feat: restore roast-of-the-day with 14-day prompt history

Separate roast generation from motivation again and pass cached roasts
from the last 14 days into the OpenRouter prompt to reduce repetition.

Co-authored-by: Cursor <cursoragent@cursor.com>

server/ai.py

@@ -1,7 +1,7 @@
 from __future__ import annotations
 
 import logging
-from datetime import datetime
+from datetime import datetime, timedelta
 from typing import Any
 from zoneinfo import ZoneInfo
 
@@ -21,6 +21,14 @@ MOTIVATION_SYSTEM = (
     "Genau ein Satz auf Deutsch, max 25 Wörter. Keine Anführungszeichen um den Spruch."
 )
 
+ROAST_SYSTEM = (
+    "Du bist ein sarkastischer, dark-humor Medikamenten-Coach für jemanden mit ADHS. "
+    "Kurz (max 2 Sätze), deutsch, witzig aber nicht gemein. Keine medizinischen Ratschläge. "
+    "Keine Anführungszeichen um den Spruch. Wiederhole keine Formulierungen oder Ideen aus der Historie."
+)
+
+ROAST_HISTORY_DAYS = 14
+
 async def _get_cache(db: aiosqlite.Connection, key: str) -> str | None:
     cur = await db.execute("SELECT content FROM ai_cache WHERE key = ?", (key,))
     row = await cur.fetchone()
@@ -87,6 +95,26 @@ def _motivation_key(day: str) -> str:
     return f"motivation:v2:{day}"
 
 
+def _roast_key(day: str) -> str:
+    return f"roast:{day}"
+
+
+async def _recent_roasts(
+    db: aiosqlite.Connection,
+    *,
+    before_day: str,
+    days: int = ROAST_HISTORY_DAYS,
+) -> list[str]:
+    end = datetime.strptime(before_day, "%Y-%m-%d").date()
+    roasts: list[str] = []
+    for offset in range(1, days + 1):
+        day = (end - timedelta(days=offset)).isoformat()
+        text = await _get_cache(db, _roast_key(day))
+        if text:
+            roasts.append(text)
+    return roasts
+
+
 async def _cached_motivation(db: aiosqlite.Connection, day: str) -> str | None:
     cached = await _get_cache(db, _motivation_key(day))
     if cached:
@@ -134,5 +162,49 @@ async def get_daily_motivation(db: aiosqlite.Connection, tz: ZoneInfo) -> dict[s
     return {"text": pick("motivation_fallback"), "source": "fallback", "day": day}
 
 
+async def generate_roast_of_the_day(
+    db: aiosqlite.Connection,
+    tz: ZoneInfo,
+    day: str | None = None,
+    *,
+    force: bool = False,
+) -> dict[str, Any]:
+    day = day or datetime.now(tz).strftime("%Y-%m-%d")
+    key = _roast_key(day)
+    if not force:
+        cached = await _get_cache(db, key)
+        if cached:
+            return {"text": cached, "source": "cache", "day": day}
+
+    stats = await compute_stats(db)
+    recent = await _recent_roasts(db, before_day=day)
+    history = ""
+    if recent:
+        lines = "\n".join(f"- {text}" for text in recent)
+        history = (
+            f"\n\nDiese Roasts der letzten {ROAST_HISTORY_DAYS} Tage wurden bereits verwendet "
+            f"(nicht wiederholen, neue Idee):\n{lines}"
+        )
+    prompt = (
+        "Schreibe den Roast-of-the-Day. "
+        f"Streak: {stats['streak']} Tage. "
+        f"Compliance über {stats['compliance_window_days']} aktive Tage: {stats['compliance_percent']}%. "
+        f"Ein sarkastischer Spruch im dark-humor Medikamenten-Coach Stil.{history}"
+    )
+    text = await _call_openrouter(prompt, system=ROAST_SYSTEM)
+    if not text:
+        text = pick("roast_fallback")
+        source = "fallback"
+    else:
+        source = "ai"
+    await _set_cache(db, key, text)
+    logger.info("Generated roast of the day for %s (%s)", day, source)
+    return {"text": text, "source": source, "day": day}
+
+
 async def get_roast_of_the_day(db: aiosqlite.Connection, tz: ZoneInfo) -> dict[str, Any]:
-    return await get_daily_motivation(db, tz)
+    day = datetime.now(tz).strftime("%Y-%m-%d")
+    cached = await _get_cache(db, _roast_key(day))
+    if cached:
+        return {"text": cached, "source": "cache", "day": day}
+    return {"text": pick("roast_fallback"), "source": "fallback", "day": day}