Glass annealer queue

Work out when each piece comes out of a glass studio's shared annealing oven.

Freshly blown glass must be cooled slowly in an oven, one batch at a time. Each piece is [arrival, glass, thickness]: the minute it is placed in the waiting rack, its glass type, and its thickest wall in millimetres. A batch can only hold pieces of one glass type, because different glass shrinks at different rates. A piece thicker than 20 mm is always annealed alone. A batch of up to capacity pieces runs for 30 + 10 * t minutes, where t is the thickness of its thickest piece, and every piece in it comes out when the run ends.

Whenever the oven is idle (at minute 0, or the moment a run ends), and also whenever a piece arrives while it is idle, look at the waiting rack, which holds the pieces that have arrived (arrival <= now) and not yet been started. Take the oldest waiting piece (the earliest arrival; equal arrivals go in list order), and let G be its glass type. The oven starts a batch right now if any of these holds:

• the oldest piece is thicker than 20 mm;
• at least capacity waiting pieces of type G are 20 mm or thinner;
• the oldest piece has already waited waitLimit minutes or more (now - arrival >= waitLimit).

The batch is then the oldest piece plus the earliest-arrived waiting pieces of type G that are 20 mm or thinner, up to capacity pieces in all (a thick oldest piece goes in alone). If none of the conditions holds, the oven stays idle and the question is asked again at the next arrival or when the oldest piece's wait reaches waitLimit, whichever comes first. A run that ends at minute f lets a new batch start at minute f.

Input: pieces, a list of [arrival, glass, thickness]; capacity and waitLimit, integers.

Output: a list with one integer per piece, in the order of pieces: the minute it comes out of the oven. Return [] for no pieces.