"""Lambda split_sales_sheet function module."""

import csv
import os.path
from urllib.parse import unquote_plus

import boto3
from common_config import logger
from constants import general
from smart_open import smart_open
from warmer_util import catch_warmer_event


@catch_warmer_event()
def handler(event, context):
    """Lambda entry point."""
    try:
        for record in event['Records']:
            bucket = record['s3']['bucket']['name']
            key = unquote_plus(record['s3']['object']['key'])

            logger.info('Bucket: ' + bucket + ' Key: ' + key)
            s3 = boto3.resource('s3')
            obj = s3.Object(bucket, unquote_plus(key))

            lines = obj.get()['Body'].read().decode().splitlines(True)
            reader = csv.reader(lines)
            logger.info('file read complete')

            count = 0
            file_count = 1
            inner_list = []
            header = []
            written_row_count = 0
            logger.info('writing to output file : ')
            chunk_size = get_chunk_size()
            for line in reader:
                if count == 0:
                    header = line
                else:
                    inner_list.append(line)
                    # if count % 40000 == 0:
                    if count % chunk_size == 0:
                        written_row_count = count
                        write_to_s3(
                            bucket, key, file_count, header, inner_list)
                        file_count += 1
                        inner_list.clear()
                count += 1
            if count > written_row_count:
                write_to_s3(bucket, key, file_count, header, inner_list)
    except Exception as e:
        logger.exception(str(e))
        raise


def write_to_s3(bucket, key, file_count, header, data):
    """Write updated CSV with filename and filesize, into new file.

    Args:
        bucket (string): S3 bucket name
        key (string): S3 key name
        file_count (int): file count to identify split file
        header (list): header of csv file
        data (list): data of csv file without header
    """
    source_url = 's3://{bucket}/{path}/{file_count}_{filename}'.format(
        bucket=bucket,
        path=general.SPLIT_SOUNDEXCHANGE_STMT_OUTPUT_PATH,
        file_count=file_count,
        filename=os.path.basename(key))

    with smart_open(source_url, 'w') as fileobj:
        writer = csv.writer(fileobj, quoting=csv.QUOTE_ALL)
        logger.info('writing to file : ' + source_url)
        writer.writerow(header)
        writer.writerows(data)


def get_chunk_size():
    """Get chunk size.

    Returns:
        int: chunk size
    """
    return general.CHUNK_SIZE