from loguru import logger

from ..config import QUERY_PATHS, TABLES, WAREHOUSES
from ..db import get_snw, get_rdb, get_s3
from ..db.queries import QueryLoader


def run_sync() -> None:
    logger.info("Starting Snowflake-to-Redshift sync")

    snw = get_snw(WAREHOUSES["large"])
    ql = QueryLoader()

    # Step 1: Create the diff table (changed ISRCs between main and mirror)
    logger.info("Creating changed table (diff between main and redshift mirror)")
    snw.execute(ql.load(QUERY_PATHS.changed_create))

    # Step 2: Query changed data BEFORE touching the mirror
    logger.info("Querying changed ISRCs from Snowflake")
    redshift_changed = TABLES["redshift_changed"]
    snowflake_changed = snw.query(f"select * from {redshift_changed}")

    if len(snowflake_changed) == 0:
        logger.info("No new or changed ISRCs — nothing to sync")
        return

    logger.info(f"Found {len(snowflake_changed)} new/changed ISRCs")

    # Step 3: Write to Redshift
    rdb = get_rdb()
    s3 = get_s3()

    rdb_main = TABLES["rdb_main"]
    rdb_changed = TABLES["rdb_changed"]

    logger.info("Truncating Redshift staging table")
    rdb.execute(f"truncate table {rdb_changed}")

    logger.info("Uploading changed data to Redshift via S3")
    s3.write_df_to_reportingDB(snowflake_changed, rdb_changed)

    logger.info("Applying changes to Redshift main table")
    rdb.execute(
        f"delete from {rdb_main} "
        f"where isrc_code in (select isrc_code from {rdb_changed})"
    )
    rdb.execute(f"insert into {rdb_main} select * from {rdb_changed}")

    # Step 4: Only AFTER successful Redshift write, rebuild the mirror as a
    # full snapshot of main. This ensures:
    #   - If Redshift write fails, the mirror is unchanged and the diff will
    #     be re-detected on the next run (no data loss).
    #   - The mirror always matches main exactly, preventing row count drift
    #     from full refreshes that remove ISRCs from main.
    logger.info("Rebuilding Snowflake mirror table as full snapshot of main")
    redshift_current = TABLES["redshift_current"]
    main_table = TABLES["main"]
    snw.execute(
        f"create or replace table {redshift_current} as "
        f"select isrc_code, isrc_origin from {main_table}"
    )

    logger.success(f"Synced {len(snowflake_changed)} ISRCs to Redshift")