import uuid
from datetime import datetime

from sqlalchemy import DateTime, String, TypeDecorator, func
from sqlalchemy.dialects import postgresql
from sqlalchemy.orm import DeclarativeBase, Mapped, mapped_column


class GUID(TypeDecorator):
    """Platform-independent GUID type that uses native UUID on PostgreSQL."""

    impl = String(36)
    cache_ok = True

    def load_dialect_impl(self, dialect):
        if dialect.name == "postgresql":
            return dialect.type_descriptor(postgresql.UUID(as_uuid=True))
        return dialect.type_descriptor(String(36))

    def process_bind_param(self, value, dialect):
        if value is None:
            return value

        if isinstance(value, uuid.UUID):
            return value if dialect.name == "postgresql" else str(value)

        parsed_value = uuid.UUID(str(value))
        return parsed_value if dialect.name == "postgresql" else str(parsed_value)

    def process_result_value(self, value, dialect):
        if value is None:
            return value

        if isinstance(value, uuid.UUID):
            return value

        return uuid.UUID(str(value))


class Base(DeclarativeBase):
    pass


class UUIDPrimaryKeyMixin:
    id: Mapped[uuid.UUID] = mapped_column(
        GUID,
        primary_key=True,
        default=uuid.uuid4,
    )


class TimestampMixin:
    date_creation: Mapped[datetime] = mapped_column(
        DateTime(timezone=True),
        server_default=func.now(),
        nullable=False,
    )
    date_modification: Mapped[datetime | None] = mapped_column(
        DateTime(timezone=True),
        onupdate=func.now(),
        nullable=True,
    )