"""Utility functions to support mocking in projects that use owsrequest."""
import json as json_tools
import re


class MockOwsResponse:
    """Fake response class that imitates response objects from requests."""

    def __init__(self, status_code, json):
        """Construct a mock response."""
        self.status_code = status_code
        self._json = json
        self.text = json_tools.dumps(json)

    def json(self):
        """Return a json payload."""
        return self._json


def mock_ows_requests(call_specs):
    r"""Mock HTTP calls that are made via owsrequest.

    Example:
        fake_json = {'foo': 'bar', 'baz': 123}
        call_specs = [
            {
                'service': 'ows-awesome',
                'path': '/awesome-thing/123',
                'status': 200,
                'json': fake_json},
            {
                'service': 'ows-other',
                'path_regex': r'/another/[0-9]+\Z',
                'status': 200,
                'json': fake_json
            }]

        monkeypatch.setattr(
            request, 'get', mock_ows_requests(call_specs))

    Args:
        call_specs (list): list of dicts defining ows calls to mock.

    Returns:
        func: function that replaces a method-specific request function.
    """
    def _path_matches(service_name, path, call_spec):
        spec_service = call_spec.get('service')
        if service_name != spec_service:
            return False

        if 'path' in call_spec:
            spec_path = call_spec.get('path')
            return path == spec_path

        if 'path_regex' in call_spec:
            spec_path_regex = call_spec.get('path_regex')
            pattern = re.compile(spec_path_regex)
            return pattern.match(path)

    def _mock_method(service_name, path, **options):
        for call_spec in call_specs:
            if _path_matches(service_name, path, call_spec):
                return MockOwsResponse(
                    status_code=call_spec.get('status'),
                    json=call_spec.get('json'))

        print(f'No test ows spec for service {service_name} and path {path}')

        raise Exception(
            'No test ows spec for service {} and path {}'.format(
                service_name, path))

    return _mock_method