feat(filter): Berlin-Bezirk filter in Einstellungen

Adds a collapsible 12-Bezirk checkbox list to the filter tab. The UI
speaks Bezirke; internally the match runs on the PLZ extracted from
flat.address and resolved to a dominant Bezirk via a curated 187-PLZ
map (berlin_districts.py).

- Migration 0011 adds user_filters.districts (CSV of selected names)
- Empty stored value = no filter = all Bezirke ticked in the UI.
  Submitting "all ticked" or "none ticked" both normalise to empty
  so the defaults and the nuclear state mean the same thing.
- When a Bezirk filter is active, flats with an unknown/unmapped PLZ
  are excluded — if the user bothered to narrow by district, sneaking
  in unplaceable flats would be the wrong default.
- Filter summary on the Wohnungen page shows "N Bezirke" so it's
  visible the filter is active.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

web/berlin_districts.py

@@ -0,0 +1,120 @@
+"""Berlin-Bezirke taxonomy + PLZ lookup.
+
+The user-visible taxonomy is the 12 Berlin Bezirke. We derive the Bezirk
+from the flat's freeform address by extracting the 5-digit PLZ and
+looking it up in PLZ_TO_DISTRICT.
+
+Some PLZs straddle two Bezirke in reality. Each is mapped to its
+dominant Bezirk — close enough for a list filter. Unmapped PLZs / flats
+without a parseable address resolve to None; the filter treats those as
+"unknown" and excludes them when any Bezirk filter is active.
+"""
+import re
+
+DISTRICTS: list[str] = [
+    "Mitte",
+    "Friedrichshain-Kreuzberg",
+    "Pankow",
+    "Charlottenburg-Wilmersdorf",
+    "Spandau",
+    "Steglitz-Zehlendorf",
+    "Tempelhof-Schöneberg",
+    "Neukölln",
+    "Treptow-Köpenick",
+    "Marzahn-Hellersdorf",
+    "Lichtenberg",
+    "Reinickendorf",
+]
+
+_DISTRICT_PLZ: dict[str, tuple[str, ...]] = {
+    "Mitte": (
+        "10115", "10117", "10119", "10178", "10179",
+        "10551", "10553", "10555", "10557", "10559",
+        "13347", "13349", "13351", "13353", "13355", "13357", "13359",
+    ),
+    "Friedrichshain-Kreuzberg": (
+        "10243", "10245", "10247", "10249",
+        "10961", "10963", "10965", "10967", "10969",
+        "10997", "10999",
+    ),
+    "Pankow": (
+        "10405", "10407", "10409",
+        "10435", "10437", "10439",
+        "13086", "13088", "13089",
+        "13125", "13127", "13129",
+        "13156", "13158", "13159",
+        "13187", "13189",
+    ),
+    "Charlottenburg-Wilmersdorf": (
+        "10585", "10587", "10589",
+        "10623", "10625", "10627", "10629",
+        "10707", "10709", "10711", "10713", "10715", "10717", "10719",
+        "10789",
+        "14050", "14052", "14053", "14055", "14057", "14059",
+        "14193", "14195", "14197", "14199",
+    ),
+    "Spandau": (
+        "13581", "13583", "13585", "13587", "13589",
+        "13591", "13593", "13595", "13597", "13599",
+        "14089",
+    ),
+    "Steglitz-Zehlendorf": (
+        "12157", "12159", "12161", "12163", "12165", "12167", "12169",
+        "12203", "12205", "12207", "12209",
+        "12247", "12249",
+        "14109", "14129",
+        "14163", "14165", "14167", "14169",
+    ),
+    "Tempelhof-Schöneberg": (
+        "10777", "10779", "10781", "10783", "10785", "10787",
+        "10823", "10825", "10827", "10829",
+        "12099", "12101", "12103", "12105", "12107", "12109",
+        "12277", "12279",
+        "12305", "12307", "12309",
+    ),
+    "Neukölln": (
+        "12043", "12045", "12047", "12049",
+        "12051", "12053", "12055", "12057", "12059",
+        "12347", "12349",
+        "12351", "12353", "12355", "12357", "12359",
+    ),
+    "Treptow-Köpenick": (
+        "12435", "12437", "12439",
+        "12459", "12487", "12489",
+        "12524", "12526", "12527",
+        "12555", "12557", "12559",
+        "12587", "12589",
+    ),
+    "Marzahn-Hellersdorf": (
+        "12619", "12621", "12623", "12627", "12629",
+        "12679", "12681", "12683", "12685", "12687", "12689",
+    ),
+    "Lichtenberg": (
+        "10315", "10317", "10318",
+        "10365", "10367", "10369",
+        "13051", "13053", "13055", "13057", "13059",
+    ),
+    "Reinickendorf": (
+        "13403", "13405", "13407", "13409",
+        "13435", "13437", "13439",
+        "13465", "13467", "13469",
+        "13503", "13505", "13507", "13509",
+    ),
+}
+
+PLZ_TO_DISTRICT: dict[str, str] = {
+    plz: district
+    for district, plzs in _DISTRICT_PLZ.items()
+    for plz in plzs
+}
+
+_PLZ_RE = re.compile(r"\b(\d{5})\b")
+
+
+def district_for_address(address: str | None) -> str | None:
+    if not address:
+        return None
+    m = _PLZ_RE.search(address)
+    if not m:
+        return None
+    return PLZ_TO_DISTRICT.get(m.group(1))

