refactor(dwh): adapt direct and REST transports

harness/tht/adapters/dwh/thoth_rest.py

@@ -0,0 +1,51 @@
+"""Thoth/PostgREST implementation of the DWH port."""
+
+from tht.config import DatabaseConfig, RestConfig
+from tht.db.introspect import introspect_rest
+from tht.execute import ExecResult, PlanSummary
+from tht.mschema.models import PhysicalSchema
+from tht.ports.dwh import DwhCapabilities, DwhHealth
+from tht.rest.client import RestClient, RestError
+from tht.rest.execute import (
+    distinct_values_rest,
+    explain_rest,
+    run_controlled_rest,
+    sample_column_rest,
+)
+
+
+class ThothRestDwhAdapter:
+    capabilities = DwhCapabilities()
+
+    def __init__(self, database: DatabaseConfig, rest: RestConfig):
+        self._database = database
+        self._client = RestClient(rest)
+
+    def health(self) -> DwhHealth:
+        try:
+            result = self._client.ping()
+        except RestError as exc:
+            return DwhHealth(ok=False, detail=str(exc))
+        ok = bool(result.get("db_connected", True))
+        return DwhHealth(ok=ok, detail=None if ok else str(result))
+
+    def introspect(self) -> PhysicalSchema:
+        return introspect_rest(
+            self._client, self._database.database, self._database.db_schema
+        )
+
+    def run_query(self, sql: str, *, limit: int | None = None) -> ExecResult:
+        return run_controlled_rest(self._client, sql, limit=10 if limit is None else limit)
+
+    def explain(self, sql: str) -> PlanSummary:
+        return explain_rest(self._client, sql)
+
+    def sample_column(self, table: str, column: str, *, limit: int) -> list[object]:
+        return sample_column_rest(
+            self._client, self._database.db_schema, table, column, limit=limit
+        )
+
+    def distinct_values(self, table: str, column: str) -> list[object]:
+        return distinct_values_rest(
+            self._client, self._database.db_schema, table, column
+        )