"""
FinMK MCP Server
================
A full Model Context Protocol (MCP) server that exposes every existing Django REST API
as an agent-callable tool. Zero business logic duplication — all tools proxy through
the existing Django REST endpoints and reuse all validation, MongoDB operations, and
business logic already in place.

Works in two modes:
  - Local dev:  LM Studio (qwen3.5:2b) calls tools via MCP protocol
  - Production: Gemini / Cerebras function-calling integrates same tools via chatbot

Usage:
  python mcp_server.py   (for LM Studio / stdio)
  npx @modelcontextprotocol/inspector python mcp_server.py  (for browser inspector)
"""

import os
import sys
import json
import httpx
import pdfplumber
from typing import Optional, Dict, Any
from mcp.server.fastmcp import FastMCP
from dotenv import load_dotenv

load_dotenv()

# ──────────────────────────────────────────────
# Configuration
# ──────────────────────────────────────────────
mcp = FastMCP("FinMK AI Agent")

PORT = os.getenv("PORT", "8000")
BASE_URL = (os.getenv("API_BASE_URL") or f"http://localhost:{PORT}/api").rstrip("/")
if os.getenv("RENDER") == "true" and not os.getenv("API_BASE_URL"):
    BASE_URL = f"http://localhost:{PORT}/api".rstrip("/")

# Shared auth state — persists for the lifetime of the MCP session
_auth: Dict[str, Optional[str]] = {
    "access_token": None,
    "refresh_token": None,
    "username": None,
}


def _headers() -> Dict[str, str]:
    h = {"Content-Type": "application/json"}
    if _auth["access_token"]:
        h["Authorization"] = f"Bearer {_auth['access_token']}"
    return h


def _require_auth() -> Optional[str]:
    """Returns an error string if not authenticated, else None."""
    if not _auth["access_token"]:
        return "Error: Not authenticated. Call 'authenticate_agent' first."
    return None


async def _get(path: str, params: Optional[Dict[str, Any]] = None) -> str:
    err = _require_auth()
    if err:
        return err
    full_path = path.lstrip("/")
    url = f"{BASE_URL}/{full_path}"
    print(f"[MCP] GET {url}", file=sys.stderr)
    async with httpx.AsyncClient(timeout=300) as client:
        try:
            r = await client.get(url, headers=_headers(), params=params)
            print(f"[MCP] Response {r.status_code} from {url}", file=sys.stderr)
            if r.status_code == 404:
                print(f"[MCP] 404 ERROR Body: {r.text[:500]}", file=sys.stderr)
            return await _handle_binary_save(r)
        except Exception as e:
            print(f"[MCP] Error: {e}", file=sys.stderr)
            return f"Error: {e}"

async def _handle_binary_save(r: httpx.Response) -> str:
    """Detects binary content (PDF/CSV) and saves to Downloads instead of returning raw bytes to Agent."""
    ctype = r.headers.get("Content-Type", "").lower()
    
    if "application/pdf" in ctype or "text/csv" in ctype:
        try:
            downloads_path = os.path.join(os.path.expanduser("~"), "Downloads")
            os.makedirs(downloads_path, exist_ok=True)
            
            # Extract filename from header or use default
            cd = r.headers.get("Content-Disposition", "")
            filename = "FinMK_Export.pdf"
            if "filename=" in cd:
                filename = cd.split("filename=")[1].strip('"')
            elif "text/csv" in ctype:
                filename = "FinMK_Export.csv"
            
            filepath = os.path.join(downloads_path, filename)
            with open(filepath, "wb") as f:
                f.write(r.content)
            
            return f"SUCCESS: The file has been generated and saved directly to your Downloads folder: {filepath}"
        except Exception as e:
            return f"Error saving binary file: {e}"
    
    # Standard text/json response
    return r.text


async def _post(path: str, payload: dict) -> str:
    err = _require_auth()
    if err:
        return err
    full_path = path.lstrip("/")
    url = f"{BASE_URL}/{full_path}"
    print(f"[MCP] POST {url} | Body: {json.dumps(payload)[:100]}...", file=sys.stderr)
    async with httpx.AsyncClient(timeout=300) as client:
        try:
            r = await client.post(url, json=payload, headers=_headers())
            print(f"[MCP] Response {r.status_code}", file=sys.stderr)
            return await _handle_binary_save(r)
        except Exception as e:
            print(f"[MCP] Error: {e}", file=sys.stderr)
            return f"Error: {e}"


