import json
import re
from datetime import datetime, timedelta
from typing import List, Optional, Tuple

import requests
from bs4 import BeautifulSoup


def _fallback_niconico_user_name(user_id: str) -> str:
    safe_user_id = re.sub(r"[^A-Za-z0-9_.-]+", "_", str(user_id)).strip("_") or "unknown"
    return f"niconico_user_{safe_user_id}"


def _extract_niconico_owner_name(videos: List[dict]) -> Optional[str]:
    for video in videos:
        essential = video.get('essential', {}) if isinstance(video, dict) else {}
        owner = essential.get('owner', {}) if isinstance(essential, dict) else {}
        name = owner.get('name') if isinstance(owner, dict) else None
        if name:
            return name
    return None


def _page_title(soup: BeautifulSoup) -> str:
    if soup.title and soup.title.string:
        return soup.title.string.strip()
    return "N/A"


def get_niconico_user_and_video_info(user_id: str, existing_video_ids: set = None, force_full_scan: bool = False) -> Tuple[Optional[str], List[Tuple[str, str, str]]]:
    print(f"[DEBUG] get_niconico_user_and_video_info called with user_id={user_id}, existing_count={len(existing_video_ids) if existing_video_ids else 0}, force_full_scan={force_full_scan}")
    
    headers = {
        "User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.124 Safari/537.36"
    }
    
    all_video_info = []
    user_name = None
    page = 1
    found_existing = False
    first_page_parsed = False
    
    while True:
        # ページ番号付きのURLを構築
        if page == 1:
            url = f"https://www.nicovideo.jp/user/{user_id}/video"
        else:
            url = f"https://www.nicovideo.jp/user/{user_id}/video?page={page}"
        
        print(f"[DEBUG] Fetching page {page}: {url}")
        import time
        start_time = time.time()
        response = requests.get(url, headers=headers, timeout=30)
        response.encoding = 'utf-8'
        print(f"[DEBUG] Request completed in {time.time() - start_time:.2f} seconds, status={response.status_code}")
        
        if response.status_code != 200:
            # 2ページ目以降で404の場合は、そのページが存在しないということなので終了
            if page > 1 and response.status_code == 404:
                print(f"Page {page} does not exist, finishing.")
                break
            print(f"Error: User ID {user_id} - Status code {response.status_code}")
            if page == 1:
                return None, []
            break

        soup = BeautifulSoup(response.text, 'html.parser')
        json_data_element = soup.find('div', id='js-initial-userpage-data')
        
        if not json_data_element or 'data-initial-data' not in json_data_element.attrs:
            # データが見つからない場合、ページが存在しない可能性がある
            if page > 1:
                print(f"No data found on page {page}, finishing.")
                break
            print(f"Error: Could not find initial data for user {user_id}")
            return None, []
        
        json_data = json_data_element['data-initial-data']
        try:
            data = json.loads(json_data)
        except json.JSONDecodeError as exc:
            print(f"Error: Could not parse initial data for user {user_id}: {exc}")
            if page == 1:
                return None, []
            break

        if page == 1:
            first_page_parsed = True

        videos = []
        if 'nvapi' in data:
            nvapi_entries = data.get('nvapi') or []
            nvapi_data = nvapi_entries[0] if isinstance(nvapi_entries, list) and nvapi_entries else {}
            if not nvapi_data:
                print(f"[WARN] Niconico user {user_id} page {page}: nvapi entries are missing.")
            elif 'body' in nvapi_data and 'data' in nvapi_data['body']:
                items = nvapi_data['body']['data'].get('items', [])
                videos = items if isinstance(items, list) else []
                # 初回のみユーザー名を取得
                if videos and user_name is None:
                    user_name = _extract_niconico_owner_name(videos)

        # ビデオが見つからない場合は終了
        if not videos:
            if page == 1:
                print(f"No videos found for user {user_id}")
                print(f"[DEBUG] Niconico user {user_id} page title: {_page_title(soup)}")
            else:
                print(f"No more videos found on page {page}, finishing.")
            break

        # 動画情報を追加
        for video in videos:
            video_id = video['essential']['id']
            video_title = video['essential']['title']
            registered_at = video['essential']['registeredAt']
            registered_at_jst = datetime.fromisoformat(registered_at.replace('Z', '+00:00')) + timedelta(hours=9)
            all_video_info.append((video_id, video_title, registered_at_jst.strftime('%Y-%m-%d %H:%M:%S')))
            
            # 既存の動画IDが見つかった場合フラグを立てる（1ページ目のみ）
            if page == 1 and existing_video_ids and video_id in existing_video_ids:
                found_existing = True
                print(f"Found existing video {video_id} on page 1")
        
        print(f"Found {len(videos)} videos on page {page}")
        
        # 1ページ目で既存動画が見つかった場合、2ページ目以降はスキップ（force_full_scanがFalseの場合のみ）
        if page == 1 and found_existing and not force_full_scan:
            print(f"Found existing videos on page 1, skipping remaining pages to save time")
            break
        elif page == 1 and found_existing and force_full_scan:
            print(f"Found existing videos on page 1, but force_full_scan is enabled, continuing to scan all pages")
        
        # 100件未満の場合は最後のページ
        if len(videos) < 100:
            print(f"Less than 100 videos on page {page}, this is the last page.")
            break
        
        # 次のページへ
        page += 1

    if not user_name and first_page_parsed:
        user_name = _fallback_niconico_user_name(user_id)
        if all_video_info:
            print(
                f"[INFO] Niconico user {user_id} display name is hidden or unavailable; "
                f"using fallback username {user_name}."
            )
        else:
            print(
                f"[INFO] Niconico user {user_id} page was parsed but no display name was available; "
                f"using fallback username {user_name}."
            )

    print(f"Total videos found: {len(all_video_info)}")
    return user_name, all_video_info

def get_youtube_channel_and_video_info(channel_id: str) -> Tuple[Optional[str], List[Tuple[str, str, str]]]:
    url = f"https://www.youtube.com/@{channel_id}/videos"
    headers = {
        "User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.124 Safari/537.36"
    }

    response = requests.get(url, headers=headers)
    if response.status_code != 200:
        print(f"Error: Channel ID {channel_id} - Status code {response.status_code}")
        return None, []

    soup = BeautifulSoup(response.text, 'html.parser')
    
    # Extract JSON data
    pattern = re.compile(r'var ytInitialData = (.+?);</script>', re.DOTALL)
    matches = pattern.search(response.text)
    if not matches:
        print(f"Error: Could not find ytInitialData for channel {channel_id}")
        return None, []

    data = json.loads(matches.group(1))

    # Extract channel name
    channel_name = soup.find('meta', property='og:title')['content']

    # Extract video information
    video_info = []
    items = data['contents']['twoColumnBrowseResultsRenderer']['tabs'][1]['tabRenderer']['content']['richGridRenderer']['contents']
    current_date = datetime.now().strftime('%Y年%m月%d日')
    
    for item in items:
        if 'richItemRenderer' in item:
            video_data = item['richItemRenderer']['content']['videoRenderer']
            video_id = video_data['videoId']
            title = video_data['title']['runs'][0]['text']
            upload_date = video_data.get('publishedTimeText', {}).get('simpleText', 'N/A')
            
            # 元の表記に現在日時を追記
            if upload_date != 'N/A':
                upload_date = f"{upload_date} ({current_date} 取得)"
            
            video_info.append((video_id, title, upload_date))

    return channel_name, video_info