CREATE OR REPLACE FUNCTION pricequote.guidance_logic(
    _target       numeric(20,5),
    _last_norm    numeric(20,5),
    _list_eff     numeric(20,5),
    _last_date    date,
    _floor_pct    numeric(10,5) DEFAULT 0.05,
    _cap_last_pct numeric(10,5) DEFAULT 1.00,
    _cap_list_pct numeric(10,5) DEFAULT 1.00
)
RETURNS TABLE (guidance_price numeric(20,5), guidance_reason text)
LANGUAGE plpgsql AS $$
DECLARE
    base_price     numeric(20,5);
    after_floor    numeric(20,5);
    after_cap_last numeric(20,5);
    final_price    numeric(20,5);
    reason         text := '';
BEGIN
    IF _target IS NULL THEN
        RETURN QUERY SELECT NULL::numeric, 'No target price available';
        RETURN;
    END IF;

    base_price := _target;

    -- floor (binds if it raises price)
    after_floor := base_price;
    IF _last_norm IS NOT NULL AND _floor_pct > 0 THEN
        after_floor := GREATEST(base_price, ROUND(_last_norm*(1-_floor_pct),5));
    END IF;

    -- cap to last (binds if it lowers price)
    after_cap_last := after_floor;
    IF _last_norm IS NOT NULL THEN
        after_cap_last := LEAST(after_floor, ROUND(_last_norm*_cap_last_pct,5));
    END IF;

    -- cap to list (binds if it lowers price)
    final_price := after_cap_last;
    IF _list_eff IS NOT NULL THEN
        final_price := LEAST(after_cap_last, ROUND(_list_eff*_cap_list_pct,5));
    END IF;

    -- build reason
    IF _last_norm IS NULL AND _list_eff IS NULL THEN
        reason := 'No prior sale or list; using target price';
    ELSE
        reason := 'Using target price';
        IF _last_norm IS NOT NULL AND _floor_pct > 0 AND after_floor > base_price THEN
            reason := reason || format(', floored to %s%% below last price', to_char((_floor_pct*100)::numeric,'FM999990.##'));
        END IF;
        IF _last_norm IS NOT NULL AND after_cap_last < after_floor THEN
            IF _cap_last_pct = 1 THEN
                reason := reason || ', capped to not exceed last price';
            ELSE
                reason := reason || format(', capped to %s%% of last price', to_char((_cap_last_pct*100)::numeric,'FM999990.##'));
            END IF;
        END IF;
        IF _list_eff IS NOT NULL AND final_price < after_cap_last THEN
            IF _cap_list_pct = 1 THEN
                reason := reason || ', capped to not exceed list price';
            ELSE
                reason := reason || format(', capped to %s%% of list price', to_char((_cap_list_pct*100)::numeric,'FM999990.##'));
            END IF;
        END IF;
    END IF;

    RETURN QUERY SELECT final_price, reason;
END $$;