Add explain analysis workflow and UI

backend/explain/story_service.py

@@ -0,0 +1,127 @@
+# -*- coding: utf-8 -*-
+"""Stock story generation for explain view."""
+
+from __future__ import annotations
+
+from datetime import datetime, timedelta
+from typing import Any
+
+from backend.data.market_store import MarketStore
+
+
+def build_stock_story(
+    *,
+    symbol: str,
+    as_of_date: str,
+    price_rows: list[dict[str, Any]],
+    news_rows: list[dict[str, Any]],
+) -> str:
+    """Build a compact markdown story from enriched news and recent price action."""
+    lines = [f"## {symbol} Story", f"As of `{as_of_date}`"]
+    if not price_rows:
+        lines.append("")
+        lines.append("No OHLC data available for story generation.")
+        return "\n".join(lines)
+
+    open_price = float(price_rows[0].get("open") or price_rows[0].get("close") or 0.0)
+    close_price = float(price_rows[-1].get("close") or 0.0)
+    price_change = ((close_price - open_price) / open_price) * 100 if open_price else 0.0
+    high_price = max(float(row.get("high") or row.get("close") or 0.0) for row in price_rows)
+    low_price = min(float(row.get("low") or row.get("close") or 0.0) for row in price_rows)
+
+    lines.append("")
+    lines.append(
+        f"The stock moved {'up' if price_change >= 0 else 'down'} "
+        f"{abs(price_change):.2f}% over the recent window, trading between "
+        f"${low_price:.2f} and ${high_price:.2f}."
+    )
+
+    positive = [row for row in news_rows if str(row.get("sentiment") or "").lower() == "positive"]
+    negative = [row for row in news_rows if str(row.get("sentiment") or "").lower() == "negative"]
+    lines.append("")
+    lines.append(
+        f"Recent coverage included {len(news_rows)} relevant articles "
+        f"({len(positive)} positive / {len(negative)} negative)."
+    )
+
+    if news_rows:
+        lines.append("")
+        lines.append("### Key Moments")
+        ranked_rows = sorted(
+            news_rows,
+            key=lambda row: (
+                0 if str(row.get("relevance") or "").lower() in {"high", "relevant"} else 1,
+                -abs(float(row.get("ret_t0") or 0.0)),
+            ),
+        )
+        for row in ranked_rows[:5]:
+            trade_date = row.get("trade_date") or str(row.get("date") or "")[:10]
+            title = row.get("title") or "Untitled"
+            key_discussion = row.get("key_discussion") or row.get("summary") or ""
+            sentiment = str(row.get("sentiment") or "neutral").lower()
+            lines.append(
+                f"- `{trade_date}` [{sentiment}] {title}: {str(key_discussion).strip()[:220]}"
+            )
+
+    if positive:
+        lines.append("")
+        lines.append("### Bullish Threads")
+        for row in positive[:3]:
+            reason = row.get("reason_growth") or row.get("key_discussion") or row.get("summary") or row.get("title")
+            lines.append(f"- {str(reason).strip()[:220]}")
+
+    if negative:
+        lines.append("")
+        lines.append("### Bearish Threads")
+        for row in negative[:3]:
+            reason = row.get("reason_decrease") or row.get("key_discussion") or row.get("summary") or row.get("title")
+            lines.append(f"- {str(reason).strip()[:220]}")
+
+    return "\n".join(lines)
+
+
+def get_or_create_stock_story(
+    store: MarketStore,
+    *,
+    symbol: str,
+    as_of_date: str,
+) -> dict[str, Any]:
+    """Return cached story or build a new one from recent market context."""
+    cached = store.get_story_cache(symbol, as_of_date=as_of_date)
+    if cached:
+        return {
+            "symbol": symbol,
+            "as_of_date": as_of_date,
+            "story": cached.get("content") or "",
+            "source": cached.get("source") or "cache",
+        }
+
+    start_date = None
+    if len(as_of_date) >= 10:
+        target_date = datetime.strptime(as_of_date[:10], "%Y-%m-%d").date()
+        start_date = (target_date - timedelta(days=29)).isoformat()
+
+    price_rows = (
+        store.get_ohlc(symbol, start_date, as_of_date)
+        if start_date
+        else []
+    )
+    news_rows = store.get_news_items_enriched(
+        symbol,
+        start_date=start_date,
+        end_date=as_of_date,
+        limit=40,
+    )
+    story = build_stock_story(
+        symbol=symbol,
+        as_of_date=as_of_date,
+        price_rows=price_rows,
+        news_rows=news_rows,
+    )
+    store.upsert_story_cache(symbol, as_of_date=as_of_date, content=story, source="local")
+    return {
+        "symbol": symbol,
+        "as_of_date": as_of_date,
+        "story": story,
+        "source": "local",
+    }