# /// script
# requires-python = ">=3.11"
# dependencies = [
#   "polars>=0.20.0",
#   "pyarrow>=18.0.0",
#   "sqlalchemy>=2.0.0",
#   "pyodbc>=5.0.0",
#   "clickhouse-connect>=0.7.0",
#   "clickhouse-sqlalchemy>=0.3.2",
#   "pyyaml>=6.0.3",
#   "python-dotenv>=1.0.0",
# ]
# ///


from __future__ import annotations

import sys
from datetime import date, datetime, timedelta

import polars as pl
import yaml


from log import log

from clickhouse_task.create_table import create_clickhouse_table
from clickhouse_task.delete_task import (
    delete_existing_data,
    truncate_table,
)

from clickhouse_task.load_table import load_to_clickhouse

from db_con.connection import (
    build_sql_server_engine,
    build_clickhouse_engine,
    get_clickhouse_client,
)

from mids import (
    MID_TABLE_COV,
    MID_TABLE_COV1,
)

from masters.dimensions import *
from masters.bridge import *
from src.fact import *


# ==========================================================
# Helpers
# ==========================================================

def table_exists(
    client,
    table_name: str,
) -> bool:

    return bool(
        client.command(
            f"EXISTS TABLE {table_name}"
        )
    )


def get_dataframe(
    fn_name: str,
    fetch_by: str,
    sql_engine,
    mids,
    run_date,
):

    fn = globals()[fn_name]

    if fetch_by == "mids":
        return fn(sql_engine, mids)

    if fetch_by == "run_date":
        return fn(sql_engine, run_date)

    return fn(sql_engine)




def get_empids_clickhouse_OQAD(
    client,
    table_name: str = "OQaD",
) -> pl.DataFrame:

    if not table_exists(client, table_name):
        log.warning(f"Table '{table_name}' does not exist.")
        return pl.DataFrame(
            schema={
                "empid": pl.Int64,
                "visitdate": pl.Date,
            }
        )

    query = f"""
    SELECT DISTINCT
        employee_id AS empid,
        visit_date AS visitdate
    FROM {table_name}
    """

    # ClickHouse -> PyArrow -> Polars
    arrow_table = client.query_arrow(query)

    return pl.from_arrow(arrow_table)

# ==========================================================
# Main
# ==========================================================

def main():

    log.info("=" * 80)
    log.info("Hello from data-move Python data pipeline!")

    # ------------------------------------------------------
    # Run Date
    # ------------------------------------------------------

    if len(sys.argv) > 1:
        run_date = datetime.strptime(
            sys.argv[1],
            "%Y-%m-%d",
        ).date()
    else:
        run_date = date.today() - timedelta(days=1)

    log.info(
        "Pipeline Run Date: %s",
        run_date,
    )

    # ------------------------------------------------------
    # Connections
    # ------------------------------------------------------

    log.info(
        "Connecting to databases..."
    )

    sql_engine = build_sql_server_engine()
    clickhouse_engine = build_clickhouse_engine()
    client = get_clickhouse_client()

    log.info(
        "Database connections established"
    )

    # ------------------------------------------------------
    # mids Keys
    # ------------------------------------------------------

    mids = MID_TABLE_COV(
        sql_engine,
        run_date,
    )

    emp_visit_df = MID_TABLE_COV1(
        sql_engine,
        run_date,
    )
    qf=fetch_quiz_empids(sql_engine,run_date)
    db_df = get_empids_clickhouse_OQAD(client)

    matched = qf.join(
    db_df,
    on=["empid", "visitdate"],
    how="inner",
)
    empids=matched["empid"].to_list()
    
    log.info(f"Fetched {len(empids):,} matched empids fetched for OQAD ")

    # ------------------------------------------------------
    # Config
    # ------------------------------------------------------

    with open(
        "y.yml",
        "r",
    ) as file:

        config = yaml.safe_load(file)

    # ------------------------------------------------------
    # Process Tables
    # ------------------------------------------------------

    for table in config["tables"]:

        table_name = table["name"]
        operation = table["operation"]
        fetch_by = table["fetch_by"]
        table_type=table["type"]

        log.info("=" * 80)
        log.info(
            "Processing Table: %s",
            table_name,
        )

        try:

            # ------------------------------------------
            # Fetch Data
            # ------------------------------------------
            if table_name =="OQaD":
                
            
                df=fetch_OQaD(  engine=sql_engine,
                                table_name=table_name,
                                table_type=table_type,
                                empids=empids,
                                run_date=run_date
                                )

                                            
            else:
                

                df = fetch_data(
                    engine=sql_engine,
                    table_name=table_name,
                    table_type=table_type,
                    mids=mids,
                    run_date=run_date,
                )

            if df.is_empty():

                log.warning(
                    "%s returned no rows",
                    table_name,
                )

                continue

            log.info(
                "Fetched %s rows",
                len(df),
            )

            # ------------------------------------------
            # Create Table If Missing
            # ------------------------------------------

            exists = table_exists(
                client,
                table_name,
            )

            if not exists:

                log.info(
                    "Creating table %s",
                    table_name,
                )

                create_clickhouse_table(
                    df=df,
                    table_name=table_name,
                    clickhouse_engine=clickhouse_engine,
                )

            # ------------------------------------------
            # Existing Table Logic
            # ------------------------------------------

            else:

                if operation == "DELETE+INSERT":

                    truncate_table(
                        client,
                        table_name,
                    )

                else:

                    delete_existing_data(
                        client=client,
                        table_name=table_name,
                        run_date=run_date,
                        mids=mids,
                        emp_visit_df=emp_visit_df,
                    )

            # ------------------------------------------
            # Load Data
            # ------------------------------------------

            load_to_clickhouse(
                client=client,
                table_name=table_name,
                df=df,
            )

            log.info(
                "%s loaded successfully (%s rows)",
                table_name,
                len(df),
            )

        except Exception:

            log.exception(
                "Failed processing table %s",
                table_name,
            )

            raise

    log.info("=" * 80)
    log.info("Pipeline Completed Successfully")
    log.info("=" * 80)


if __name__ == "__main__":
    main()