import json
import os
import uuid
import logging

import boto3

LOG = logging.getLogger()
LOG.setLevel(logging.INFO)


def main(event, context):
    LOG.info("EVENT: " + json.dumps(event))

    query_string_params = event["queryStringParameters"]
    if query_string_params is not None:
        target_url = query_string_params['targetUrl']
        if target_url is not None:
            return create_short_url(event)

    path_parameters = event['pathParameters']
    if path_parameters is not None:
        if path_parameters['proxy'] is not None:
            return read_short_url(event)

    return {
        'statusCode': 200,
        'body': 'usage: ?targetUrl=URL'
    }


def create_short_url(event):
    # Pull out the DynamoDB table name from environment
    table_name = os.environ.get('TABLE_NAME')

    # Parse targetUrl
    target_url = event["queryStringParameters"]['targetUrl']

    # Create a unique id (take first 8 chars)
    id = str(uuid.uuid4())[0:8]

    # Create item in DynamoDB
    dynamodb = boto3.resource('dynamodb')
    table = dynamodb.Table(table_name)
    table.put_item(Item={
        'id': id,
        'target_url': target_url
    })

    # Create the redirect URL
    url = "https://" \
        + event["requestContext"]["domainName"] \
        + event["requestContext"]["path"] \
        + id

    return {
        'statusCode': 200,
        'headers': {'Content-Type': 'text/plain'},
        'body': "Created URL: %s" % url
    }


def read_short_url(event):
    # Parse redirect ID from path
    id = event['pathParameters']['proxy']

    # Pull out the DynamoDB table name from the environment
    table_name = os.environ.get('TABLE_NAME')

    # Load redirect target from DynamoDB
    ddb = boto3.resource('dynamodb')
    table = ddb.Table(table_name)
    response = table.get_item(Key={'id': id})
    LOG.info("RESPONSE: " + json.dumps(response))

    item = response.get('Item', None)
    if item is None:
        return {
            'statusCode': 400,
            'headers': {'Content-Type': 'text/plain'},
            'body': 'No redirect found for ' + id
        }

    # Respond with a redirect
    # target_url must include protocol:"https:// or http://"
    return {
        'statusCode': 301,
        'headers': {
            'Location': item.get('target_url')
        }
    }