main.py

import os
import asyncio
import json
import logging
from typing import AsyncGenerator

from fastapi import FastAPI, HTTPException, Query
from fastapi.responses import StreamingResponse
from pydantic import BaseModel
from dotenv import load_dotenv
import aiohttp
from bs4 import BeautifulSoup

# --- Configuration ---
logging.basicConfig(level=logging.INFO)
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.")

# API URLs and Models
SNAPZION_API_URL = "https://search.snapzion.com/get-snippets"
LLM_API_URL = "https://api.inference.net/v1/chat/completions"
LLM_MODEL = "mistralai/mistral-nemo-12b-instruct/fp-8"

# Headers for external services
SNAPZION_HEADERS = { 'Content-Type': 'application/json', 'User-Agent': 'AI-Deep-Research-Agent/1.0' }
SCRAPING_HEADERS = { 'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/140.0.0.0 Safari/537.36' }
LLM_HEADERS = { "Authorization": f"Bearer {LLM_API_KEY}", "Content-Type": "application/json" }

# --- Pydantic Models for Request Body ---
class DeepResearchRequest(BaseModel):
    query: str

# --- FastAPI App Initialization ---
app = FastAPI(
    title="AI Deep Research API",
    description="Provides single-shot AI search and streaming deep research completions.",
    version="2.0.0"
)

# --- Core Service Functions (Reused and New) ---

async def call_snapzion_search(session: aiohttp.ClientSession, query: str) -> list:
    try:
        async with session.post(SNAPZION_API_URL, headers=SNAPZION_HEADERS, json={"query": query}, timeout=15) as response:
            response.raise_for_status()
            data = await response.json()
            return data.get("organic_results", [])
    except Exception as e:
        logger.error(f"Snapzion search failed for query '{query}': {e}")
        return [] # Return empty list on failure instead of crashing

async def scrape_url(session: aiohttp.ClientSession, url: str) -> str:
    if url.lower().endswith('.pdf'): return "Error: PDF content cannot be scraped."
    try:
        async with session.get(url, headers=SCRAPING_HEADERS, timeout=10, ssl=False) as response:
            if response.status != 200: return f"Error: 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()
            return " ".join(soup.stripped_strings)
    except Exception as e:
        logger.warning(f"Scraping failed for {url}: {e}")
        return f"Error: {e}"

async def search_and_scrape(session: aiohttp.ClientSession, query: str) -> tuple[str, list]:
    """Performs the search and scrape pipeline for a given query."""
    search_results = await call_snapzion_search(session, query)
    sources = search_results[:4] # Use top 4 sources per sub-query
    if not sources: return "", []

    scrape_tasks = [scrape_url(session, source["link"]) for source in sources]
    scraped_contents = await asyncio.gather(*scrape_tasks)

    context = "\n\n".join(
        f"Source [{i+1}] (from {sources[i]['link']}):\n{content}"
        for i, content in enumerate(scraped_contents) if not content.startswith("Error:")
    )
    return context, sources

# --- Streaming Deep Research Logic ---

async def run_deep_research_stream(query: str) -> AsyncGenerator[str, None]:
    """The main async generator for the deep research process."""
    
    def format_sse(data: dict) -> str:
        """Formats a dictionary as a Server-Sent Event string."""
        return f"data: {json.dumps(data)}\n\n"

    try:
        async with aiohttp.ClientSession() as session:
            # Step 1: Generate Sub-Questions
            yield format_sse({"event": "status", "data": "Generating research plan..."})
            sub_question_prompt = {
                "model": LLM_MODEL,
                "messages": [{
                    "role": "user",
                    "content": f"You are a research planner. Based on the user's query '{query}', generate a list of 3 to 4 crucial sub-questions that would form the basis of a comprehensive research report. Respond with ONLY a JSON array of strings. Example: [\"Question 1?\", \"Question 2?\"]"
                }]
            }
            async with session.post(LLM_API_URL, headers=LLM_HEADERS, json=sub_question_prompt) as response:
                response.raise_for_status()
                result = await response.json()
                try:
                    sub_questions = json.loads(result['choices'][0]['message']['content'])
                except (json.JSONDecodeError, IndexError):
                    yield format_sse({"event": "error", "data": "Failed to parse sub-questions from LLM."})
                    return
            
            yield format_sse({"event": "plan", "data": sub_questions})

            # Step 2: Concurrently research all sub-questions
            research_tasks = [search_and_scrape(session, sq) for sq in sub_questions]
            all_research_results = []
            
            for i, task in enumerate(asyncio.as_completed(research_tasks)):
                yield format_sse({"event": "status", "data": f"Researching: \"{sub_questions[i]}\""})
                result = await task
                all_research_results.append(result)

            # Step 3: Consolidate all context and sources
            yield format_sse({"event": "status", "data": "Consolidating research..."})
            full_context = "\n\n---\n\n".join(res[0] for res in all_research_results if res[0])
            all_sources = [source for res in all_research_results for source in res[1]]
            unique_sources = list({s['link']: s for s in all_sources}.values()) # Deduplicate sources
            
            if not full_context.strip():
                yield format_sse({"event": "error", "data": "Failed to gather any research context."})
                return

            # Step 4: Generate the final report with streaming
            yield format_sse({"event": "status", "data": "Generating final report..."})
            
            final_report_prompt = f"""
You are a research analyst. Your task is to synthesize the provided context into a comprehensive, well-structured report on the topic: "{query}".
Use the context below exclusively. Do not use outside knowledge. Structure the report with markdown headings.

## Research Context ##
{full_context}
"""
            
            final_report_payload = {
                "model": LLM_MODEL,
                "messages": [{"role": "user", "content": final_report_prompt}],
                "stream": True # Enable streaming from the LLM
            }

            async with session.post(LLM_API_URL, headers=LLM_HEADERS, json=final_report_payload) as response:
                response.raise_for_status()
                async for line in response.content:
                    if line.strip():
                        # The inference API might wrap its stream chunks in a 'data: ' prefix
                        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)
                            content = chunk.get("choices", [{}])[0].get("delta", {}).get("content")
                            if content:
                                yield format_sse({"event": "chunk", "data": content})
                        except json.JSONDecodeError:
                            continue # Ignore empty or malformed lines

            yield format_sse({"event": "sources", "data": unique_sources})
            
    except Exception as e:
        logger.error(f"An error occurred during deep research: {e}")
        yield format_sse({"event": "error", "data": str(e)})
    finally:
        yield format_sse({"event": "done", "data": "Deep research complete."})


# --- API Endpoints ---

@app.get("/", include_in_schema=False)
def root():
    return {"message": "AI Deep Research API is active. See /docs for details."}

@app.post("/v1/deepresearch/completions")
async def deep_research_endpoint(request: DeepResearchRequest):
    """
    Performs a multi-step, streaming deep research task.

    **Events Streamed:**
    - `status`: Provides updates on the current stage of the process.
    - `plan`: The list of sub-questions that will be researched.
    - `chunk`: A piece of the final generated report.
    - `sources`: The list of web sources used for the report.
    - `error`: Indicates a fatal error occurred.
    - `done`: Signals the end of the stream.
    """
    return StreamingResponse(
        run_deep_research_stream(request.query),
        media_type="text/event-stream"
    )