import os
import re
import json
import time
import shutil
import asyncio
import logging
import traceback
from chardet import detect
from httpx import AsyncClient, RequestError
from typing import List, Dict, Any, Optional
from fastapi.staticfiles import StaticFiles
from fastapi import FastAPI, Request, HTTPException, UploadFile, File, Form
from fastapi.responses import StreamingResponse, JSONResponse, FileResponse
from fastapi.middleware.cors import CORSMiddleware
from dotenv import load_dotenv
from tenacity import RetryError
from openai import RateLimitError
from anthropic import RateLimitError as AnthropicRateLimitError
from google.api_core.exceptions import ResourceExhausted
from src.helpers.helper import get_folder_size, clear_folder

logger = logging.getLogger()
logger.setLevel(logging.INFO)

# Path to the .env file
ENV_FILE_PATH = os.getenv("WRITABLE_DIR", "/tmp") + "/.env"

# Define the upload directory and maximum folder size
UPLOAD_DIRECTORY = os.getenv("WRITABLE_DIR", "/tmp") + "/uploads"
MAX_FOLDER_SIZE = 10 * 1024 * 1024  # 10 MB in bytes

CONTEXT_LENGTH = 128000
BUFFER = 10000
MAX_TOKENS_ALLOWED = CONTEXT_LENGTH - BUFFER

# Per-session state
SESSION_STORE: Dict[str, Dict[str, Any]] = {}   

# Format error message for SSE
def format_error_sse(event_type: str, data: str) -> str:
    lines = data.splitlines()
    sse_message = f"event: {event_type}\n"
    for line in lines:
        sse_message += f"data: {line}\n"
    sse_message += "\n"
    return sse_message

# Stop the task on error (non-fastapi)
def stop_on_error():
    state = SESSION_STORE

    if "process_task" in state:
        state["process_task"].cancel()
        del state["process_task"]

# Get OAuth tokens for MCP tools
def get_oauth_token(provider: str) -> Optional[str]:
    if "oauth_tokens" in SESSION_STORE and provider in SESSION_STORE["oauth_tokens"]:
        token_data = SESSION_STORE["oauth_tokens"][provider]
        # Check if token is expired (1 hour)
        if time.time() - token_data["timestamp"] < 3600:
            return token_data["token"]
        else:
            # Token expired, remove it
            del SESSION_STORE["oauth_tokens"][provider]
            logger.info(f"{provider} token expired and removed")
    return None

# Initialize the components
async def initialize_components():
    load_dotenv(ENV_FILE_PATH, override=True)

    from src.search.search_engine import SearchEngine
    from src.query_processing.query_processor import QueryProcessor
    # from src.rag.neo4j_graphrag import Neo4jGraphRAG
    from src.rag.graph_rag import GraphRAG
    from src.evaluation.evaluator import Evaluator
    from src.reasoning.reasoner import Reasoner
    from src.crawl.crawler import CustomCrawler
    from src.utils.api_key_manager import APIKeyManager
    from src.query_processing.late_chunking.late_chunker import LateChunker
    from src.integrations.mcp_client import MCPClient

    state = SESSION_STORE

    manager = APIKeyManager()
    manager._reinit()
    state['search_engine'] = SearchEngine()
    state['query_processor'] = QueryProcessor()
    state['crawler'] = CustomCrawler(max_concurrent_requests=1000)
    # state['graph_rag'] = Neo4jGraphRAG(num_workers=os.cpu_count() * 2)
    state['graph_rag'] = GraphRAG(num_workers=os.cpu_count() * 2)
    state['evaluator'] = Evaluator()
    state['reasoner'] = Reasoner()
    state['model'] = manager.get_llm()
    state['late_chunker'] = LateChunker()
    state["mcp_client"] = MCPClient()

    state["initialized"] = True
    state["session_id"] = await state["crawler"].create_session()

# Main function to process user queries
async def process_query(user_query: str, sse_queue: asyncio.Queue):
    state = SESSION_STORE

    try:
        # --- Categorize the query ---
        category = await state["query_processor"].classify_query(user_query)
        cat_lower = category.lower().strip()
        user_query = re.sub(r'category:.*', '', user_query, flags=re.IGNORECASE).strip()

        # --- Read and extract user-provided files and links ---     
        # Initialize caches if not present
        if "user_files_cache" not in state:
            state["user_files_cache"] = {}
        if "user_links_cache" not in state:
            state["user_links_cache"] = {}
        
        # Extract user-provided context
        user_context = ""
        user_links = state.get("user_provided_links", [])
        
        # Read new uploaded files
        if state["session_id"]:
            session_upload_path = os.path.join(UPLOAD_DIRECTORY, state["session_id"])
            if os.path.exists(session_upload_path):
                for filename in os.listdir(session_upload_path):
                    file_path = os.path.join(session_upload_path, filename)
                    if os.path.isfile(file_path):
                        # Check if file is already in cache
                        if filename not in state["user_files_cache"]:
                            try:
                                await sse_queue.put(("step", "Reading User-Provided Files..."))
                                
                                # Always read as binary first
                                with open(file_path, 'rb') as f:
                                    file_bytes = f.read()
                                
                                # Try to decode with multiple strategies
                                file_content = None
                                
                                # Strategy 1: Try UTF-8 with BOM handling
                                try:
                                    # Handle UTF-8 BOM if present
                                    if file_bytes.startswith(b'\xef\xbb\xbf'):
                                        file_content = file_bytes[3:].decode('utf-8')
                                    else:
                                        file_content = file_bytes.decode('utf-8')
                                    logger.info(f"Successfully decoded {filename} as UTF-8")
                                except UnicodeDecodeError:
                                    # Strategy 2: Try other common encodings
                                    for encoding in ['utf-8-sig', 'latin-1', 'cp1252', 'iso-8859-1', 'windows-1252']:
                                        try:
                                            file_content = file_bytes.decode(encoding)
                                            logger.info(f"Successfully decoded {filename} with {encoding}")
                                            break
                                        except UnicodeDecodeError:
                                            continue
                                    
