app.py

"""Shared-state API for the Tokyo Flat Finder viewer.

Stores the couple's likes/dislikes/notes and syncs them across devices.
State is held in memory and persisted to a PRIVATE HF Dataset (state.json) so
it survives Space restarts. Every request must carry the shared X-App-Key.

Env (set as Space secrets):
  HF_TOKEN     write token for the dataset
  DATASET_REPO e.g. ArthurZ/tokyo-flat-finder-state
  APP_SECRET   shared key the viewer sends as X-App-Key
"""
from __future__ import annotations

import html as _html
import json
import os
import pathlib
import threading

from fastapi import FastAPI, Header, HTTPException
from fastapi.middleware.cors import CORSMiddleware
from fastapi.responses import HTMLResponse
from huggingface_hub import HfApi, hf_hub_download
from pydantic import BaseModel

# Slim public listing data for the shareable preview page (baked at deploy).
try:
    PUBLIC = json.loads(pathlib.Path("public_listings.json").read_text())
except Exception:
    PUBLIC = {}

HF_TOKEN = os.environ.get("HF_TOKEN")
DATASET_REPO = os.environ.get("DATASET_REPO", "")
APP_SECRET = os.environ.get("APP_SECRET", "")
STATE_FILE = "state.json"

api = HfApi(token=HF_TOKEN)
_lock = threading.Lock()
_state: dict = {"userStates": {}, "notes": {}}


def _load() -> None:
    global _state
    try:
        path = hf_hub_download(DATASET_REPO, STATE_FILE, repo_type="dataset",
                               token=HF_TOKEN)
        with open(path) as f:
            data = json.load(f)
        _state = {"userStates": data.get("userStates", {}), "notes": data.get("notes", {})}
    except Exception:
        _state = {"userStates": {}, "notes": {}}


def _persist() -> None:
    buf = json.dumps(_state, ensure_ascii=False).encode("utf-8")
    api.upload_file(path_or_fileobj=buf, path_in_repo=STATE_FILE,
                    repo_id=DATASET_REPO, repo_type="dataset",
                    commit_message="update shared state")


app = FastAPI()
app.add_middleware(
    CORSMiddleware, allow_origins=["*"], allow_methods=["*"], allow_headers=["*"],
)


@app.on_event("startup")
def _startup() -> None:
    _load()


def _auth(key: str | None) -> None:
    if not APP_SECRET or key != APP_SECRET:
        raise HTTPException(status_code=403, detail="bad key")


@app.get("/health")
def health() -> dict:
    return {"ok": True, "listings": len(_state["userStates"]), "notes": len(_state["notes"])}


@app.get("/state")
def get_state(x_app_key: str | None = Header(default=None)) -> dict:
    _auth(x_app_key)
    return _state


class UserStateIn(BaseModel):
    listingId: str
    handle: str  # "me" | "partner"
    state: str   # "unseen" | "like" | "dislike" | "veto"


@app.post("/user_state")
def set_user_state(body: UserStateIn, x_app_key: str | None = Header(default=None)) -> dict:
    _auth(x_app_key)
    with _lock:
        us = _state["userStates"]
        cur = us.get(body.listingId, {})
        if body.state == "unseen":
            cur.pop(body.handle, None)
        else:
            cur[body.handle] = body.state
        if cur:
            us[body.listingId] = cur
        else:
            us.pop(body.listingId, None)
        _persist()
    return {"ok": True}


class NoteIn(BaseModel):
    listingId: str
    note: str


@app.post("/note")
def set_note(body: NoteIn, x_app_key: str | None = Header(default=None)) -> dict:
    _auth(x_app_key)
    with _lock:
        if body.note.strip():
            _state["notes"][body.listingId] = body.note
        else:
            _state["notes"].pop(body.listingId, None)
        _persist()
    return {"ok": True}


# --- Public shareable preview page (no key — anyone with the link) -----------
@app.get("/p/{listing_id}", response_class=HTMLResponse)
def preview(listing_id: str) -> str:
    d = PUBLIC.get(listing_id)
    if not d:
        return HTMLResponse("<h1>Listing not found</h1>", status_code=404)
    e = _html.escape
    yen = f"¥{d['rent_jpy']:,}" if d.get("rent_jpy") else "—"
    eur = f"€{round(d['rent_jpy'] / 186):,}" if d.get("rent_jpy") else ""  # ponytail: fixed 186 rate
    lat, lon = d.get("lat"), d.get("lon")
    ote = (f"{d['ote_min']} min" + (" · " + "→".join(d["ote_lines"]) if d.get("ote_lines") else "")) \
        if d.get("ote_min") is not None else "—"
    photos = "".join(f'<img src="{e(u)}" loading="lazy">' for u in d.get("photos", []))
    gmap = f"https://www.google.com/maps/search/?api=1&query={lat},{lon}"
    osm = (f"https://www.openstreetmap.org/export/embed.html?bbox={lon-0.012},{lat-0.01},"
           f"{lon+0.012},{lat+0.01}&layer=mapnik&marker={lat},{lon}") if lat and lon else ""
    return f"""<!doctype html><html lang="en"><head><meta charset="utf-8">
<meta name="viewport" content="width=device-width,initial-scale=1">
<title>{e(d.get('title') or 'Listing')}</title>
<style>
 body{{margin:0;font:16px/1.5 -apple-system,Segoe UI,Roboto,sans-serif;background:#f5f3ee;color:#2a2a2a}}
 .wrap{{max-width:560px;margin:0 auto;background:#fff;min-height:100vh}}
 .photos{{display:flex;overflow-x:auto;scroll-snap-type:x mandatory}}
 .photos img{{width:100%;flex:0 0 100%;height:240px;object-fit:cover;scroll-snap-align:center}}
 .pad{{padding:16px 18px}}
 h1{{font-size:19px;margin:0 0 8px}}
 .badges{{color:#555;font-size:14px;margin-bottom:12px}}
 .rent{{font-size:24px;font-weight:700}}.rent small{{font-size:14px;color:#888;font-weight:400}}
 .row{{display:flex;gap:8px;margin:10px 0;font-size:15px}}.row b{{min-width:96px;color:#555;font-weight:600}}
 iframe{{width:100%;height:260px;border:0;border-radius:10px;margin-top:8px}}
 a.btn{{display:block;text-align:center;background:#28a55b;color:#fff;text-decoration:none;
   padding:14px;border-radius:10px;font-weight:600;margin-top:14px}}
</style></head><body><div class="wrap">
<div class="photos">{photos}</div>
<div class="pad">
 <h1>🏠 {e(d.get('title') or '')}</h1>
 <div class="badges">{e(d.get('layout') or '?')} · {d.get('size_m2') or '?'} m² · {e(d.get('ward') or '')}</div>
 <div class="rent">{eur} <small>/mo · {yen}</small></div>
 <div class="row"><b>→ Otemachi</b><span>{e(ote)}</span></div>
 {f'<iframe src="{osm}"></iframe>' if osm else ''}
 <a class="btn" href="{gmap}" target="_blank" rel="noopener">📍 Open in Google Maps</a>
 {f'<a class="btn" style="background:#3b82f6" href="{e(d["url"])}" target="_blank" rel="noopener">↗ View original listing</a>' if d.get("url") else ''}
</div></div></body></html>"""