-- broker.broker_get
-- Claims the next eligible job from a queue: pending, available (backoff
-- elapsed), no incomplete dependency, and visible under the caller's RLS
-- tenant. Grants a lease (lease_token) that broker_run must present back.
-- Returns: p_retval (0=success, >0=infra error), p_errmsg, p_job_id, p_lease_token.

CREATE OR REPLACE FUNCTION broker.broker_get(
    p_queue_number INTEGER,
    p_instance_id BIGINT DEFAULT NULL,
    p_lease_seconds INTEGER DEFAULT 60,
    OUT p_retval INTEGER,
    OUT p_errmsg TEXT,
    OUT p_job_id BIGINT,
    OUT p_lease_token UUID
)
RETURNS RECORD
LANGUAGE plpgsql
AS $$
DECLARE
    v_job_id BIGINT;
    v_lease_token UUID;
BEGIN
    p_retval := 0;
    p_errmsg := '';
    p_job_id := NULL;
    p_lease_token := NULL;

    IF p_queue_number IS NULL OR p_queue_number <= 0 THEN
        p_retval := 1;
        p_errmsg := 'Invalid queue number';
        RETURN;
    END IF;

    IF p_lease_seconds IS NULL OR p_lease_seconds <= 0 THEN
        p_lease_seconds := 60;
    END IF;

    SELECT candidate.id_broker_jobs
    INTO v_job_id
    FROM broker.broker_jobs candidate
    WHERE candidate.job_queue = p_queue_number
      AND candidate.complete_status = 0
      AND candidate.available_at <= NOW()
      AND NOT EXISTS (
        SELECT 1
        FROM broker.broker_job_dependency d
        JOIN broker.broker_jobs dep ON dep.id_broker_jobs = d.depends_on_job_id
        WHERE d.job_id = candidate.id_broker_jobs
          AND dep.complete_status <> 2
      )
    ORDER BY candidate.job_priority DESC, candidate.created_at ASC, candidate.id_broker_jobs ASC
    LIMIT 1
    FOR UPDATE SKIP LOCKED;

    IF NOT FOUND THEN
        RETURN;
    END IF;

    v_lease_token := gen_random_uuid();

    UPDATE broker.broker_jobs
    SET complete_status = 1,  -- running
        started_at = NOW(),
        rid_broker_queueinstance = p_instance_id,
        attempt_count = attempt_count + 1,
        lease_token = v_lease_token,
        leased_at = NOW(),
        lease_expires_at = NOW() + make_interval(secs => p_lease_seconds),
        updated_at = NOW()
    WHERE id_broker_jobs = v_job_id;

    p_job_id := v_job_id;
    p_lease_token := v_lease_token;

EXCEPTION
    WHEN OTHERS THEN
        p_retval := 2;
        p_errmsg := SQLERRM;
        RAISE WARNING 'broker_get error: %', SQLERRM;
END;
$$;

COMMENT ON FUNCTION broker.broker_get IS 'Claims the next eligible job from a queue and grants a lease';