Add clickable facet pills for mobile-friendly DSL filter composition

- Create reusable dsl_facets.py component with clickable pills that compose
  DSL filter expressions by appending field:value to the filter input
- Add /api/facets endpoint for dynamic facet count refresh via HTMX
- Fix select dropdown dark mode styling with color-scheme: dark in SelectStyles
- Integrate facet pills into all DSL filter screens: registry, move, and
  all action forms (tag-add, tag-end, attrs, outcome, status-correct)
- Update routes to fetch and pass facet counts, locations, and species
- Add comprehensive unit tests for component and API endpoint
- Add E2E tests for facet pill click behavior and dark mode select visibility

This enables tap-based filter composition on mobile without requiring typing.
Facet counts update dynamically as filters are applied via HTMX.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

tests/e2e/test_facet_pills.py

@@ -0,0 +1,192 @@
+# ABOUTME: E2E tests for DSL facet pills component.
+# ABOUTME: Tests click-to-filter, dynamic count updates, and dark mode visibility.
+
+import pytest
+from playwright.sync_api import Page, expect
+
+pytestmark = pytest.mark.e2e
+
+
+class TestFacetPillsOnMoveForm:
+    """Test facet pills functionality on the move form."""
+
+    def test_facet_pills_visible_on_move_page(self, page: Page, live_server):
+        """Verify facet pills section is visible on move page."""
+        page.goto(f"{live_server.url}/move")
+        expect(page.locator("body")).to_be_visible()
+
+        # Should see facet pills container
+        facet_container = page.locator("#dsl-facet-pills")
+        expect(facet_container).to_be_visible()
+
+    def test_click_species_facet_updates_filter(self, page: Page, live_server):
+        """Clicking a species facet pill updates the filter input."""
+        page.goto(f"{live_server.url}/move")
+        expect(page.locator("body")).to_be_visible()
+
+        # Click on a species facet pill (e.g., duck)
+        duck_pill = page.locator('[data-facet-field="species"][data-facet-value="duck"]')
+        expect(duck_pill).to_be_visible()
+        duck_pill.click()
+
+        # Filter input should now contain species:duck
+        filter_input = page.locator("#filter")
+        expect(filter_input).to_have_value("species:duck")
+
+    def test_click_multiple_facets_composes_filter(self, page: Page, live_server):
+        """Clicking multiple facet pills composes the filter."""
+        page.goto(f"{live_server.url}/move")
+        expect(page.locator("body")).to_be_visible()
+
+        # Click species facet
+        duck_pill = page.locator('[data-facet-field="species"][data-facet-value="duck"]')
+        expect(duck_pill).to_be_visible()
+        duck_pill.click()
+
+        # Click sex facet
+        female_pill = page.locator('[data-facet-field="sex"][data-facet-value="female"]')
+        expect(female_pill).to_be_visible()
+        female_pill.click()
+
+        # Filter should contain both
+        filter_input = page.locator("#filter")
+        filter_value = filter_input.input_value()
+        assert "species:duck" in filter_value
+        assert "sex:female" in filter_value
+
+    def test_facet_counts_update_after_filter(self, page: Page, live_server):
+        """Facet counts update dynamically when filter changes."""
+        page.goto(f"{live_server.url}/move")
+        expect(page.locator("body")).to_be_visible()
+
+        # Get initial species counts
+        facet_container = page.locator("#dsl-facet-pills")
+        expect(facet_container).to_be_visible()
+
+        # Click species:duck to filter
+        duck_pill = page.locator('[data-facet-field="species"][data-facet-value="duck"]')
+        duck_pill.click()
+
+        # Wait for HTMX updates
+        page.wait_for_timeout(1000)
+
+        # Facet counts should have updated - only alive duck-related counts shown
+        # The sex facet should now show counts for ducks only
+        sex_section = page.locator("#dsl-facet-pills").locator("text=Sex").locator("..")
+        expect(sex_section).to_be_visible()
+
+    def test_selection_preview_updates_after_facet_click(self, page: Page, live_server):
+        """Selection preview updates after clicking a facet pill."""
