_price,
    bids,
    time_since_posted,
    shipping_fee,
  )


def save_advertisements_to_csv(advertisements: list[Advertisement], filename: str):
  with open(filename, 'w') as file:
    writer = csv.DictWriter(file, fieldnames=Advertisement.__dataclass_fields__.keys())
    writer.writeheader()
    for advertisement in advertisements:
      writer.writerow(advertisement.__dict__)


def main():
  progress_bar = tqdm(KEYWORDS)
  progress_bar.set_description("Scraping websites...")

  for keyword in progress_bar:
    timestamp = datetime.now()
    advertisements = crawl_search_index_for_keyword(keyword)

    formatted_timestamp = timestamp.astimezone().replace(microsecond=0).isoformat().replace(':', '-')
    save_advertisements_to_csv(advertisements, f'{formatted_timestamp}-{keyword}.csv')


if __name__ == "__main__":
  main()