feat: add compare, trends routes, embedder service, and phase5 tests

app/routes/pages.py

@@ -1,9 +1,13 @@
 """页面路由 — 首页、日期页、论文详情。"""
 
+from __future__ import annotations
+
+import logging
 from datetime import date, datetime, timedelta
+from pathlib import Path
 from zoneinfo import ZoneInfo
 
-from fastapi import APIRouter, Depends, HTTPException, Request
+from fastapi import APIRouter, Depends, HTTPException, Query, Request
 from fastapi.responses import RedirectResponse
 from fastapi.templating import Jinja2Templates
 from sqlalchemy.orm import Session, joinedload
@@ -12,6 +16,8 @@ from app.config import settings
 from app.database import get_db
 from app.models import Paper
 
+logger = logging.getLogger(__name__)
+
 router = APIRouter()
 templates = Jinja2Templates(directory="app/templates")
 
@@ -99,11 +105,132 @@ def paper_detail(arxiv_id: str, request: Request, db: Session = Depends(get_db))
     if paper.summary_status:
         summary_state = paper.summary_status.status
 
+    # Phase 5: 相似论文推荐
+    similar_papers = _get_similar_papers(db, arxiv_id, top_k=6)
+
+    # Phase 5: 图片画廊
+    images = _get_paper_images(arxiv_id)
+
     return templates.TemplateResponse(
         request, "detail.html",
         {
             "paper": paper,
             "summary_state": summary_state,
+            "similar_papers": similar_papers,
+            "paper_images": images,
+            "chroma_enabled": settings.CHROMA_ENABLED,
             "page_title": paper.title_zh or paper.title_en,
         },
     )
+
+
+# ── 相似论文 API (Phase 5) ────────────────────────────────────────────
+
+
+@router.get("/api/similar/{arxiv_id}")
+def similar_api(
+    arxiv_id: str,
+    top_k: int = Query(default=5, ge=1, le=20),
+    db: Session = Depends(get_db),
+):
+    """返回与指定论文相似的论文列表（JSON）。"""
+    similar = _get_similar_papers(db, arxiv_id, top_k=top_k + 1)
+    # 排除自身
+    items = [s for s in similar if s["arxiv_id"] != arxiv_id][:top_k]
+    return {"results": items}
+
+
+def _get_similar_papers(db: Session, arxiv_id: str, top_k: int = 6) -> list[dict]:
+    """从 ChromaDB 获取相似论文，返回 [{arxiv_id, title_zh, distance, paper_date}, ...]。"""
+    if not settings.CHROMA_ENABLED:
+        return []
+
+    try:
+        from app.services.embedder import search_similar
+
+        # 用论文的 arxiv_id 从 ChromaDB 查询
+        col = None
+        try:
+            from app.services.embedder import get_collection
+            col = get_collection()
+        except Exception:
+            return []
+
+        if col is None:
+            return []
+
+        # 获取当前论文的 embedding
+        result = col.get(ids=[arxiv_id], include=["embeddings"])
+        if not result["embeddings"] or not result["embeddings"][0]:
+            return []
+
+        vec = result["embeddings"][0]
+        count = col.count()
+        if count == 0:
+            return []
+
+        results = col.query(
+            query_embeddings=[vec],
+            n_results=min(top_k, count),
+            include=["metadatas", "distances"],
+        )
+
+        if not results["ids"] or not results["ids"][0]:
+            return []
+
+        # 从 DB 加载论文信息
+        similar_ids = results["ids"][0]
+        distances = results["distances"][0] if results["distances"] else [0.0] * len(similar_ids)
+
+        # 排除自身
+        papers_info = {}
+        for i, sid in enumerate(similar_ids):
+            if sid != arxiv_id:
+                papers_info[sid] = distances[i]
+
+        if not papers_info:
+            return []
+
+        papers = (
+            db.query(Paper)
+            .filter(Paper.arxiv_id.in_(list(papers_info.keys())))
+            .options(joinedload(Paper.tags))
+            .all()
+        )
+
+        items = []
+        for p in papers:
+            items.append({
+                "arxiv_id": p.arxiv_id,
+                "title_zh": p.title_zh or p.title_en,
+                "distance": papers_info.get(p.arxiv_id, 0.0),
+                "paper_date": p.paper_date.isoformat() if p.paper_date else "",
+                "tags": [t.tag for t in p.tags[:3]],
+            })
+
+        # 按距离排序
+        items.sort(key=lambda x: x["distance"])
+        return items
+
+    except Exception:
+        logger.exception("Failed to get similar papers for %s", arxiv_id)
+        return []
+
+
+# ── 图片画廊 (Phase 5) ────────────────────────────────────────────────
+
+
+def _get_paper_images(arxiv_id: str) -> list[dict]:
+    """获取论文提取的图片列表。"""
+    images_dir = Path("data/papers") / arxiv_id / "images"
+    if not images_dir.exists():
+        return []
+
+    images = []
+    for img_file in sorted(images_dir.iterdir()):
+        if img_file.suffix.lower() in (".png", ".jpg", ".jpeg", ".gif", ".svg"):
+            images.append({
+                "url": f"/papers/{arxiv_id}/images/{img_file.name}",
+                "name": img_file.name,
+            })
+    return images