async def _patch(path: str, payload: dict) -> str:
    err = _require_auth()
    if err:
        return err
    full_path = path.lstrip("/")
    url = f"{BASE_URL}/{full_path}"
    print(f"[MCP] PATCH {url} | Body: {json.dumps(payload)[:100]}...", file=sys.stderr)
    async with httpx.AsyncClient(timeout=300) as client:
        try:
            r = await client.patch(url, json=payload, headers=_headers())
            print(f"[MCP] Response {r.status_code}", file=sys.stderr)
            return r.text
        except Exception as e:
            print(f"[MCP] Error: {e}", file=sys.stderr)
            return f"Error: {e}"


async def _delete(path: str) -> str:
    err = _require_auth()
    if err:
        return err
    full_path = path.lstrip("/")
    url = f"{BASE_URL}/{full_path}"
    print(f"[MCP] DELETE {url}", file=sys.stderr)
    async with httpx.AsyncClient(timeout=30) as client:
        try:
            r = await client.delete(url, headers=_headers())
            print(f"[MCP] Response {r.status_code}", file=sys.stderr)
            if r.status_code in (200, 204):
                return json.dumps({"success": True, "status": r.status_code})
            return r.text
        except Exception as e:
            print(f"[MCP] Error: {e}", file=sys.stderr)
            return f"Error: {e}"


# ══════════════════════════════════════════════
# AUTH TOOLS
# ══════════════════════════════════════════════

@mcp.tool()
async def authenticate_agent(username: str, password: str) -> str:
    """
    Log into the FinMK backend with username and password.
    Optional if already logged in via session/token.
    """
    url = f"{BASE_URL}/auth/login/"
    print(f"[MCP] Authenticating: {username} at {url}", file=sys.stderr)
    async with httpx.AsyncClient(timeout=15) as client:
        try:
            r = await client.post(
                url,
                json={"username": username, "password": password}
            )
            print(f"[MCP] Auth Response: {r.status_code}", file=sys.stderr)
            if r.status_code != 200:
                ret = f"Login failed ({r.status_code}): {r.text}"
                print(f"[MCP] {ret}", file=sys.stderr)
                return ret
            data = r.json()
            _auth["access_token"] = data.get("access")
            _auth["refresh_token"] = data.get("refresh")
            _auth["username"] = username
            return f"Authenticated as '{username}'. Session is active — you can now call all other tools."
        except Exception as e:
            err = f"Connection error to {BASE_URL}: {e}"
            print(f"[MCP] {err}", file=sys.stderr)
            return err


@mcp.tool()
async def get_auth_status() -> str:
    """Check whether the AI agent is currently authenticated."""
    if _auth["access_token"]:
        return f"Authenticated as '{_auth['username']}'. Session is active."
    return "Not authenticated. Call 'authenticate_agent' first."


# ══════════════════════════════════════════════
# DASHBOARD
# ══════════════════════════════════════════════

@mcp.tool()
async def get_dashboard_summary() -> str:
    """
    Get the full financial dashboard: total income, expenses, savings, net balance,
    budget adherence, recent transactions, and category breakdowns.
    """
    return await _get("/finance/dashboard-summary/")


# ══════════════════════════════════════════════
# TRANSACTIONS — INCOME
# ══════════════════════════════════════════════

@mcp.tool()
async def list_incomes() -> str:
    """List all income transactions for the authenticated user, sorted by date descending."""
    return await _get("/finance/income/")


@mcp.tool()
async def add_income(title: str, amount: float, date: str, category: str = "") -> str:
    """
    Add a new income transaction.
    - title: Description (e.g. 'Freelance project payment')
    - amount: Positive number (e.g. 5000.00)
    - date: YYYY-MM-DD format (e.g. '2025-03-15')
    - category: (Optional) Leave empty for auto-classification by AI
    """
    payload: Dict[str, Any] = {"title": title, "amount": amount, "date": date}
    if category:
        payload["category"] = category
    return await _post("/finance/income/", payload)


@mcp.tool()
async def update_income(income_id: str, title: str = "", amount: float = 0, date: str = "", category: str = "") -> str:
    """
    Update an existing income transaction by its ID.
    Only provide fields you want to change.
    """
    payload: Dict[str, Any] = {}
    if title:
        payload["title"] = title
    if amount:
        payload["amount"] = amount
    if date:
        payload["date"] = date
    if category:
        payload["category"] = category
    if not payload:
        return "Error: Provide at least one field to update."
    return await _patch(f"/finance/income/{income_id}/", payload)


@mcp.tool()
async def delete_income(income_id: str) -> str:
    """Delete an income transaction permanently by its ID."""
    return await _delete(f"/finance/income/{income_id}/")


# ══════════════════════════════════════════════
# TRANSACTIONS — EXPENSE
# ══════════════════════════════════════════════

@mcp.tool()
async def list_expenses() -> str:
    """List all expense transactions for the authenticated user, sorted by date descending."""
    return await _get("/finance/expense/")


