Office badge register that tracks worker hours and pay

Build a register for an office. Workers badge in and out; the register keeps their time in the office and works out their pay. It comes in levels; each level adds methods to the same class. Timestamps are integers and increase across calls.

Level 1: workers and time

• add_worker(worker_id: str, position: str, compensation: int) -> bool — compensation is pay per time unit. False if the worker exists.
• register(worker_id: str, timestamp: int) -> str — the first call enters the office, the next leaves, and so on. Returns "registered", or "invalid_request" for an unknown worker.
• get(worker_id: str) -> int | None — total time from completed visits (in, then out); None for an unknown worker.

Level 2: ranking

• top_n_workers(n: int, position: str) -> list[str] — workers currently in that position, most time first, ties by id; each as "id(time)".

Level 3: promotions and salary

• promote(worker_id, new_position, new_compensation, timestamp) -> str — takes effect at timestamp; time already in the office stays with the old position's total.
• calc_salary(worker_id: str, start: int, end: int) -> int — pay for time in the office inside [start, end), at the rate in force at each moment.

Level 4: bonus windows

• add_bonus_window(start: int, end: int) -> None — time worked inside [start, end) pays double.

Example

add_worker("ana", "dev", 10)   -> True
add_worker("bo", "dev", 12)    -> True
register("ana", 10); register("bo", 12); register("ana", 25); register("bo", 40)
register("cy", 5)              -> "invalid_request"
get("ana") -> 15    get("bo") -> 28
top_n_workers(5, "dev")        -> ["bo(28)", "ana(15)"]

register("ana", 50); promote("ana", "lead", 20, 60); register("ana", 70)
calc_salary("ana", 0, 100)     -> 450    # 15 × 10 + 10 × 10 + 10 × 20
calc_salary("ana", 55, 65)     -> 150    # 5 × 10 + 5 × 20
top_n_workers(5, "lead")       -> ["ana(35)"]

add_bonus_window(15, 30)
calc_salary("bo", 0, 100)      -> 516    # 28 × 12, plus 15 × 12 doubled

Constraints

• Up to 10^5 calls; times up to 10^9.

Clarifying questions

• Does a visit still in progress count toward get or calc_salary?
• After a promotion, does top_n_workers count all of the worker's time, or only time in the new position?
• Can bonus windows overlap, and does overlapping double twice?

What a strong answer covers

• Per worker, a sorted list of completed visits and a sorted list of (start, rate) changes.
• calc_salary as interval arithmetic: clip each visit to [start, end) and split at rate changes and bonus windows; binary search to skip visits outside the range.
• Top-n with a sort per query or a sorted structure per position, and the trade-off.
• Tests at boundaries: visits touching start or end, a promotion in the middle of a visit.

Follow-ups

• Report each worker's pay for a month in one call, fast.
• Undo the last registration.
• Workers can be in several offices; badge events arrive out of order.