-- Read-only PG role for the Overlord Agent's `query_telemetry_db` MCP tool.
--
-- This is the second line of defense (the first is the sqlglot parser in
-- agent/tools.py:assert_read_only). Even a parser bypass cannot mutate
-- because this role only has SELECT.
--
-- Apply on the dereth-db container:
--   docker exec dereth-db psql -U postgres -d dereth -f - < agent/sql/0001_overlord_agent_ro.sql
-- (substitute the password before running, or keep as a placeholder and
-- ALTER ROLE … PASSWORD '…' separately)

DO $$
BEGIN
    IF NOT EXISTS (SELECT 1 FROM pg_roles WHERE rolname = 'overlord_agent_ro') THEN
        CREATE ROLE overlord_agent_ro NOINHERIT LOGIN PASSWORD 'change-me-set-via-alter-role';
    END IF;
END$$;

GRANT CONNECT ON DATABASE dereth TO overlord_agent_ro;
GRANT USAGE ON SCHEMA public TO overlord_agent_ro;

-- Grant SELECT on all current public tables.
GRANT SELECT ON ALL TABLES IN SCHEMA public TO overlord_agent_ro;
GRANT SELECT ON ALL SEQUENCES IN SCHEMA public TO overlord_agent_ro;

-- And on any future tables created in public.
ALTER DEFAULT PRIVILEGES IN SCHEMA public
    GRANT SELECT ON TABLES TO overlord_agent_ro;

-- TimescaleDB-internal schema (chunks live here). Read on hypertable chunks
-- requires SELECT on _timescaledb_internal too.
GRANT USAGE ON SCHEMA _timescaledb_internal TO overlord_agent_ro;
GRANT SELECT ON ALL TABLES IN SCHEMA _timescaledb_internal TO overlord_agent_ro;
ALTER DEFAULT PRIVILEGES IN SCHEMA _timescaledb_internal
    GRANT SELECT ON TABLES TO overlord_agent_ro;