transcription/.github/instructions/ui.instructions.md

description, applyTo

description	applyTo
Use when modifying the NiceGUI application under src/transcription/ui. Defines ownership and dependency boundaries for UI registration, pages, components, services, persistence, state, and static assets.	src/transcription/ui/**/*.py

UI Conceptual Boundaries

Keep dependencies flowing in this direction:

ui/__init__.py -> pages -> components

Pages may depend on application services and framework-provided dependencies. Components may depend on smaller components and shared presentation helpers. Services and domain modules must never depend on the UI.

Package Root

• Keep ui/__init__.py as the UI composition root: register global assets, register pages, and mount NiceGUI on FastAPI.
• Do not put feature rendering, service calls, persistence, or route-specific state in the package root.

Pages

• Pages own route registration and route-level orchestration.
• Resolve request or application dependencies, call services, adapt returned data for presentation when needed, and coordinate refresh, navigation, and notifications here.
• Do not query, mutate, commit, or roll back the database from a page. Do not import database engines, sessions, operations, or query-building APIs. Persistence belongs to services or workflow functions.
• Framework dependency types may cross into page handlers only to construct or invoke services; do not pass sessions or session factories into components.
• Keep business rules, lifecycle transitions, transaction boundaries, and cross-service workflows out of page callbacks.

Components

• Components own reusable rendering, widget-local state, input normalization, and presentation-only formatting.
• Expose user actions through typed callback parameters. The calling page decides which service or workflow runs and what refresh or navigation follows.
• Do not register routes, resolve request/app state, instantiate services, or access persistence from components.
• Components may accept ORM models returned by services as read-only snapshots. Only use fields and relationships that the service loaded eagerly; never mutate models, trigger lazy loading, or expose session behavior.
• A component may compose lower-level components, but it must not import from pages.

Shared UI Infrastructure

• Keep app-wide navigation and layout primitives in components/app_shell.py.
• Keep generic table/event adaptation in components/table/common.py; feature-specific columns, row read models, and formatting belong in the feature table module.
• Keep exception normalization and user-facing error display in components/error_presenter.py; preserve AppError details and operation identifiers at page/component boundaries.

CSS Assets

• Keep CSS under ui/static and split it into manageable, feature-oriented files. Do not grow a monolithic stylesheet or embed substantial style blocks in Python components.
• Load each stylesheet from the page, component, or composition root that needs it with ui.add_css(...). Use shared registration only for genuinely application-wide styles.
• Read stylesheet text through importlib.resources.files(...) so loading works from installed packages and is independent of the working directory.
• Centralize CSS reading in one typed helper cached by relative resource path with functools.cache or an equivalent unbounded lru_cache. Cache the immutable stylesheet text to avoid repeated resource I/O during component renders; keep NiceGUI registration decisions at the caller.
• Do not encode application behavior in CSS or other static assets.

State and Side Effects

• Limit component state to ephemeral interaction state such as loading flags, form values, dialogs, and expansion state.
• Application and worker state must be resolved at the page or application boundary and passed through narrow interfaces such as callbacks or notifier protocols.
• Keep filesystem, network, provider, and worker orchestration behind application services or dedicated adapters. UI code may trigger those operations but must not implement them.