from BaseHTTPServer import BaseHTTPRequestHandler


class FilterMatchError(Exception):
    """Used to describe when a filter does not match a request."""
    pass


class WebhookRequestHandler(BaseHTTPRequestHandler):
    """Extends the BaseHTTPRequestHandler class and handles the incoming
    HTTP requests."""

    def do_POST(self):
        """Invoked on incoming POST requests"""
        from threading import Timer
        import logging
        import json

        logger = logging.getLogger()
        logger.info('Incoming request from %s:%s' % (self.client_address[0], self.client_address[1]))

        content_type = self.headers.getheader('content-type')
        content_length = int(self.headers.getheader('content-length'))
        request_body = self.rfile.read(content_length)

        # Test case debug data
        test_case = {
            'headers': dict(self.headers),
            'payload': json.loads(request_body),
            'config': {},
            'expected': {'status': 200, 'data': [{'deploy': 0}]}
        }

        # Extract request headers and make all keys to lowercase (makes them easier to compare)
        request_headers = dict(self.headers)
        request_headers = dict((k.lower(), v) for k, v in request_headers.iteritems())

        try:

            # Will raise a ValueError exception if it fails
            ServiceRequestParser = self.figure_out_service_from_request(request_headers, request_body)

            # Unable to identify the source of the request
            if not ServiceRequestParser:
                self.send_error(400, 'Unrecognized service')
                logger.error('Unable to find appropriate handler for request. The source service is not supported.')
                test_case['expected']['status'] = 400
                return

            # Send HTTP response before the git pull and/or deploy commands?
            if not 'detailed-response' in self._config or not self._config['detailed-response']:
                self.send_response(200, 'OK')
                self.send_header('Content-type', 'text/plain')
                self.end_headers()

            logger.info('Handling the request with %s' % ServiceRequestParser.__name__)

            # Could be GitHubParser, GitLabParser or other
            repo_configs, ref, action, webhook_urls = ServiceRequestParser(self._config).get_repo_params_from_request(request_headers, request_body)
            logger.debug("Event details - ref: %s; action: %s" % (ref or "master", action))

            if len(repo_configs) == 0:
                self.send_error(400, 'Bad request')
                logger.warning('The URLs references in the webhook did not match any repository entry in the config. For this webhook to work, make sure you have at least one repository configured with one of the following URLs; %s' % ', '.join(webhook_urls))
                test_case['expected']['status'] = 400
                return

            # Make git pulls and trigger deploy commands
            res = self.process_repositories(repo_configs, ref, action, request_body)

            if 'detailed-response' in self._config and self._config['detailed-response']:
                self.send_response(200, 'OK')
                self.send_header('Content-type', 'application/json')
                self.end_headers()
                self.wfile.write(json.dumps(res))
                self.wfile.close()

            # Add additional test case data
            test_case['config'] = {
                'url': 'url' in repo_configs[0] and repo_configs[0]['url'],
                'branch': 'branch' in repo_configs[0] and repo_configs[0]['branch'],
                'remote': 'remote' in repo_configs[0] and repo_configs[0]['remote'],
                'deploy': 'echo test!'
            }

        except ValueError, e:
            self.send_error(400, 'Unprocessable request')
            logger.warning('Unable to process incoming request from %s:%s' % (self.client_address[0], self.client_address[1]))
            test_case['expected']['status'] = 400
            return

        except Exception, e:

            if 'detailed-response' in self._config and self._config['detailed-response']:
                self.send_error(500, 'Unable to process request')

            test_case['expected']['status'] = 500

            raise e

        finally:

            # Save the request as a test case
            if 'log-test-case' in self._config and self._config['log-test-case']:
                self.save_test_case(test_case)

    def log_message(self, format, *args):
        """Overloads the default message logging method to allow messages to
        go through our custom logger instead."""
        import logging
        logger = logging.getLogger()
        logger.info("%s - %s" % (self.client_address[0],
                                          format%args))

    def figure_out_service_from_request(self, request_headers, request_body):
        """Parses the incoming request and attempts to determine whether
        it originates from GitHub, GitLab or any other known service."""
        import json
        import logging
        import parsers

        logger = logging.getLogger()
        data = json.loads(request_body)

        if not isinstance(data, dict):
            raise ValueError("Invalid JSON object")

        user_agent = 'user-agent' in request_headers and request_headers['user-agent']
        content_type = 'content-type' in request_headers and request_headers['content-type']

        # Assume GitLab if the X-Gitlab-Event HTTP header is set
        if 'x-gitlab-event' in request_headers:

            # Special Case for Gitlab CI
            if content_type == "application/json" and "build_status" in data:
                return parsers.GitLabCIRequestParser
            else:
                return parsers.GitLabRequestParser

