import enum
from datetime import datetime
from typing import Optional

from sqlmodel import Field, Relationship, SQLModel


class TransactionType(str, enum.Enum):
    COMPRA = "COMPRA"
    DEVOLUCION = "DEVOLUCION"


class TransactionSource(str, enum.Enum):
    CREDIT_CARD = "CREDIT_CARD"
    CASH = "CASH"
    TRANSFER = "TRANSFER"


class Currency(str, enum.Enum):
    CRC = "CRC"
    USD = "USD"


class Bank(str, enum.Enum):
    BAC = "BAC"
    BCR = "BCR"
    DAVIVIENDA = "DAVIVIENDA"


# --- Category ---


class CategoryBase(SQLModel):
    name: str = Field(index=True, unique=True)
    icon: str = "tag"
    auto_match_patterns: Optional[str] = Field(
        default=None,
        description="Comma-separated merchant substrings for auto-matching",
    )


class Category(CategoryBase, table=True):
    id: Optional[int] = Field(default=None, primary_key=True)
    transactions: list["Transaction"] = Relationship(back_populates="category")


class CategoryCreate(CategoryBase):
    pass


class CategoryRead(CategoryBase):
    id: int


class CategoryUpdate(SQLModel):
    name: Optional[str] = None
    icon: Optional[str] = None
    auto_match_patterns: Optional[str] = None


# --- Account ---


class AccountBase(SQLModel):
    bank: Bank
    currency: Currency
    label: str = Field(description="e.g. 'BAC Colones', 'BAC Dólares'")
    balance: float = 0.0


class Account(AccountBase, table=True):
    id: Optional[int] = Field(default=None, primary_key=True)
    updated_at: datetime = Field(default_factory=datetime.utcnow)


class AccountCreate(AccountBase):
    pass


class AccountRead(AccountBase):
    id: int
    updated_at: datetime


class AccountUpdate(SQLModel):
    balance: Optional[float] = None
    label: Optional[str] = None


# --- Transaction ---


class TransactionBase(SQLModel):
    amount: float
    currency: Currency = Currency.CRC
    merchant: str
    city: Optional[str] = None
    date: datetime
    card_type: Optional[str] = None
    card_last4: Optional[str] = None
    authorization_code: Optional[str] = None
    reference: Optional[str] = None
    transaction_type: TransactionType = TransactionType.COMPRA
    source: TransactionSource = TransactionSource.CREDIT_CARD
    bank: Bank = Bank.BAC
    notes: Optional[str] = None
    category_id: Optional[int] = Field(default=None, foreign_key="category.id")


class Transaction(TransactionBase, table=True):
    id: Optional[int] = Field(default=None, primary_key=True)
    created_at: datetime = Field(default_factory=datetime.utcnow)
    category: Optional[Category] = Relationship(back_populates="transactions")


class TransactionCreate(TransactionBase):
    pass


class TransactionRead(TransactionBase):
    id: int
    created_at: datetime
    category: Optional[CategoryRead] = None


class TransactionUpdate(SQLModel):
    amount: Optional[float] = None
    currency: Optional[Currency] = None
    merchant: Optional[str] = None
    city: Optional[str] = None
    date: Optional[datetime] = None
    transaction_type: Optional[TransactionType] = None
    source: Optional[TransactionSource] = None
    notes: Optional[str] = None
    category_id: Optional[int] = None