# app.py
import asyncio
import json
from typing import List, Dict, Any

import aiohttp
from fastapi import FastAPI, HTTPException, Request
from fastapi.responses import StreamingResponse, JSONResponse
from pydantic import BaseModel
from starlette.middleware.cors import CORSMiddleware
import asyncio
import aiohttp
import urllib.parse
from bs4 import BeautifulSoup as bs
import json
import random
import html
from bs4 import NavigableString, Tag
from rich import print

class BingScraper:
    # Rotating User-Agent list.
    USER_AGENTS = [
        "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/116.0.0.0 Safari/537.36",
        "Mozilla/5.0 (Macintosh; Intel Mac OS X 12_0) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/15.0 Safari/605.1.15",
        "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:104.0) Gecko/20100101 Firefox/104.0",
        "Mozilla/5.0 (Linux; Android 10; SM-G975F) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/115.0.0.0 Mobile Safari/537.36"
    ]

    # Optional proxy list (empty if not used for fastest performance).
    PROXIES = [
        # "http://proxy1.example.com:8080",
        # "http://proxy2.example.com:8080",
    ]

    def __init__(self):
        pass

    @classmethod
    def get_random_headers(cls):
        """Return HTTP headers with a random User-Agent."""
        return {
            "User-Agent": random.choice(cls.USER_AGENTS),
            "Accept": "text/html,application/xhtml+xml,application/xml;""q=0.9,image/avif,image/webp,*/*;q=0.8","Accept-Language": "en-GB,en-US;q=0.9,en;q=0.8","Cache-Control": "no-cache","Pragma": "no-cache","Cookie": "MUID=12164D9908FD6B8C103F5871090F6AAA; _EDGE_V=1; MUIDB=12164D9908FD6B8C103F5871090F6AAA; SRCHD=AF=NOFORM; SRCHUID=V=2&GUID=26D35EBC20D44E418642BA10D7C14F42&dmnchg=1; ak_bmsc=17AB29B1FF4DE4D83B080A7E5CD24350~000000000000000000000000000000~YAAQNtjIFzUD3a2WAQAAnKvFuRtoko96GJe/vh01R588ZQYnYquFWtB0CzXeN5JGXZWgz7CwJqtckHuj3Z70qUhOcji4vkzhCMc/u91gnAIA0zCu7FcDeEJQgRx6n9MxhjrDAel2IIezGUgh+5ktFvDgUIO05s06PqDAtIUzuc9yTrbdAJi3iZvxFFKdGnbQkJ5krI9w3auWhY6i7JvcUPiDsbzzv0Chj1MxzRT1zdkP1B/JFtz+s5d8rUfagFpQporeRG/9gdid4qUPWvPHD6k98AdCTBYOysMHH2z9ErrD5PCO2mLK/RPrJSoqqN4d2mtnWeHNeF897PioJk0nOJw/IrseF0EgdsscKs7NVg/e3Mp27FTEIBduBRa93vvaabLMxg38; _UR=QS=0&TQS=0&Pn=0; BFBUSR=BFBHP=0; _HPVN=CS=eyJQbiI6eyJDbiI6MSwiU3QiOjAsIlFzIjowLCJQcm9kIjoiUCJ9LCJTYyI6eyJDbiI6MSwiU3QiOjAsIlFzIjowLCJQcm9kIjoiSCJ9LCJReiI6eyJDbiI6MSwiU3QiOjAsIlFzIjowLCJQcm9kIjoiVCJ9LCJBcCI6dHJ1ZSwiTXV0ZSI6dHJ1ZSwiTGFkIjoiMjAyNS0wNS0xMFQwMDowMDowMFoiLCJJb3RkIjowLCJHd2IiOjAsIlRucyI6MCwiRGZ0IjpudWxsLCJNdnMiOjAsIkZsdCI6MCwiSW1wIjoyLCJUb2JuIjowfQ==; _Rwho=u=d&ts=2025-05-10; ipv6=hit=1746877082438&t=4; _EDGE_S=F=1&SID=159E288249896C4D3A4D3D6A487B6D96&mkt=en-in; USRLOC=HS=1&ELOC=LAT=28.648426055908203|LON=77.1643295288086|N=Delhi%2C%20Delhi|ELT=1|; SRCHUSR=DOB=20250510&DS=1; MMCASM=ID=94A07BAF860D449DA2A4ABC8CAAC2538; _RwBf=r=0&ilt=9&ihpd=1&ispd=1&rc=24&rb=0&rg=200&pc=21&mtu=0&rbb=0&clo=0&v=9&l=2025-05-10T07:00:00.0000000Z&lft=0001-01-01T00:00:00.0000000&aof=0&ard=0001-01-01T00:00:00.0000000&rwdbt=0&rwflt=0&rwaul2=0&g=&o=2&p=&c=&t=0&s=0001-01-01T00:00:00.0000000+00:00&ts=2025-05-10T11:00:39.6623875+00:00&rwred=0&wls=&wlb=&wle=&ccp=&cpt=&lka=0&lkt=0&aad=0&TH=&cid=0&gb=; _SS=SID=159E288249896C4D3A4D3D6A487B6D96&R=24&RB=0&GB=0&RG=200&RP=21; SRCHHPGUSR=SRCHLANG=en&IG=00DEBA4A2B754BC983011302535541CA&PV=10.0.0&DM=1&BRW=S&BRH=M&CW=1094&CH=738&SCW=1177&SCH=2902&DPR=1.3&UTC=330&WTS=63882470261&PRVCW=1094&PRVCH=738&EXLTT=1&HV=1746874838&HVE=CfDJ8GtUudZcSi1Enm88WwQKtCf-s_3m7rtBIR85jW2Uv01W2IjDUasKRdncp2MkJ7Bl7PxVetzuZETt8bkyd54iRcMP8SVUsClaL2I5uvRiGiSldOKFjy7i69jYPS-egJOhCGf717H5WHFvCI4UwespMZgxZkdo8SVoBwOlx_yQKpA2qtpqV7t6wYd7etwY1FpUaA&BCML=0&BCSRLANG=&ADLT=OFF"

