Added a theme selector

backend/app/api/admin.py

@@ -19,6 +19,7 @@ from backend.app.services.email_service import (
     smtp_configured,
 )
 from backend.app.services.email_verification import create_verification_token
+from backend.app.services.theme_service import THEMES, get_enabled_themes, save_enabled_themes
 from backend.app.core.config import settings
 
 router = APIRouter()
@@ -49,6 +50,10 @@ class AdminSmtpUpdate(BaseModel):
     smtp_use_tls: bool = True
 
 
+class AdminThemesUpdate(BaseModel):
+    themes: list[str]
+
+
 def validate_smtp_values(payload: AdminSmtpUpdate, current: dict | None = None) -> dict:
     smtp_host = payload.smtp_host.strip()
     smtp_from = payload.smtp_from.strip()
@@ -139,6 +144,20 @@ def get_admin_smtp_settings(_: dict = Depends(require_admin)):
     return public_smtp_settings(get_smtp_settings())
 
 
+@router.get('/themes')
+def get_admin_themes(_: dict = Depends(require_admin)):
+    return {'themes': THEMES, 'enabled': get_enabled_themes()}
+
+
+@router.put('/themes')
+def update_admin_themes(payload: AdminThemesUpdate, _: dict = Depends(require_admin)):
+    try:
+        enabled = save_enabled_themes(payload.themes)
+    except ValueError as error:
+        raise HTTPException(status_code=422, detail=str(error)) from error
+    return {'themes': THEMES, 'enabled': enabled}
+
+
 @router.put('/smtp')
 def update_admin_smtp_settings(payload: AdminSmtpUpdate, _: dict = Depends(require_admin)):
     current = get_smtp_settings()

backend/app/api/public.py

@@ -6,6 +6,7 @@ from fastapi.security import HTTPAuthorizationCredentials, HTTPBearer
 
 from backend.app.services.link_service import list_public_links, list_public_users
 from backend.app.services.token_service import validate_token
+from backend.app.services.theme_service import THEMES, get_enabled_themes
 
 router = APIRouter()
 optional_bearer = HTTPBearer(auto_error=False)
@@ -16,6 +17,12 @@ def public_users():
     return list_public_users()
 
 
+@router.get('/themes')
+def public_themes():
+    enabled = get_enabled_themes()
+    return [{'id': theme, **THEMES[theme]} for theme in enabled]
+
+
 @router.get('/feed')
 @router.get('/feed/{username}')
 def public_feed(

backend/app/services/email_service.py

@@ -35,14 +35,14 @@ def save_smtp_settings(values: dict) -> None:
         conn.commit()
 
 
-def smtp_configured() -> bool:
-    smtp = get_smtp_settings()
+def smtp_configured(smtp_values: dict | None = None) -> bool:
+    smtp = smtp_values or get_smtp_settings()
     return bool(smtp['smtp_host'] and smtp['smtp_from'])
 
 
 def send_message(email: str, subject: str, body: str, smtp_values: dict | None = None) -> None:
     smtp = smtp_values or get_smtp_settings()
-    if not smtp_configured():
+    if not smtp_configured(smtp):
         raise RuntimeError('SMTP is not configured; set LINKLOG_SMTP_HOST and LINKLOG_SMTP_FROM')
 
     message = EmailMessage()