@mcp.tool()
async def add_expense(title: str, amount: float, date: str, category: str = "") -> str:
    """
    Add a new expense transaction.
    - title: Description (e.g. 'Grocery shopping at Reliance Fresh')
    - amount: Positive number (e.g. 1200.50)
    - date: YYYY-MM-DD format
    - category: (Optional) Leave empty for auto-classification by AI
    """
    payload: Dict[str, Any] = {"title": title, "amount": amount, "date": date}
    if category:
        payload["category"] = category
    return await _post("/finance/expense/", payload)


@mcp.tool()
async def update_expense(expense_id: str, title: str = "", amount: float = 0, date: str = "", category: str = "") -> str:
    """
    Update an existing expense transaction by its ID.
    Only provide fields you want to change.
    """
    payload: Dict[str, Any] = {}
    if title:
        payload["title"] = title
    if amount:
        payload["amount"] = amount
    if date:
        payload["date"] = date
    if category:
        payload["category"] = category
    if not payload:
        return "Error: Provide at least one field to update."
    return await _patch(f"/finance/expense/{expense_id}/", payload)


@mcp.tool()
async def delete_expense(expense_id: str) -> str:
    """Delete an expense transaction permanently by its ID."""
    return await _delete(f"/finance/expense/{expense_id}/")


@mcp.tool()
async def list_all_transactions() -> str:
    """
    List ALL transactions (both incomes and expenses) in one call.
    Returns a combined JSON with 'incomes' and 'expenses' arrays.
    """
    err = _require_auth()
    if err:
        return err
    async with httpx.AsyncClient(timeout=30) as client:
        try:
            inc_r, exp_r = await client.get(f"{BASE_URL}/finance/income/", headers=_headers()), \
                           await client.get(f"{BASE_URL}/finance/expense/", headers=_headers())
            return json.dumps({
                "incomes": inc_r.json() if inc_r.status_code == 200 else [],
                "expenses": exp_r.json() if exp_r.status_code == 200 else [],
            }, indent=2, default=str)
        except Exception as e:
            return f"Error: {e}"


@mcp.tool()
async def delete_transaction(transaction_id: str, transaction_type: str) -> str:
    """
    Delete an income or expense by ID.
    - transaction_type: must be 'income' or 'expense'
    """
    if transaction_type not in ("income", "expense"):
        return "Error: transaction_type must be 'income' or 'expense'."
    return await _delete(f"/finance/{transaction_type}/{transaction_id}/")


# ══════════════════════════════════════════════
# BUDGETS
# ══════════════════════════════════════════════

@mcp.tool()
async def get_budgets() -> str:
    """List all budget limits set by the user across categories and months."""
    return await _get("/finance/budget/")


@mcp.tool()
async def create_budget(category: str, limit_amount: float, month: str) -> str:
    """
    Create a new budget limit for a category.
    - category: Expense category name (e.g. 'Food & Dining')
    - limit_amount: Maximum allowed spending (e.g. 5000.00)
    - month: YYYY-MM format (e.g. '2025-03') or 'all' for a permanent limit
    """
    return await _post("/finance/budget/", {
        "category": category,
        "limit_amount": limit_amount,
        "month": month,
    })


@mcp.tool()
async def update_budget(budget_id: str, limit_amount: float) -> str:
    """Update the spending limit of an existing budget entry by its ID."""
    return await _patch(f"/finance/budget/{budget_id}/", {"limit_amount": limit_amount})


@mcp.tool()
async def delete_budget(budget_id: str) -> str:
    """Delete a budget entry permanently by its ID."""
    return await _delete(f"/finance/budget/{budget_id}/")


# ══════════════════════════════════════════════
# SAVINGS GOALS
# ══════════════════════════════════════════════

@mcp.tool()
async def get_savings_goals() -> str:
    """List all savings goals with their target amounts and current progress."""
    return await _get("/finance/savings-goals/")


@mcp.tool()
async def create_savings_goal(name: str, target_amount: float, current_amount: float = 0.0, deadline: str = "") -> str:
    """
    Create a new savings goal.
    - name: Goal name (e.g. 'Emergency Fund', 'Europe Trip')
    - target_amount: Goal target in the user's currency
    - current_amount: Amount already saved (default 0)
    - deadline: Optional target date in YYYY-MM-DD format
    """
    payload: Dict[str, Any] = {"name": name, "target_amount": target_amount, "current_amount": current_amount}
    if deadline:
        payload["deadline"] = deadline
    return await _post("/finance/savings-goals/", payload)


