from __future__ import annotations

import re
from urllib.parse import quote_plus, urljoin

import httpx
from bs4 import BeautifulSoup
from markdownify import markdownify
from mcp.server.fastmcp import FastMCP

mcp = FastMCP(
    "Web Search MCP",
    instructions="MCP server for searching the web and fetching page content.",
)

_USER_AGENT = (
    "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 "
    "(KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36"
)
_HEADERS = {
    "User-Agent": _USER_AGENT,
    "Accept": "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8",
    "Accept-Language": "en-US,en;q=0.9",
}

_TIMEOUT = 15.0


def _get_client() -> httpx.Client:
    return httpx.Client(
        headers=_HEADERS,
        timeout=_TIMEOUT,
        follow_redirects=True,
    )


# ---------------------------------------------------------------------------
# Search
# ---------------------------------------------------------------------------


def _parse_duckduckgo(html: str) -> list[dict]:
    """Parse DuckDuckGo HTML search results."""
    soup = BeautifulSoup(html, "html.parser")
    results: list[dict] = []

    for result_div in soup.select(".result"):
        title_tag = result_div.select_one(".result__a")
        snippet_tag = result_div.select_one(".result__snippet")
        if not title_tag:
            continue

        href = title_tag.get("href", "")
        # DuckDuckGo wraps URLs in a redirect; extract the actual URL
        if "uddg=" in str(href):
            from urllib.parse import parse_qs, urlparse

            parsed = urlparse(str(href))
            qs = parse_qs(parsed.query)
            href = qs.get("uddg", [str(href)])[0]

        results.append(
            {
                "title": title_tag.get_text(strip=True),
                "url": str(href),
                "snippet": snippet_tag.get_text(strip=True) if snippet_tag else "",
            }
        )

    return results


@mcp.tool()
def web_search(query: str, max_results: int = 10) -> list[dict]:
    """Search the web using DuckDuckGo and return results.

    Args:
        query: The search query string.
        max_results: Maximum number of results to return. Default 10.
    """
    url = f"https://html.duckduckgo.com/html/?q={quote_plus(query)}"
    with _get_client() as client:
        try:
            resp = client.get(url)
            resp.raise_for_status()
        except httpx.HTTPStatusError as e:
            return [
                {"error": f"HTTP {e.response.status_code}: {e.response.reason_phrase}"}
            ]
        except httpx.RequestError as e:
            return [{"error": f"Request failed: {e}"}]

    results = _parse_duckduckgo(resp.text)
    return results[:max_results]


# ---------------------------------------------------------------------------
# Fetch page
# ---------------------------------------------------------------------------

_STRIP_TAGS = {
    "script",
    "style",
    "nav",
    "footer",
    "header",
    "noscript",
    "svg",
    "img",
    "iframe",
}


def _clean_html(html: str, base_url: str) -> str:
    """Convert HTML to clean markdown."""
    soup = BeautifulSoup(html, "html.parser")

    # Remove unwanted tags
    for tag in soup.find_all(_STRIP_TAGS):
        tag.decompose()

    # Resolve relative URLs
    for a_tag in soup.find_all("a", href=True):
        a_tag["href"] = urljoin(base_url, a_tag["href"])

    # Convert to markdown
    md = markdownify(str(soup), heading_style="ATX", strip=["img"])

    # Collapse excessive blank lines
    md = re.sub(r"\n{3,}", "\n\n", md)
    return md.strip()


@mcp.tool()
def fetch_page(url: str, max_length: int = 20000) -> dict:
    """Fetch a web page and return its content as markdown.

    Args:
        url: The URL to fetch.
        max_length: Maximum character length of returned content. Default 20000.
    """
    with _get_client() as client:
        try:
            resp = client.get(url)
            resp.raise_for_status()
        except httpx.HTTPStatusError as e:
            return {
                "error": f"HTTP {e.response.status_code}: {e.response.reason_phrase}",
                "url": url,
            }
        except httpx.RequestError as e:
            return {"error": str(e), "url": url}

    content_type = resp.headers.get("content-type", "")
    if "text/html" not in content_type and "application/xhtml" not in content_type:
        return {
            "url": str(resp.url),
            "content_type": content_type,
            "content": resp.text[:max_length],
        }

    md = _clean_html(resp.text, str(resp.url))
    truncated = len(md) > max_length
    return {
        "url": str(resp.url),
        "title": _extract_title(resp.text),
        "content": md[:max_length],
        "truncated": truncated,
    }


def _extract_title(html: str) -> str:
    soup = BeautifulSoup(html, "html.parser")
    tag = soup.find("title")
    return tag.get_text(strip=True) if tag else ""


# ---------------------------------------------------------------------------
# Multi-search: search + fetch top results in one call
# ---------------------------------------------------------------------------


@mcp.tool()
def search_and_read(
    query: str, num_pages: int = 3, max_page_length: int = 10000
) -> list[dict]:
    """Search the web and fetch the top results in one step.

    This combines web_search and fetch_page: it searches for the query,
    then fetches and converts the top results to markdown.

    Args:
        query: The search query string.
        num_pages: Number of top results to fetch. Default 3.
        max_page_length: Max characters per page. Default 10000.
    """
    results = web_search(query, max_results=num_pages)
    output: list[dict] = []
    for r in results:
        page = fetch_page(r["url"], max_length=max_page_length)
        output.append(
            {
                "search_title": r["title"],
                "search_snippet": r["snippet"],
                **page,
            }
        )
    return output


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