65 lines
2.5 KiB
GDScript
65 lines
2.5 KiB
GDScript
class_name SimulationSnapshot
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extends RefCounted
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const SCHEMA_VERSION := 1
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static func capture(clock: SimulationKernel, state: Node, extra := {}) -> Dictionary:
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var snapshot := {
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&"schema_version": SCHEMA_VERSION,
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&"clock": clock.clock_snapshot(),
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&"game_state": state.create_snapshot(),
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}
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if extra is Dictionary and not extra.is_empty():
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snapshot[&"systems"] = extra.duplicate(true)
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return snapshot
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static func validate(snapshot: Dictionary) -> Dictionary:
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var errors: Array[String] = []
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var schema_value: Variant = snapshot.get(&"schema_version", null)
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if not _is_nonnegative_integer(schema_value) or int(schema_value) != SCHEMA_VERSION:
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errors.append("unsupported_schema_version")
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if not snapshot.get(&"clock", null) is Dictionary:
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errors.append("missing_clock")
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else:
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var clock_data: Dictionary = snapshot[&"clock"]
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if not _is_nonnegative_integer(clock_data.get(&"absolute_minute", null)):
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errors.append("invalid_absolute_minute")
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var speed_value: Variant = clock_data.get(&"speed", null)
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if not _is_nonnegative_integer(speed_value) or int(speed_value) not in [1, 2, 3, 4]:
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errors.append("invalid_speed")
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# Legacy envelopes may omit these fields and retain restore_clock's
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# paused=true/version=0 defaults. Present fields cannot be coerced.
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if typeof(clock_data.get(&"paused", true)) != TYPE_BOOL:
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errors.append("invalid_paused")
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if not _is_nonnegative_integer(clock_data.get(&"snapshot_version", 0)):
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errors.append("invalid_snapshot_version")
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if not snapshot.get(&"game_state", null) is Dictionary:
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errors.append("missing_game_state")
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return {
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&"ok": errors.is_empty(),
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&"errors": errors,
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}
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static func _is_nonnegative_integer(value: Variant) -> bool:
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if typeof(value) == TYPE_INT:
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return value >= 0
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# JSON numbers are floats, but exact integral values remain compatible.
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# Avoid an overflowing float-to-int conversion at the signed int64 limit.
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if typeof(value) != TYPE_FLOAT or not is_finite(value):
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return false
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return value >= 0 and value < 9223372036854775808.0 and value == floor(value)
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static func restore(snapshot: Dictionary, clock: SimulationKernel, state: Node) -> bool:
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var validation := validate(snapshot)
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if not validation[&"ok"]:
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return false
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var previous_clock := clock.clock_snapshot()
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var previous_state: Dictionary = state.create_snapshot()
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if not clock.restore_clock(snapshot[&"clock"]):
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return false
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if not state.restore_snapshot(snapshot[&"game_state"]):
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clock.restore_clock(previous_clock)
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state.restore_snapshot(previous_state)
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return false
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return true
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