#!/usr/bin/env python3
"""
Extract source tables from Postgres into DuckDB using the DuckDB Python library.
Reads SQL commands from scripts/extract.sql with environment variable interpolation.
"""
import os
import sys
from pathlib import Path
import duckdb

def main():
    repo_root = Path(__file__).resolve().parent.parent
    db_path = repo_root / "data" / "DB" / "dbt_nba.duckdb"
    sql_path = repo_root / "scripts" / "extract.sql"
    
    postgres_url = os.getenv("POSTGRES_URL")
    if not postgres_url:
        print("ERROR: POSTGRES_URL environment variable is not set", file=sys.stderr)
        print(f"Please export POSTGRES_URL or configure it in {repo_root}/.env", file=sys.stderr)
        sys.exit(1)
        
    db_path.parent.mkdir(parents=True, exist_ok=True)
    if db_path.exists():
        db_path.unlink()
        
    with open(sql_path, "r", encoding="utf-8") as f:
        sql = f.read()
        
    # Replace variable
    sql = sql.replace("${POSTGRES_URL}", postgres_url)
    
    print(f"==> Connecting to DuckDB at {db_path}...")
    con = duckdb.connect(str(db_path))
    try:
        print("==> Executing extraction queries...")
        con.execute(sql)
        print("==> Extraction complete successfully!")
    finally:
        con.close()

if __name__ == "__main__":
    main()