# Webhooks for external integrations.
import re
from functools import partial
from typing import Any, Callable, Dict, List, Optional, Text

from django.http import HttpRequest, HttpResponse
from django.utils.translation import ugettext as _

from zerver.decorator import api_key_only_webhook_view
from zerver.lib.actions import check_send_stream_message
from zerver.lib.request import REQ, has_request_variables
from zerver.lib.response import json_error, json_success
from zerver.lib.webhooks.git import SUBJECT_WITH_BRANCH_TEMPLATE, \
    SUBJECT_WITH_PR_OR_ISSUE_INFO_TEMPLATE, \
    get_commits_comment_action_message, get_force_push_commits_event_message, \
    get_issue_event_message, get_pull_request_event_message, \
    get_push_commits_event_message, get_push_tag_event_message, \
    get_remove_branch_event_message
from zerver.models import UserProfile

BITBUCKET_SUBJECT_TEMPLATE = '{repository_name}'
USER_PART = 'User {display_name}(login: {username})'

BITBUCKET_FORK_BODY = USER_PART + ' forked the repository into [{fork_name}]({fork_url}).'
BITBUCKET_COMMIT_STATUS_CHANGED_BODY = ('[System {key}]({system_url}) changed status of'
                                        ' {commit_info} to {status}.')


PULL_REQUEST_SUPPORTED_ACTIONS = [
    'approved',
    'unapproved',
    'created',
    'updated',
    'rejected',
    'fulfilled',
    'comment_created',
    'comment_updated',
    'comment_deleted',
]

class UnknownTriggerType(Exception):
    pass


@api_key_only_webhook_view('Bitbucket2')
@has_request_variables
def api_bitbucket2_webhook(request: HttpRequest, user_profile: UserProfile,
                           payload: Dict[str, Any]=REQ(argument_type='body'),
                           stream: str=REQ(default='bitbucket'),
                           branches: Optional[Text]=REQ(default=None)) -> HttpResponse:
    type = get_type(request, payload)
    if type != 'push':
        subject = get_subject_based_on_type(payload, type)
        body = get_body_based_on_type(type)(payload)
        check_send_stream_message(user_profile, request.client,
                                  stream, subject, body)
    else:
        # ignore push events with no changes
        if not payload['push']['changes']:
            return json_success()
        branch = get_branch_name_for_push_event(payload)
        if branch and branches:
            if branches.find(branch) == -1:
                return json_success()
        subjects = get_push_subjects(payload)
        bodies_list = get_push_bodies(payload)
        for body, subject in zip(bodies_list, subjects):
            check_send_stream_message(user_profile, request.client,
                                      stream, subject, body)
    return json_success()

def get_subject_for_branch_specified_events(payload: Dict[str, Any],
                                            branch_name: Optional[Text]=None) -> Text:
    return SUBJECT_WITH_BRANCH_TEMPLATE.format(
        repo=get_repository_name(payload['repository']),
        branch=get_branch_name_for_push_event(payload) if branch_name is None else branch_name
    )

def get_push_subjects(payload: Dict[str, Any]) -> List[str]:
    subjects_list = []
    for change in payload['push']['changes']:
        potential_tag = (change['new'] or change['old'] or {}).get('type')
        if potential_tag == 'tag':
            subjects_list.append(str(get_subject(payload)))
        else:
            if change.get('new'):
                branch_name = change['new']['name']
            else:
                branch_name = change['old']['name']
            subjects_list.append(str(get_subject_for_branch_specified_events(payload, branch_name)))
    return subjects_list

def get_subject(payload: Dict[str, Any]) -> str:
    assert(payload['repository'] is not None)
    return BITBUCKET_SUBJECT_TEMPLATE.format(repository_name=get_repository_name(payload['repository']))

def get_subject_based_on_type(payload: Dict[str, Any], type: str) -> Text:
    if type.startswith('pull_request'):
        return SUBJECT_WITH_PR_OR_ISSUE_INFO_TEMPLATE.format(
            repo=get_repository_name(payload['repository']),
            type='PR',
            id=payload['pullrequest']['id'],
            title=payload['pullrequest']['title']
        )
    if type.startswith('issue'):
        return SUBJECT_WITH_PR_OR_ISSUE_INFO_TEMPLATE.format(
            repo=get_repository_name(payload['repository']),
            type='Issue',
            id=payload['issue']['id'],
            title=payload['issue']['title']
        )
    return get_subject(payload)

def get_type(request: HttpRequest, payload: Dict[str, Any]) -> str:
    event_key = request.META.get("HTTP_X_EVENT_KEY")
    if payload.get('push'):
        return 'push'
    elif payload.get('fork'):
        return 'fork'
    elif payload.get('comment') and payload.get('commit'):
        return 'commit_comment'
    elif payload.get('commit_status'):
        return 'change_commit_status'
    elif payload.get('issue'):
        if payload.get('changes'):
            return "issue_updated"
        if payload.get('comment'):
            return 'issue_commented'
        return "issue_created"
    elif payload.get('pullrequest'):
        pull_request_template = 'pull_request_{}'
        action = re.match('pullrequest:(?P<action>.*)$', event_key)
        if action:
            action = action.group('action')
            if action in PULL_REQUEST_SUPPORTED_ACTIONS:
                return pull_request_template.format(action)
    raise UnknownTriggerType("We don't support {} event type".format(event_key))