                                    # Strategy 3: If all else fails, use chardet for detection
                                    if file_content is None:
                                        try:
                                            
                                            detected = detect(file_bytes)
                                            if detected['encoding']:
                                                file_content = file_bytes.decode(detected['encoding'])
                                                logger.info(f"Decoded {filename} with detected encoding: {detected['encoding']}")
                                        except:
                                            pass
                                    
                                    # Final fallback: Use UTF-8 with replacement
                                    if file_content is None:
                                        file_content = file_bytes.decode('utf-8', errors='replace')
                                        logger.warning(f"Had to use error replacement for {filename}")
                                
                                # Store the decoded content
                                state["user_files_cache"][filename] = file_content
                                logger.info(f"Successfully cached file {filename}, length: {len(file_content)} chars")
                                
                            except Exception as e:
                                logger.error(f"Error reading file {filename}: {str(e)}")
                                state["user_files_cache"][filename] = ""  # Cache empty to avoid retrying
        
        # Add all cached file contents
        for filename, content in state["user_files_cache"].items():
            if content:
                user_context += f"\n[USER PROVIDED FILE: {filename} START]\n{content}\n[USER PROVIDED FILE: {filename} END]\n\n"
        
        # Crawl new user-provided links
        if user_links:
            await sse_queue.put(("step", "Crawling User-Provided Links..."))
            new_links = [link for link in user_links if link not in state["user_links_cache"]]
            
            if new_links:
                # Only crawl new links
                link_contents = await state['crawler'].fetch_page_contents(
                    new_links,
                    user_query,
                    state["session_id"],
                    max_attempts=1
                )
                # Cache the new contents
                for link, content in zip(new_links, link_contents):
                    if not isinstance(content, Exception) and content:
                        state["user_links_cache"][link] = content
                    else:
                        state["user_links_cache"][link] = ""  # Cache empty to avoid retrying
        
        # Add all cached link contents
        for link, content in state["user_links_cache"].items():
            if content:
                idx = user_links.index(link) + 1 if link in user_links else 0
                user_context += f"\n[USER PROVIDED LINK {idx} START]\n{content}\n[USER PROVIDED LINK {idx} END]\n\n"

        # --- Fetch apps data from MCP service ---
        app_context = ""
        selected_services = state.get("selected_services", {})
        
        # Check if any services are selected
        has_google = selected_services.get("google", [])
        has_microsoft = selected_services.get("microsoft", [])
        has_slack = selected_services.get("slack", False)
        
        if has_google or has_microsoft or has_slack:
            await sse_queue.put(("step", "Fetching Data From Connected Apps..."))
            
            # Fetch from each provider in parallel
            tasks = []
            
            # Google services
            if has_google and len(has_google) > 0:
                google_token = get_oauth_token("google")
                tasks.append(
                    state['mcp_client'].fetch_app_data(
                        provider="google",
                        services=has_google,
                        query=user_query,
                        user_id=state["session_id"],
                        access_token=google_token
                    )
                )
            
            # Microsoft services
            if has_microsoft and len(has_microsoft) > 0:
                microsoft_token = get_oauth_token("microsoft")
                tasks.append(
                    state['mcp_client'].fetch_app_data(
                        provider="microsoft",
                        services=has_microsoft,
                        query=user_query,
                        user_id=state["session_id"],
                        access_token=microsoft_token
                    )
                )
            
            # Slack
            if has_slack:
                slack_token = get_oauth_token("slack")
                tasks.append(
                    state['mcp_client'].fetch_app_data(
                        provider="slack",
                        services=[],  # Slack doesn't have sub-services
                        query=user_query,
                        user_id=state["session_id"],
                        access_token=slack_token
                    )
                )
            
            # Execute all requests in parallel
            if tasks:
                results = await asyncio.gather(*tasks, return_exceptions=True)
                print("=== Main ===")
                print(f"Raw results fetched from fetch_mcp_data:-\n{results}")
                
                # Process results
                for i, result in enumerate(results):
                    if isinstance(result, Exception):
                        logger.error(f"Error fetching app data: {result}")
                    elif isinstance(result, dict):
                        # Determine which provider this result is from
                        if i == 0 and has_google:
                            provider = "google"
                        elif (i == 1 and has_microsoft) or (i == 0 and not has_google and has_microsoft):
                            provider = "microsoft"
                        else:
                            provider = "slack"
                        
                        # Format the data
                        formatted_context = state['mcp_client'].format_as_context(provider, result)
                        if formatted_context:
                            app_context += formatted_context
                
                # Log how much app data we got
                if app_context:
                    logger.info(f"Retrieved app data: {len(app_context)} characters")
        
        # Prepend app context to user context
        if app_context:
            user_context = app_context + "\n\n" + user_context
        
        # Upgrade basic to advanced if user has provided links
        if cat_lower == "basic" and user_links:
            cat_lower = "advanced"

        # --- Process the query based on the category ---
        if cat_lower == "basic":
            response = ""
            chunk_counter = 1
            if user_context: # Include user context if available
                print(f"User Context:-\n{user_context}")
                await sse_queue.put(("step", "Generating Response..."))
                async for chunk in state["reasoner"].answer(user_query, user_context, query_type="basic"):
                    await sse_queue.put(("token", json.dumps({"chunk": chunk, "index": chunk_counter})))
                    response += chunk
                    chunk_counter += 1
            else: # No user context provided
                async for chunk in state["reasoner"].answer(user_query):
                    await sse_queue.put(("token", json.dumps({"chunk": chunk, "index": chunk_counter})))
                    response += chunk
                    chunk_counter += 1

            await sse_queue.put(("final_message", response))
            SESSION_STORE["chat_history"].append({"query": user_query, "response": response})
            
            await sse_queue.put(("action", {
                "name": "evaluate",
                "payload": {"query": user_query, "response": response}
            }))

            await sse_queue.put(("complete", "done"))

        elif cat_lower == "advanced":
            await sse_queue.put(("step", "Searching..."))

