import os as PI_OS
import polars as PI_POLARS


# Import
def FC_IMPORT_TEXT(
        ZVFCI_ST_SOURCE_FILE, 
        ZVFCI_ST_FOLDER, 
        ZVFCI_ST_DELIMITER,
        ZVFCI_ST_PREFIX,
        ZVFCI_LI_NUM_COLS
    ):     
    ZV_ST_FILE_PATH = PI_OS.path.join(ZVFCI_ST_FOLDER, ZVFCI_ST_SOURCE_FILE)

    ZVFCI_LI_ENCODINGS = [
        'utf8',
        'utf-8-sig',
        'utf8-lossy',
        'windows-1252',
        'latin1',
        'iso-8859-1',
        'iso-8859-15',
        'utf-16',
        'utf-16-le',
        'utf-16-be',
        'cp1250',
        'cp1251',
        'cp1253',
        'cp1254',
        'cp1257'    
   ]
    ZV_ER_ALL = None
    ZV_DF_HEADER = None
    for ZV_ST_ENCODING in ZVFCI_LI_ENCODINGS:
        try:

            ZV_DF_HEADER = PI_POLARS.read_csv(
                ZV_ST_FILE_PATH,
                separator=ZVFCI_ST_DELIMITER,
                encoding=ZV_ST_ENCODING,
                has_header=True,
                n_rows=1,
                infer_schema_length=0,
                quote_char=None
            )
            ZV_LI_COLS = ZV_DF_HEADER.columns
            break

        except Exception as ZV_ER:
            print(f'Cannot encode using: {ZV_ER}')
            
    if not ZV_DF_HEADER is None:

        ZV_DI_SCHEMA_OVERRIDES = {ZV_COL: PI_POLARS.Utf8 for ZV_COL in ZV_LI_COLS}

        ZV_DF = PI_POLARS.read_csv(
            ZV_ST_FILE_PATH,
            separator=ZVFCI_ST_DELIMITER,
            encoding=ZV_ST_ENCODING,
            ignore_errors=True,
            has_header=True,
            schema_overrides=ZV_DI_SCHEMA_OVERRIDES,
            infer_schema_length=0,
            null_values=[''],
            quote_char=None        
        ).fill_null('')

        for ZV_COL in ZV_DF.columns:
            ZV_DF = ZV_DF.rename(
                {
                    ZV_COL: f'{ZVFCI_ST_PREFIX}{ZV_COL}'
                }
            )

        for ZV_COL in ZVFCI_LI_NUM_COLS:
            ZV_DF = ZV_DF.with_columns(
                [
                    PI_POLARS.col(f'{ZV_COL}')
                    .cast(PI_POLARS.Float64, strict=False)
                    .alias(f'{ZV_COL}')
                ]
            )

        return ZV_DF