# Travel recommendation backend

This FastAPI service is the server-only AI boundary for the Guangming travel POC. It defaults to deterministic `mock` mode. Model credentials belong only in `server/.env` or the deployment environment and must never be added to the mini-program build.

The mini-program calls this service when `VITE_TRAVEL_ASSISTANT_API_BASE_URL` is set (`.env.development` points it at `http://localhost:8000`). If that variable is empty, or the service is unreachable or returns an error, the client silently falls back to its deterministic local planner — so the demo always works. The model only ever recommends POIs from a coordinate-free client whitelist; route geometry, transfer estimates, and final itinerary time remain client responsibilities. The itinerary page labels the result `真实 AI 推荐` (real), `远端演示规划` (mock), or `本地 POC 规划` (local fallback).

## Contract

`POST /api/v1/plans` accepts a planning request and a coordinate-free POI whitelist:

```json
{
  "mode": "custom",
  "preferences": {
    "destination": "深圳市光明区",
    "themes": ["亲子"],
    "pace": "moderate",
    "interests": ["自然风光"],
    "transport": "public_transport"
  },
  "durationMinutes": 240,
  "selectedPoiIds": ["poi_a", "poi_b"],
  "candidates": [
    {
      "id": "poi_a",
      "name": "Example A",
      "categoryCode": "urban_park",
      "tagCodes": ["family_friendly"],
      "summary": "Coordinate-free summary",
      "recommendationIndex": 4
    },
    {
      "id": "poi_b",
      "name": "Example B",
      "categoryCode": "cultural_venue",
      "tagCodes": ["indoor_venue"],
      "summary": "Coordinate-free summary",
      "recommendationIndex": 5
    }
  ]
}
```

The response contains only POI IDs, reasons, and suggested order. In `custom` mode all 2-8 user-selected IDs are retained. The model never receives `origin`, and never owns coordinates, route geometry, transfer estimates, or final itinerary time; those remain deterministic client responsibilities.

`GET /api/v1/health` reports `mode` (`mock` or `real`), whether real-model credentials are `configured`, and whether the selected mode is `ready`.

## Run locally

```bash
cd server
python3 -m venv .venv
.venv/bin/python -m pip install -e '.[test]'
cd ..
corepack pnpm server:dev
```

Run tests from the repository root:

```bash
corepack pnpm server:test
```

## Real model mode

Mock mode is deterministic and needs no credentials. To use a real model, set `LLM_MODE=real` in `server/.env` (gitignored) with any OpenAI-compatible endpoint — for example Zhipu GLM:

```
LLM_MODE=real
OPENAI_BASE_URL=https://open.bigmodel.cn/api/paas/v4
OPENAI_MODEL=glm-4-flash
OPENAI_API_KEY=<your key>
```

`GET /api/v1/health` then reports `mode=real, configured=true, ready=true`. With `pnpm server:dev` running, generate a plan from the mini-program (H5 dev server on `:5173` is already in `CORS_ORIGINS`; for `mp-weixin` enable “不校验合法域名” in the devtools). To force the local planner again, unset `VITE_TRAVEL_ASSISTANT_API_BASE_URL` or stop the server.