+        page.goto(f"{live_server.url}/move")
+        expect(page.locator("body")).to_be_visible()
+
+        # Click species facet
+        duck_pill = page.locator('[data-facet-field="species"][data-facet-value="duck"]')
+        expect(duck_pill).to_be_visible()
+        duck_pill.click()
+
+        # Wait for HTMX updates to selection container
+        page.wait_for_timeout(1000)
+
+        # Selection container should show filtered animals
+        selection_container = page.locator("#selection-container")
+        expect(selection_container).to_be_visible()
+
+
+class TestFacetPillsOnOutcomeForm:
+    """Test facet pills functionality on the outcome form."""
+
+    def test_facet_pills_visible_on_outcome_page(self, page: Page, live_server):
+        """Verify facet pills section is visible on outcome page."""
+        page.goto(f"{live_server.url}/actions/outcome")
+        expect(page.locator("body")).to_be_visible()
+
+        # Should see facet pills container
+        facet_container = page.locator("#dsl-facet-pills")
+        expect(facet_container).to_be_visible()
+
+    def test_click_facet_on_outcome_form(self, page: Page, live_server):
+        """Clicking a facet pill on outcome form updates filter."""
+        page.goto(f"{live_server.url}/actions/outcome")
+        expect(page.locator("body")).to_be_visible()
+
+        # Click on a species facet pill
+        duck_pill = page.locator('[data-facet-field="species"][data-facet-value="duck"]')
+        expect(duck_pill).to_be_visible()
+        duck_pill.click()
+
+        # Filter input should now contain species:duck
+        filter_input = page.locator("#filter")
+        expect(filter_input).to_have_value("species:duck")
+
+
+class TestFacetPillsOnTagAddForm:
+    """Test facet pills functionality on the tag add form."""
+
+    def test_facet_pills_visible_on_tag_add_page(self, page: Page, live_server):
+        """Verify facet pills section is visible on tag add page."""
+        page.goto(f"{live_server.url}/actions/tag-add")
+        expect(page.locator("body")).to_be_visible()
+
+        # Should see facet pills container
+        facet_container = page.locator("#dsl-facet-pills")
+        expect(facet_container).to_be_visible()
+
+
+class TestFacetPillsOnRegistry:
+    """Test facet pills on registry replace existing facets."""
+
+    def test_registry_facet_pills_visible(self, page: Page, live_server):
+        """Verify facet pills appear in registry sidebar."""
+        page.goto(f"{live_server.url}/registry")
+        expect(page.locator("body")).to_be_visible()
+
+        # Should see facet pills in sidebar
+        facet_container = page.locator("#dsl-facet-pills")
+        expect(facet_container).to_be_visible()
+
+    def test_registry_facet_click_updates_filter(self, page: Page, live_server):
+        """Clicking a facet in registry updates the filter."""
+        page.goto(f"{live_server.url}/registry")
+        expect(page.locator("body")).to_be_visible()
+
+        # Click on species facet
+        duck_pill = page.locator('[data-facet-field="species"][data-facet-value="duck"]')
+        expect(duck_pill).to_be_visible()
+        duck_pill.click()
+
+        # Filter input should be updated
+        filter_input = page.locator("#filter")
+        expect(filter_input).to_have_value("species:duck")
+
+
+class TestSelectDarkMode:
+    """Test select dropdown visibility in dark mode."""
+
+    def test_select_options_visible_on_move_form(self, page: Page, live_server):
+        """Verify select dropdown options are readable in dark mode."""
+        page.goto(f"{live_server.url}/move")
+        expect(page.locator("body")).to_be_visible()
+
+        # Click to open destination dropdown
+        select = page.locator("#to_location_id")
+        expect(select).to_be_visible()
+
+        # Check the select has proper dark mode styling
+        # Note: We check computed styles to verify color-scheme is set
+        color_scheme = select.evaluate("el => window.getComputedStyle(el).colorScheme")
+        # Should have dark color scheme for native dark mode option styling
+        assert "dark" in color_scheme.lower() or color_scheme == "auto"
+
+    def test_outcome_select_options_visible(self, page: Page, live_server):
+        """Verify outcome dropdown options are readable."""
