"""This lambda responds for image transcoding."""
from __future__ import print_function
import os
import uuid
from PIL import Image
import boto3

s3_client = boto3.client('s3')


def transcode_images(image_path, result_paths):
    """Open image and save in given formats.

    Args:
        image_path: (str): Path to downloaded file.
        result_paths: (list(dict)): List of paths for tmp directory and s3.
    """
    with Image.open(image_path) as image:
        for path in result_paths:
            image.save(path['tmp_path'])


def generate_paths(key):
    """Generate output paths.

    Args:
        key: (str): Path to file in s3.
    """
    file_name, ext = os.path.splitext(key)

    return [
        {
            'output': 'img/jpg/{}.jpg'.format(file_name),
            'tmp_path': '/tmp/{}{}.jpg'.format(uuid.uuid4(), file_name)
        },
        {
            'output': 'img/tiff/{}.tiff'.format(file_name),
            'tmp_path': '/tmp/{}{}.tiff'.format(uuid.uuid4(), file_name)
        }
    ]


def handler(event, context):
    """Lambda handler.

    Args:
        event: (dict): Information about uploaded file.
        context: (dict): Environment state.
    Returns:
        dict: Dict with transcoding results.
    """
    input_bucket = event['bucket']
    output_backet = os.environ.get('OUTPUT_BUCKET')
    key = event['key']
    download_path = '/tmp/{}{}'.format(uuid.uuid4(), key)

    try:
        s3_client.download_file(input_bucket, key, download_path)
        output_paths = generate_paths(key)
        transcode_images(download_path, output_paths)
        for path in output_paths:
            s3_client.upload_file(path['tmp_path'], output_backet,
                                  path['output'])
    except Exception as e:
        print("Can't transcode image.")
        return {'status': 'Error', 'message': str(e.args)}

    return {'status': 'OK', 'message': ''}