from pydantic import BaseModel, Field, validator
from typing import Optional, List
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 = Field(..., description="Category name (e.g., Groceries, Transport)")
    category_id: Optional[str] = Field(None, description="Category ID from database")
    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

class RecommendationRequest(BaseModel):
    user_id: str = Field(..., description="User identifier")
    category_id: str = Field(..., description="Category ID to check for previous data")
    budget_amount: Optional[float] = Field(None, gt=0, description="Current budget amount for this category (optional)")
    
    @validator('budget_amount')
    def validate_budget_amount(cls, v):
        if v is not None:
            if v <= 0:
                raise ValueError('budget_amount must be greater than 0')
            # Auto-cap unreasonably large numbers instead of rejecting
            # This handles corrupted data gracefully - cap at 1 trillion
            if v > 1e12:  # More than 1 trillion is likely corrupted data
                print(f"⚠️ Auto-capping corrupted budget_amount: {v:,.2e} -> 1,000,000,000,000")
                return 1e12  # Cap at 1 trillion instead of rejecting
        return v

class RecommendationResponse(BaseModel):
    has_previous_data: bool
    message: Optional[str] = None
    recommendations: Optional[List[BudgetRecommendation]] = None

class RecommendationByNameRequest(BaseModel):
    user_id: str = Field(..., description="User identifier")
    category_name: str = Field(..., description="Head Category name (e.g., 'Food & Drinks', 'Shopping', 'Housing')")
    budget_amount: Optional[float] = Field(None, gt=0, description="Current budget amount for this category (optional)")
    
    @validator('budget_amount')
    def validate_budget_amount(cls, v):
        if v is not None:
            if v <= 0:
                raise ValueError('budget_amount must be greater than 0')
            if v > 1e12:
                print(f"⚠️ Auto-capping corrupted budget_amount: {v:,.2e} -> 1,000,000,000,000")
                return 1e12
        return v