@mcp.tool()
async def update_savings_goal(goal_id: str, name: str = "", target_amount: float = 0, current_amount: float = -1, deadline: str = "") -> str:
    """
    Update an existing savings goal by its ID. Provide only the fields to change.
    Use current_amount to log deposits/progress toward the goal.
    """
    payload: Dict[str, Any] = {}
    if name:
        payload["name"] = name
    if target_amount:
        payload["target_amount"] = target_amount
    if current_amount >= 0:
        payload["current_amount"] = current_amount
    if deadline:
        payload["deadline"] = deadline
    if not payload:
        return "Error: Provide at least one field to update."
    return await _patch(f"/finance/savings-goals/{goal_id}/", payload)


@mcp.tool()
async def delete_savings_goal(goal_id: str) -> str:
    """Delete a savings goal permanently by its ID."""
    return await _delete(f"/finance/savings-goals/{goal_id}/")


# ══════════════════════════════════════════════
# ANALYTICS
# ══════════════════════════════════════════════

@mcp.tool()
async def get_cash_flow_forecast() -> str:
    """
    Get a machine-learning cash flow forecast for the next 3 months based on
    historical income and expense patterns. Powered by Moirai / ARIMA models.
    """
    return await _get("/analytics/forecast/")


@mcp.tool()
async def get_income_forecast() -> str:
    """Get a detailed income forecast using time-series ML models."""
    return await _get("/analytics/income/forecast/")


@mcp.tool()
async def get_anomaly_report() -> str:
    """
    Get the anomaly detection report. Returns unusual/suspicious transactions
    identified by the Isolation Forest algorithm that may warrant review.
    """
    return await _get("/analytics/anomalies/")


# ══════════════════════════════════════════════
# USER PROFILE
# ══════════════════════════════════════════════

@mcp.tool()
async def get_user_profile() -> str:
    """Retrieve the authenticated user's profile: name, email, currency preference, etc."""
    return await _get("/auth/profile/")


@mcp.tool()
async def update_user_profile(first_name: str = "", last_name: str = "", email: str = "", currency: str = "") -> str:
    """
    Update the user's profile settings. Only provide fields to change.
    - currency: ISO currency code (e.g. 'USD', 'INR', 'EUR')
    """
    payload: Dict[str, Any] = {}
    if first_name:
        payload["first_name"] = first_name
    if last_name:
        payload["last_name"] = last_name
    if email:
        payload["email"] = email
    if currency:
        payload["currency"] = currency
    if not payload:
        return "Error: Provide at least one field to update."
    return await _patch("/auth/profile/", payload)


# ══════════════════════════════════════════════
# CHAT HISTORY
# ══════════════════════════════════════════════

@mcp.tool()
async def get_chat_history() -> str:
    """Retrieve the last 50 chat messages for the authenticated user."""
    return await _get("/chat/message/")


@mcp.tool()
async def clear_chat_history() -> str:
    """Clear all chat history for the authenticated user. This action is irreversible."""
    return await _delete("/chat/message/clear-all/")


# ══════════════════════════════════════════════
# REPORTING & EXPORT
# ══════════════════════════════════════════════

@mcp.tool()
async def generate_comprehensive_report(provider: str = "Auto Mode") -> str:
    """
    Generate a full financial intelligence report combining all data, trends,
    forecasts, budget adherence and AI-powered insights.
    - provider: AI model to use for narrative: 'Auto Mode', 'Gemini', 'OpenRouter', 'Cerebras', 'Groq'
    """
    return await _get(f"/finance/comprehensive-report/?provider={provider}")


@mcp.tool()
async def get_financial_summary() -> str:
    """
    A lightweight version of the comprehensive report.
    Returns only the top 5 critical financial highlights.
    Optimized for smaller AI models (e.g. Qwen 2b).
    """
    data_str = await _get("/finance/comprehensive-report/")
    try:
        data = json.loads(data_str)
        summary = {
            "metric_date": data.get("metric_date"),
            "net_worth": data.get("savings_wealth", {}).get("current_net_worth"),
            "savings_rate": data.get("executive_overview", {}).get("savings_rate"),
            "health_score": data.get("health_scorecard", {}).get("overall_score"),
            "stability": data.get("health_scorecard", {}).get("metrics", {}).get("stability"),
            "behavioral_insight": data.get("behavioral_analysis", {}).get("insight_text"),
            "runway": data.get("solvency_runway")
        }
        return json.dumps(summary, indent=2)
    except:
        return data_str # Fallback to raw if parsing fails


@mcp.tool()
async def export_data() -> str:
    """
    Export financial data as a professional Analytics PDF report.
    The report includes transaction history, AI insights, and forecasts.
    The file will be saved directly to your Downloads folder.
    """
    # 1. Start background task
    res_str = await _post("/finance/generate-report/", {"type": "pdf", "format": "pdf"})
    try:
        data = json.loads(res_str)
        task_id = data.get("task_id")
        if not task_id: 
            return res_str
        
