from pydantic import BaseModel, Field
from typing import Optional
from datetime import datetime
from enum import Enum

class ExpenseType(str, Enum):
    INCOME = "income"
    EXPENSE = "expense"

class Expense(BaseModel):
    user_id: str
    amount: float = Field(..., gt=0, description="Expense amount")
    category: str = Field(..., description="Expense category (e.g., Groceries, Transport)")
    description: Optional[str] = None
    date: datetime
    type: ExpenseType = ExpenseType.EXPENSE

class Budget(BaseModel):
    user_id: str
    category: str
    amount: float = Field(..., gt=0, description="Budget amount")
    period: str = Field(..., description="Budget period: daily, weekly, monthly, yearly")
    start_date: datetime
    end_date: Optional[datetime] = None

class BudgetRecommendation(BaseModel):
    category: str
    average_expense: float
    recommended_budget: float
    reason: str
    confidence: float = Field(..., ge=0, le=1, description="Confidence score (0-1)")
    action: Optional[str] = Field(
        None,
        description="AI suggestion: increase, decrease, or keep"
    )

class CategoryExpense(BaseModel):
    category: str
    average_monthly_expense: float
    total_expenses: int
    months_analyzed: int