1 files changed, 100 insertions, 0 deletions
diff --git a/src/srht_contrib/services/aggregator.py b/src/srht_contrib/services/aggregator.py
new file mode 100644
index 0000000..800329a
--- /dev/null
+++ b/src/srht_contrib/services/aggregator.py
@@ -0,0 +1,100 @@
+from __future__ import annotations
+
+from dataclasses import dataclass
+from datetime import date
+
+from sqlalchemy import func, select
+from sqlalchemy.orm import Session
+
+from srht_contrib.models import ContributionEvent
+from srht_contrib.schemas import ContributionCalendarResponse, ContributionDay, ContributionStatsResponse
+from srht_contrib.utils.dates import date_range, date_to_utc_bounds
+
+
+@dataclass(slots=True)
+class DailyAggregate:
+    date: date
+    count: int
+    score: float
+
+
+class ContributionAggregator:
+    def build_calendar(self, db: Session, actor: str, start: date, end: date) -> ContributionCalendarResponse:
+        aggregates = self._query_daily_aggregates(db, actor, start, end)
+        by_day = {row.date: row for row in aggregates}
+        days = [
+            ContributionDay(
+                date=day,
+                count=by_day.get(day, DailyAggregate(date=day, count=0, score=0.0)).count,
+                score=by_day.get(day, DailyAggregate(date=day, count=0, score=0.0)).score,
+            )
+            for day in date_range(start, end)
+        ]
+        return ContributionCalendarResponse(actor=actor, from_date=start, to_date=end, days=days)
+
+    def build_stats(self, db: Session, actor: str, start: date, end: date) -> ContributionStatsResponse:
+        calendar = self.build_calendar(db, actor, start, end)
+        active_days = [day for day in calendar.days if day.count > 0]
+        streaks = self._streak_lengths(calendar.days)
+        current_streak = self._current_streak(calendar.days)
+
+        return ContributionStatsResponse(
+            actor=actor,
+            from_date=start,
+            to_date=end,
+            total_events=sum(day.count for day in calendar.days),
+            total_score=round(sum(day.score for day in calendar.days), 2),
+            active_days=len(active_days),
+            longest_streak=max(streaks, default=0),
+            current_streak=current_streak,
+        )
+
+    def _query_daily_aggregates(self, db: Session, actor: str, start: date, end: date) -> list[DailyAggregate]:
+        start_dt, _ = date_to_utc_bounds(start)
+        _, end_dt = date_to_utc_bounds(end)
+
+        stmt = (
+            select(
+                func.date(ContributionEvent.occurred_at).label("day"),
+                func.count(ContributionEvent.id).label("count"),
+                func.coalesce(func.sum(ContributionEvent.weight), 0.0).label("score"),
+            )
+            .where(ContributionEvent.actor == actor)
+            .where(ContributionEvent.occurred_at >= start_dt)
+            .where(ContributionEvent.occurred_at <= end_dt)
+            .group_by(func.date(ContributionEvent.occurred_at))
+            .order_by(func.date(ContributionEvent.occurred_at))
+        )
+        rows = db.execute(stmt).all()
+        return [
+            DailyAggregate(
+                date=date.fromisoformat(str(row.day)),
+                count=int(row.count),
+                score=round(float(row.score), 2),
+            )
+            for row in rows
+        ]
+
+    @staticmethod
+    def _streak_lengths(days: list[ContributionDay]) -> list[int]:
+        streaks: list[int] = []
+        current = 0
+        for day in days:
+            if day.count > 0:
+                current += 1
+            elif current > 0:
+                streaks.append(current)
+                current = 0
+        if current > 0:
+            streaks.append(current)
+        return streaks
+
+    @staticmethod
+    def _current_streak(days: list[ContributionDay]) -> int:
+        streak = 0
+        for day in reversed(days):
+            if day.count > 0:
+                streak += 1
+            else:
+                break
+        return streak