        }


    @classmethod
    def get_random_proxy(cls):
        """Return a random proxy if available."""
        if cls.PROXIES:
            return random.choice(cls.PROXIES)
        return None

    async def fetch_html(self, url, session):
        """Fetch HTML content asynchronously with minimal overhead."""
        headers = self.get_random_headers()
        proxy = self.get_random_proxy()
        try:
            async with session.get(url, headers=headers, proxy=proxy, timeout=30) as response:
                if response.status != 200:
                    print(f"Failed to fetch {url}: HTTP {response.status}")
                    return None
                return await response.text()
        except Exception as e:
            print(f"Error fetching {url}: {e}")
            return None

    # ===== Text Search Methods =====
    async def fetch_bing_text(self, query, session):
        """Fetch Bing search results HTML for the given query."""
        encoded_query = urllib.parse.quote_plus(query)
        url = f'https://www.bing.com/search?q={encoded_query}'
        return await self.fetch_html(url, session)

    def parse_text_results(self, html):
        """
        Parse the Bing HTML using BeautifulSoup to extract:
          - icon (if available)
          - URL
          - Title
          - Abstract (or fallback text)
          - Additional columns (if available)
        """
        soup = bs(html, 'lxml')
        results = []
        result_no = 0
        main_containers = soup.find_all(id="b_results")
        for container in main_containers:
            list_results = container.find_all(class_='b_algo')
            for cont in list_results:
                result_no += 1
                try:
                    icon = 'https:' + cont.find_all(class_='rms_iac')[0].get('data-src')
                except Exception:
                    icon = None
                try:
                    URL = cont.find_all(class_='tilk')[0].get('href')
                except Exception:
                    continue
                try:
                    Title = cont.find_all('h2')[0].get_text(strip=True)
                except Exception:
                    Title = "No Title"
                try:
                    abstract_elem = cont.find_all(class_='b_caption')
                    if abstract_elem and abstract_elem[0].get_text(strip=True):
                        Abstract = abstract_elem[0].get_text(strip=True)
                    else:
                        Abstract = cont.find_all(class_='b_algoSlug')[0].get_text(strip=True)
                except Exception:
                    Abstract = "No Abstract"
                other = []
                try:
                    for column in cont.find_all(class_='b_rc_gb_sub_column'):
                        for div in column.find_all('div'):
                            try:
                                sub_title = div.find_all(class_='b_rc_gb_sub_title')[0].get_text(strip=True)
                            except Exception:
                                sub_title = "No Sub-title"
                            try:
                                sub_description = div.find_all(class_='b_rc_gb_text_wrapper')[0].get_text(strip=True)
                            except Exception:
                                sub_description = ""
                            if sub_description:
                                other.append({'Title': sub_title, 'Description': sub_description})
                except Exception:
                    other = None
                results.append({
                    'no': result_no,
                    'icon': icon,
                    'URL': URL,
                    'Title': Title,
                    'Abstract': Abstract,
                    'other': other
                })
        return results