            optimized_query = await state['search_engine'].generate_optimized_query(user_query)
            search_results = await state['search_engine'].search(
                optimized_query,
                num_results=3,
                exclude_filetypes=["pdf"]
            )

            urls = [r.get('link', 'No URL') for r in search_results]
            search_contents = await state['crawler'].fetch_page_contents(
                urls,
                user_query,
                state["session_id"],
                max_attempts=1
            )

            # Start with user-provided context
            contents = user_context

            # Add crawled contents
            if search_contents:
                for k, content in enumerate(search_contents, 1):
                    if isinstance(content, Exception):
                        print(f"Error fetching content: {content}")
                    elif content:
                        contents += f"[SOURCE {k} START]\n{content}\n[SOURCE {k} END]\n\n"

            if len(contents.strip()) > 0:
                await sse_queue.put(("step", "Generating Response..."))

                token_count = state['model'].get_num_tokens(contents)
                if token_count > MAX_TOKENS_ALLOWED:
                    contents = await state['late_chunker'].chunker(contents, user_query, MAX_TOKENS_ALLOWED)

                await sse_queue.put(("sources_read", len(search_contents)))

                response = ""
                chunk_counter = 1
                async for chunk in state["reasoner"].answer(user_query, contents):
                    await sse_queue.put(("token", json.dumps({"chunk": chunk, "index": chunk_counter})))
                    response += chunk
                    chunk_counter += 1

                sources_for_answer = []
                for idx, (result, content) in enumerate(zip(search_results, search_contents), 1):
                    if content:  # Only include if content was successfully fetched
                        sources_for_answer.append({
                            "id": idx,
                            "title": result.get('title', 'No Title'),
                            "link": result.get('link', 'No URL')
                        })

                await sse_queue.put(("final_message", response))
                await sse_queue.put(("final_sources", json.dumps(sources_for_answer)))
                
                SESSION_STORE["chat_history"].append({"query": user_query, "response": response})
                SESSION_STORE["answer"] = response
                SESSION_STORE["source_contents"] = contents

                await sse_queue.put(("action", {
                    "name": "sources",
                    "payload": {"search_results": search_results, "search_contents": search_contents}
                }))
                await sse_queue.put(("action", {
                    "name": "evaluate",
                    "payload": {"query": user_query, "contents": [contents], "response": response}
                }))

                await sse_queue.put(("complete", "done"))
            else:
                await sse_queue.put(("error", "No results found."))

        elif cat_lower == "pro":
            current_search_results = []
            current_search_contents = []

            await sse_queue.put(("step", "Thinking..."))

            start = time.time()
            intent = await state['query_processor'].get_query_intent(user_query)
            sub_queries, _ = await state['query_processor'].decompose_query(user_query, intent)

            async def sub_query_task(sub_query):
                try:
                    await sse_queue.put(("step", "Searching..."))
                    await sse_queue.put(("task", (sub_query, "RUNNING")))
                    
                    optimized_query = await state['search_engine'].generate_optimized_query(sub_query)
                    search_results = await state['search_engine'].search(
                        optimized_query,
                        num_results=10,
                        exclude_filetypes=["pdf"]
                    )
                    filtered_urls = await state['search_engine'].filter_urls(
                        sub_query,
                        category,
                        search_results
                    )
                    current_search_results.extend(filtered_urls)
                    
                    # Combine search results with user-provided links
                    all_search_results = search_results + \
                    [{"link": url, "title": f"User provided: {url}", "snippet": ""} for url in user_links]         
                    urls = [r.get('link', 'No URL') for r in all_search_results]

                    search_contents = await state['crawler'].fetch_page_contents(
                        urls,
                        sub_query,
                        state["session_id"],
                        max_attempts=1
                    )
                    current_search_contents.extend(search_contents)

                    contents = user_context
                    if search_contents:
                        for k, c in enumerate(search_contents, 1):
                            if isinstance(c, Exception):
                                logger.info(f"Error fetching content: {c}")
                            elif c:
                                contents += f"[SOURCE {k} START]\n{c}\n[SOURCE {k} END]\n\n"

                    if len(contents.strip()) > 0:
                        await sse_queue.put(("task", (sub_query, "DONE")))
                    else:
                        await sse_queue.put(("task", (sub_query, "FAILED")))

                    return contents
                
                except (RateLimitError, ResourceExhausted, AnthropicRateLimitError, RetryError):
                    await sse_queue.put(("task", (sub_query, "FAILED")))
                    return ""

            tasks = []
            if len(sub_queries) > 1 and sub_queries[0] != user_query:
                for sub_query in sub_queries:
                    tasks.append(sub_query_task(sub_query))
                    
            results = await asyncio.gather(*tasks)
            end = time.time()

            # Start with user-provided context
            contents = user_context
            
            # Add searched contents
            contents += "\n\n".join(r for r in results if r.strip())

            unique_results = []
            seen = set()
            for entry in current_search_results:
                link = entry["link"]
                if link not in seen:
                    seen.add(link)
                    unique_results.append(entry)
            current_search_results = unique_results
            current_search_contents = list(set(current_search_contents))

            if len(contents.strip()) > 0:
                await sse_queue.put(("step", "Generating Response..."))

