Refactor visualizer into modular package

visualizer/data_loader.py

@@ -0,0 +1,53 @@
+import sqlite3
+from typing import Sequence, List, Optional
+from pathlib import Path
+import sys
+
+# Allow running as a script from anywhere
+sys.path.insert(0, str(Path(__file__).resolve().parent.parent.parent))
+
+from utils.scrap import DB_PATH, get_connection
+
+Row = Sequence
+
+def load_ads_data(
+    channel_id: str, start_date: Optional[str] = None, end_date: Optional[str] = None
+) -> List[Row]:
+    """Load ad break data from the database for a given channel and date range."""
+    conn = get_connection(DB_PATH)
+    try:
+        query = """
+            SELECT channel_id, start_ts, end_ts, ad_date
+            FROM ads WHERE channel_id = ?
+        """
+        params = [channel_id]
+
+        if start_date:
+            query += " AND ad_date >= ?"
+            params.append(start_date)
+        if end_date:
+            query += " AND ad_date <= ?"
+            params.append(end_date)
+
+        query += " ORDER BY start_ts ASC"
+
+        cursor = conn.execute(query, params)
+        return cursor.fetchall()
+    except sqlite3.OperationalError as exc:
+        raise SystemExit(
+            "SQLite query failed. Ensure the collector ran at least once (table 'ads' must exist)."
+        ) from exc
+    finally:
+        conn.close()
+
+
+def list_channels() -> List[str]:
+    """List all channel IDs present in the database."""
+    conn = get_connection(DB_PATH)
+    try:
+        cursor = conn.execute(
+            "SELECT DISTINCT channel_id FROM ads ORDER BY channel_id ASC"
+        )
+        return [row[0] for row in cursor.fetchall()]
+    finally:
+        conn.close()