    async def search_text(self, query, session):
        """Perform a text search (regular and news) and return parsed results."""
        real_query = query
        news_query = query + " news"
        # Run both searches concurrently.
        real_html_task = asyncio.create_task(self.fetch_bing_text(real_query, session))
        news_html_task = asyncio.create_task(self.fetch_bing_text(news_query, session))
        real_html, news_html = await asyncio.gather(real_html_task, news_html_task)
        if not real_html or not news_html:
            print("Failed to retrieve one or both text searches.")
            return None
        real_results = self.parse_text_results(real_html)
        news_results = self.parse_text_results(news_html)
        return {
            "query_results": real_results,
            "news_results": news_results
        }

    # ===== Video Search Methods =====
    async def fetch_bing_video(self, query, session):
        """
        Fetch Bing video search results HTML for the given query.
        The URL below targets Bing's video search endpoint.
        """
        encoded_query = urllib.parse.quote_plus(query)
        url = f'https://www.bing.com/videos/search?q={encoded_query}&adlt=off'
        return await self.fetch_html(url, session)

    def parse_video_results(self, html_content):
        """
        Parse the Bing video search HTML to extract:
          - Video URL (from the mmeta JSON)
          - Title (from an element with class "mc_vtvc_title")
          - Thumbnail URL (from the mmeta JSON)
          - Duration (if available)
          - Source (if available)
        """
        soup = bs(html_content, 'lxml')
        video_results = []
        result_no = 0

        # Find all divs with class "mc_vtvc" that have an mmeta attribute.
        video_divs = soup.find_all("div", class_="mc_vtvc", attrs={"mmeta": True})
        for div in video_divs:
            result_no += 1
            mmeta_raw = div.get("mmeta")
            try:
                # Unescape and parse the JSON metadata.
                mmeta_json = json.loads(html.unescape(mmeta_raw))
            except Exception as e:
                mmeta_json = {}
                print(f"Error parsing mmeta JSON: {e}")
            # Retrieve video URL and thumbnail from the metadata.
            video_url = mmeta_json.get("murl") or mmeta_json.get("pgurl")
            thumbnail = mmeta_json.get("turl")
            # Find the title; often stored in an element with class "mc_vtvc_title".
            title_elem = div.find(class_="mc_vtvc_title")
            title = title_elem.get_text(strip=True) if title_elem else "No Title"
            # Look for duration within an element that may contain a duration value.
            duration_elem = div.find(class_="mc_bc_rc")
            duration = duration_elem.get_text(strip=True) if duration_elem else None
            # Optionally, extract the video source if available.
            source_elem = div.find(class_="mc_vtvc_meta_source")
            source = source_elem.get_text(strip=True) if source_elem else None

            video_results.append({
                "no": result_no,
                "Video URL": video_url,
                "Title": title,
                "Thumbnail": thumbnail,
                "Duration": duration,
                "Source": source,
                "Meta": mmeta_json  # Additional metadata if needed.
            })
        return video_results

    async def search_video(self, query, session):
        """Perform a video search and return parsed results."""
        html_content = await self.fetch_bing_video(query, session)
        if not html_content:
            print("Failed to retrieve video search results.")
            return None
        video_results = self.parse_video_results(html_content)
        return {
            "query": query,
            "video_results": video_results
        }

    # ===== Image Search Methods =====
    async def fetch_bing_image(self, query, session):
        """Fetch Bing images search results HTML for the given query."""
        encoded_query = urllib.parse.quote_plus(query)
        # Using the URL structure with &ch=803.
        url = f'https://www.bing.com/images/search?q={encoded_query}'
        return await self.fetch_html(url, session)

