import argparse
import asyncio
import csv
import json
import os
import sys
import urllib.parse
from datetime import datetime, date, timedelta
import aiohttp


async def delay(ms: int):
    """Async delay in milliseconds."""
    await asyncio.sleep(ms / 1000)


API_BASE_URL = "https://ygp.gdzwfw.gov.cn/ggzy-portal"


def parse_args():
    parser = argparse.ArgumentParser(description="广东省公共资源交易平台数据抓取")
    parser.add_argument("--start-date", help="开始日期 (YYYY-MM-DD)")
    parser.add_argument("--end-date", help="结束日期 (YYYY-MM-DD)")
    parser.add_argument("--output", "-o", default="results.csv", help="输出CSV文件路径 (默认: results.csv)")
    return parser.parse_args()


def parse_api_date(date_str):
    """Parses date string from API (YYYYMMDDHHMMSS) to date object."""
    if not date_str:
        return None
    try:
        return datetime.strptime(date_str, "%Y%m%d%H%M%S").date()
    except ValueError:
        return None


def parse_csv_datetime(date_str):
    """Parses CSV datetime string (YYYY-MM-DD HH:mm:ss) to date object."""
    if not date_str:
        return None
    try:
        return datetime.strptime(date_str, "%Y-%m-%d %H:%M:%S").date()
    except ValueError:
        return None


def format_datetime(date_str):
    """Formats API date string (YYYYMMDDHHMMSS) to YYYY-MM-DD HH:mm:ss."""
    if not date_str:
        return ""
    try:
        dt = datetime.strptime(date_str, "%Y%m%d%H%M%S")
        return dt.strftime("%Y-%m-%d %H:%M:%S")
    except ValueError:
        return date_str


def read_existing_csv(csv_path):
    """
    Reads existing CSV file and returns:
    - existing_data: list of rows (excluding header)
    - min_date: oldest date in the file
    - max_date: newest date in the file
    """
    if not os.path.exists(csv_path):
        return [], None, None

    existing_data = []
    min_date = None
    max_date = None

    try:
        with open(csv_path, "r", encoding="utf-8-sig", newline="") as f:
            reader = csv.reader(f)
            header = next(reader, None)  # Skip header
            if not header:
                return [], None, None

            for row in reader:
                if len(row) >= 2:
                    existing_data.append(row)
                    # Parse date from row (index 1 is 发布时间)
                    row_date = parse_csv_datetime(row[1])
                    if row_date:
                        if min_date is None or row_date < min_date:
                            min_date = row_date
                        if max_date is None or row_date > max_date:
                            max_date = row_date
    except Exception as e:
        print(f"Warning: Error reading existing CSV: {e}", file=sys.stderr)
        return [], None, None

    return existing_data, min_date, max_date


def construct_detail_url(item):
    """Constructs the detail page URL based on item data.

    URL format derived from useJump-b2a96f17.js:
    https://ygp.gdzwfw.gov.cn/#/44/new/jygg/{edition}/{tradingType}?noticeId=...

    Route config: /new/jygg/:edition(v1|v2|v3)/:tradingType
    """
    edition = item.get("edition", "v3")
    trading_type = item.get("noticeSecondType", "A")

    base_url = f"https://ygp.gdzwfw.gov.cn/#/44/new/jygg/{edition}/{trading_type}"

    params = {
        "noticeId": item.get("noticeId", ""),
        "projectCode": item.get("projectCode", ""),
        "bizCode": item.get("tradingProcess", item.get("bizCode", "")),
        "siteCode": item.get("regionCode", item.get("siteCode", "")),
        "publishDate": item.get("publishDate", ""),
        "source": item.get("pubServicePlat", ""),
        "titleDetails": item.get("noticeSecondTypeDesc", ""),
        "classify": item.get("projectType", "")
    }

    params = {k: v for k, v in params.items() if v}

    query = urllib.parse.urlencode(params)
    return f"{base_url}?{query}"


def build_search_payload(page_num=1, publish_start_time="", publish_end_time=""):
    """Build the search API payload.

    Args:
        page_num: Page number
        publish_start_time: Start time in format YYYYMMDDHHMMSS
        publish_end_time: End time in format YYYYMMDDHHMMSS
    """
    return {
        "pageNo": page_num,
        "pageSize": 50,  # Fixed page size 50
        "keyword": "",
        "siteCode": "44",
        "secondType": "",
        "tradingProcess": "513,2C52,3C52",  # Fixed to search for 中标结果
        "thirdType": "[]",
        "projectType": "",
        "publishStartTime": publish_start_time,  # Format: YYYYMMDDHHMMSS
        "publishEndTime": publish_end_time,      # Format: YYYYMMDDHHMMSS
        "type": "trading-type"
    }


def process_items(items):
    """Process a batch of items - API already filters by tradingProcess and date range."""
    page_results = []

    for item in items:
        title = item.get("noticeTitle", "")
        pub_date_str = item.get("publishDate", "")

        page_results.append({
            "项目标题": title,
            "发布时间": format_datetime(pub_date_str),
            "详细链接": construct_detail_url(item)
        })

    return page_results


async def fetch_page(session, page_num, publish_start_time="", publish_end_time=""):
    """Fetch a single page of data from the API."""
    url = f"{API_BASE_URL}/search/v2/items"
    payload = build_search_payload(page_num, publish_start_time, publish_end_time)