+        page.goto(f"{live_server.url}/actions/outcome")
+        expect(page.locator("body")).to_be_visible()
+
+        # Check outcome dropdown has proper styling
+        select = page.locator("#outcome")
+        expect(select).to_be_visible()
+
+        # Verify the select can be interacted with
+        select.click()
+        expect(select).to_be_focused()

tests/test_api_facets.py

@@ -0,0 +1,195 @@
+# ABOUTME: Unit tests for /api/facets endpoint.
+# ABOUTME: Tests dynamic facet count retrieval based on filter.
+
+import os
+import time
+
+import pytest
+from starlette.testclient import TestClient
+
+from animaltrack.events.payloads import AnimalCohortCreatedPayload
+from animaltrack.events.store import EventStore
+from animaltrack.projections import ProjectionRegistry
+from animaltrack.projections.animal_registry import AnimalRegistryProjection
+from animaltrack.projections.event_animals import EventAnimalsProjection
+from animaltrack.projections.intervals import IntervalProjection
+from animaltrack.services.animal import AnimalService
+
+
+def make_test_settings(
+    csrf_secret: str = "test-secret",
+    trusted_proxy_ips: str = "127.0.0.1",
+    dev_mode: bool = True,
+):
+    """Create Settings for testing by setting env vars temporarily."""
+    from animaltrack.config import Settings
+
+    old_env = os.environ.copy()
+    try:
+        os.environ["CSRF_SECRET"] = csrf_secret
+        os.environ["TRUSTED_PROXY_IPS"] = trusted_proxy_ips
+        os.environ["DEV_MODE"] = str(dev_mode).lower()
+        return Settings()
+    finally:
+        os.environ.clear()
+        os.environ.update(old_env)
+
+
+@pytest.fixture
+def client(seeded_db):
+    """Create a test client for the app."""
+    from animaltrack.web.app import create_app
+
+    settings = make_test_settings(trusted_proxy_ips="testclient")
+    app, rt = create_app(settings=settings, db=seeded_db)
+    return TestClient(app, raise_server_exceptions=True)
+
+
+@pytest.fixture
+def projection_registry(seeded_db):
+    """Create a ProjectionRegistry with animal projections registered."""
+    registry = ProjectionRegistry()
+    registry.register(AnimalRegistryProjection(seeded_db))
+    registry.register(EventAnimalsProjection(seeded_db))
+    registry.register(IntervalProjection(seeded_db))
+    return registry
+
+
+@pytest.fixture
+def animal_service(seeded_db, projection_registry):
+    """Create an AnimalService for testing."""
+    event_store = EventStore(seeded_db)
+    return AnimalService(seeded_db, event_store, projection_registry)
+
+
+@pytest.fixture
+def location_strip1_id(seeded_db):
+    """Get Strip 1 location ID from seeded data."""
+    row = seeded_db.execute("SELECT id FROM locations WHERE name = 'Strip 1'").fetchone()
+    return row[0]
+
+
+@pytest.fixture
+def location_strip2_id(seeded_db):
+    """Get Strip 2 location ID from seeded data."""
+    row = seeded_db.execute("SELECT id FROM locations WHERE name = 'Strip 2'").fetchone()
+    return row[0]
+
+
+@pytest.fixture
+def ducks_at_strip1(seeded_db, animal_service, location_strip1_id):
+    """Create 5 female ducks at Strip 1."""
+    payload = AnimalCohortCreatedPayload(
+        species="duck",
+        count=5,
+        life_stage="adult",
+        sex="female",
+        location_id=location_strip1_id,
+        origin="purchased",
+    )
+    ts_utc = int(time.time() * 1000)
+    event = animal_service.create_cohort(payload, ts_utc, "test_user")
+    return event.entity_refs["animal_ids"]
+
+
+@pytest.fixture
+def geese_at_strip2(seeded_db, animal_service, location_strip2_id):
+    """Create 3 male geese at Strip 2."""