    def parse_image_results(self, html):
        """
        Parse the Bing images HTML using BeautifulSoup to extract detailed image data.
        For each image result (<li> inside a <ul class="dgControl_list">), extract:
          - JSON data from the 'm' attribute in <a class="iusc">
          - Image resolution from the <span class="nowrap"> tag inside <div class="img_info hon">
          - The hosting domain from the <div class="lnkw"> tag.
        """
        soup = bs(html, 'lxml')
        image_results = []
        # Find all <ul> elements that contain image results.
        ul_lists = soup.find_all("ul", class_="dgControl_list")
        for ul in ul_lists:
            li_elements = ul.find_all("li")
            for li in li_elements:
                image_data = {}
                try:
                    # Extract the JSON details from the anchor tag.
                    a_tag = li.find("a", class_="iusc")
                    if not a_tag:
                        continue
                    m_json_str = a_tag.get("m")
                    if not m_json_str:
                        continue
                    try:
                        # Parse the JSON string.
                        details = json.loads(m_json_str)
                    except Exception as e:
                        print(f"JSON parsing error: {e}")
                        continue
                    # Copy all available keys from the JSON.
                    image_data.update(details)
                    # Extract additional details from the HTML.
                    # Resolution: from <div class="img_info hon"> -> <span class="nowrap">
                    img_info = li.find("div", class_="img_info")
                    if img_info:
                        resolution_span = img_info.find("span", class_="nowrap")
                        if resolution_span:
                            image_data["resolution"] = resolution_span.get_text(strip=True)
                    # Domain: from <div class="lnkw"> -> <a> text.
                    lnkw_div = li.find("div", class_="lnkw")
                    if lnkw_div:
                        domain_a = lnkw_div.find("a")
                        if domain_a:
                            image_data["domain"] = domain_a.get_text(strip=True)
                    image_results.append(image_data)
                except Exception as e:
                    print(f"Error parsing an image result: {e}")
                    continue
        return image_results

    async def search_image(self, query, session):
        """Perform an image search and return parsed results."""
        image_html = await self.fetch_bing_image(query, session)
        if not image_html:
            print("Failed to retrieve image search results.")
            return None
        image_results = self.parse_image_results(image_html)
        return {
            "query": query,
            "image_results": image_results
        }

    # ===== Wikipedia Search and Extraction Methods =====
    @staticmethod
    def format_anchor(tag):
        """
        Format an <a> tag into the desired output format:
        (Link Text)[Full_URL]
        """
        href = tag.get("href", "")
        if href.startswith("/") or href.startswith("#"):
            href = "https://en.wikipedia.org" + href
        text = tag.get_text(strip=True)
        return f"({text})[{href}]"

    @classmethod
    def extract_text(cls, element):
        """
        Recursively extract text from an element.
        - For <a> tags, return the formatted version and do not process its children.
        - For other tags, process only their immediate children.
        """
        if isinstance(element, NavigableString):
            return element.strip()
        if isinstance(element, Tag):
            if element.name in ["style", "script", "noscript"]:
                return ""
            if element.name == "a":
                return cls.format_anchor(element)
            texts = []
            for child in element.children:
                t = cls.extract_text(child)
                if t:
                    texts.append(t)
            return " ".join(texts).strip()
        return ""

    @classmethod
    def process_infobox(cls, table):
        """
        Process the infobox table row by row using recursive extraction.
        Returns a list of strings where each line represents a row.
        """
        lines = []
        for row in table.find_all("tr"):
            header_cell = row.find("th")
            data_cell = row.find("td")
            header_text = cls.extract_text(header_cell) if header_cell else ""
            data_text = cls.extract_text(data_cell) if data_cell else ""
            if header_text and data_text:
                lines.append(f"{header_text}: {data_text}")
            elif header_text:
                lines.append(header_text)
            elif data_text:
                lines.append(data_text)
        return lines

    @classmethod
    def process_paragraph(cls, p_tag):
        """
        Process the paragraph (<p> tag) using recursive extraction.
        """
        return cls.extract_text(p_tag)

    async def extract_page_content(self, url, session):
        """
        Fetch the Wikipedia page HTML once and extract both the infobox and a
        paragraph with sufficient content.
        """
        html_content = await self.fetch_html(url, session)
        if not html_content:
            print("Failed to fetch the page.")
            return None, None

        soup = bs(html_content, "lxml")
        # Extract infobox.
        table = soup.find("table", class_="infobox")
        infobox_lines = self.process_infobox(table) if table else None

        # Extract a paragraph with sufficient content.
        content_div = soup.find("div", class_="mw-content-ltr")
        paragraph_text = None
        if content_div:
            paragraphs = content_div.find_all("p")
            for p in paragraphs:
                text = self.process_paragraph(p)
                # Only choose a paragraph if it has at least 5 words (adjust threshold as needed)
                if len(text.split()) >= 5:
                    paragraph_text = text
                    break

