"""App entrypoint."""

import json
import os
import urllib

from flask import Flask
from flask import jsonify
from flask import make_response
from flask import request as flask_request

app = Flask(__name__)


@app.route('/')
def hello():
    """Hi."""
    return 'Hello, cruel world!'


@app.route('/2015-03-31/functions/<string:function_name>/invocations', methods=['POST'])  # noqa:E501
def router(function_name):
    """Forward request to lambda function, re-write error codes."""
    func_url = f'http://{function_name}:8080/2015-03-31/functions/function/invocations'  # noqa:E501
    func_request = urllib.request.Request(func_url, data=flask_request.data)

    # https://docs.aws.amazon.com/lambda/latest/dg/python-exceptions.html
    set_function_error_header = False

    with urllib.request.urlopen(func_request) as func_response:
        func_response_data = func_response.read()
        if func_response.code == 200:
            response_data = json.loads(func_response_data.decode('utf-8'))
            if 'errorType' in response_data:
                set_function_error_header = True

    print(function_name, func_response.code, func_response_data, flush=True)
    response = make_response(
        jsonify(response_data),
        func_response.code
    )
    if set_function_error_header:
        response.headers['X-Amz-Function-Error'] = True
    return response


if __name__ == '__main__':
    app.run(debug=True, host='0.0.0.0', port=os.getenv('PORT', 5000))