                token_count = state['model'].get_num_tokens(contents)
                if token_count > MAX_TOKENS_ALLOWED:
                    contents = await state['late_chunker'].chunker(
                        text=contents,
                        query=user_query,
                        max_tokens=MAX_TOKENS_ALLOWED
                    )
                    logger.info(f"Number of tokens in the answer: {token_count}")
                    logger.info(f"Number of tokens in the content: {state['model'].get_num_tokens(contents)}")

                await sse_queue.put(("sources_read", len(current_search_contents)))
                
                response = ""
                chunk_counter = 1
                is_first_chunk = True
                async for chunk in state['reasoner'].answer(user_query, contents):
                    if is_first_chunk:
                        await sse_queue.put(("step", f"Thought and searched for {int(end - start)} seconds"))
                        is_first_chunk = False

                    await sse_queue.put(("token", json.dumps({"chunk": chunk, "index": chunk_counter})))
                    response += chunk
                    chunk_counter += 1

                sources_for_answer = []
                for idx, (result, content) in enumerate(zip(current_search_results, current_search_contents), 1):
                    if content:  # Only include if content was successfully fetched
                        sources_for_answer.append({
                            "id": idx,
                            "title": result.get('title', 'No Title'),
                            "link": result.get('link', 'No URL')
                        })

                await sse_queue.put(("final_message", response))
                await sse_queue.put(("final_sources", json.dumps(sources_for_answer)))

                SESSION_STORE["chat_history"].append({"query": user_query, "response": response})
                SESSION_STORE["answer"] = response
                SESSION_STORE["source_contents"] = contents

                await sse_queue.put(("action", {
                    "name": "sources",
                    "payload": {
                        "search_results": current_search_results, 
                        "search_contents": current_search_contents
                    }
                }))
                await sse_queue.put(("action", {
                    "name": "evaluate",
                    "payload": {"query": user_query, "contents": [contents], "response": response}
                }))

                await sse_queue.put(("complete", "done"))
            else:
                await sse_queue.put(("error", "No results found."))

        elif cat_lower == "super":
            current_search_results = []
            current_search_contents = []

            await sse_queue.put(("step", "Thinking..."))

            start = time.time()
            main_query_intent = await state['query_processor'].get_query_intent(user_query)
            sub_queries, _ = await state['query_processor'].decompose_query(user_query, main_query_intent)

            await sse_queue.put(("step", "Searching..."))

            async def sub_query_task(sub_query):
                try:
                    async def sub_sub_query_task(sub_sub_query):
                        optimized_query = await state['search_engine'].generate_optimized_query(sub_sub_query)
                        search_results = await state['search_engine'].search(
                            optimized_query,
                            num_results=10,
                            exclude_filetypes=["pdf"]
                        )
                        filtered_urls = await state['search_engine'].filter_urls(
                            sub_sub_query,
                            category,
                            search_results
                        )
                        current_search_results.extend(filtered_urls)

                        urls = [r.get('link', 'No URL') for r in filtered_urls]
                        search_contents = await state['crawler'].fetch_page_contents(
                            urls,
                            sub_sub_query,
                            state["session_id"],
                            max_attempts=1,
                            timeout=20
                        )
                        current_search_contents.extend(search_contents)

                        contents = ""
                        if search_contents:
                            for k, c in enumerate(search_contents, 1):
                                if isinstance(c, Exception):
                                    logger.info(f"Error fetching content: {c}")
                                elif c:
                                    contents += f"[SOURCE {k} START]\n{c}\n[SOURCE {k} END]\n\n"

                        return contents
                    
                    await sse_queue.put(("task", (sub_query, "RUNNING")))

                    sub_sub_queries, _ = await state['query_processor'].decompose_query(sub_query)

                    tasks = []
                    if len(sub_sub_queries) > 1 and sub_sub_queries[0] != user_query:
                        for sub_sub_query in sub_sub_queries:
                            tasks.append(sub_sub_query_task(sub_sub_query))

                    results = await asyncio.gather(*tasks)

                    if any(result.strip() for result in results):
                        await sse_queue.put(("task", (sub_query, "DONE")))
                    else:
                        await sse_queue.put(("task", (sub_query, "FAILED")))

                    return results
                
                except (RateLimitError, ResourceExhausted, AnthropicRateLimitError, RetryError):
                    await sse_queue.put(("task", (sub_query, "FAILED")))
                    return []

            tasks = []
            if len(sub_queries) > 1 and sub_queries[0] != user_query:
                for sub_query in sub_queries:
                    tasks.append(sub_query_task(sub_query))

            results = await asyncio.gather(*tasks)
            end = time.time()

            # Start with user-provided context
            previous_contents = []
            if user_context:
                previous_contents.append(user_context)

            for result in results:
                if result:
                    for content in result:
                        if isinstance(content, str) and len(content.strip()) > 0:
                            previous_contents.append(content)
            contents = "\n\n".join(previous_contents)

            unique_results = []
            seen = set()
            for entry in current_search_results:
                link = entry["link"]
                if link not in seen:
                    seen.add(link)
                    unique_results.append(entry)
            current_search_results = unique_results
            current_search_contents = list(set(current_search_contents))

            if len(contents.strip()) > 0:
                await sse_queue.put(("step", "Generating Response..."))

                token_count = state['model'].get_num_tokens(contents)
                if token_count > MAX_TOKENS_ALLOWED:
                    contents = await state['late_chunker'].chunker(
                        text=contents,
                        query=user_query,
                        max_tokens=MAX_TOKENS_ALLOWED
                    )
                    logger.info(f"Number of tokens in the answer: {token_count}")
                    logger.info(f"Number of tokens in the content: {state['model'].get_num_tokens(contents)}")

                await sse_queue.put(("sources_read", len(current_search_contents)))
                
                response = ""
                chunk_counter = 1
                is_first_chunk = True
                async for chunk in state['reasoner'].answer(user_query, contents):
                    if is_first_chunk:
                        await sse_queue.put(("step", f"Thought and searched for {int(end - start)} seconds"))
                        is_first_chunk = False

                    await sse_queue.put(("token", json.dumps({"chunk": chunk, "index": chunk_counter})))
                    response += chunk
                    chunk_counter += 1

                sources_for_answer = []
                for idx, (result, content) in enumerate(zip(current_search_results, current_search_contents), 1):
                    if content:  # Only include if content was successfully fetched
                        sources_for_answer.append({
                            "id": idx,
                            "title": result.get('title', 'No Title'),
                            "link": result.get('link', 'No URL')
                        })

                await sse_queue.put(("final_message", response))
                await sse_queue.put(("final_sources", json.dumps(sources_for_answer)))

