backend/main.py

from fastapi import FastAPI, HTTPException
from fastapi.middleware.cors import CORSMiddleware
from pydantic import BaseModel
import uvicorn
import os
from dotenv import load_dotenv
from typing import Any, Dict
load_dotenv()

# Local module imports (we'll implement these next)
from backend import ai_agent
from backend import expense_manager
from backend import budget_allocator
from backend import reminder_system

# App init
app = FastAPI(title="FinSync AI Backend")

# Allow CORS from Streamlit / local dev
app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

# Pydantic models
class AnalyzeRequest(BaseModel):
    user_id: str
    text: str

class ExpenseRequest(BaseModel):
    user_id: str
    name: str
    amount: float
    category: str = ""
    date: str = ""

class ReminderRequest(BaseModel):
    user_id: str
    name: str
    date: str
    amount: float = 0.0
    notes: str = ""

# Simple health check
@app.get("/health")
async def health():
    return {"status": "ok", "service": "finsync-backend"}

# Analyze / natural language endpoint
@app.post("/analyze")
async def analyze(req: AnalyzeRequest):
    """
    Send user natural command to AI agent; AI responds with action/intention and human-readable reply.
    Example use-cases:
      - "Show my expenses this month"
      - "Set reminder to pay rent on 2025-11-10"
      - "Add expense Rent 500"
    """
    try:
        response: Dict[str, Any] = ai_agent.parse_and_respond(user_id=req.user_id, text=req.text)
        return {"ok": True, "result": response}
    except Exception as e:
        raise HTTPException(status_code=500, detail=str(e))

# Add expense endpoint
@app.post("/add_expense")
async def add_expense(req: ExpenseRequest):
    """
    Add an expense into the database.json (demo DB).
    """
    try:
        entry = {
            "user_id": req.user_id,
            "name": req.name,
            "amount": float(req.amount),
            "category": req.category or "Uncategorized",
            "date": req.date or expense_manager.today_iso(),
        }
        expense_manager.add_expense(entry)
        return {"ok": True, "expense": entry}
    except Exception as e:
        raise HTTPException(status_code=500, detail=str(e))

# List expenses for a user
@app.get("/expenses")
async def get_expenses(user_id: str):
    try:
        items = expense_manager.list_expenses(user_id=user_id)
        return {"ok": True, "expenses": items}
    except Exception as e:
        raise HTTPException(status_code=500, detail=str(e))

# Get budget suggestion
@app.get("/budget")
async def get_budget(user_id: str):
    try:
        expenses = expense_manager.list_expenses(user_id=user_id)
        suggestion = budget_allocator.suggest_budget(user_id=user_id, expenses=expenses)
        return {"ok": True, "budget": suggestion}
    except Exception as e:
        raise HTTPException(status_code=500, detail=str(e))

# Add reminder
@app.post("/reminder")
async def add_reminder(req: ReminderRequest):
    try:
        reminder = {
            "user_id": req.user_id,
            "name": req.name,
            "date": req.date,
            "amount": float(req.amount),
            "notes": req.notes
        }
        reminder_system.add_reminder(reminder)
        return {"ok": True, "reminder": reminder}
    except Exception as e:
        raise HTTPException(status_code=500, detail=str(e))

# List reminders
@app.get("/reminders")
async def list_reminders(user_id: str):
    try:
        items = reminder_system.list_reminders(user_id=user_id)
        return {"ok": True, "reminders": items}
    except Exception as e:
        raise HTTPException(status_code=500, detail=str(e))

if __name__ == "__main__":
    port = int(os.environ.get("BACKEND_PORT", 8000))
    uvicorn.run("backend.main:app", host="0.0.0.0", port=port, reload=True)