"""Lambda to begin step machine execution upon S3 trigger."""
import json
import os

from common.helpers.bulk_asset import load_bulk_asset_json

import config

from constants.artwork import NEW_ROOT_SUBFOLDER
from util.s3_image import get_image_from_s3
from util.s3_image import repair_image
from util.s3_image import save_image_to_s3


def handler(event, context):
    """Lambda handler entry point."""
    correlation_id = event.get('correlation_id')

    logger = config.get_current_logger(correlation_id)

    # Show event content
    logger.info(f'pre_process_art received: {event}')

    # DDEX_INGESTER_INTEGRATION: Skip ddex-ingester context JSON, load basic
    #  JSON elements
    asset = load_bulk_asset_json(event)
    product = asset.product

    bucket = product.artwork.bucket
    key = product.artwork.key
    file_name = os.path.split(key)[1]

    logger.info('Processing image file: {}'.format(bucket + '/' + key))

    try:
        # Get image
        img = get_image_from_s3(bucket, key, correlation_id)
        logger.info('Transform and Save image: {}'.format(key))
    except Exception as e:
        error_str = f'Pre-process artwork asset error: ' \
                    f'Could not find {file_name} on S3'

        msg = f'{error_str}: {str(e)}'
        logger.error(msg)
        raise e

    try:
        # Transform image
        img = repair_image(file_name, img, correlation_id)
        logger.info('Transforming {}'.format(file_name))
    except Exception as e:
        error_str = f'Pre-process artwork asset error: ' \
                    f'Could not transform {file_name}'

        msg = f'{error_str}: {str(e)}'
        logger.error(msg)
        raise e

    # New key contains source bucket and new root.
    new_target_key = os.path.join(NEW_ROOT_SUBFOLDER, bucket, key)
    try:
        new_target_key = save_image_to_s3(
            img=img,
            bucket=config.STAGING_S3_BUCKET,
            key=new_target_key,
            dpi=(300, 300),
            correlation_id=correlation_id)
        # Change key to reflect .jpg extension
        file_name = os.path.split(new_target_key)[1]
        logger.info(f'Saving {file_name}')
    except Exception as e:
        error_str = f'Pre-process artwork asset error: ' \
                    f'Could not save {file_name}'

        msg = f'{error_str}: {str(e)}'
        logger.error(msg)
        raise e

    asset.product.artwork.bucket = config.STAGING_S3_BUCKET
    # Ensure the correct file/key names are passed to the next lambda.
    asset.product.artwork.filename = file_name
    asset.product.artwork.key = new_target_key

    return json.loads(json.dumps(asset, default=lambda s: vars(s)))