                SESSION_STORE["chat_history"].append({"query": user_query, "response": response})
                SESSION_STORE["answer"] = response
                SESSION_STORE["source_contents"] = contents

                await sse_queue.put(("action", {
                    "name": "sources",
                    "payload": {
                        "search_results": current_search_results, 
                        "search_contents": current_search_contents
                    }
                }))
                await sse_queue.put(("action", {
                    "name": "evaluate",
                    "payload": {"query": user_query, "contents": [contents], "response": response}
                }))

                await sse_queue.put(("complete", "done"))
            else:
                await sse_queue.put(("error", "No results found."))

        elif cat_lower == "ultra":
            current_search_results = []
            current_search_contents = []

            match = re.search(
                r"^This is the previous context of the conversation:\s*.*?\s*Current Query:\s*(.*)$", 
                user_query, 
                flags=re.DOTALL | re.MULTILINE
            )
            if match:
                user_query = match.group(1)

            await sse_queue.put(("step", "Thinking..."))
            await asyncio.sleep(0.01)   # Sleep for a short time to allow the message to be sent

            async def on_event_callback(event_type, data):
                if event_type == "graph_operation":
                    if data["operation_type"] == "creating_new_graph":
                        await sse_queue.put(("step", "Creating New Graph..."))

                    elif data["operation_type"] == "modifying_existing_graph":
                        await sse_queue.put(("step", "Modifying Existing Graph..."))

                    elif data["operation_type"] == "loading_existing_graph":
                        await sse_queue.put(("step", "Loading Existing Graph..."))

                elif event_type == "sub_query_created":
                    sub_query = data["sub_query"]
                    await sse_queue.put(("task", (sub_query, "RUNNING")))

                elif event_type == "search_process_started":
                    await sse_queue.put(("step", "Searching..."))

                elif event_type == "sub_query_processed":
                    sub_query = data["sub_query"]
                    await sse_queue.put(("task", (sub_query, "DONE")))

                elif event_type == "sub_query_failed":
                    sub_query = data["sub_query"]
                    await sse_queue.put(("task", (sub_query, "FAILED")))

                elif event_type == "search_results_filtered":
                    current_search_results.extend(data["filtered_urls"])

                    filtered_urls = data["filtered_urls"]
                    current_search_results.extend(filtered_urls)

                elif event_type == "search_contents_fetched":
                    current_search_contents.extend(data["contents"])

                    contents = data["contents"]
                    current_search_contents.extend(contents)
                
                elif event_type == "search_process_completed":
                    await sse_queue.put(("step", "Processing final graph tasks..."))
                    await asyncio.sleep(0.01)   # Sleep for a short time to allow the message to be sent

            state['graph_rag'].set_on_event_callback(on_event_callback)

            start = time.time()
            # state['graph_rag'].initialize_schema()
            await state['graph_rag'].process_graph(
                user_query,
                similarity_threshold=0.8,
                relevance_threshold=0.8,
                max_tokens_allowed=MAX_TOKENS_ALLOWED
            )
            end = time.time()

            unique_results = []
            seen = set()
            for entry in current_search_results:
                link = entry["link"]
                if link not in seen:
                    seen.add(link)
                    unique_results.append(entry)
            current_search_results = unique_results
            current_search_contents = list(set(current_search_contents))

            await sse_queue.put(("step", "Generating Response..."))

            answer = state['graph_rag'].query_graph(user_query)
            if answer:
                # Start with user-provided context
                previous_contents = []
                if user_context:
                    previous_contents.append(user_context)

                token_count = state['model'].get_num_tokens(answer)
                if token_count > MAX_TOKENS_ALLOWED:
                    answer = await state['late_chunker'].chunker(
                        text=answer,
                        query=user_query,
                        max_tokens=MAX_TOKENS_ALLOWED
                    )
                    logger.info(f"Number of tokens in the answer: {token_count}")
                    logger.info(f"Number of tokens in the content: {state['model'].get_num_tokens(answer)}")

                await sse_queue.put(("sources_read", len(current_search_contents)))

                response = ""
                chunk_counter = 1
                is_first_chunk = True
                async for chunk in state['reasoner'].answer(user_query, answer):
                    if is_first_chunk:
                        await sse_queue.put(("step", f"Thought and searched for {int(end - start)} seconds"))
                        is_first_chunk = False

                    await sse_queue.put(("token", json.dumps({"chunk": chunk, "index": chunk_counter})))
                    response += chunk
                    chunk_counter += 1

                sources_for_answer = []
                for idx, (result, content) in enumerate(zip(current_search_results, current_search_contents), 1):
                    if content:  # Only include if content was successfully fetched
                        sources_for_answer.append({
                            "id": idx,
                            "title": result.get('title', 'No Title'),
                            "link": result.get('link', 'No URL')
                        })

                await sse_queue.put(("final_message", response))
                await sse_queue.put(("final_sources", json.dumps(sources_for_answer)))
                
                SESSION_STORE["chat_history"].append({"query": user_query, "response": response})
                SESSION_STORE["answer"] = response
                SESSION_STORE["source_contents"] = contents

                await sse_queue.put(("action", {
                    "name": "sources",
                    "payload": {"search_results": current_search_results, "search_contents": current_search_contents},
                }))
                await sse_queue.put(("action", {
                    "name": "graph",
                    "payload": {"query": user_query},
                }))
                await sse_queue.put(("action", {
                    "name": "evaluate",
                    "payload": {"query": user_query, "contents": [answer], "response": response},
                }))

                await sse_queue.put(("complete", "done"))
            else:
                await sse_queue.put(("error", "No results found."))

        else:
            await sse_queue.put(("final_message", "I'm not sure how to handle your query."))

    except Exception as e:
        await sse_queue.put(("error", str(e)))
        traceback.print_exc()
        stop()

