"""Amazon DynamoDB Write Module (PRIVATE)."""

import json
import logging
from pathlib import Path
from typing import Any, Dict, List, Mapping, Optional, Union

import boto3
import pandas as pd

from ._utils import _validate_items, get_table

_logger: logging.Logger = logging.getLogger(__name__)


def put_json(
    path: Union[str, Path],
    table_name: str,
    boto3_session: Optional[boto3.Session] = None,
) -> None:
    """Write all items from JSON file to a DynamoDB.

    The JSON file can either contain a single item which will be inserted in the DynamoDB or an array of items
    which all be inserted.

    Parameters
    ----------
    path : Union[str, Path]
        Path as str or Path object to the JSON file which contains the items.
    table_name : str
        Name of the Amazon DynamoDB table.
    boto3_session : boto3.Session(), optional
        Boto3 Session. The default boto3 Session will be used if boto3_session receive None.

    Returns
    -------
    None
        None.

    Examples
    --------
    Writing contents of JSON file

    >>> import awswrangler as wr
    >>> wr.dynamodb.put_json(
    ...     path='items.json',
    ...     table_name='table'
    ... )
    """
    # Loading data from file
    with open(path, "r") as f:
        items = json.load(f)
    if isinstance(items, dict):
        items = [items]

    put_items(items=items, table_name=table_name, boto3_session=boto3_session)


def put_csv(
    path: Union[str, Path],
    table_name: str,
    boto3_session: Optional[boto3.Session] = None,
    **pandas_kwargs: Any,
) -> None:
    """Write all items from a CSV file to a DynamoDB.

    Parameters
    ----------
    path : Union[str, Path]
        Path as str or Path object to the CSV file which contains the items.
    table_name : str
        Name of the Amazon DynamoDB table.
    boto3_session : boto3.Session(), optional
        Boto3 Session. The default boto3 Session will be used if boto3_session receive None.
    pandas_kwargs :
        KEYWORD arguments forwarded to pandas.read_csv(). You can NOT pass `pandas_kwargs` explicit, just add valid
        Pandas arguments in the function call and Wrangler will accept it.
        e.g. wr.dynamodb.put_csv('items.csv', 'my_table', sep='|', na_values=['null', 'none'], skip_blank_lines=True)
        https://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.read_csv.html

    Returns
    -------
    None
        None.

    Examples
    --------
    Writing contents of CSV file

    >>> import awswrangler as wr
    >>> wr.dynamodb.put_csv(
    ...     path='items.csv',
    ...     table_name='table'
    ... )

    Writing contents of CSV file using pandas_kwargs

    >>> import awswrangler as wr
    >>> wr.dynamodb.put_csv(
    ...     path='items.csv',
    ...     table_name='table',
    ...     sep='|',
    ...     na_values=['null', 'none']
    ... )
    """
    # Loading data from file
    df = pd.read_csv(path, **pandas_kwargs)

    put_df(df=df, table_name=table_name, boto3_session=boto3_session)


def put_df(
    df: pd.DataFrame,
    table_name: str,
    boto3_session: Optional[boto3.Session] = None,
) -> None:
    """Write all items from a DataFrame to a DynamoDB.

    Parameters
    ----------
    df : pd.DataFrame
        Pandas DataFrame https://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.DataFrame.html
    table_name : str
        Name of the Amazon DynamoDB table.
    boto3_session : boto3.Session(), optional
        Boto3 Session. The default boto3 Session will be used if boto3_session receive None.

    Returns
    -------
    None
        None.

    Examples
    --------
    Writing rows of DataFrame

    >>> import awswrangler as wr
    >>> import pandas as pd
    >>> wr.dynamodb.put_df(
    ...     df=pd.DataFrame({'key': [1, 2, 3]}),
    ...     table_name='table'
    ... )
    """
    items: List[Mapping[str, Any]] = [v.dropna().to_dict() for k, v in df.iterrows()]

    put_items(items=items, table_name=table_name, boto3_session=boto3_session)


def put_items(
    items: Union[List[Dict[str, Any]], List[Mapping[str, Any]]],
    table_name: str,
    boto3_session: Optional[boto3.Session] = None,
) -> None:
    """Insert all items to the specified DynamoDB table.

    Parameters
    ----------
    items : Union[List[Dict[str, Any]], List[Mapping[str, Any]]]
        List which contains the items that will be inserted.
    table_name : str
        Name of the Amazon DynamoDB table.
    boto3_session : boto3.Session(), optional
        Boto3 Session. The default boto3 Session will be used if boto3_session receive None.

    Returns
    -------
    None
        None.

    Examples
    --------
    Writing items

    >>> import awswrangler as wr
    >>> wr.dynamodb.put_items(
    ...     items=[{'key': 1}, {'key': 2, 'value': 'Hello'}],
    ...     table_name='table'
    ... )
    """
    _logger.debug("Inserting items into DynamoDB table")

    dynamodb_table = get_table(table_name=table_name, boto3_session=boto3_session)
    _validate_items(items=items, dynamodb_table=dynamodb_table)
    with dynamodb_table.batch_writer() as writer:
        for item in items:
            writer.put_item(Item=item)