Build Unified Filter Bottom Sheet & Filter State Manager

[pedrazamiguez]

Problem / Motivation

As part of Phase 3 (Expenses Analytics & Filters), multiple filter mechanisms (search, categories, members, date ranges) are being added to the Expenses List screen. Implementing all of these directly on the main screen would severely clutter the UI, violating the "Whitespace" and "Premium" pillars of the Horizon Narrative design language. A unified orchestration mechanism is required to hold complex filters in a bottom sheet and manage the unified active filter state.

Note: To keep the expenses list screen as clean as possible, only the search bar should remain on the main screen. The category chips (#1501) should also be moved into this bottom sheet filter. In the future, the search bar could become omni-functional and suggest categories dynamically as the user types.

Proposed Solution

• Create a new domain data class, ExpenseFilterCriteria, to hold the active filter state (search query, selected categories, selected members, date range).
• In ExpensesViewModel, expose a MutableStateFlow<ExpenseFilterCriteria> and use combine with the expensesFlow to apply the filters in-memory on Dispatchers.Default.
• Create a new UI component (e.g., ExpenseFilterBottomSheet) using the ActionBottomSheet from :core:design-system to house the complex filters (Categories, Members, Dates) to keep the main screen clean.
• Ensure the active filter state is bundled into the MVI UiState so the UI can accurately reflect active filter badges and provide a "Clear Filters" action.

Acceptance Criteria

• ExpenseFilterCriteria model is created.
• ExpensesViewModel successfully filters expenses in-memory based on the active criteria using Dispatchers.Default.
• ExpenseFilterBottomSheet is created (using ActionBottomSheet) and can be opened/closed from the Expenses List screen.
• All existing tests pass; new unit tests added for the ExpensesViewModel filtering logic.
• make fast-check passes during iterative development (~15–30s).
• make check > build.log 2>&1 && echo "Check passed successfully" || (tail -n 100 build.log && exit 1) passes with 0 failures before merging.
• No new detekt findings introduced.

Out of Scope

• Implementing the Search Bar (handled in Implement a search bar on the Expenses List screen #1500).
• Implementing Category multi-select chips (handled in Implement category multi-select chip filters on the Expenses List screen #1501).
• Implementing Member/Payer filters (handled in Implement member/payer filters on the Expenses List screen #1502).
• Implementing Date Range filters (handled in Implement date range filters on the Expenses List screen #1503).

Related Issues / PRs

• Child of Track final stages of MVP development and release readiness #1401 (Phase 3 Checkpoint).
• Blocks Implement category multi-select chip filters on the Expenses List screen #1501, Implement member/payer filters on the Expenses List screen #1502 and Implement date range filters on the Expenses List screen #1503.

[github-actions]

🌱 Branch created

feature/SPLTRP-1523

This branch has been automatically created based on develop.

🚀 Getting started

Fetch and switch to this branch with the latest changes from develop:

git fetch origin
git checkout feature/SPLTRP-1523
git pull origin develop

📌 When creating your PR

• Base branch: develop
• Title:

  [SPLTRP-1523]: Build Unified Filter Bottom Sheet & Filter State Manager
  

• Description: Closes #1523