"""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:
    territories.response for more details.
"""


from flask import g
from flask import jsonify
from flask import request
from territories import config
from territories import response
from territories.api import app
from territories.logic import territories
from territories.util import handler_util
from territories.validation import validators


@app.route(config.HEALTH_CHECK)
def health():
    """Check the health of the application."""
    return jsonify({'status': 'ok'})


@app.route('/standards')
@handler_util.validate_header(validators.HEADER_VALIDATOR)
def get_standards():
    """Get all supported standards.

    Returns:
        flask.Response: A 200 response with JSON payload containing list of
            all standards, supported by the service.
    """
    log_message = 'GET /standards'

    g.log.info(log_message)

    result = territories.get_standards()
    return response.flaskify(result)


@app.route('/territory/<standard>')
@handler_util.validate_header(validators.HEADER_VALIDATOR)
def get_territories(standard):
    """Get all territories in requested standard.

    Args:
        standard (str): one of the supported standards

    Returns:
        flask.Response: A 200 response with JSON payload containing list of
            territories for a given standard.
    """
    log_message = f'GET /territory/(standard): standard={standard}; '

    g.log.info(log_message)

    result = territories.get_territories(standard)
    headers = {'Cache-Control': 'max-age=86400'}

    return response.flaskify(result, headers)


@app.route('/conversion/<input_standard>/<output_standard>')
@handler_util.validate_header(validators.HEADER_VALIDATOR)
def convert_territories(input_standard, output_standard):
    """Get converted countries given source and target standard.

    Request parameters:
        territory_code_a2 (str): comma-separated list of territories

    Args:
        input_standard: standard to convert from
        output_standard: standard to convert to

    Returns:
        flask.Response: A 200 response with JSON payload containing list of
            converted countries.
    """
    territory_codes = request.args.get('territory_code_a2', '')

    log_message = (
        'GET /conversion/(input_standard)/(output_standard): '
        'input_standard={};'
        'output_standard={};'
        'territory_code_a2={}').format(
        input_standard, output_standard, territory_codes)

    g.log.info(log_message)

    result = territories.convert_territories(
        input_standard, output_standard, territory_codes.split(','))
    return response.flaskify(result)


@app.route('/complement/<standard>')
@handler_util.validate_header(validators.HEADER_VALIDATOR)
def get_complement_territories(standard):
    """Get inverted countries list.

    Request parameters:
        territory_code_a2 (str): comma-separated list of territories

    Args:
        standard (str): standard name

    Returns:
        flask.Response: list of territories complement to the given input.
            Please note, that the response can contain empty list, in cases
            when input list contains full set of countries of a given standard.
    """
    territory_codes = request.args.get('territory_code_a2', '')

    log_message = (
        'GET /complement/(standard): '
        'standard={};'
        'territory_code_a2={}').format(standard, territory_codes)

    g.log.info(log_message)
    territories_list = territory_codes.split(',') if territory_codes else []
    result = territories.get_complement(standard, territories_list)
    return response.flaskify(result)


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

    Note: Exception will also be sent to Sentry if config.SENTRY_DSN 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 response.flaskify(response.create_fatal_response(message))