web/common.py

@@ -126,7 +126,7 @@ def _is_htmx(request: Request) -> bool:
 # ---------------------------------------------------------------------------
 
 FILTER_KEYS = ("rooms_min", "rooms_max", "max_rent", "min_size",
-               "wbs_required", "max_age_hours")
+               "wbs_required", "max_age_hours", "districts")
 
 
 def _has_filters(f) -> bool:
@@ -175,6 +175,13 @@ def _filter_summary(f) -> str:
         parts.append("ohne WBS")
     if f["max_age_hours"]:
         parts.append(f"≤ {int(f['max_age_hours'])} h alt")
+    try:
+        districts_csv = (f["districts"] or "").strip()
+    except (KeyError, IndexError):
+        districts_csv = ""
+    if districts_csv:
+        n = sum(1 for d in districts_csv.split(",") if d.strip())
+        parts.append(f"{n} Bezirk{'e' if n != 1 else ''}")
     return " · ".join(parts)
 
 

web/db.py

@@ -270,6 +270,11 @@ MIGRATIONS: list[str] = [
     ALTER TABLE flats ADD COLUMN offline_at TEXT;
     CREATE INDEX IF NOT EXISTS idx_flats_offline ON flats(offline_at);
     """,
+    # 0011: per-user Berlin-Bezirk filter. CSV of selected Bezirk names;
+    # empty = no filter (= all Bezirke match).
+    """
+    ALTER TABLE user_filters ADD COLUMN districts TEXT NOT NULL DEFAULT '';
+    """,
 ]
 
 
@@ -463,7 +468,7 @@ def get_filters(user_id: int) -> sqlite3.Row:
 def update_filters(user_id: int, data: dict) -> None:
     _ensure_user_rows(user_id)
     allowed = {"rooms_min", "rooms_max", "max_rent", "min_size",
-               "wbs_required", "max_age_hours"}
+               "wbs_required", "max_age_hours", "districts"}
     clean = {k: data.get(k) for k in allowed if k in data}
     if not clean:
         return

web/matching.py

@@ -37,6 +37,17 @@ def flat_matches_filter(flat: dict, f: dict | None) -> bool:
         if wbs_str and wbs_str not in ("kein", "nein", "no", "ohne", "-"):
             return False
 
+    # Berlin-Bezirk filter. Empty string = no filter = all Bezirke match.
+    # When active, flats with an unknown/unmapped PLZ are excluded — if the
+    # user bothered to narrow by district, we shouldn't sneak in flats we
+    # couldn't place.
+    districts_csv = (f.get("districts") or "").strip()
+    if districts_csv:
+        selected = {d.strip() for d in districts_csv.split(",") if d.strip()}
+        flat_district = (flat.get("district") or "").strip()
+        if not flat_district or flat_district not in selected:
+            return False
+
     return True
 
 

web/routes/einstellungen.py

@@ -7,6 +7,7 @@ from fastapi.responses import HTMLResponse, RedirectResponse
 
 import db
 from auth import current_user, hash_password, require_csrf, require_user
+from berlin_districts import DISTRICTS
 from common import base_context, client_ip, templates
 from matching import row_to_dict
 from notifications import telegram_send
@@ -40,6 +41,13 @@ def tab_settings(request: Request, section: str):
         ctx["profile"] = db.get_profile(u["id"])
     elif section == "filter":
         ctx["filters"] = row_to_dict(db.get_filters(u["id"]))
+        stored = (ctx["filters"].get("districts") or "").strip()
+        # Empty stored value = no filter = all Bezirke ticked in the UI.
+        ctx["all_districts"] = DISTRICTS
+        ctx["selected_districts"] = (
+            set(DISTRICTS) if not stored
+            else {d.strip() for d in stored.split(",") if d.strip()}
+        )
     elif section == "benachrichtigungen":
         ctx["notifications"] = db.get_notifications(u["id"])
         ctx["notif_flash"] = request.query_params.get("flash") or ""

web/routes/wohnungen.py

@@ -27,6 +27,7 @@ from common import (
     client_ip,
     templates,
 )
+from berlin_districts import DISTRICTS, district_for_address
 from matching import flat_matches_filter, row_to_dict
 