# Create a FastAPI app
app = FastAPI()

# Define allowed origins
origins = [
    "http://localhost:3000",
    "https://localhost:3000",
    "http://localhost:7860",
    "https://localhost:7860",
    "http://localhost:8000",
    "https://localhost:8000",
    "http://localhost",
    "https://localhost"
]

# Add the CORS middleware to your FastAPI app
app.add_middleware(
    CORSMiddleware,
    allow_origins=origins,  # Allows only these origins
    allow_credentials=True,
    allow_methods=["*"],    # Allows all HTTP methods (GET, POST, etc.)
    allow_headers=["*"],    # Allows all headers
)

# Serve the React app (the production build) at the root URL.
app.mount("/static", StaticFiles(directory="frontend/build/static", html=True), name="static")

# Define the routes for the FastAPI app

# Define the route for sources action to display search results
@app.post("/action/sources")
def action_sources(payload: Dict[str, Any]) -> Dict[str, Any]:
    try:
        search_contents = payload.get("search_contents", [])
        search_results = payload.get("search_results", [])
        sources = []
        word_limit = 15  # Maximum number of words for the description

        for result, contents in zip(search_results, search_contents):
            if contents:
                title = result.get('title', 'No Title')
                link = result.get('link', 'No URL')
                snippet = result.get('snippet', 'No snippet')
                cleaned = re.sub(r'<[^>]+>|\[\/?.*?\]', '', snippet)
                
                words = cleaned.split()
                if len(words) > word_limit:
                    description = " ".join(words[:word_limit]) + "..."
                else:
                    description = " ".join(words)
                
                source_obj = {
                    "title": title,
                    "link": link,
                    "description": description
                }
                sources.append(source_obj)

        return {"result": sources}
    except Exception as e:
        return JSONResponse(content={"error": str(e)}, status_code=500)
    
# Define the route for graph action to display the graph
@app.post("/action/graph")
def action_graph() -> Dict[str, Any]:
    state = SESSION_STORE

    try:
        html_str = state['graph_rag'].display_graph()

        return {"result": html_str}
    except Exception as e:
        return JSONResponse(content={"error": str(e)}, status_code=500)

# Define the route for evaluate action to display evaluation results
@app.post("/action/evaluate")
async def action_evaluate(payload: Dict[str, Any]) -> Dict[str, Any]:
    state = SESSION_STORE

    try:
        query = payload.get("query", "")
        contents = payload.get("contents", [])
        response = payload.get("response", "")
        metrics = payload.get("metrics", [])
        result = await state["evaluator"].evaluate_response(query, response, contents, include_metrics=metrics)
        
        return {"result": result}
    except Exception as e:
        return JSONResponse(content={"error": str(e)}, status_code=500)
    
# Define the route for excerpts action to display excerpts from the sources
@app.post("/action/excerpts")
async def action_excerpts() -> Dict[str, Any]:
    def validate_excerpts_format(excerpts):
        if not isinstance(excerpts, list):
            return False
        for item in excerpts:
            if not isinstance(item, dict):
                return False
            for statement, sources in item.items():
                if not isinstance(statement, str) or not isinstance(sources, dict):
                    return False
                for src_num, excerpt in sources.items():
                    if not (isinstance(src_num, int) or isinstance(src_num, str)):
                        return False
                    if not isinstance(excerpt, str):
                        return False
        return True

    try:
        state = SESSION_STORE
        response = state["answer"]
        contents = state["source_contents"]

        if not response or not contents:
            raise ValueError("Required data for excerpts not found")
        
        excerpts_list = await state["reasoner"].get_excerpts(response, contents)
        cleaned_excerpts = re.sub(
            r'```[\w\s]*\n?|```|~~~[\w\s]*\n?|~~~', '', excerpts_list, flags=re.MULTILINE | re.DOTALL
        ).strip()
        
        try:
            excerpts = eval(cleaned_excerpts)
        except Exception:
            print(f"Error parsing excerpts:\n{cleaned_excerpts}")
            raise ValueError("Excerpts could not be parsed as a Python list.")

        if not validate_excerpts_format(excerpts):
            print(f"Excerpts format validation failed:\n{excerpts}")
            raise ValueError("Excerpts are not in the required format.")

        print(f"Excerpts:\n{excerpts}")
        return {"result": excerpts}
    except Exception as e:
        print(f"Error in action_excerpts: {e}")
        return JSONResponse(content={"error": str(e)}, status_code=500)

# Define the route for settings to set or update the environment variables
@app.post("/settings")
async def update_settings(data: Dict[str, Any]):
    from src.helpers.helper import (
        prepare_provider_key_updates,
        prepare_proxy_list_updates,
        update_env_vars
    )
    
    provider = data.get("Model_Provider", "").strip()
    model_name = data.get("Model_Name", "").strip()
    multiple_api_keys = data.get("Model_API_Keys", "").strip()
    brave_api_key = data.get("Brave_Search_API_Key", "").strip()
    proxy_list = data.get("Proxy_List", "").strip()
    model_temperature = str(data.get("Model_Temperature", 0.0))
    model_top_p = str(data.get("Model_Top_P", 1.0))

    prov_lower = provider.lower()
    key_updates = prepare_provider_key_updates(prov_lower, multiple_api_keys)
    env_updates = {}
    env_updates.update(key_updates)
    px = prepare_proxy_list_updates(proxy_list)

    if px: 
        env_updates.update(px)

    env_updates["BRAVE_API_KEY"] = brave_api_key
    env_updates["MODEL_PROVIDER"] = prov_lower
    env_updates["MODEL_NAME"] = model_name
    env_updates["MODEL_TEMPERATURE"] = model_temperature
    env_updates["MODEL_TOP_P"] = model_top_p

    update_env_vars(env_updates)
    load_dotenv(override=True)
    await initialize_components()

    return {"success": True}

# Define the route for adding/uploading content for a specific session
@app.post("/add-content")
async def add_content(files: Optional[List[UploadFile]] = File(None), urls: str = Form(...)):
    state = SESSION_STORE
    session_id = state.get("session_id")

    if not session_id:
        raise HTTPException(status_code=400, detail="Session ID is not set. Please start a session first.")
    