        # 2. Poll until complete
        import asyncio
        print(f"[MCP] Polling task {task_id}...", file=sys.stderr)
        for _ in range(30): # 45 seconds max (30 * 1.5)
            await asyncio.sleep(1.5)
            poll_res = await _get(f"/finance/generate-report/?task_id={task_id}")
            try:
                poll_data = json.loads(poll_res)
                if poll_data.get("status") == "completed":
                    print(f"[MCP] Task {task_id} completed. Downloading...", file=sys.stderr)
                    # 3. Download final (This triggers _handle_binary_save)
                    return await _get(f"/finance/generate-report/?task_id={task_id}&download=true")
                if poll_data.get("status") == "failed":
                    return f"Error: PDF generation failed: {poll_data.get('error')}"
            except:
                # If it's not JSON, maybe it's the error message or the status text
                if "completed" in poll_res.lower():
                     return await _get(f"/finance/generate-report/?task_id={task_id}&download=true")
                pass
        return "Error: Timeout waiting for PDF generation. The process is still running in the background."
    except Exception as e:
        print(f"[MCP] Polling Error: {e}", file=sys.stderr)
        return res_str


@mcp.tool()
async def send_email_report(email: str, provider: str = "Auto Mode") -> str:
    """
    Send a comprehensive financial report to a specific email address.
    """
    return await _post("/finance/send-email-report/", {"email": email, "provider": provider})


# ══════════════════════════════════════════════
# ADVANCED TRANSACTION TOOLS
# ══════════════════════════════════════════════

@mcp.tool()
async def get_transaction_categories() -> str:
    """Retrieve all available income and expense categories."""
    return await _get("/finance/transactions/categories/")


@mcp.tool()
async def bulk_delete_transactions() -> str:
    """Delete ALL transactions for the authenticated user. USE WITH EXTREME CAUTION."""
    return await _post("/finance/transactions/delete-all/", {})


@mcp.tool()
async def read_pdf_document(file_path: str) -> str:
    """
    Extract text content from a PDF file (e.g., reports, statements).
    - file_path: Absolute path to the PDF file on the local system.
    """
    if not os.path.exists(file_path):
        return f"Error: File not found at {file_path}"
    
    if not file_path.lower().endswith(".pdf"):
        return "Error: This tool only supports PDF files."

    try:
        text_content = []
        with pdfplumber.open(file_path) as pdf:
            for i, page in enumerate(pdf.pages):
                page_text = page.extract_text()
                if page_text:
                    text_content.append(f"--- Page {i+1} ---\n{page_text}")
        
        if not text_content:
            return "Note: PDF was opened but no text could be extracted (it might be an image-only PDF)."
            
        full_text = "\n\n".join(text_content)
        # Limit text to avoid overwhelming the AI if it's huge
        if len(full_text) > 50000:
            full_text = full_text[:50000] + "... [Text Truncated for Brevity]"
            
        return full_text
    except Exception as e:
        return f"Error reading PDF: {e}"


@mcp.tool()
async def scan_receipt(file_path: str) -> str:
    """
    Scan a receipt image to extract transaction details using AI OCR.
    - file_path: Absolute path to the receipt image on the local system.
    """
    # Note: File upload via MCP proxy requires reading the file and sending as multipart/form-data
    # Since this is a proxy, we'll try to use the existing OCR endpoint
    if not os.path.exists(file_path):
        return f"Error: File not found at {file_path}"
    
    async with httpx.AsyncClient(timeout=60) as client:
        try:
            with open(file_path, "rb") as f:
                files = {"file": f}
                # Security: Remove Content-Type so httpx can set multipart/form-data correctly
                headers = _headers()
                if "Content-Type" in headers: del headers["Content-Type"]
                
                r = await client.post(f"{BASE_URL}/finance/transactions/scan-receipt/", files=files, headers=headers)
                return r.text
        except Exception as e:
            return f"Error: {e}"


@mcp.tool()
async def process_voice_command(command: str) -> str:
    """
    Process a natural language voice command to log transactions or query data.
    - command: The spoken text (e.g., 'I spent 500 rupees on coffee today')
    """
    return await _post("/finance/voice/command/", {"command": command})