backend/app/services/theme_service.py

@@ -0,0 +1,46 @@
+## Copyright © 2026 Olaf Kolkman
+## SPDX-License-Identifier: GPL-3.0-or-later
+
+import json
+
+from backend.app.database import get_connection
+
+
+THEMES = {
+    'plain-day': {'label': 'Plain Day', 'description': 'A bright, neutral daytime theme.'},
+    'plain-night': {'label': 'Plain Night', 'description': 'A neutral dark nighttime theme.'},
+    'latte': {'label': 'Catppuccin Latte', 'description': 'Catppuccin light theme.'},
+    'frappe': {'label': 'Catppuccin Frappe', 'description': 'Catppuccin soft dark theme.'},
+    'macchiato': {'label': 'Catppuccin Macchiato', 'description': 'Catppuccin medium dark theme.'},
+    'mocha': {'label': 'Catppuccin Mocha', 'description': 'Catppuccin deep dark theme.'},
+    'dracula': {'label': 'Dracula', 'description': 'A vivid dark theme with high-contrast accents.'},
+    'nord': {'label': 'Nord', 'description': 'A cool, muted blue-gray theme.'},
+    'solarized': {'label': 'Solarized', 'description': 'A balanced theme available in a light style.'},
+}
+DEFAULT_ENABLED_THEMES = tuple(THEMES)
+
+
+def get_enabled_themes() -> list[str]:
+    with get_connection() as conn:
+        row = conn.execute('SELECT value FROM app_settings WHERE name = ?', ('enabled_themes',)).fetchone()
+    if row is None:
+        return list(DEFAULT_ENABLED_THEMES)
+    try:
+        configured = json.loads(row['value'])
+    except (TypeError, json.JSONDecodeError):
+        return list(DEFAULT_ENABLED_THEMES)
+    return [theme for theme in configured if theme in THEMES] or ['mocha']
+
+
+def save_enabled_themes(themes: list[str]) -> list[str]:
+    selected = list(dict.fromkeys(theme for theme in themes if theme in THEMES))
+    if not selected:
+        raise ValueError('At least one theme must be enabled')
+    with get_connection() as conn:
+        conn.execute(
+            '''INSERT INTO app_settings (name, value, updated_at) VALUES (?, ?, CURRENT_TIMESTAMP)
+               ON CONFLICT(name) DO UPDATE SET value = excluded.value, updated_at = CURRENT_TIMESTAMP''',
+            ('enabled_themes', json.dumps(selected)),
+        )
+        conn.commit()
+    return selected

backend/tests/test_api.py

@@ -62,9 +62,25 @@ def test_configuration_requires_authentication_and_admin_role():
     assert client.get('/api/admin/smtp', headers=login_headers('bob')).status_code == 403
 
 
+def test_admin_can_select_multiple_themes():
+    headers = login_headers()
+    response = client.put('/api/admin/themes', headers=headers, json={
+        'themes': ['plain-day', 'plain-night', 'latte', 'frappe', 'macchiato', 'mocha', 'dracula', 'nord', 'solarized'],
+    })
+    assert response.status_code == 200
+    assert response.json()['enabled'] == ['plain-day', 'plain-night', 'latte', 'frappe', 'macchiato', 'mocha', 'dracula', 'nord', 'solarized']
+    public_response = client.get('/api/public/themes')
+    assert public_response.status_code == 200
+    assert [theme['id'] for theme in public_response.json()] == response.json()['enabled']
+
+    assert client.put('/api/admin/themes', headers=headers, json={'themes': []}).status_code == 422
+
+
 def test_admin_can_save_and_validate_smtp_settings():
     headers = login_headers()
     original = get_smtp_settings()
+    with get_connection() as conn:
+        original_row = conn.execute('SELECT value FROM app_settings WHERE name = ?', ('smtp',)).fetchone()
     response = client.put('/api/admin/smtp', headers=headers, json={
         'smtp_host': 'smtp.example.com',
         'smtp_port': 587,
@@ -97,7 +113,18 @@ def test_admin_can_save_and_validate_smtp_settings():
             'smtp_use_tls': False,
         })
 
-    client.put('/api/admin/smtp', headers=headers, json=original)
+    with get_connection() as conn:
+        if original_row is None:
+            conn.execute('DELETE FROM app_settings WHERE name = ?', ('smtp',))
+        else:
+            conn.execute(
+                'UPDATE app_settings SET value = ?, updated_at = CURRENT_TIMESTAMP WHERE name = ?',
+                (original_row['value'], 'smtp'),
+            )
+        conn.commit()
+    with get_connection() as conn:
+        conn.execute('DELETE FROM app_settings WHERE name = ?', ('admin_smtp_mail_rate',))
+        conn.commit()
 
 
 def test_admin_reports_smtp_validation_errors():