#!/usr/bin/env python3
"""
Download Wikipedia articles for LightRAG ingestion testing.

This script fetches plain text from Wikipedia articles across diverse domains
to create a test dataset with intentional entity overlap for testing:
- Entity merging and summarization
- Cross-domain relationships
- Parallel processing optimizations

Usage:
    python lightrag/evaluation/download_wikipedia.py
    python lightrag/evaluation/download_wikipedia.py --output wiki_docs/
    python lightrag/evaluation/download_wikipedia.py --domains medical,climate
"""

import argparse
import asyncio
from pathlib import Path

import httpx

# Wikipedia API endpoint (no auth required)
WIKI_API = "https://en.wikipedia.org/w/api.php"

# User-Agent required by Wikipedia API policy
# See: https://meta.wikimedia.org/wiki/User-Agent_policy
USER_AGENT = "LightRAG-Test-Downloader/1.0 (https://github.com/HKUDS/LightRAG; claude@example.com)"

# Article selection by domain - chosen for entity overlap
# WHO → Medical + Climate
# Carbon/Emissions → Climate + Finance (ESG)
# Germany/Brazil → Sports + general knowledge
ARTICLES = {
    "medical": ["Diabetes", "COVID-19"],
    "finance": ["Stock_market", "Cryptocurrency"],
    "climate": ["Climate_change", "Renewable_energy"],
    "sports": ["FIFA_World_Cup", "Olympic_Games"],
}


async def fetch_article(title: str, client: httpx.AsyncClient) -> dict | None:
    """Fetch Wikipedia article text via API.

    Args:
        title: Wikipedia article title (use underscores for spaces)
        client: Async HTTP client

    Returns:
        Dict with title, content, and source; or None if not found
    """
    params = {
        "action": "query",
        "titles": title,
        "prop": "extracts",
        "explaintext": True,  # Plain text, no HTML
        "format": "json",
    }
    response = await client.get(WIKI_API, params=params)

    # Check for HTTP errors
    if response.status_code != 200:
        print(f"    HTTP {response.status_code} for {title}")
        return None

    # Handle empty response
    if not response.content:
        print(f"    Empty response for {title}")
        return None

    try:
        data = response.json()
    except Exception as e:
        print(f"    JSON parse error for {title}: {e}")
        return None

    pages = data.get("query", {}).get("pages", {})

    for page_id, page in pages.items():
        if page_id != "-1":  # -1 = not found
            return {
                "title": page.get("title", title),
                "content": page.get("extract", ""),
                "source": f"wikipedia_{title}",
            }
    return None


async def download_articles(
    domains: list[str],
    output_dir: Path,
) -> list[dict]:
    """Download all articles for selected domains.

    Args:
        domains: List of domain names (e.g., ["medical", "climate"])
        output_dir: Directory to save downloaded articles

    Returns:
        List of article metadata dicts
    """
    output_dir.mkdir(parents=True, exist_ok=True)
    articles = []

    headers = {"User-Agent": USER_AGENT}
    async with httpx.AsyncClient(timeout=30.0, headers=headers) as client:
        for domain in domains:
            titles = ARTICLES.get(domain, [])
            if not titles:
                print(f"[{domain.upper()}] Unknown domain, skipping")
                continue

            print(f"[{domain.upper()}] Downloading {len(titles)} articles...")

            for title in titles:
                article = await fetch_article(title, client)
                if article:
                    # Save to file
                    filename = f"{domain}_{title.lower().replace(' ', '_')}.txt"
                    filepath = output_dir / filename
                    filepath.write_text(article["content"])

                    word_count = len(article["content"].split())
                    print(f"  ✓ {title}: {word_count:,} words")

                    articles.append(
                        {
                            "domain": domain,
                            "title": article["title"],
                            "file": str(filepath),
                            "words": word_count,
                            "source": article["source"],
                        }
                    )
                else:
                    print(f"  ✗ {title}: Not found")

    return articles


async def main():
    parser = argparse.ArgumentParser(description="Download Wikipedia test articles")
    parser.add_argument(
        "--output",
        "-o",
        type=str,
        default="lightrag/evaluation/wiki_documents",
        help="Output directory for downloaded articles",
    )
    parser.add_argument(
        "--domains",
        "-d",
        type=str,
        default="medical,finance,climate,sports",
        help="Comma-separated domains to download",
    )
    args = parser.parse_args()

    domains = [d.strip() for d in args.domains.split(",")]
    output_dir = Path(args.output)

    print("=== Wikipedia Article Downloader ===")
    print(f"Domains: {', '.join(domains)}")
    print(f"Output: {output_dir}/")
    print()

    articles = await download_articles(domains, output_dir)

    total_words = sum(a["words"] for a in articles)
    print()
    print(f"✓ Downloaded {len(articles)} articles ({total_words:,} words total)")
    print(f"  Output: {output_dir}/")

    # Print summary by domain
    print("\nBy domain:")
    for domain in domains:
        domain_articles = [a for a in articles if a["domain"] == domain]
        domain_words = sum(a["words"] for a in domain_articles)
        print(f"  {domain}: {len(domain_articles)} articles, {domain_words:,} words")


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