@mcp.tool()
async def upload_transactions(file_path: str) -> str:
    """
    Upload a CSV or Excel file containing multiple transactions for bulk import.
    - file_path: Absolute path to the .csv or .xlsx file on the local system.
    """
    if not os.path.exists(file_path):
        return f"Error: File not found at {file_path}"
    
    url = f"{BASE_URL}/finance/transactions/upload/"
    print(f"[MCP] Uploading transactions from {file_path} to {url}", file=sys.stderr)
    async with httpx.AsyncClient(timeout=60) as client:
        try:
            with open(file_path, "rb") as f:
                files = {"file": f}
                # Security: Remove Content-Type so httpx can set multipart/form-data correctly
                headers = _headers()
                if "Content-Type" in headers: del headers["Content-Type"]
                
                r = await client.post(url, files=files, headers=headers)
                print(f"[MCP] Upload Response: {r.status_code}", file=sys.stderr)
                return r.text
        except Exception as e:
            err = f"Error: {e}"
            print(f"[MCP] {err}", file=sys.stderr)
            return err


# ══════════════════════════════════════════════
# AUTH & USER MANAGEMENT
# ══════════════════════════════════════════════

@mcp.tool()
async def register_user(username: str, password: str, email: str, first_name: str = "", last_name: str = "") -> str:
    """Create a new user account in FinMK."""
    payload = {
        "username": username,
        "password": password,
        "email": email,
        "first_name": first_name,
        "last_name": last_name
    }
    url = f"{BASE_URL}/auth/register/"
    print(f"[MCP] Registering user: {username} at {url}", file=sys.stderr)
    async with httpx.AsyncClient(timeout=15) as client:
        try:
            r = await client.post(url, json=payload)
            print(f"[MCP] Register Response: {r.status_code}", file=sys.stderr)
            if r.status_code == 201:
                return f"Success: User '{username}' registered. You can now call 'authenticate_agent' to log in."
            return f"Registration failed ({r.status_code}): {r.text}"
        except Exception as e:
            err = f"Connection error: {e}"
            print(f"[MCP] {err}", file=sys.stderr)
            return err


@mcp.tool()
async def refresh_auth_token() -> str:
    """Refresh the session access token using the refresh token."""
    if not _auth["refresh_token"]:
        return "Error: No refresh token available. Log in first."
    
    async with httpx.AsyncClient(timeout=15) as client:
        try:
            r = await client.post(f"{BASE_URL}/auth/token/refresh/", json={"refresh": _auth["refresh_token"]})
            if r.status_code == 200:
                data = r.json()
                _auth["access_token"] = data.get("access")
                return "Access token refreshed successfully."
            return f"Token refresh failed: {r.text}"
        except Exception as e:
            return f"Connection error: {e}"


# ══════════════════════════════════════════════
# CHAT MANAGEMENT
# ══════════════════════════════════════════════

@mcp.tool()
async def delete_chat_message(msg_id: str) -> str:
    """Delete a specific chat message by its ID."""
    return await _delete(f"/chat/message/{msg_id}/")


# ══════════════════════════════════════════════
# DIRECT MONGODB READ/WRITE TOOLS
# ══════════════════════════════════════════════

@mcp.tool()
async def get_my_full_data() -> str:
    """
    Retrieve the COMPLETE MongoDB document for the currently authenticated user.
    This includes all financial data, settings, and profile info in one JSON blob.
    """
    err = _require_auth()
    if err:
        return err

    username = _auth.get("username")
    if not username:
        return "Error: Username not found in session. Please authenticate first."

    try:
        import django
        from django.conf import settings
        if not settings.configured:
            os.environ.setdefault("DJANGO_SETTINGS_MODULE", "expense_tracker.settings")
            django.setup()
        
        from expense_tracker.utils import MongoDBClient
        from bson import json_util

        db = MongoDBClient.get_client()
        user_doc = db.users.find_one({"username": username})
        if not user_doc:
            return f"Error: No MongoDB document found for user '{username}'."

        # Security: Remove sensitive fields
        if "password" in user_doc: del user_doc["password"]
        if "is_staff" in user_doc: del user_doc["is_staff"]
        if "is_superuser" in user_doc: del user_doc["is_superuser"]

        return json.dumps(json.loads(json_util.dumps(user_doc)), indent=2)
    except Exception as e:
        return f"MongoDB Error: {e}"