+    payload = AnimalCohortCreatedPayload(
+        species="goose",
+        count=3,
+        life_stage="adult",
+        sex="male",
+        location_id=location_strip2_id,
+        origin="purchased",
+    )
+    ts_utc = int(time.time() * 1000)
+    event = animal_service.create_cohort(payload, ts_utc, "test_user")
+    return event.entity_refs["animal_ids"]
+
+
+class TestApiFacetsEndpoint:
+    """Test GET /api/facets endpoint."""
+
+    def test_facets_endpoint_exists(self, client, ducks_at_strip1):
+        """Verify the facets endpoint responds."""
+        response = client.get("/api/facets")
+        assert response.status_code == 200
+
+    def test_facets_returns_html_partial(self, client, ducks_at_strip1):
+        """Facets endpoint returns HTML partial for HTMX swap."""
+        response = client.get("/api/facets")
+        assert response.status_code == 200
+        content = response.text
+
+        # Should be HTML with facet pills structure
+        assert 'id="dsl-facet-pills"' in content
+        assert "Species" in content
+
+    def test_facets_respects_filter(self, client, ducks_at_strip1, geese_at_strip2):
+        """Facets endpoint applies filter and shows filtered counts."""
+        # Get facets filtered to ducks only
+        response = client.get("/api/facets?filter=species:duck")
+        assert response.status_code == 200
+        content = response.text
+
+        # Should show sex facets for ducks (5 female)
+        assert "female" in content.lower()
+        # Should not show goose sex (male) since we filtered to ducks
+        # (actually it might show male=0 or not at all)
+
+    def test_facets_shows_count_for_alive_animals(self, client, ducks_at_strip1):
+        """Facets show counts for alive animals by default."""
+        response = client.get("/api/facets")
+        assert response.status_code == 200
+        content = response.text
+
+        # Should show species with counts
+        assert "duck" in content.lower() or "Duck" in content
+        # Count 5 should appear
+        assert "5" in content
+
+    def test_facets_with_empty_filter(self, client, ducks_at_strip1, geese_at_strip2):
+        """Empty filter returns all alive animals' facets."""
+        response = client.get("/api/facets?filter=")
+        assert response.status_code == 200
+        content = response.text
+
+        # Should have facet pills
+        assert 'id="dsl-facet-pills"' in content
+
+    def test_facets_with_location_filter(self, client, ducks_at_strip1, geese_at_strip2):
+        """Location filter shows facets for that location only."""
+        response = client.get('/api/facets?filter=location:"Strip 1"')
+        assert response.status_code == 200
+        content = response.text
+
+        # Should show ducks (at Strip 1)
+        assert "duck" in content.lower() or "Duck" in content
+
+    def test_facets_includes_htmx_swap_attributes(self, client, ducks_at_strip1):
+        """Returned HTML has proper ID for HTMX swap targeting."""
+        response = client.get("/api/facets")
+        assert response.status_code == 200
+        content = response.text
+
+        # Must have same ID for outerHTML swap to work
+        assert 'id="dsl-facet-pills"' in content
+
+
+class TestApiFacetsWithSelectionPreview:
+    """Test facets endpoint integrates with selection preview workflow."""
+
+    def test_facets_and_preview_use_same_filter(self, client, ducks_at_strip1, geese_at_strip2):
+        """Both endpoints interpret the same filter consistently."""
+        filter_str = "species:duck"
+
+        # Get facets
+        facets_resp = client.get(f"/api/facets?filter={filter_str}")
+        assert facets_resp.status_code == 200
+
+        # Get selection preview
+        preview_resp = client.get(f"/api/selection-preview?filter={filter_str}")
+        assert preview_resp.status_code == 200
+
+        # Both should work with the same filter

tests/test_dsl_facets.py

@@ -0,0 +1,233 @@
+# ABOUTME: Unit tests for DSL facet pills template component.
