main.py

import os
import asyncio
import json
import logging
import random
import re
from typing import AsyncGenerator, Optional, Tuple, List
from urllib.parse import unquote

from fastapi import FastAPI
from fastapi.responses import StreamingResponse
from fastapi.middleware.cors import CORSMiddleware
from pydantic import BaseModel
from dotenv import load_dotenv
import aiohttp
from bs4 import BeautifulSoup

# --- Configuration ---
logging.basicConfig(level=logging.INFO, format='%(asctime)s - %(levelname)s - %(message)s')
logger = logging.getLogger(__name__)

load_dotenv()
LLM_API_KEY = os.getenv("LLM_API_KEY")

if not LLM_API_KEY:
    raise RuntimeError("LLM_API_KEY must be set in a .env file.")
else:
    logger.info("LLM API Key loaded successfully.")

# --- Constants & Headers ---
LLM_API_URL = "https://api.typegpt.net/v1/chat/completions"
LLM_MODEL = "meta-llama/Llama-4-Maverick-17B-128E-Instruct-FP8"
MAX_SOURCES_TO_PROCESS = 15

# Real Browser User Agents for SCRAPING
USER_AGENTS = [
    "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/128.0.0.0 Safari/537.36",
    "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/128.0.0.0 Safari/537.36",
    "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:129.0) Gecko/20100101 Firefox/129.0"
]

LLM_HEADERS = {"Authorization": f"Bearer {LLM_API_KEY}", "Content-Type": "application/json", "Accept": "application/json"}

class DeepResearchRequest(BaseModel):
    query: str

app = FastAPI(
    title="AI Deep Research API",
    description="Provides robust, long-form, streaming deep research completions using the DuckDuckGo Search API.",
    version="9.3.0"  # Using direct DuckDuckGo HTML API
)

# Enable CORS for all origins
app.add_middleware(CORSMiddleware, allow_origins=["*"], allow_credentials=True, allow_methods=["*"], allow_headers=["*"])

# --- Helper Functions ---
def extract_json_from_llm_response(text: str) -> Optional[list]:
    match = re.search(r'\[.*\]', text, re.DOTALL)
    if match:
        try:
            return json.loads(match.group(0))
        except json.JSONDecodeError:
            return None
    return None

# --- Core Service Functions ---
async def call_duckduckgo_search(session: aiohttp.ClientSession, query: str, max_results: int = 10) -> List[dict]:
    """Performs a search by directly scraping the DuckDuckGo HTML interface."""
    logger.info(f"Searching DuckDuckGo for: '{query}'")
    search_url = "https://html.duckduckgo.com/html/"
    params = {"q": query}
    headers = {"User-Agent": random.choice(USER_AGENTS)}

    try:
        async with session.post(search_url, data=params, headers=headers, ssl=False) as response:
            if response.status != 200:
                logger.error(f"DuckDuckGo search failed with status {response.status} for query '{query}'")
                return []

            html = await response.text()
            soup = BeautifulSoup(html, "html.parser")
            results = []

            for result in soup.find_all('div', class_='result'):
                title_elem = result.find('a', class_='result__a')
                snippet_elem = result.find('a', class_='result__snippet')
                link_elem = result.find('a', class_='result__url')

                if title_elem and snippet_elem and link_elem:
                    # Extract the raw href which is a redirect
                    raw_href = link_elem.get('href', '')
                    
                    # The actual URL is in a query parameter 'uddg'
                    parsed_url_match = re.search(r'uddg=([^&]+)', raw_href)
                    if parsed_url_match:
                        # URL decode the extracted URL
                        link = unquote(parsed_url_match.group(1))
                    else:
                        continue # Skip if we can't find the clean URL

                    title = title_elem.get_text(strip=True)
                    snippet = snippet_elem.get_text(strip=True)
                    
                    results.append({'title': title, 'link': link, 'snippet': snippet})
                    if len(results) >= max_results:
                        break
            
            logger.info(f"Found {len(results)} sources from DuckDuckGo for: '{query}'")
            return results
    except Exception as e:
        logger.error(f"DuckDuckGo search failed for query '{query}': {e}", exc_info=True)
        return []

async def research_and_process_source(session: aiohttp.ClientSession, source: dict) -> Tuple[str, dict]:
    headers = {'User-Agent': random.choice(USER_AGENTS)}
    try:
        logger.info(f"Scraping: {source['link']}")
        if source['link'].lower().endswith('.pdf'):
            raise ValueError("PDF content")
        async with session.get(source['link'], headers=headers, timeout=10, ssl=False) as response:
            if response.status != 200:
                raise ValueError(f"HTTP status {response.status}")
            html = await response.text()
            soup = BeautifulSoup(html, "html.parser")
            for tag in soup(['script', 'style', 'nav', 'footer', 'header', 'aside']):
                tag.decompose()
            content = " ".join(soup.stripped_strings)
            if not content.strip():
                raise ValueError("Parsed content is empty.")
            return content, source
    except Exception as e:
        logger.warning(f"Scraping failed for {source['link']} ({e}). Falling back to snippet.")
        return source.get('snippet', ''), source