@mcp.tool()
async def query_mongodb(collection: str, filter_json: str = "{}", limit: int = 20) -> str:
    """
    Execute a query directly on MongoDB Atlas (Read-only).
    - collection: MongoDB collection name ('users', 'income', 'expense', etc.)
    - filter_json: JSON string of MongoDB query filter (e.g. '{"category": "Food"}')
    - limit: Maximum number of documents to return (max 50)
    """
    err = _require_auth()
    if err:
        return err

    limit = min(limit, 50)
    try:
        query_filter = json.loads(filter_json)
    except json.JSONDecodeError as e:
        return f"Error: filter_json is not valid JSON — {e}"

    try:
        import django
        from django.conf import settings
        if not settings.configured:
            os.environ.setdefault("DJANGO_SETTINGS_MODULE", "expense_tracker.settings")
            django.setup()
            
        from expense_tracker.utils import MongoDBClient
        from bson import json_util

        db = MongoDBClient.get_client()
        docs = list(db[collection].find(query_filter).limit(limit))
        return json.dumps(json.loads(json_util.dumps(docs)), indent=2)
    except Exception as e:
        return f"MongoDB query error: {e}"
        result = db[collection].delete_many(query_filter)
        return json.dumps({"success": True, "deleted_count": result.deleted_count})
    except Exception as e:
        return f"MongoDB delete error: {e}"


# ══════════════════════════════════════════════
# API STATUS
# ══════════════════════════════════════════════

@mcp.tool()
async def get_api_status() -> str:
    """
    Check the health status of all AI providers (Gemini, OpenRouter, Cerebras, LM Studio)
    and the MongoDB connection. Useful for diagnosing connectivity issues.
    """
    async with httpx.AsyncClient(timeout=10) as client:
        try:
            r = await client.get(f"{BASE_URL}/finance/status/")
            return r.text
        except Exception as e:
            return f"Could not reach backend: {e}"


# --- WAVE 2: ADVANCED FINANCE TOOLS ---

@mcp.tool()
async def get_sample_data_preview() -> str:
    """Get statistics about available sample transaction data."""
    return await _get("/finance/sample-data/preview/")

@mcp.tool()
async def load_sample_data() -> str:
    """Load sample transactions into the authenticated user's account."""
    return await _post("/finance/sample-data/load/", {})

@mcp.tool()
async def get_budget_category_stats() -> str:
    """Get AI-driven insights into average monthly spending by category compared to budgets."""
    res = await _get("/finance/budget/")
    try:
        data = json.loads(res)
        return json.dumps(data.get("categories", []), indent=2)
    except:
        return res

@mcp.tool()
async def get_historical_category_trends() -> str:
    """Get multi-month historical trends for expense and income categories."""
    res = await _get("/finance/dashboard-summary/")
    try:
        data = json.loads(res)
        return json.dumps({
            "expense_trends": data.get("category_trends", []),
            "income_trends": data.get("income_category_trends", [])
        }, indent=2)
    except:
        return res

@mcp.tool()
async def search_transactions_adv(query: str, start_date: str = "", end_date: str = "") -> str:
    """Advanced search for transactions with optional date filters (YYYY-MM-DD)."""
    params = {"search": query}
    if start_date: params["start_date"] = start_date
    if end_date: params["end_date"] = end_date
    return await _get("/finance/transactions/list/", params=params)

# --- ADVANCED ANALYTICS (EXECUTIVE ENGINE) ---

@mcp.tool()
async def get_financial_health_score() -> str:
    """Get a comprehensive financial health and stability score (0-100)."""
    res = await _get("/finance/comprehensive-report/")
    try:
        data = json.loads(res)
        return json.dumps({
            "health_score": data.get("executive_overview", {}).get("stability_score"),
            "savings_rate": data.get("executive_overview", {}).get("savings_rate"),
            "insight": data.get("behavioral_insight")
        }, indent=2)
    except:
        return res

@mcp.tool()
async def get_tax_liability_estimate() -> str:
    """Get an AI-powered estimate of potential tax liability based on income patterns."""
    res = await _get("/finance/comprehensive-report/")
    try:
        data = json.loads(res)
        return json.dumps(data.get("tax_liability", {}), indent=2)
    except:
        return res

@mcp.tool()
async def get_solvency_runway() -> str:
    """Calculate how many months you can survive on current savings (Solvency Runway)."""
    res = await _get("/finance/comprehensive-report/")
    try:
        data = json.loads(res)
        return json.dumps(data.get("solvency_runway", {}), indent=2)
    except:
        return res

@mcp.tool()
async def get_recurring_payments() -> str:
    """Detect and list suspected recurring payments and subscriptions."""
    res = await _get("/finance/comprehensive-report/")
    try:
        data = json.loads(res)
        return json.dumps(data.get("recurring_commitments", []), indent=2)
    except:
        return res

@mcp.tool()
async def get_financial_velocity() -> str:
    """Get the 'velocity' of your money—how fast you are earning vs. spending."""
    res = await _get("/finance/comprehensive-report/")
    try:
        data = json.loads(res)
        return json.dumps(data.get("velocity", {}), indent=2)
    except:
        return res

