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

from tht.adapters.dwh import PostgresDwhAdapter, ThothRestDwhAdapter
from tht.adapters.vector import PgVectorStore, 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,
                statement_timeout_ms=cfg.execution.statement_timeout_ms,
            )
        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":
            reader = resource.reader or resource.connection
            if require_write and resource.writer is None:
                raise ConfigError("Vector writer non configurato per pgvector_direct")
            return PgVectorStore(
                reader,
                resource.writer,
                expected_dimension=cfg.embeddings.dim if cfg.embeddings is not None else None,
            )
        case "thoth_vector_http":
            if require_write and resource.writer is None:
                raise ConfigError("Vector writer non configurato")
            return ThothHttpVectorStore(
                VectorRestClient(resource.reader) if resource.reader is not None else None,
                VectorRestClient(resource.writer) if resource.writer is not None else None,
                expected_dimension=cfg.embeddings.dim if cfg.embeddings 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.writer or 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"]