import requests
from bs4 import BeautifulSoup
import pandas as pd
import time

def get_danmu(urls):
# 从给定的 URL 列表中获取弹幕数据，并保存到 Excel 文件。
    # 获取 BV 号
    bv_ids = extract_bv_ids(urls)
    
    # 获取 cid 号
    cids = fetch_cids(bv_ids)
    
    # 获取弹幕数据
    danmu_data = fetch_danmu_data(cids)
    
    # 解析弹幕数据
    all_danmu = parse_danmu(danmu_data)
    
    # 保存到 Excel 文件
    save_danmu_to_excel(all_danmu)
    
    return all_danmu

def extract_bv_ids(urls):
#  从 URL 列表中提取 BV 号。

    bv_ids = []
    for url in urls:
        parts = url.split('/')
        bv_ids.extend(part for part in parts if part.startswith('BV'))
    return bv_ids

def fetch_cids(bv_ids):
#   根据 BV 号列表获取 cid 号列表。
    cids = []
    headers = {
        "User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/128.0.0.0 Safari/537.36 Edg/128.0.0.0"
    }

    for bv_id in bv_ids:
        url = f"https://api.bilibili.com/x/player/pagelist?bvid={bv_id}&jsonp=jsonp"
        try:
            response = requests.get(url, headers=headers)
            response.raise_for_status()
            data = response.json()
            if data.get('code') == 0 and data.get('data'):
                cids.append(data['data'][0]['cid'])
        except requests.RequestException as e:
            print(f"Error fetching CID for BV {bv_id}: {e}")
        time.sleep(0.5)  # 避免过于频繁的请求

    print(f"CID count: {len(cids)}")
    return cids

def fetch_danmu_data(cids):

#   根据 cid 号列表获取弹幕数据。
    danmu_data = []
    fail_count = 0
    headers = {
        "User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/128.0.0.0 Safari/537.36 Edg/128.0.0.0"
    }

    for cid in cids:
        url = f"https://api.bilibili.com/x/v1/dm/list.so?oid={cid}"
        try:
            response = requests.get(url, headers=headers)
            response.raise_for_status()
            response.encoding = 'utf-8'
            danmu_data.append(response.text)
        except requests.RequestException as e:
            print(f"Error fetching danmu for CID {cid}: {e}")
            fail_count += 1
        time.sleep(0.5)  # 避免过于频繁的请求

    print(f"Danmu data count: {len(danmu_data)}")
    if fail_count > 0:
        print(f"Failed to fetch {fail_count} danmu data pages")
    
    return danmu_data

def parse_danmu(danmu_data):

#  解析弹幕数据。

    all_danmu = []
    for html in danmu_data:
        soup = BeautifulSoup(html, 'html.parser')
        all_danmu.extend(d.get_text() for d in soup.find_all('d'))
    
    print(f"Total danmu count: {len(all_danmu)}")
    return all_danmu

def save_danmu_to_excel(all_danmu):
# 将弹幕数据保存到 Excel 文件。

    df = pd.DataFrame({'danmu': all_danmu})
    df.to_excel("all_danmu_data.xlsx", index=False, engine='openpyxl')
    print("Danmu data saved to all_danmu_data.xlsx")