        # Assume GitHub if the X-GitHub-Event HTTP header is set
        elif 'x-github-event' in request_headers:

            return parsers.GitHubRequestParser

        # Assume BitBucket if the User-Agent HTTP header is set to
        # 'Bitbucket-Webhooks/2.0' (or something similar)
        elif user_agent and user_agent.lower().find('bitbucket') != -1:

            return parsers.BitBucketRequestParser

        # This handles old GitLab requests and Gogs requests for example.
        elif content_type == "application/json":

            logger.info("Received event from unknown origin.")
            return parsers.GenericRequestParser

        logger.error("Unable to recognize request origin. Don't know how to handle the request.")
        return

    def process_repositories(self, repo_configs, ref, action, request_body):
        """Verify that the suggested repositories has matching settings and
        issue git pull and/or deploy commands."""
        import os
        import time
        import logging
        from wrappers import GitWrapper
        from lock import Lock
        import json

        logger = logging.getLogger()
        data = json.loads(request_body)

        result = []

        # Process each matching repository
        for repo_config in repo_configs:

            repo_result = {}

            try:
                # Verify that all filters matches the request (if any filters are specified)
                if 'filters' in repo_config:

                    # At least one filter must match
                    for filter in repo_config['filters']:

                        # All options specified in the filter must match
                        for filter_key, filter_value in filter.iteritems():

                            # Ignore filters with value None (let them pass)
                            if filter_value == None:
                                continue

                            # Support for earlier version so it's non-breaking functionality
                            if filter_key == 'action' and filter_value == action:
                                continue

                            # Interpret dots in filter name as path notations 
                            node_value = data
                            for node_key in filter_key.split('.'):

                                # If the path is not valid the filter does not match
                                if not node_key in node_value:
                                    logger.info("Filter '%s'' does not match since the path is invalid" % (filter_key))
                                    raise FilterMatchError()

                                node_value = node_value[node_key]

                            if filter_value == node_value:
                                continue

                            # If the filter value is set to True. the filter
                            # will pass regardless of the actual value 
                            if filter_value == True:
                                continue

                            logger.info("Filter '%s'' does not match ('%s' != '%s')" % (filter_key, filter_value, (str(node_value)[:75] + '..') if len(str(node_value)) > 75 else str(node_value)))

                            raise FilterMatchError()

            except FilterMatchError as e:

                # Filter does not match, do not process this repo config
                continue

            # In case there is no path configured for the repository, no pull will
            # be made.
            if not 'path' in repo_config:
                res = GitWrapper.deploy(repo_config)
                repo_result['deploy'] = res
                result.append(repo_result)
                continue

            running_lock = Lock(os.path.join(repo_config['path'], 'status_running'))
            waiting_lock = Lock(os.path.join(repo_config['path'], 'status_waiting'))
            try:

                # Attempt to obtain the status_running lock
                while not running_lock.obtain():

                    # If we're unable, try once to obtain the status_waiting lock
                    if not waiting_lock.has_lock() and not waiting_lock.obtain():
                        logger.error("Unable to obtain the status_running lock nor the status_waiting lock. Another process is " +
                                        "already waiting, so we'll ignore the request.")

                        # If we're unable to obtain the waiting lock, ignore the request
                        break

                    # Keep on attempting to obtain the status_running lock until we succeed
                    time.sleep(5)

                n = 4
                res = None
                while n > 0:

                    # Attempt to pull up a maximum of 4 times
                    res = GitWrapper.pull(repo_config)
                    repo_result['git pull'] = res

                    # Return code indicating success?
                    if res == 0:
                        break

                    n -= 1

                if 0 < n:
                    res = GitWrapper.deploy(repo_config)
                    repo_result['deploy'] = res

            #except Exception as e:
            #    logger.error('Error during \'pull\' or \'deploy\' operation on path: %s' % repo_config['path'])
            #    logger.error(e)
            #    raise e

            finally:

                # Release the lock if it's ours
                if running_lock.has_lock():
                    running_lock.release()

                # Release the lock if it's ours
                if waiting_lock.has_lock():
                    waiting_lock.release()

                result.append(repo_result)

        return result

    def save_test_case(self, test_case):
        """Log request information in a way it can be used as a test case."""
        import time
        import json
        import os

        # Mask some header values
        masked_headers = ['x-github-delivery', 'x-hub-signature']
        for key in test_case['headers']:
            if key in masked_headers:
                test_case['headers'][key] = 'xxx'

        target = '%s-%s.tc.json' % (self.client_address[0], time.strftime("%Y%m%d%H%M%S"))
        if 'log-test-case-dir' in self._config and self._config['log-test-case-dir']:
            target = os.path.join(self._config['log-test-case-dir'], target)

        file = open(target, 'w')
        file.write(json.dumps(test_case, sort_keys=True, indent=4))
        file.close()