import socket
import aiohttp
import asyncio
import urllib.parse
import validators
from typing import Any, AsyncIterator, Dict, Iterator, List, Sequence, Union

from langchain_community.document_loaders import (
    WebBaseLoader,
)
from langchain_core.documents import Document


from open_webui.constants import ERROR_MESSAGES
from open_webui.config import ENABLE_RAG_LOCAL_WEB_FETCH
from open_webui.env import SRC_LOG_LEVELS

import logging

log = logging.getLogger(__name__)
log.setLevel(SRC_LOG_LEVELS["RAG"])


def validate_url(url: Union[str, Sequence[str]]):
    if isinstance(url, str):
        if isinstance(validators.url(url), validators.ValidationError):
            raise ValueError(ERROR_MESSAGES.INVALID_URL)
        if not ENABLE_RAG_LOCAL_WEB_FETCH:
            # Local web fetch is disabled, filter out any URLs that resolve to private IP addresses
            parsed_url = urllib.parse.urlparse(url)
            # Get IPv4 and IPv6 addresses
            ipv4_addresses, ipv6_addresses = resolve_hostname(parsed_url.hostname)
            # Check if any of the resolved addresses are private
            # This is technically still vulnerable to DNS rebinding attacks, as we don't control WebBaseLoader
            for ip in ipv4_addresses:
                if validators.ipv4(ip, private=True):
                    raise ValueError(ERROR_MESSAGES.INVALID_URL)
            for ip in ipv6_addresses:
                if validators.ipv6(ip, private=True):
                    raise ValueError(ERROR_MESSAGES.INVALID_URL)
        return True
    elif isinstance(url, Sequence):
        return all(validate_url(u) for u in url)
    else:
        return False


def safe_validate_urls(url: Sequence[str]) -> Sequence[str]:
    valid_urls = []
    for u in url:
        try:
            if validate_url(u):
                valid_urls.append(u)
        except ValueError:
            continue
    return valid_urls


def resolve_hostname(hostname):
    # Get address information
    addr_info = socket.getaddrinfo(hostname, None)

    # Extract IP addresses from address information
    ipv4_addresses = [info[4][0] for info in addr_info if info[0] == socket.AF_INET]
    ipv6_addresses = [info[4][0] for info in addr_info if info[0] == socket.AF_INET6]

    return ipv4_addresses, ipv6_addresses


class SafeWebBaseLoader(WebBaseLoader):
    """WebBaseLoader with enhanced error handling for URLs."""

    def _unpack_fetch_results(
        self, results: Any, urls: List[str], parser: Union[str, None] = None
    ) -> List[Any]:
        """Unpack fetch results into BeautifulSoup objects."""
        from bs4 import BeautifulSoup

        final_results = []
        for i, result in enumerate(results):
            url = urls[i]
            if parser is None:
                if url.endswith(".xml"):
                    parser = "xml"
                else:
                    parser = self.default_parser
                self._check_parser(parser)
            final_results.append(BeautifulSoup(result, parser, **self.bs_kwargs))
        return final_results

    async def ascrape_all(
        self, urls: List[str], parser: Union[str, None] = None
    ) -> List[Any]:
        """Async fetch all urls, then return soups for all results."""
        results = await self.fetch_all(urls)
        return self._unpack_fetch_results(results, urls, parser=parser)

    def lazy_load(self) -> Iterator[Document]:
        """Lazy load text from the url(s) in web_path with error handling."""
        for path in self.web_paths:
            try:
                soup = self._scrape(path, bs_kwargs=self.bs_kwargs)
                text = soup.get_text(**self.bs_get_text_kwargs)

                # Build metadata
                metadata = {"source": path}
                if title := soup.find("title"):
                    metadata["title"] = title.get_text()
                if description := soup.find("meta", attrs={"name": "description"}):
                    metadata["description"] = description.get(
                        "content", "No description found."
                    )
                if html := soup.find("html"):
                    metadata["language"] = html.get("lang", "No language found.")

                yield Document(page_content=text, metadata=metadata)
            except Exception as e:
                # Log the error and continue with the next URL
                log.error(f"Error loading {path}: {e}")

    async def alazy_load(self) -> AsyncIterator[Document]:
        """Async lazy load text from the url(s) in web_path."""
        results = await self.ascrape_all(self.web_paths)
        for path, soup in zip(self.web_paths, results):
            text = soup.get_text(**self.bs_get_text_kwargs)
            metadata = {"source": path}
            if title := soup.find("title"):
                metadata["title"] = title.get_text()
            if description := soup.find("meta", attrs={"name": "description"}):
                metadata["description"] = description.get(
                    "content", "No description found."
                )
            if html := soup.find("html"):
                metadata["language"] = html.get("lang", "No language found.")
            yield Document(page_content=text, metadata=metadata)

    async def aload(self) -> list[Document]:
        """Load data into Document objects."""
        return [document async for document in self.alazy_load()]


def get_web_loader(
    urls: Union[str, Sequence[str]],
    verify_ssl: bool = True,
    requests_per_second: int = 2,
):
    # Check if the URLs are valid
    safe_urls = safe_validate_urls([urls] if isinstance(urls, str) else urls)

    return SafeWebBaseLoader(
        safe_urls,
        verify_ssl=verify_ssl,
        requests_per_second=requests_per_second,
        continue_on_failure=True,
    )