Initial commit: Auto-Charger Logging Web-App

MQTT-Collector (Python/paho-mqtt) speichert abgeschlossene go-e
Wallbox-Ladungen in SQLite; Next.js-Web-App zeigt sie als Tabelle mit
Energie-Summen (Monat/Jahr/gesamt) im werte-next-Design. Zwei
Docker-Container mit gemeinsamem DB-Volume.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

collector/db.py

@@ -0,0 +1,50 @@
+"""SQLite-Helfer für den Collector (Schema-Init + Schreibzugriffe)."""
+
+import os
+import sqlite3
+from datetime import datetime
+from pathlib import Path
+
+SCHEMA_PATH = Path(__file__).with_name("schema.sql")
+
+
+def get_db_path() -> str:
+    return os.environ.get("DB_PATH", "/data/charges.db")
+
+
+def connect() -> sqlite3.Connection:
+    path = get_db_path()
+    Path(path).parent.mkdir(parents=True, exist_ok=True)
+    conn = sqlite3.connect(path)
+    conn.row_factory = sqlite3.Row
+    conn.execute("PRAGMA journal_mode=WAL;")
+    return conn
+
+
+def init_db() -> None:
+    """Legt Schema idempotent an und setzt install_date beim ersten Start."""
+    schema = SCHEMA_PATH.read_text(encoding="utf-8")
+    conn = connect()
+    try:
+        conn.executescript(schema)
+        conn.execute(
+            "INSERT OR IGNORE INTO meta (key, value) VALUES ('install_date', ?)",
+            (datetime.now().isoformat(timespec="seconds"),),
+        )
+        conn.commit()
+    finally:
+        conn.close()
+
+
+def insert_charge(start_time: str, end_time: str, duration_s: int, energy_wh: float) -> None:
+    conn = connect()
+    try:
+        conn.execute(
+            """INSERT INTO charges (start_time, end_time, duration_s, energy_wh, created_at)
+               VALUES (?, ?, ?, ?, ?)""",
+            (start_time, end_time, duration_s, energy_wh,
+             datetime.now().isoformat(timespec="seconds")),
+        )
+        conn.commit()
+    finally:
+        conn.close()