+# ABOUTME: Tests HTML generation for facet pill structure and HTMX attributes.
+
+from fasthtml.common import to_xml
+
+from animaltrack.repositories.animals import FacetCounts
+
+
+class TestDslFacetPills:
+    """Test the dsl_facet_pills component."""
+
+    def test_facet_pills_renders_with_counts(self):
+        """Facet pills component renders species counts as pills."""
+        from animaltrack.web.templates.dsl_facets import dsl_facet_pills
+
+        facets = FacetCounts(
+            by_species={"duck": 5, "goose": 3},
+            by_sex={"female": 4, "male": 3, "unknown": 1},
+            by_life_stage={"adult": 6, "juvenile": 2},
+            by_location={"loc1": 5, "loc2": 3},
+        )
+        locations = []
+        species_list = []
+
+        result = dsl_facet_pills(facets, "filter", locations, species_list)
+        html = to_xml(result)
+
+        # Should have container with proper ID
+        assert 'id="dsl-facet-pills"' in html
+        # Should have data attributes for JavaScript
+        assert 'data-facet-field="species"' in html
+        assert 'data-facet-value="duck"' in html
+        assert 'data-facet-value="goose"' in html
+
+    def test_facet_pills_has_htmx_attributes_for_refresh(self):
+        """Facet pills container has HTMX attributes for dynamic refresh."""
+        from animaltrack.web.templates.dsl_facets import dsl_facet_pills
+
+        facets = FacetCounts(
+            by_species={"duck": 5},
+            by_sex={},
+            by_life_stage={},
+            by_location={},
+        )
+
+        result = dsl_facet_pills(facets, "filter", [], [])
+        html = to_xml(result)
+
+        # Should have HTMX attributes for updating facets
+        assert "hx-get" in html
+        assert "/api/facets" in html
+        assert "hx-trigger" in html
+        assert "#filter" in html  # References the filter input
+
+    def test_facet_pills_renders_all_facet_sections(self):
+        """Facet pills renders species, sex, life_stage, and location sections."""
+        from animaltrack.web.templates.dsl_facets import dsl_facet_pills
+
+        facets = FacetCounts(
+            by_species={"duck": 5},
+            by_sex={"female": 3},
+            by_life_stage={"adult": 4},
+            by_location={"loc1": 5},
+        )
+
+        result = dsl_facet_pills(facets, "filter", [], [])
+        html = to_xml(result)
+
+        # Should have all section headers
+        assert "Species" in html
+        assert "Sex" in html
+        assert "Life Stage" in html
+        assert "Location" in html
+
+    def test_facet_pills_includes_counts_in_pills(self):
+        """Each pill shows the count alongside the label."""
+        from animaltrack.web.templates.dsl_facets import dsl_facet_pills
+
+        facets = FacetCounts(
+            by_species={"duck": 12},
+            by_sex={},
+            by_life_stage={},
+            by_location={},
+        )
+
+        result = dsl_facet_pills(facets, "filter", [], [])
+        html = to_xml(result)
+
+        # Should show count 12
+        assert ">12<" in html or ">12 " in html or " 12<" in html
+
+    def test_facet_pills_uses_location_names(self):
+        """Location facets use human-readable names from location list."""
+        from animaltrack.models.reference import Location
+        from animaltrack.web.templates.dsl_facets import dsl_facet_pills
+
+        facets = FacetCounts(
+            by_species={},
+            by_sex={},
+            by_life_stage={},
+            by_location={"01ARZ3NDEKTSV4RRFFQ69G5FAV": 5},
+        )
+        locations = [
+            Location(
+                id="01ARZ3NDEKTSV4RRFFQ69G5FAV",
+                name="Strip 1",
+                active=True,
+                created_at_utc=0,
+                updated_at_utc=0,
+            )
+        ]
+
+        result = dsl_facet_pills(facets, "filter", locations, [])
+        html = to_xml(result)
+
+        # Should display location name
+        assert "Strip 1" in html
+
+    def test_facet_pills_uses_species_names(self):
+        """Species facets use human-readable names from species list."""