        return infobox_lines, paragraph_text

    async def search_wikipedia_url(self, query, session):
        """
        Perform a Bing search for the query and return a Wikipedia URL if found.
        """
        # Correct the search query by appending "wikipedia.org"
        encoded_query = urllib.parse.quote_plus(query + " wikipedia.org")
        bing_url = f"https://www.bing.com/search?q={encoded_query}"
        html_content = await self.fetch_html(bing_url, session)
        if not html_content:
            return None
        soup = bs(html_content, "lxml")
        # Try different containers for search results.
        results = soup.find_all("li", class_="b_algo") or soup.find_all("div", class_="b_algo")
        for result in results:
            a_tag = result.find("a", href=True)
            if a_tag and "wikipedia.org" in a_tag["href"]:
                return a_tag["href"]
        return None

    async def get_wikipedia_url_concurrently(self, query, session, num_attempts=10):
        """
        Launch num_attempts concurrent search tasks for a Wikipedia URL.
        Return the first found Wikipedia URL and cancel the other tasks.
        """
        tasks = [asyncio.create_task(self.search_wikipedia_url(query, session)) for _ in range(num_attempts)]
        done, pending = await asyncio.wait(tasks, return_when=asyncio.FIRST_COMPLETED)
        wiki_url = None
        for task in done:
            wiki_url = task.result()
            if wiki_url:
                break
        for task in pending:
            task.cancel()
        return wiki_url

    async def search_wikipedia(self, query, session):
        """
        Search Bing for a Wikipedia URL and extract its infobox and a paragraph.
        """
        wiki_url = await self.get_wikipedia_url_concurrently(query, session, num_attempts=10)
        if not wiki_url:
            print("Could not find a Wikipedia URL for the query.")
            return None
        print(f"\nFound Wikipedia URL: {wiki_url}\n")
        infobox_lines, paragraph_text = await self.extract_page_content(wiki_url, session)
        return {
            "wikipedia_url": wiki_url,
            "infobox": infobox_lines,
            "paragraph": paragraph_text
        }

# New wrapper class providing a unified API interface.
class BingScraperAPI:
    """
    A unified API that exposes methods as:
      - search(query)
      - video(query)
      - images(query)
      - wikipedia(query)
    In addition, a new asynchronous generator 'fetch' is provided to run multiple
    providers concurrently and yield results as soon as they become available.
    """
    def __init__(self):
        self.scraper = BingScraper()

    async def search(self, query):
        """Perform a regular and news text search."""
        async with aiohttp.ClientSession() as session:
            return await self.scraper.search_text(query, session)

    async def video(self, query):
        """Perform a video search."""
        async with aiohttp.ClientSession() as session:
            return await self.scraper.search_video(query, session)

    async def images(self, query):
        """Perform an image search."""
        async with aiohttp.ClientSession() as session:
            return await self.scraper.search_image(query, session)

    async def wikipedia(self, query):
        """Perform a Wikipedia search and extract infobox and content."""
        async with aiohttp.ClientSession() as session:
            return await self.scraper.search_wikipedia(query, session)

    async def fetch(self, providers, param):
        """
        Accepts:
          - providers: a list of provider names (e.g., ["search", "video", "images"])
          - param: a list of query parameters.
            If a single parameter is provided, it is used for all providers.
            Otherwise, the number of parameters must match the number of providers.
        
        Launches tasks concurrently and yields (provider_name, result) as soon as each is available.
        """
        # Map provider names to the corresponding methods.
        provider_map = {
            "search": self.search,
            "video": self.video,
            "images": self.images,
            "wikipedia": self.wikipedia
        }

        # Determine query parameters to use for each provider.
        if len(param) == 1:
            params = [param[0]] * len(providers)
        elif len(param) == len(providers):
            params = param
        else:
            raise ValueError("The number of query parameters must be either 1 or equal to the number of providers.")

        tasks = []
        for prov, q in zip(providers, params):
            if prov not in provider_map:
                raise ValueError(f"Unknown provider: {prov}")
            # Schedule the provider call.
            task = asyncio.create_task(provider_map[prov](q))
            tasks.append((prov, task))

        # Yield results as they become available.
        for prov, task in tasks:
            try:
                result = await asyncio.wait_for(task, timeout=60)
                yield prov, result
            except Exception as e:
                yield prov, {"error": str(e)}


app = FastAPI(title="BingScraper API (FastAPI wrapper)")

# Allow CORS for local dev; change origins in production
app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],
    allow_methods=["*"],
    allow_headers=["*"],
)