    session_upload_path = os.path.join(UPLOAD_DIRECTORY, session_id)
    os.makedirs(session_upload_path, exist_ok=True)

    saved_filenames = []
    if files:
        total_new_files_size = sum(file.size for file in files)
        current_folder_size = get_folder_size(session_upload_path)

        # Check if the total size exceeds the maximum allowed folder size
        if current_folder_size + total_new_files_size > MAX_FOLDER_SIZE:
            raise HTTPException(
                status_code=400,
                detail=f"Cannot add files as total storage would exceed 10 MB. Current size: {current_folder_size / (1024 * 1024):.2f} MB"
            )
        
        for file in files:
            file_path = os.path.join(session_upload_path, file.filename)
            try:
                with open(file_path, "wb") as buffer:
                    shutil.copyfileobj(file.file, buffer)
                saved_filenames.append(file.filename)
            finally:
                file.file.close()

    try:
        parsed_urls = json.loads(urls)
        print(f"Received links: {parsed_urls}")
    except json.JSONDecodeError:
        raise HTTPException(status_code=400, detail="Invalid URL format.")
    
    # Store user-provided links in session
    if parsed_urls:
        SESSION_STORE["user_provided_links"] = parsed_urls

    return {
        "message": "Content added successfully",
        "files_added": saved_filenames,
        "links_added": parsed_urls
    }

# Define the route to update the selected services for searching
@app.post("/api/selected-services")
async def update_selected_services(data: Dict[str, Any]):
    state = SESSION_STORE
    
    selected_services = data.get("services", {})
    state["selected_services"] = selected_services
    
    logger.info(f"Updated selected services: {selected_services}")
    
    return {"success": True, "services": selected_services}

# Define the route to receive OAuth tokens from the frontend
@app.post("/api/session-token")
async def receive_session_token(data: Dict[str, Any]):
    # Helper function to exchange Slack code for OAuth token
    async def exchange_slack_code_for_token(code: str, redirect_uri: str) -> Dict[str, Any]:
        # Get Slack OAuth credentials from environment
        client_id = os.getenv("SLACK_CLIENT_ID")
        client_secret = os.getenv("SLACK_CLIENT_SECRET")
        
        if not client_id or not client_secret:
            logger.error("Slack OAuth credentials not configured")
            raise HTTPException(
                status_code=500, 
                detail="Slack OAuth credentials not configured"
            )
        
        # Prepare the request to Slack's OAuth endpoint
        url = "https://slack.com/api/oauth.v2.access"
        
        # Form data for the request
        data = {
            "code": code,
            "client_id": client_id,
            "client_secret": client_secret,
            "redirect_uri": redirect_uri
        }
        
        try:
            # Make the request to exchange code for token
            async with AsyncClient() as client:
                response = await client.post(
                    url,
                    data=data,
                    headers={"Content-Type": "application/x-www-form-urlencoded"}
                )
            
            # Parse the response
            result = response.json()
            
            # Check if the request was successful
            if not result.get("ok"):
                error = result.get("error", "Unknown error")
                logger.error(f"Slack OAuth error: {error}")
                raise HTTPException(
                    status_code=400, 
                    detail=f"Slack authentication failed: {error}"
                )
            
            # Log the full response for debugging
            logger.info("Slack OAuth endpoint response: %s", result.get("ok"))
            
            # Extract access_token: Check authed_user first (for user tokens), then root (for bot tokens)
            access_token = result.get("authed_user", {}).get("access_token") or result.get("access_token")
            if not access_token:
                logger.error("Slack OAuth token exchange failed: No access token found in response")
                raise HTTPException(
                    status_code=400, 
                    detail="Slack authentication failed: No access token found in response"
                )
            
            # Determine token_type: From authed_user if user token, else root
            token_type = result.get("authed_user", {}).get("token_type") or result.get("token_type", "bot")
            
            # Extract other fields
            return {
                "access_token": access_token,
                "token_type": token_type,
                "scope": result.get("authed_user", {}).get("scope") or result.get("scope", ""),
                "bot_user_id": result.get("bot_user_id"),
                "app_id": result.get("app_id"),
                "team": result.get("team", {}),
                "enterprise": result.get("enterprise"),
                "authed_user": result.get("authed_user", {}),
                "is_enterprise_install": result.get("is_enterprise_install", False)
            }
        
        except RequestError as e:
            logger.error(f"Error making request to Slack: {e}")
            raise HTTPException(
                status_code=500,
                detail="Failed to communicate with Slack OAuth service"
            )
        except Exception as e:
            logger.error(f"Unexpected error during Slack OAuth: {e}")
            raise HTTPException(
                status_code=500,
                detail="An unexpected error occurred during authentication"
            )
    
    provider = data.get("provider")  # 'google', 'microsoft', 'slack'
    token = data.get("token")
    code = data.get("code")  # For Slack authorization code
    team_id = data.get("team_id")  # For Slack workspace
    team_name = data.get("team_name")  # For Slack workspace name
    
    if not provider:
        raise HTTPException(status_code=400, detail="Provider is required")
    
    # Initialize oauth_tokens if it doesn't exist
    if "oauth_tokens" not in SESSION_STORE:
        SESSION_STORE["oauth_tokens"] = {}
    
    token_data = {
        "timestamp": time.time()
    }
    
    # Handle Slack OAuth code exchange
    if provider == "slack" and code:
        try:
            # Build the redirect URI (must match what was sent in the initial OAuth request)
            request_origin = data.get("origin", "https://localhost:3000")
            redirect_uri = f"{request_origin}/auth-receiver.html"
            
            # Exchange the code for an access token
            slack_response = await exchange_slack_code_for_token(code, redirect_uri)
            
            # Store the access token
            token_data["token"] = slack_response["access_token"]
            token_data["token_type"] = slack_response.get("token_type", "bot")
            token_data["scope"] = slack_response.get("scope", "")
            
