"""Application Handlers.

Requests are redirected to handlers, which are responsible for getting
information from the URL and passing it down to the logic layer. The way
each layer talks to each other is through Response objects which defines the
type status of the data and the data itself.

Please note: the Orchard uses the term handlers over views as convention
for clarity

See:
    oto.response for more details.
"""


from flask import g
from flask import jsonify
from flask import request
from oto import response
from oto import status
from oto.adaptors.flask import flaskify

from notifications import config
from notifications.api import app
from notifications.constants import error
from notifications.logic import notifications


@app.route(config.HEALTH_CHECK, methods=['GET'])
def health():
    """Check the health of the application."""
    return jsonify({'status': 'ok'})


@app.route('/unsubscribe', methods=['GET'])
def unsubscribe():
    """Unsubscribe a user from a feed.

    Returns:
        jinja2.Template: the unsubscribed template.
    """
    user_id = request.args.get('user_id')
    feed_name = request.args.get('feed_name')
    feed_id = request.args.get('feed_id')
    token = request.args.get('key')

    if not user_id or not feed_name or not feed_id or not token:
        return flaskify(response.create_error_response(
            status=status.BAD_REQUEST,
            code=error.ERROR_CODE_BAD_REQUEST,
            message=error.ERROR_MESSAGE_MISSING_PARAMETERS))

    return notifications.unsubscribe(user_id, feed_name, feed_id, token)


@app.errorhandler(500)
def exception_handler(error):
    """Handle error when uncaught exception is raised.

    Default exception handler.
    Note: Exception will also be sent to Sentry if config.SENTRY is set.

    Returns:
        flask.Response: A 500 response with JSON 'code' & 'message' payload.
    """
    message = (
        'The server encountered an internal error '
        'and was unable to complete your request.')
    g.log.exception(error)
    return flaskify(response.create_fatal_response(message))