# --- Streaming Deep Research Logic ---
async def run_deep_research_stream(query: str) -> AsyncGenerator[str, None]:
    def format_sse(data: dict) -> str:
        return f"data: {json.dumps(data)}\n\n"

    try:
        async with aiohttp.ClientSession() as session:
            yield format_sse({"event": "status", "data": "Generating research plan..."})
            plan_prompt = {
                "model": LLM_MODEL,
                "messages": [{
                    "role": "user",
                    "content": f"Generate 3-4 key sub-questions for a research report on '{query}'. Your response MUST be ONLY the raw JSON array. Example: [\"Question 1?\"]"
                }]
            }
            try:
                async with session.post(LLM_API_URL, headers=LLM_HEADERS, json=plan_prompt, timeout=25) as response:
                    response.raise_for_status()
                    result = await response.json()
                    sub_questions = result if isinstance(result, list) else extract_json_from_llm_response(result['choices'][0]['message']['content'])
                    if not isinstance(sub_questions, list):
                        raise ValueError(f"Invalid plan from LLM: {result}")
            except Exception as e:
                yield format_sse({"event": "error", "data": f"Could not generate research plan. Reason: {e}"})
                return

            yield format_sse({"event": "plan", "data": sub_questions})

            yield format_sse({"event": "status", "data": f"Searching sources for {len(sub_questions)} topics..."})
            search_tasks = [call_duckduckgo_search(session, sq) for sq in sub_questions]
            all_search_results = await asyncio.gather(*search_tasks)
            unique_sources = list({source['link']: source for results in all_search_results for source in results}.values())

            if not unique_sources:
                yield format_sse({"event": "error", "data": "All search queries returned zero usable sources."})
                return

            sources_to_process = unique_sources[:MAX_SOURCES_TO_PROCESS]
            yield format_sse({"event": "status", "data": f"Found {len(unique_sources)} unique sources. Processing the top {len(sources_to_process)}..."})

            processing_tasks = [research_and_process_source(session, source) for source in sources_to_process]
            consolidated_context, all_sources_used = "", []

            for task in asyncio.as_completed(processing_tasks):
                content, source_info = await task
                if content:
                    consolidated_context += f"Source: {source_info['link']}\nContent: {content}\n\n---\n\n"
                    all_sources_used.append(source_info)

            if not consolidated_context.strip():
                yield format_sse({"event": "error", "data": "Failed to gather any research context."})
                return

            yield format_sse({"event": "status", "data": "Synthesizing final report..."})
            report_prompt = f'Synthesize the provided context into a long-form, comprehensive, multi-page report on "{query}". Use markdown. Elaborate extensively on each point. Base your entire report ONLY on the provided context.\n\n## Research Context ##\n{consolidated_context}'
            report_payload = {"model": LLM_MODEL, "messages": [{"role": "user", "content": report_prompt}], "stream": True}

            async with session.post(LLM_API_URL, headers=LLM_HEADERS, json=report_payload) as response:
                response.raise_for_status()
                async for line in response.content:
                    line_str = line.decode('utf-8').strip()
                    if line_str.startswith('data:'):
                        line_str = line_str[5:].strip()
                    if line_str == "[DONE]":
                        break
                    try:
                        chunk = json.loads(line_str)
                        choices = chunk.get("choices")
                        if choices and isinstance(choices, list) and len(choices) > 0:
                            content = choices[0].get("delta", {}).get("content")
                            if content:
                                yield format_sse({"event": "chunk", "data": content})
                    except json.JSONDecodeError:
                        continue

            yield format_sse({"event": "sources", "data": all_sources_used})
    except Exception as e:
        logger.error(f"A critical error occurred: {e}", exc_info=True)
        yield format_sse({"event": "error", "data": f"An unexpected error occurred: {str(e)}"})

@app.post("/deep-research", response_class=StreamingResponse)
async def deep_research_endpoint(request: DeepResearchRequest):
    """
    Accepts a query and streams back a detailed research report.
    Events: status, plan, chunk, sources, error
    """
    return StreamingResponse(run_deep_research_stream(request.query), media_type="text/event-stream")

if __name__ == "__main__":
    import uvicorn
    uvicorn.run(app, host="0.0.0.0", port=8000)