Design a Localized Usage-Limit Response and Compose Snackbar

In an Android chat-app exercise, a message request can fail because the selected model has reached its usage limit. Design the API error data and Compose client behavior so a Snackbar identifies the model, offers an "Upgrade to Plus" link or action, and tells the user to retry after the indicated number of hours. Support multiple languages and explain what happens if two messages produce limit errors in quick succession. This is a design scenario, not a statement of any live product's quota or upgrade policy. ### Constraints & Assumptions - The server determines whether the usage limit has been reached. - The client must render localized text and an actionable upgrade destination. - Distinguish a retry estimate from a guarantee that a later request will succeed. ### Clarifying Questions to Ask - Does the response supply a retry duration, reset instant, or both, and how is clock skew handled? - Should repeated errors for the same model/reset window be coalesced? - Must the upgrade affordance be an inline link or is the Snackbar action suitable? ### Part 1 — Define the Error Contract Specify structured fields the client needs without forcing it to parse an English sentence. #### What This Part Should Cover - Stable error identity, affected model, retry information, and upgrade action. - Localization responsibility and safe navigation. - Unknown-field or missing-data fallback behavior. ### Part 2 — Show the Snackbar in Compose Explain the host state, coroutine/effect trigger, rapid error handling, and action callback. #### What This Part Should Cover - A stable Snackbar host and lifecycle-aware event handling. - Single-display/queue behavior and deliberate deduplication policy. - Prevention of repeated side effects during recomposition. ```hint Calling a suspending display operation directly while a composable renders is not the same as handling a new error event. ``` ### What a Strong Answer Covers Connect a machine-readable server error to localized, accessible UI behavior. Explain both the two-request race and the lifecycle of the coroutine that displays or queues the Snackbar. ### Follow-up Questions - What if the screen leaves the composition while a Snackbar is queued? - How would a language change affect an error still waiting to be shown? - How would you avoid showing stale retry information?