Instructions

Context

• This task implements the Preview step of the OPML import wizard (part of the "Preview and Select Sources" user story). The Upload step will have populated ImportSession.parsed_sources (JSONB) with entries parsed from the OPML and ImportSession exists for the current admin user. The engine uses Turbo Frames, Turbo Streams, Tailwind, server-side pagination helpers, and a Source model/table (sourcemon_sources) for duplicate detection. Selection state for the wizard must persist in ImportSession.selected_source_ids (JSONB) while the ImportSession exists.

Goals

• Render a paginated Preview table of parsed OPML entries with columns: feed URL, title, and “Already Imported” status.
• Mark duplicate entries (feed URL matched against existing sourcemon_sources) as “Already Imported” and make them non-selectable.
• Show malformed/parsing-error entries (from parsed_sources) with inline error indicator and make them non-selectable.
• Provide filters: All, New Sources, Existing Sources (server-side filtering).
• Allow admin to select/unselect valid entries; persist selections across filter changes and step navigation by updating ImportSession.selected_source_ids.
• Prevent proceeding to the next wizard step when no sources are selected and surface a clear warning.

Technical Guidelines

• Rendering & UI
  • Implement the Preview step view as a Turbo Frame (consistent with engine conventions used for sources index tables). The table content must be server-rendered (HTML partials) and replaceable via turbo_frame_tag updates.
  • Table columns: feed URL (clickable/visible text), title (as parsed), and “Already Imported” status (visual badge/icon). Malformed rows must show a clear inline error message/toolip and a disabled checkbox.
  • Use Tailwind classes and accessibility patterns consistent with other engine tables and forms.
  • Add filter controls (All / New / Existing) that trigger full-frame GET requests (targeting the preview Turbo Frame) and support pagination & stateful checkbox persistence.
• Data & Selection Persistence
  • Persist and read selection state in ImportSession.selected_source_ids (JSONB). Store a stable identifier for each parsed entry that can be used across requests. If parsed_sources includes a unique temp id, use it; otherwise use feed_url as the canonical identifier for selection storage (feed_url is required for duplicate detection).
  • When rendering rows, mark checkboxes checked if their identifier appears in ImportSession.selected_source_ids.
  • Update ImportSession.selected_source_ids via server endpoints (e.g., POST/PATCH from the preview frame) whenever a user toggles selection or submits the preview form. The controller actions must sanitize params and scope updates to the current ImportSession and current admin user.
  • Ensure ImportSession model uses integer user_id as configured in the tech brief. (This task reads/updates ImportSession only; ensure permission checks enforce admin-only access.)
• Duplicate & Malformed Handling
  • Duplicate detection: treat a parsed entry as an "existing" duplicate if its feed URL exactly matches an existing source record (sourcemon_sources). Mark duplicates visually and make their selection control disabled.
  • Malformed entries: rely on parser-set flags in ImportSession.parsed_sources to identify malformed entries; render error details inline and disable selection.
• Filters & Pagination
  • Implement server-side filtering logic:
    • All => show all parsed_sources (including malformed and duplicates).
    • New Sources => parsed entries that are valid and not duplicate.
    • Existing Sources => parsed entries flagged as duplicate (already imported).
  • Implement server-side pagination for the preview table using existing pagination helpers/patterns used elsewhere in the engine (do not load entire list into browser for very large files).
  • Preserve selection state across pagination and filter changes by reading/writing ImportSession.selected_source_ids (i.e., selections are global to the ImportSession, not only per page).
• Navigation & Progression Block
  • Provide UI validation that blocks “Next” navigation when ImportSession.selected_source_ids is empty (or contains no enabled/valid entries). Show a clear, inline warning message in the Preview step explaining at least one valid source must be selected.
• Security & Conventions
  • Enforce admin-only access for all preview endpoints using existing SourceMonitor authentication hooks.
  • Use strong parameter sanitization for any incoming params (filter, page, selection updates).
  • Follow the engine’s Turbo/Tailwind/Accessibility patterns and Turbo Frame naming conventions so later steps and Turbo Streams integrate cleanly.
• Integration points (do not reimplement)
  • Read parsed entries from ImportSession.parsed_sources (populated by the Upload/Parsing step).
  • For duplicate detection, query the canonical Source model/table (sourcemon_sources / SourceMonitor::Source) — match by feed URL only.
  • Use existing pagination helpers and table rendering conventions used by the Sources index.

Out of scope

• Health check job orchestration, Turbo Stream live broadcasting for health — that is handled in the Health Check step.
• Upload/parsing implementation (Add OPML Upload & Synchronous Parsing) and ImportSession creation — assume ImportSession.parsed_sources exists with required fields.
• Per-feed settings UI or per-feed overrides.
• Client-only selection persistence (all persistence must be server-backed in ImportSession.selected_source_ids).
• Retry semantics for failed persistence or selection race-handling beyond simple idempotent updates and param sanitization.

Suggested research

• Inspect ImportSession model and its parsed_sources schema to confirm the entry shape and any temporary identifiers (or confirm to use feed_url as identifier).
• Review the wizard controller/routes for Preview step (ImportSession/wizard controller) to determine the Turbo Frame name and route endpoints for updating selection and paginated frame rendering.
• Review existing sources index/table implementation and pagination helpers to follow consistent Turbo Frame patterns and CSS classes:
  • app/views/source_monitor/sources/index.html.erb and its table partials
  • existing pagination helpers under lib/source_monitor/pagination or helpers used in sources index
• Inspect Source model / table for feed_url column and any scopes used for matching (sourcemon_sources / SourceMonitor::Source).
• Check authentication hooks and parameter sanitizer patterns used by controllers to ensure admin-only access and strong param handling (e.g., SourceMonitor.config.authentication, SourceMonitor::Security::ParameterSanitizer).