# Pydantic model for request validation
class FetchRequest(BaseModel):
    providers: List[str]
    param: List[str]


# Allowed providers -> underlying scraper call names (these call the low-level methods)
ALLOWED_PROVIDERS = {
    "search": "search_text",
    "video": "search_video",
    "images": "search_image",
    "wikipedia": "search_wikipedia"
}


async def _run_provider(scraper: BingScraperAPI, provider: str, query: str, session: aiohttp.ClientSession, timeout: float = 30.0) -> Dict[str, Any]:
    """
    Run a single provider using the underlying BingScraper methods (reusing the given session).
    Returns a dict: {"provider": provider, "result": ...}
    """
    # Map provider to the low-level method on scraper.scraper
    low_level = ALLOWED_PROVIDERS.get(provider)
    if not low_level:
        raise ValueError(f"Unknown provider: {provider}")

    method = getattr(scraper.scraper, low_level, None)
    if not method or not asyncio.iscoroutinefunction(method):
        raise RuntimeError(f"Provider method not found or not async: {low_level}")

    try:
        # Run the provider with a per-call timeout
        result = await asyncio.wait_for(method(query, session), timeout=timeout)
        return {"provider": provider, "result": result}
    except asyncio.CancelledError:
        raise
    except Exception as e:
        return {"provider": provider, "error": str(e)}


@app.post("/v1/agents/websearch")
async def fetch_post(payload: FetchRequest):
    """
    Accepts JSON:
    {
      "providers": ["search", "images"],
      "param": ["who is elon musk", "elon musk"]
    }
    Returns JSON mapping provider -> result as they finish (collected).
    """
    providers = payload.providers
    param = payload.param

    if not providers:
        raise HTTPException(status_code=400, detail="providers must be a non-empty list")
    if not param:
        raise HTTPException(status_code=400, detail="param must be a non-empty list")

    # Expand params list to match providers (if user passed single param)
    if len(param) == 1:
        params = [param[0]] * len(providers)
    elif len(param) == len(providers):
        params = param
    else:
        raise HTTPException(status_code=400, detail="param length must be 1 or equal to length of providers")

    # Validate providers
    for p in providers:
        if p not in ALLOWED_PROVIDERS:
            raise HTTPException(status_code=400, detail=f"Unsupported provider: {p}")

    scraper_api = BingScraperAPI()

    # Use a single aiohttp session for all provider calls (faster)
    async with aiohttp.ClientSession() as session:
        tasks = [
            asyncio.create_task(_run_provider(scraper_api, prov, q, session))
            for prov, q in zip(providers, params)
        ]

        results = {}
        # Collect results as they finish
        for coro in asyncio.as_completed(tasks):
            res = await coro
            prov = res.get("provider")
            # store either result or error
            results[prov] = res.get("result") if "result" in res else {"error": res.get("error")}

        return JSONResponse(results)


@app.get("/v1/agents/websearch/stream")
async def stream(request: Request, providers: str, params: str):
    """
    Stream results as Server-Sent Events (SSE).
    Query string example:
    /stream?providers=search,images&params=who%20is%20elon%20musk,elon%20musk
    Each SSE event will be JSON:
    {"provider": "<provider>", "result": <result or error>}
    """
    prov_list = [p.strip() for p in providers.split(",") if p.strip()]
    param_list = [p.strip() for p in params.split(",") if p.strip()]

    if not prov_list:
        raise HTTPException(status_code=400, detail="providers query param required")
    if not param_list:
        raise HTTPException(status_code=400, detail="params query param required")

    if len(param_list) == 1:
        param_list = [param_list[0]] * len(prov_list)
    elif len(param_list) != len(prov_list):
        raise HTTPException(status_code=400, detail="params must have length 1 or equal to providers length")

    for p in prov_list:
        if p not in ALLOWED_PROVIDERS:
            raise HTTPException(status_code=400, detail=f"Unsupported provider: {p}")

    scraper_api = BingScraperAPI()

    async def event_generator():
        # Create one session for all calls
        async with aiohttp.ClientSession() as session:
            tasks = [
                asyncio.create_task(_run_provider(scraper_api, prov, q, session))
                for prov, q in zip(prov_list, param_list)
            ]

            for coro in asyncio.as_completed(tasks):
                if await request.is_disconnected():
                    # client disconnected
                    for t in tasks:
                        t.cancel()
                    break
                res = await coro
                # SSE format: data: <json>\n\n
                payload = json.dumps(res, default=str)
                yield f"data: {payload}\n\n"

    return StreamingResponse(event_generator(), media_type="text/event-stream")


# Optional root endpoint
@app.get("/")
async def root():
    return {"msg": "BingScraper FastAPI wrapper. Use POST /fetch or GET /stream"}


# To run:
# uvicorn app:app --host 0.0.0.0 --port 8000 --reload