+        from animaltrack.models.reference import Species
+        from animaltrack.web.templates.dsl_facets import dsl_facet_pills
+
+        facets = FacetCounts(
+            by_species={"duck": 5},
+            by_sex={},
+            by_life_stage={},
+            by_location={},
+        )
+        species_list = [
+            Species(
+                code="duck",
+                name="Duck",
+                active=True,
+                created_at_utc=0,
+                updated_at_utc=0,
+            )
+        ]
+
+        result = dsl_facet_pills(facets, "filter", [], species_list)
+        html = to_xml(result)
+
+        # Should display species name
+        assert "Duck" in html
+
+    def test_facet_pills_empty_facets_not_shown(self):
+        """Empty facet sections are not rendered."""
+        from animaltrack.web.templates.dsl_facets import dsl_facet_pills
+
+        facets = FacetCounts(
+            by_species={"duck": 5},
+            by_sex={},  # Empty
+            by_life_stage={},  # Empty
+            by_location={},  # Empty
+        )
+
+        result = dsl_facet_pills(facets, "filter", [], [])
+        html = to_xml(result)
+
+        # Should show Species but not empty sections
+        assert "Species" in html
+        # Sex section header should not appear since no sex facets
+        # (we count section headers, not raw word occurrences)
+
+    def test_facet_pills_onclick_calls_javascript(self):
+        """Pill click handler uses JavaScript to update filter."""
+        from animaltrack.web.templates.dsl_facets import dsl_facet_pills
+
+        facets = FacetCounts(
+            by_species={"duck": 5},
+            by_sex={},
+            by_life_stage={},
+            by_location={},
+        )
+
+        result = dsl_facet_pills(facets, "filter", [], [])
+        html = to_xml(result)
+
+        # Should have onclick or similar handler
+        assert "onclick" in html or "hx-on:click" in html
+
+
+class TestFacetPillsSection:
+    """Test the facet_pill_section helper function."""
+
+    def test_section_sorts_by_count_descending(self):
+        """Pills are sorted by count in descending order."""
+        from animaltrack.web.templates.dsl_facets import facet_pill_section
+
+        counts = {"a": 1, "b": 5, "c": 3}
+        result = facet_pill_section("Test", counts, "filter", "field")
+        html = to_xml(result)
+
+        # "b" (count 5) should appear before "c" (count 3) which appears before "a" (count 1)
+        pos_b = html.find('data-facet-value="b"')
+        pos_c = html.find('data-facet-value="c"')
+        pos_a = html.find('data-facet-value="a"')
+
+        assert pos_b < pos_c < pos_a, "Pills should be sorted by count descending"
+
+    def test_section_returns_none_for_empty_counts(self):
+        """Empty counts returns None (no section rendered)."""
+        from animaltrack.web.templates.dsl_facets import facet_pill_section
+
+        result = facet_pill_section("Test", {}, "filter", "field")
+        assert result is None
+
+    def test_section_applies_label_map(self):
+        """Label map transforms values to display labels."""
+        from animaltrack.web.templates.dsl_facets import facet_pill_section
+
+        counts = {"val1": 5}
+        label_map = {"val1": "Display Label"}
+        result = facet_pill_section("Test", counts, "filter", "field", label_map)
+        html = to_xml(result)
+
+        assert "Display Label" in html
+
+
+class TestDslFacetPillsScript:
+    """Test the JavaScript for facet pills interaction."""
+
+    def test_script_included_in_component(self):
+        """Facet pills component includes the JavaScript for interaction."""
+        from animaltrack.web.templates.dsl_facets import dsl_facet_pills_script
+
+        result = dsl_facet_pills_script("filter")
+        html = to_xml(result)
+
+        # Should be a script element
+        assert "<script" in html.lower()
+        # Should have function to handle pill clicks
+        assert "appendFacetToFilter" in html or "addFacetToFilter" in html