 
@@ -64,6 +65,7 @@ def _wohnungen_context(user) -> dict:
         if not flat_matches_filter({
             "rooms": f["rooms"], "total_rent": f["total_rent"], "size": f["size"],
             "wbs": f["wbs"],
+            "district": district_for_address(f["address"]),
         }, filters):
             continue
         flats_view.append({"row": f, "last": latest_apps.get(f["id"])})
@@ -209,18 +211,12 @@ def flat_image(slug: str, index: int):
 
 
 @router.post("/actions/filters")
-async def action_save_filters(
+async def action_save_filters(request: Request, user=Depends(require_user)):
-    request: Request,
+    """The Bezirk filter uses multi-valued `districts` checkboxes, which
-    csrf: str = Form(...),
+    FastAPI's Form(...) args don't express cleanly — read the whole form
-    rooms_min: str = Form(""),
+    via request.form() so we can getlist() on it."""
-    rooms_max: str = Form(""),
+    form = await request.form()
-    max_rent: str = Form(""),
+    require_csrf(user["id"], form.get("csrf", ""))
-    min_size: str = Form(""),
-    wbs_required: str = Form(""),
-    max_age_hours: str = Form(""),
-    user=Depends(require_user),
-):
-    require_csrf(user["id"], csrf)
 
     def _f(v):
         v = (v or "").strip().replace(",", ".")
@@ -233,13 +229,24 @@ async def action_save_filters(
         except ValueError:
             return None
 
+    # Canonicalise district selection against the known set. Treat "all
+    # ticked" and "none ticked" identically as "no filter" so the default
+    # and the nuclear-no-results states both mean the same thing.
+    all_districts = set(DISTRICTS)
+    submitted = {d for d in form.getlist("districts") if d in all_districts}
+    if submitted in (set(), all_districts):
+        districts_csv = ""
+    else:
+        districts_csv = ",".join(d for d in DISTRICTS if d in submitted)
+
     db.update_filters(user["id"], {
-        "rooms_min": _f(rooms_min),
+        "rooms_min": _f(form.get("rooms_min", "")),
-        "rooms_max": _f(rooms_max),
+        "rooms_max": _f(form.get("rooms_max", "")),
-        "max_rent": _f(max_rent),
+        "max_rent": _f(form.get("max_rent", "")),
-        "min_size": _f(min_size),
+        "min_size": _f(form.get("min_size", "")),
-        "wbs_required": (wbs_required or "").strip(),
+        "wbs_required": (form.get("wbs_required") or "").strip(),
-        "max_age_hours": _i(max_age_hours),
+        "max_age_hours": _i(form.get("max_age_hours", "")),
+        "districts": districts_csv,
     })
     db.log_audit(user["username"], "filters.updated", user_id=user["id"], ip=client_ip(request))
     return RedirectResponse("/", status_code=303)

web/templates/_settings_filter.html

@@ -43,6 +43,30 @@
             {% endfor %}
         </select>
     </div>
+    <div class="col-span-2 md:col-span-3">
+        <details class="border border-soft rounded p-3"
+                 {% if selected_districts|length != all_districts|length %}open{% endif %}>
+            <summary class="cursor-pointer font-medium text-sm select-none">
+                Stadtteile
+                <span class="text-slate-500 text-xs ml-1">
+                    {% if selected_districts|length == all_districts|length %}alle{% else %}{{ selected_districts|length }} / {{ all_districts|length }}{% endif %}
+                </span>
+            </summary>
+            <div class="grid grid-cols-2 md:grid-cols-3 gap-2 mt-3">
+                {% for d in all_districts %}
+                <label class="flex items-center gap-2 text-sm">
+                    <input type="checkbox" name="districts" value="{{ d }}"
+                           {% if d in selected_districts %}checked{% endif %}>
+                    <span>{{ d }}</span>
+                </label>
+                {% endfor %}
+            </div>
+            <p class="text-xs text-slate-500 mt-2">
+                Standard: alle angekreuzt. Wohnungen ohne erkennbare Berliner PLZ werden
+                ausgeblendet, sobald du mindestens einen Haken entfernst.
+            </p>
+        </details>
+    </div>
     <div class="col-span-2 md:col-span-3">
         <button class="btn btn-primary" type="submit">Filter speichern</button>
     </div>