"""Main Handler."""
import json
from typing import Dict

from bulk_metadata_ingester_common.constants.file import (
    CSV_DELIMITER,
    CSV_QUOTECHAR)
from bulk_metadata_ingester_common.utils.jitter import jitter
from bulk_metadata_ingester_common.utils.logging import get_current_logger
from bulk_metadata_ingester_common.utils.release_utils import (
    get_release_track_list)
import config
from config import graphql_gateway
from lambdacommon.aws import s3
import pandas as pd


def handler(event: Dict, context: object) -> Dict:
    """Lambda Entrypoint."""
    key = event.get('key')
    bucket = event.get('bucket')
    correlation_id = event.get('correlation_id')

    logger = get_current_logger(
        config.ENVIRONMENT,
        config.LAMBDA_NAME,
        logging_level=config.LOGGING_LEVEL,
        correlation_id=correlation_id)

    # Jitter calls - Sleep for randomness
    jitter(logger)

    graphql_gateway.set_headers(
        {
            'Orchard-User-Id': config.OA_USER,
            'Correlation-Id': correlation_id
        }
    )

    # Log lambda begins message
    logger.info(f'write_to_csv received: {event}')

    json_data = get_release_track_list(bucket, key)

    write_to_csv(bucket, key, json_data, logger)

    return event


def write_to_csv(
        bucket: str,
        key: str,
        json_data: Dict,
        logger: object):
    """Write JSON to CSV."""
    # Remove the index values from the data to be converted
    data = list(json_data.values())
    flattened_data = []

    # Turn a list of lists of dicts into a list of dicts
    # Each list represents a product and each dict represents a track
    for product in data:
        for track in product:
            flattened_data.append(track)

    # Convert model data to JSON string
    json_str = json.dumps(flattened_data)

    # Convert JSON string to CSV binary data
    df = pd.read_json(json_str)
    csv_data = df.to_csv(
        encoding='utf-8',
        sep=CSV_DELIMITER,
        escapechar=CSV_QUOTECHAR,
        index=None
    ).encode('utf-8')

    # Make CSV key with the same name as the JSON key
    split_key = key.split('/')
    file_name = split_key[-1].split('.')[0]

    csv_key = 'generated_csv/' + file_name + '.csv'
    logger.info(f'Writing CSV file to bucket: {bucket} and key: {csv_key}')

    # Write JSON in same dir as source key as list
    s3.resource.Object(bucket, csv_key).put(Body=csv_data)