CREATE TABLE IF NOT EXISTS rag_answer_feedback (
    feedback_id uuid PRIMARY KEY,
    trace_id uuid NOT NULL REFERENCES rag_retrieval_trace(trace_id) ON DELETE CASCADE,
    conversation_id varchar(128),
    rating varchar(16) NOT NULL CHECK (rating IN ('helpful', 'not_helpful')),
    comment text CHECK (comment IS NULL OR char_length(comment) <= 2000),
    created_at timestamptz NOT NULL DEFAULT now(),
    updated_at timestamptz NOT NULL DEFAULT now(),
    UNIQUE (trace_id)
);

CREATE INDEX IF NOT EXISTS rag_answer_feedback_created_at_idx
    ON rag_answer_feedback (created_at DESC);