# 2026-03-21 — pg-counter: считает строки по prefix, возвращает статистику.
# Тестирует: SELECT COUNT с WHERE LIKE, агрегация, concurrent reads.
import os, psycopg2

def count(event):
    prefix = event.get("prefix", "")
    conn = psycopg2.connect(
        host=os.environ["PGHOST"], port=int(os.environ.get("PGPORT", 5432)),
        dbname=os.environ["PGDATABASE"], user=os.environ["PGUSER"],
        password=os.environ["PGPASSWORD"], sslmode=os.environ.get("PGSSLMODE", "require"),
    )
    try:
        with conn.cursor() as cur:
            if prefix:
                cur.execute("SELECT COUNT(*) FROM terraform_demo_table WHERE title LIKE %s", (f"{prefix}%",))
            else:
                cur.execute("SELECT COUNT(*) FROM terraform_demo_table")
            total = cur.fetchone()[0]
            cur.execute("SELECT COUNT(*) FROM terraform_demo_table WHERE created_at > now() - interval '1 hour'")
            last_hour = cur.fetchone()[0]
        return {"total": total, "last_hour": last_hour, "prefix": prefix or "*"}
    finally:
        conn.close()