mirror of
https://github.com/rommapp/romm.git
synced 2026-04-23 06:54:40 +00:00
Georges-Antoine Assi
74 lines
2.4 KiB
Python
74 lines
2.4 KiB
Python
from __future__ import annotations
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from datetime import datetime
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from typing import Literal, NamedTuple
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from utils.datetime import to_utc
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SyncAction = Literal["upload", "download", "conflict", "no_op"]
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class SyncComparisonResult(NamedTuple):
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action: SyncAction
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reason: str
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def compare_save_state(
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*,
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client_hash: str | None,
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client_updated_at: datetime,
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server_hash: str | None,
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server_updated_at: datetime,
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device_last_synced_at: datetime | None,
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) -> SyncComparisonResult:
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"""Compare client and server save state to determine the sync action.
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Returns a (action, reason) tuple where action is one of:
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- upload: client save should be uploaded to server
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- download: server save should be downloaded to client
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- conflict: both sides changed, needs resolution
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- no_op: saves are in sync
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"""
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client_ts = to_utc(client_updated_at)
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server_ts = to_utc(server_updated_at)
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# If hashes match, saves are identical
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if client_hash and server_hash and client_hash == server_hash:
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return SyncComparisonResult("no_op", "Content is identical")
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# If we have a last sync timestamp, use it to determine which side changed
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if device_last_synced_at:
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synced_ts = to_utc(device_last_synced_at)
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client_changed = client_ts > synced_ts
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server_changed = server_ts > synced_ts
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if client_changed and server_changed:
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return SyncComparisonResult(
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"conflict", "Both sides changed since last sync"
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)
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if client_changed:
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return SyncComparisonResult("upload", "Client save is newer than last sync")
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if server_changed:
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return SyncComparisonResult(
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"download", "Server save is newer than last sync"
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)
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return SyncComparisonResult("no_op", "No changes since last sync")
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# No sync history: fall back to timestamp comparison
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if client_ts > server_ts:
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return SyncComparisonResult("upload", "Client save is newer (no sync history)")
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if server_ts > client_ts:
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return SyncComparisonResult(
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"download", "Server save is newer (no sync history)"
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)
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# Same timestamp, different hashes (or missing hashes)
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if client_hash != server_hash:
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return SyncComparisonResult("conflict", "Same timestamp but different content")
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return SyncComparisonResult("no_op", "Saves appear identical")
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