            # Store team/workspace information
            team_info = slack_response.get("team", {})
            token_data["team_id"] = team_info.get("id", team_id)
            token_data["team_name"] = team_info.get("name", team_name)
            token_data["team_domain"] = team_info.get("domain", "")
            
            # Store enterprise information if available
            if slack_response.get("enterprise"):
                token_data["enterprise"] = slack_response["enterprise"]
                token_data["is_enterprise_install"] = slack_response.get("is_enterprise_install", False)
            
            # Store authed user information
            if slack_response.get("authed_user"):
                token_data["authed_user"] = slack_response["authed_user"]
            
            # Log successful exchange
            logger.info(f"Successfully exchanged Slack code for access token. Team: {token_data.get('team_name', 'Unknown')}")
            
        except HTTPException:
            raise  # Re-raise HTTP exceptions
        except Exception as e:
            logger.error(f"Failed to exchange Slack code: {e}")
            raise HTTPException(
                status_code=500,
                detail="Failed to complete Slack authentication"
            )
    
    elif provider in ["google", "microsoft"] and token:
        # For Google and Microsoft, we already have the token
        token_data["token"] = token
    
    else:
        raise HTTPException(
            status_code=400, 
            detail=f"Invalid authentication data for provider: {provider}"
        )
    
    # Store the token data
    SESSION_STORE["oauth_tokens"][provider] = token_data
    
    # Return success response with workspace info for Slack
    response_data = {
        "success": True, 
        "message": f"{provider} token stored successfully"
    }
    
    if provider == "slack" and "team_name" in token_data:
        response_data["workspace"] = {
            "id": token_data.get("team_id"),
            "name": token_data.get("team_name"),
            "domain": token_data.get("team_domain")
        }
    
    return response_data

# Define the route for cleaning up a session if the session ID matches
@app.post("/cleanup")
async def cleanup_session():
    state = SESSION_STORE
    session_id = state.get("session_id")
    
    if not session_id:
        raise HTTPException(status_code=400, detail="Session ID is not set. Please start a session first.")
    
    session_upload_path = os.path.join(UPLOAD_DIRECTORY, session_id)
    if session_id:
        # Clear the session upload directory
        clear_folder(session_upload_path)

        # Clear user-provided links and caches
        SESSION_STORE["user_provided_links"] = []
        SESSION_STORE["user_files_cache"] = {}
        SESSION_STORE["user_links_cache"] = {}
        SESSION_STORE["selected_services"] = {}
        SESSION_STORE["oauth_tokens"] = {}

        return {"message": "Cleanup successful."}
    
    return {"message": "No session ID provided, cleanup skipped."}

@app.on_event("startup")
def init_chat():
    if not SESSION_STORE:
        print("Initializing chat...")

        # Create the upload directory if it doesn't exist
        print("Creating upload directory...")
        os.makedirs(UPLOAD_DIRECTORY, exist_ok=True)

        # Initialize the session store
        SESSION_STORE["settings_saved"] = False
        SESSION_STORE["session_id"] = None
        SESSION_STORE["answer"] = None
        SESSION_STORE["source_contents"] = None
        SESSION_STORE["chat_history"] = []
        SESSION_STORE["user_provided_links"] = []
        SESSION_STORE["user_files_cache"] = {}
        SESSION_STORE["user_links_cache"] = {}
        SESSION_STORE["selected_services"] = {}
        SESSION_STORE["oauth_tokens"] = {}

        print("Chat initialized!")
        return {"sucess": True}
    else:
        print("Chat already initialized!")
        return {"success": False}

@app.get("/message-sse")
async def sse_message(request: Request, user_message: str):
    state = SESSION_STORE
    sse_queue = asyncio.Queue()

    async def event_generator():
        # Build the prompt
        context = state["chat_history"][-3:]
        if context:
            prompt = \
f"""This is the previous context of the conversation:
{context}

Current Query:
{user_message}"""
        else:
            prompt = user_message  

        task = asyncio.create_task(process_query(prompt, sse_queue))
        state["process_task"] = task

        while True:
            if await request.is_disconnected():
                task.cancel()
                break
            try:
                event_type, data = await asyncio.wait_for(sse_queue.get(), timeout=5)

                if event_type == "token":
                    yield f"event: token\ndata: {data}\n\n"

                elif event_type == "final_message":
                    yield f"event: final_message\ndata: {data}\n\n"

                elif event_type == "final_sources":
                    yield f"event: final_sources\ndata: {data}\n\n"

                elif event_type == "error":
                    stop_on_error()
                    yield format_error_sse("error", data)

                elif event_type == "step":
                    yield f"event: step\ndata: {data}\n\n"

                elif event_type == "task":
                    subq, status = data
                    j = {"task": subq, "status": status}
                    yield f"event: task\ndata: {json.dumps(j)}\n\n"

                elif event_type == "sources_read":
                    yield f"event: sources_read\ndata: {data}\n\n"

                elif event_type == "action":
                    yield f"event: action\ndata: {json.dumps(data)}\n\n"

                elif event_type == "complete":
                    yield f"event: complete\ndata: {data}\n\n"
                    break

                else:
                    yield f"event: message\ndata: {data}\n\n"

            except asyncio.TimeoutError:
                if task.done():
                    break
                continue

            except asyncio.CancelledError:
                break

        if not task.done():
            task.cancel()

        if "process_task" in state:
            del state["process_task"]

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

@app.post("/stop")
def stop():
    state = SESSION_STORE

    if "process_task" in state:
        state["process_task"].cancel()
        del state["process_task"]

    return {"message": "Stopped task manually"}

# Catch-all route for frontend paths.
@app.get("/{full_path:path}")
async def serve_frontend(full_path: str, request: Request):    
    index_path = os.path.join("frontend", "build", "index.html")
    if not os.path.exists(index_path):
        raise HTTPException(status_code=500, detail="Frontend build not found")
    return FileResponse(index_path)