    headers = {
        "Content-Type": "application/json",
        "User-Agent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36",
        "Accept": "application/json, text/plain, */*",
        "Origin": "https://ygp.gdzwfw.gov.cn",
        "Referer": "https://ygp.gdzwfw.gov.cn/"
    }

    try:
        async with session.post(url, json=payload, headers=headers) as response:
            if response.status != 200:
                print(f"API Error: {response.status}", file=sys.stderr)
                return None
            return await response.json()
    except Exception as e:
        print(f"Error fetching page {page_num}: {e}", file=sys.stderr)
        return None


def deduplicate_results(new_results, existing_data):
    """Remove duplicates from new_results based on existing_data."""
    # Create a set of existing URLs for fast lookup
    existing_urls = set()
    for row in existing_data:
        if len(row) >= 3:
            existing_urls.add(row[2])  # 详细链接 is the 3rd column

    # Filter out duplicates
    unique_results = []
    for r in new_results:
        if r["详细链接"] not in existing_urls:
            unique_results.append(r)

    return unique_results


def format_api_datetime(dt):
    """Format datetime to API format YYYYMMDDHHMMSS."""
    return dt.strftime("%Y%m%d%H%M%S")


async def run():
    args = parse_args()

    today = date.today()
    # Default: last 3 months
    three_months_ago = today - timedelta(days=90)
    start_date = three_months_ago
    end_date = today

    # Always use incremental mode - read existing CSV if exists
    existing_data = []
    csv_min_date = None
    csv_max_date = None

    if os.path.exists(args.output):
        existing_data, csv_min_date, csv_max_date = read_existing_csv(args.output)
        if csv_min_date and csv_max_date:
            print(f"Existing data range: {csv_min_date} to {csv_max_date}", file=sys.stderr)
            print(f"Existing records: {len(existing_data)}", file=sys.stderr)

    # Determine date range
    if args.start_date:
        try:
            start_date = datetime.strptime(args.start_date, "%Y-%m-%d").date()
        except ValueError:
            print(f"Error: Invalid start date format: {args.start_date}", file=sys.stderr)
            sys.exit(1)
    elif csv_max_date:
        # Without explicit start_date, fetch from max_date+1 to today
        start_date = csv_max_date + timedelta(days=1)

    if args.end_date:
        try:
            end_date = datetime.strptime(args.end_date, "%Y-%m-%d").date()
        except ValueError:
            print(f"Error: Invalid end date format: {args.end_date}", file=sys.stderr)
            sys.exit(1)

    if start_date > end_date:
        print(f"Info: Start date {start_date} is after end date {end_date}, no new data to fetch.", file=sys.stderr)
        print(f"Existing records: {len(existing_data)}", file=sys.stderr)
        sys.exit(0)

    # Format time for API: YYYYMMDDHHMMSS
    start_datetime = datetime.combine(start_date, datetime.min.time())
    end_datetime = datetime.combine(end_date, datetime.max.time().replace(microsecond=0))
    publish_start_time = format_api_datetime(start_datetime)
    publish_end_time = format_api_datetime(end_datetime)

    print(f"Crawling range: {start_date} to {end_date}", file=sys.stderr)
    print(f"API time range: {publish_start_time} to {publish_end_time}", file=sys.stderr)
    print(f"Output file: {args.output}", file=sys.stderr)

    # Collect all new results first
    new_results = []

    async with aiohttp.ClientSession() as session:
        page_num = 1

        while True:
            print(f"Processing page {page_num}...", file=sys.stderr)

            await delay(500)

            resp = await fetch_page(session, page_num, publish_start_time, publish_end_time)

            if resp is None:
                print("Failed to fetch data. Stopping.", file=sys.stderr)
                break

            data = resp.get("data", {})
            items = data.get("pageData", [])

            if not items:
                print("No more items.", file=sys.stderr)
                break

            results = process_items(items)
            new_results.extend(results)

            # Print to console immediately
            for r in results:
                print(json.dumps(r, ensure_ascii=False))
                sys.stdout.flush()

            pages = data.get("pageTotal", 0)

            if page_num >= pages:
                print("Reached last page.", file=sys.stderr)
                break

            page_num += 1
            await delay(1000)

    print(f"\nNew results fetched: {len(new_results)}", file=sys.stderr)

    # Always deduplicate against existing data
    if existing_data:
        new_results = deduplicate_results(new_results, existing_data)
        print(f"After deduplication: {len(new_results)}", file=sys.stderr)

    # Write to CSV: new data first, then existing data
    # Use utf-8-sig to add BOM for Excel to auto-detect encoding and delimiter
    with open(args.output, "w", newline="", encoding="utf-8-sig") as csv_file:
        csv_writer = csv.writer(csv_file, delimiter=",", quoting=csv.QUOTE_MINIMAL)
        csv_writer.writerow(["项目标题", "发布时间", "详细链接"])

        # Write new results first (newer data)
        for r in new_results:
            csv_writer.writerow([r["项目标题"], r["发布时间"], r["详细链接"]])

        # Write existing data (older data)
        for row in existing_data:
            csv_writer.writerow(row[:3])  # Only write first 3 columns

    total_records = len(new_results) + len(existing_data)
    print(f"Total records in CSV: {total_records}", file=sys.stderr)


if __name__ == "__main__":
    asyncio.run(run())