| """Portable action replays, checked by running the authoritative engine again.""" |
|
|
| from typing import Any |
|
|
| from stackcraft.engine import new_game, step |
| from stackcraft.schema import RULES_VERSION, GameState |
|
|
| SCHEMA_VERSION = 1 |
|
|
|
|
| def _summary(state: GameState) -> dict[str, int | bool]: |
| return { |
| "score": state.score, |
| "lines": state.lines, |
| "pieces": state.piece_index, |
| "terminal": state.terminal, |
| } |
|
|
|
|
| def make_replay(seed: int, actions: list[str]) -> dict[str, Any]: |
| artifact = { |
| "schema_version": SCHEMA_VERSION, |
| "rules_version": RULES_VERSION, |
| "seed": seed, |
| "actions": list(actions), |
| } |
| frames = replay_states(artifact) |
| artifact["final"] = _summary(frames[-1]) |
| return artifact |
|
|
|
|
| def replay_states(artifact: dict[str, Any]) -> list[GameState]: |
| """Reject malformed actions, incompatible versions, and false summaries.""" |
| if not isinstance(artifact, dict): |
| raise ValueError("replay must be a JSON object") |
| version = artifact.get("schema_version") |
| if type(version) is not int or version != SCHEMA_VERSION: |
| raise ValueError("unsupported replay schema_version") |
| if artifact.get("rules_version") != RULES_VERSION: |
| raise ValueError("unsupported replay rules_version") |
| seed = artifact.get("seed") |
| if type(seed) is not int: |
| raise ValueError("replay seed must be an integer") |
| actions = artifact.get("actions") |
| if not isinstance(actions, list) or any(not isinstance(a, str) for a in actions): |
| raise ValueError("replay actions must be a list of action IDs") |
| states = [new_game(seed)] |
| for index, action in enumerate(actions): |
| try: |
| states.append(step(states[-1], action).state) |
| except ValueError as error: |
| raise ValueError(f"invalid replay move {index}: {error}") from error |
| if "final" in artifact: |
| expected = _summary(states[-1]) |
| final = artifact["final"] |
| if ( |
| not isinstance(final, dict) |
| or final.keys() != expected.keys() |
| or any(type(final[key]) is not type(value) for key, value in expected.items()) |
| or final != expected |
| ): |
| raise ValueError("replay final summary does not match simulated outcome") |
| return states |
|
|
