from __future__ import annotations

import uuid

from sqlalchemy import String, TypeDecorator
from sqlalchemy.dialects.postgresql import UUID as PG_UUID
from sqlalchemy.orm import DeclarativeBase


class GUID(TypeDecorator):
    """Platform-independent UUID type.

    PostgreSQL keeps native UUID columns; SQLite test databases store canonical
    UUID strings so bind/result behavior stays consistent.
    """

    impl = String
    cache_ok = True

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

    def process_bind_param(self, value, dialect):
        if value is None:
            return None
        if dialect.name == "sqlite":
            return str(value)
        return value

    def process_result_value(self, value, dialect):
        if value is None:
            return None
        if dialect.name == "sqlite" and isinstance(value, str):
            return uuid.UUID(value)
        return value


class Base(DeclarativeBase):
    type_annotation_map = {
        uuid.UUID: GUID(),
    }

    pass