Implement Role-Based Route Guard GoRouter integration
epic-role-based-access-control-ui-and-navigation-task-010 — Build the RoleRouteGuard as a GoRouter redirect callback. On every navigation event, validate the user's active role against the target route's required permissions using Permission Checker Service. Redirect global admins to the No-Access Screen route. Redirect unauthorized role access to the appropriate fallback route. Register the guard in the GoRouter configuration.
Acceptance Criteria
Technical Requirements
Execution Context
Tier 4 - 323 tasks
Can start after Tier 3 completes
Implementation Notes
GoRouter's redirect callback receives GoRouterState but cannot be async. Read active role from a synchronously accessible source — a Riverpod provider ref.read() or a BLoC's current state property. Define RoutePermissionMap as a static const Map
This is critical for role switches triggering guard re-evaluation without explicit navigation. Avoid putting business logic in the redirect callback — delegate to RoleRouteGuard.evaluate(route, role) which is pure and testable. The guard should treat an unrecognized/null role the same as unauthenticated.
Testing Requirements
Unit tests for RoleRouteGuard redirect logic: (1) given global_admin role + any route → returns '/no-access', (2) given unauthenticated state + protected route → returns '/login', (3) given coordinator role + coordinator-permitted route → returns null, (4) given peer_mentor role + coordinator-only route → returns fallback route, (5) given org_admin role + permitted route → returns null. Integration test: configure GoRouter with guard, navigate to restricted route with wrong role and assert redirect. Test deep link scenario: simulate app open with deep link to restricted route and assert guard fires. Target 100% branch coverage on redirect logic.
Combining GoRouter's declarative redirect logic in the route guard with StatefulShellRoute's stateful branch management is known to produce subtle bugs where the shell rebuilds unnecessarily on role switches, losing tab state or causing double-navigation events.
Mitigation & Contingency
Mitigation: Implement the route guard as a GoRouter redirect callback that only evaluates role from an already-resolved Riverpod provider (not async). Use a dedicated ShellRoute navigator key per tab branch to anchor state independently of role-driven rebuilds. Write integration tests for the full navigation graph.
Contingency: If StatefulShellRoute state loss is confirmed during QA, fall back to a manual tab state preservation approach using a TabStateManager service that caches the last route per tab and restores it after role switches, decoupling tab state from the shell lifecycle.
The role-based home screen must render three significantly different layouts (coordinator dashboard, peer mentor activity summary, org admin overview). If these variants are implemented as a single widget with conditionals, the file will become unmaintainable and difficult to test in isolation, especially as each variant grows with downstream feature additions.
Mitigation & Contingency
Mitigation: Design the role-based home screen as a router/dispatcher widget that delegates to three separate variant widgets (CoordinatorHomeView, PeerMentorHomeView, OrgAdminHomeView). Each variant is independently testable and can be developed by separate team members in parallel.
Contingency: If variant coupling has already occurred before this risk is addressed, refactor to the dispatcher pattern in a dedicated cleanup task before feature handoff. The dispatcher pattern is a straightforward extraction that carries low refactoring risk.
The no-access screen must link global admin users to the correct admin portal URL, which may differ per organization (NHF, HLF, Blindeforbundet each have their own admin portals). Hardcoding a single URL will result in wrong or broken links for some global admin users.
Mitigation & Contingency
Mitigation: Source the admin portal URL from the organization's configuration record in Supabase rather than hardcoding it. The no-access screen reads the active org context and resolves the portal URL dynamically. Provide a safe fallback to a generic Norse Digital Products support page if the URL is not configured.
Contingency: If dynamic URL resolution is not ready when the no-access screen ships, display a static instruction to contact the organization's administrator along with a support email address as an interim measure, and track the URL configuration task as a follow-up.