@mcp.tool()
async def get_ai_recommendations() -> str:
    """Get personalized AI-generated financial recommendations and action items."""
    res = await _get("/finance/comprehensive-report/")
    try:
        data = json.loads(res)
        return json.dumps(data.get("recommendations", []), indent=2)
    except:
        return res

@mcp.tool()
async def simulate_goal_completion(goal_id: str) -> str:
    """Predict the exact date a savings goal will be reached based on your net cash flow."""
    report_res = await _get("/finance/comprehensive-report/")
    goals_res = await _get("/finance/savings-goals/")
    try:
        report_data = json.loads(report_res)
        goals_data = json.loads(goals_res)
        
        net_flow = report_data.get("executive_overview", {}).get("net_savings", 0)
        if net_flow <= 0:
            return "Simulation Error: Your net savings flow is negative or zero. You cannot reach this goal at your current spending rate."
        
        target_goal = next((g for g in goals_data if g["id"] == goal_id), None)
        if not target_goal:
            return f"Goal ID {goal_id} not found."
            
        remaining = target_goal["target_amount"] - target_goal["current_amount"]
        months_needed = remaining / net_flow
        
        from datetime import datetime, timedelta
        predicted_date = (datetime.now() + timedelta(days=months_needed * 30)).strftime('%Y-%m-%d')
        
        return json.dumps({
            "goal_name": target_goal["title"],
            "remaining_amount": remaining,
            "monthly_savings_pacing": round(net_flow, 2),
            "predicted_months_to_complete": round(months_needed, 1),
            "estimated_completion_date": predicted_date
        }, indent=2)
    except:
        return "Simulation Error: Unable to compute prediction."


# ══════════════════════════════════════════════
# TOOL CATALOGUE (for injection into AI prompts)
# ══════════════════════════════════════════════

MCP_TOOL_CATALOGUE = """
## 🚨 CRITICAL: TOOL CALLING FORMAT
You MUST call tools using the standard MCP JSON format. 
DO NOT use XML tags. Use plain JSON.

### ✅ CORRECT JSON FORMAT (Example):
```json
{
  "name": "add_income",
  "arguments": {
    "title": "Salary",
    "amount": 5000,
    "date": "2025-03-01"
  }
}
```

## AI AGENT CAPABILITIES - MASTER TOOLSET

### Authentication & Users
- `authenticate_agent(username, password)` — Login (Optional if already logged in)
- `get_auth_status()` — Check if authenticated
- `register_user(...)` — Create new account
- `refresh_auth_token()` — Refresh JWT access token
- `get_user_profile()` — View profile info
- `update_user_profile(...)` — Update name, email, currency

### Dashboard & Analytics
- `get_dashboard_summary()` — Full financial overview
- `get_cash_flow_forecast()` — 3-month ML cash flow forecast
- `get_income_forecast()` — Income forecast
- `get_anomaly_report()` — Unusual transaction detection

### Transactions
- `list_all_transactions()` — All incomes + expenses
- `list_incomes()` / `list_expenses()` — Specific lists
- `add_income(...)` / `add_expense(...)` — Add new
- `update_income(...)` / `update_expense(...)` — Edit existing
- `delete_income(...)` / `delete_expense(...)` — Delete existing
- `get_transaction_categories()` — List all categories
- `bulk_delete_transactions()` — Delete ALL data (Caution!)
- `upload_transactions(file_path)` — Bulk import from CSV/Excel

### Advanced Features
- `export_data(format)` — Export to PDF/CSV
- `send_email_report(email)` — Email the report
- `scan_receipt(file_path)` — AI OCR for receipts
- `process_voice_command(command)` — Natural language processing
- `generate_comprehensive_report()` — AI-powered narrative report
- `get_financial_health_score()` — Executive stability & savings report
- `get_tax_liability_estimate()` — Estimate potential tax owed
- `get_solvency_runway()` — Months of survival on savings
- `get_recurring_payments()` — Subscriptions & recurring bills
- `get_ai_recommendations()` — Personalized financial advice
- `simulate_goal_completion(goal_id)` — Predictive goal reaching date

### Data & Search
- `search_transactions_adv(query, start_date?, end_date?)` — Power search
- `get_historical_category_trends()` — Multi-month trends
- `get_budget_category_stats()` — Avg spend vs Budgets
- `get_sample_data_preview()` / `load_sample_data()` — Test data management

### Chat
- `get_chat_history()` — Recent chat messages
- `clear_chat_history()` — Wipe all chat history
- `delete_chat_message(msg_id)` — Remove one message

### Direct Database Access
- `get_my_full_data()` — Get your COMPLETE user document (High Performance).
- `query_mongodb(collection, filter)` — Read-only access to collections.
- `get_api_status()` — Health check.
"""


if __name__ == "__main__":
    mcp.run()