"""
寓信ETL
合同业务明细表 - bill_flow和bill_detail关联表
"""

import pandas as pd
from sqlalchemy import create_engine, text
from sqlalchemy.types import NVARCHAR, Date, DECIMAL, INTEGER
from datetime import datetime, timedelta
from tqdm import tqdm
import json
from dateutil.relativedelta import relativedelta
import calendar
from urllib.parse import quote_plus
from utils import load_config, truncate_target_db, update_column_comment
import json


debug = False
if debug:
    debug_condition = ''
    pass
else:
    debug_condition = ''
    pass

cols = {
    'flow_id': [NVARCHAR(32), '流水ID'],
    'money': [DECIMAL(14, 2), '金额'],
    'is_exempt': [INTEGER, '是否免除'],
    'bill_detail_id': [NVARCHAR(32), '账单明细ID'],
}


def query_total(conn) -> int:
    query = """
        select 
            count(1)
        from yuxin_finance.fin_finance_bill_flow
        where is_delete=0 and is_valid=1 {debug_condition}
        """.format(debug_condition=debug_condition)
    return conn.execute(text(query)).scalar()


def extract(conn, batch_size, i) -> pd.DataFrame:
    """ This API extracts data from
    """
    query = """
        select 
            id 'flow_id', bill_detail_info
        from yuxin_finance.fin_finance_bill_flow
        where is_delete=0 and is_valid=1 {debug_condition}
        limit {batch_size} offset {offset}
        """.format(batch_size=batch_size, offset=i, debug_condition=debug_condition)
    source_data = pd.read_sql(query, con=conn)
    return source_data


def transform(conn, data) -> pd.DataFrame:
    """ Transforms the dataset into desired structure and filters
    """

    df_data = []
    for index, row in data.iterrows():
        # print(row['flow_id'], row['bill_detail_info'])
        details = json.loads(row['bill_detail_info'])
        for detail in details:
            df_data.append({
                'flow_id': row['flow_id'],
                'money': detail['money'],
                'is_exempt': detail['isExempt'],
                'bill_detail_id': detail['billDetailId'],
            })
        pass

    columns = [k for k, v in cols.items()]
    df = pd.DataFrame(df_data, columns=columns)
    return df


def load(conn, df: pd.DataFrame, target_db) -> None:
    """ Loads data into a MySQL database
    """
    # Define the column types for the table
    dtypes = {key: value[0] for key, value in cols.items()}
    # create target table with df.dtypes
    df.to_sql(target_db, con=conn, if_exists='append',
              index=False, dtype=dtypes)


def etl():
    config = load_config('production')

    target_db = 'bi_bill_flow_detail_'

    connection_string = 'mysql+pymysql://{username}:{pwd}@{host}:{port}/{db}?charset=utf8'\
        .format(username=config['mysql']['username'],
                pwd=quote_plus(config['mysql']['password']),
                host=config['mysql']['host'],
                port=config['mysql']['port'],
                db=config['mysql']['db'])

    engine = create_engine(connection_string)

    with engine.begin() as conn:
        # Get the total number of rows
        total = query_total(conn)
        # Define the batch size
        batch_size = 100

        truncate_target_db(conn, target_db)

        if debug:
            total = 200
            batch_size = 100
        print('total', total)

        # Write the data to the table in batches
        for i in tqdm(range(0, total, batch_size)):
            data = extract(conn, batch_size, i)
            data = transform(conn, data)

            if debug:
                print(data.head())
            load(conn, data, target_db)

        update_column_comment(conn, target_db, cols)


etl()