"""Central construction of deployment-specific adapters."""

from tht.adapters.dwh import PostgresDwhAdapter, ThothRestDwhAdapter
from tht.adapters.vector import LegacyDirectVectorStore, ThothHttpVectorStore
from tht.config import Config, ConfigError
from tht.db.connection import make_engine
from tht.ports.dwh import DwhAdapter
from tht.ports.vector import VectorStore
from tht.vectorstore.rest_client import VectorRestClient


def build_dwh(cfg: Config) -> DwhAdapter:
    """Build the DWH adapter selected by the validated workspace resource."""
    resource = cfg.dwh
    match resource.type:
        case "postgres_direct":
            return PostgresDwhAdapter(resource.connection)
        case "thoth_rest":
            return ThothRestDwhAdapter(resource.database, resource.endpoint)
        case other:  # pragma: no cover - Pydantic's discriminator rejects this first.
            raise ConfigError(f"Adapter DWH non supportato: {other}")


def build_vector_store(cfg: Config, *, require_write: bool = False) -> VectorStore:
    """Build the vector adapter, optionally requiring an HTTP writer credential."""
    resource = cfg.vectors
    if resource is None:
        raise ConfigError("Risorsa vectors non configurata")

    match resource.type:
        case "pgvector_direct":
            if require_write:
                raise ConfigError("Vector writer non configurato per pgvector_direct")
            dim = cfg.embeddings.dim if cfg.embeddings is not None else 768
            return LegacyDirectVectorStore(
                make_engine(resource.connection),
                schema=resource.connection.db_schema,
                dim=dim,
            )
        case "thoth_vector_http":
            if resource.reader is None:
                raise ConfigError("Vector reader non configurato")
            if require_write and resource.writer is None:
                raise ConfigError("Vector writer non configurato")
            return ThothHttpVectorStore(
                VectorRestClient(resource.reader),
                VectorRestClient(resource.writer) if resource.writer is not None else None,
            )
        case other:  # pragma: no cover - Pydantic's discriminator rejects this first.
            raise ConfigError(f"Adapter vector non supportato: {other}")


def build_vector_loader(cfg: Config, collection: str):
    """Compatibility construction for legacy collection sync commands."""
    resource = cfg.vectors
    if resource is None:
        raise ConfigError("Risorsa vectors non configurata")
    if cfg.embeddings is None:
        raise ConfigError("Embeddings non configurati")

    if resource.type == "thoth_vector_http" and resource.writer is not None and (
        cfg.profile == "workstation" or resource.direct is None
    ):
        from tht.vectorstore.rest_writer import RestVectorWriter

        return RestVectorWriter(VectorRestClient(resource.writer), table=collection)

    connection = (
        resource.connection if resource.type == "pgvector_direct" else resource.direct
    )
    if connection is None:
        raise ConfigError("Vector writer non configurato")
    from tht.vectorstore.store import VectorStore as TableVectorStore

    return TableVectorStore(
        make_engine(connection),
        schema=connection.db_schema,
        table=collection,
        dim=cfg.embeddings.dim,
    )


__all__ = ["build_dwh", "build_vector_loader", "build_vector_store"]