def get_body_based_on_type(type: str) -> Callable[[Dict[str, Any]], Text]:
    fn = GET_SINGLE_MESSAGE_BODY_DEPENDING_ON_TYPE_MAPPER.get(type)
    assert callable(fn)  # type parameter should be pre-checked, so not None
    return fn

def get_push_bodies(payload: Dict[str, Any]) -> List[Text]:
    messages_list = []
    for change in payload['push']['changes']:
        potential_tag = (change['new'] or change['old'] or {}).get('type')
        if potential_tag == 'tag':
            messages_list.append(get_push_tag_body(payload, change))
        elif change.get('closed'):
            messages_list.append(get_remove_branch_push_body(payload, change))
        elif change.get('forced'):
            messages_list.append(get_force_push_body(payload, change))
        else:
            messages_list.append(get_normal_push_body(payload, change))
    return messages_list

def get_remove_branch_push_body(payload: Dict[str, Any], change: Dict[str, Any]) -> Text:
    return get_remove_branch_event_message(
        get_user_username(payload),
        change['old']['name'],
    )

def get_force_push_body(payload: Dict[str, Any], change: Dict[str, Any]) -> Text:
    return get_force_push_commits_event_message(
        get_user_username(payload),
        change['links']['html']['href'],
        change['new']['name'],
        change['new']['target']['hash']
    )

def get_commit_author_name(commit: Dict[str, Any]) -> Text:
    if commit['author'].get('user'):
        return commit['author']['user'].get('username')
    return commit['author']['raw'].split()[0]

def get_normal_push_body(payload: Dict[str, Any], change: Dict[str, Any]) -> Text:
    commits_data = [{
        'name': get_commit_author_name(commit),
        'sha': commit.get('hash'),
        'url': commit.get('links').get('html').get('href'),
        'message': commit.get('message'),
    } for commit in change['commits']]

    return get_push_commits_event_message(
        get_user_username(payload),
        change['links']['html']['href'],
        change['new']['name'],
        commits_data,
        is_truncated=change['truncated']
    )

def get_fork_body(payload: Dict[str, Any]) -> str:
    return BITBUCKET_FORK_BODY.format(
        display_name=get_user_display_name(payload),
        username=get_user_username(payload),
        fork_name=get_repository_full_name(payload['fork']),
        fork_url=get_repository_url(payload['fork'])
    )

def get_commit_comment_body(payload: Dict[str, Any]) -> Text:
    comment = payload['comment']
    action = u'[commented]({})'.format(comment['links']['html']['href'])
    return get_commits_comment_action_message(
        get_user_username(payload),
        action,
        comment['commit']['links']['html']['href'],
        comment['commit']['hash'],
        comment['content']['raw'],
    )

def get_commit_status_changed_body(payload: Dict[str, Any]) -> str:
    commit_id = re.match('.*/commit/(?P<commit_id>[A-Za-z0-9]*$)',
                         payload['commit_status']['links']['commit']['href'])
    if commit_id:
        commit_info = "{}/{}".format(get_repository_url(payload['repository']),
                                     commit_id.group('commit_id'))
    else:
        commit_info = 'commit'

    return BITBUCKET_COMMIT_STATUS_CHANGED_BODY.format(
        key=payload['commit_status']['key'],
        system_url=payload['commit_status']['url'],
        commit_info=commit_info,
        status=payload['commit_status']['state']
    )

def get_issue_commented_body(payload: Dict[str, Any]) -> Text:
    action = '[commented]({}) on'.format(payload['comment']['links']['html']['href'])
    return get_issue_action_body(payload, action)

def get_issue_action_body(payload: Dict[str, Any], action: str) -> Text:
    issue = payload['issue']
    assignee = None
    message = None
    if action == 'created':
        if issue['assignee']:
            assignee = issue['assignee'].get('username')
        message = issue['content']['raw']

    return get_issue_event_message(
        get_user_username(payload),
        action,
        issue['links']['html']['href'],
        issue['id'],
        message,
        assignee
    )

def get_pull_request_action_body(payload: Dict[str, Any], action: str) -> Text:
    pull_request = payload['pullrequest']
    return get_pull_request_event_message(
        get_user_username(payload),
        action,
        get_pull_request_url(pull_request),
        pull_request.get('id')
    )

def get_pull_request_created_or_updated_body(payload: Dict[str, Any], action: str) -> Text:
    pull_request = payload['pullrequest']
    assignee = None
    if pull_request.get('reviewers'):
        assignee = pull_request.get('reviewers')[0]['username']

    return get_pull_request_event_message(
        get_user_username(payload),
        action,
        get_pull_request_url(pull_request),
        pull_request.get('id'),
        target_branch=pull_request['source']['branch']['name'],
        base_branch=pull_request['destination']['branch']['name'],
        message=pull_request['description'],
        assignee=assignee
    )

def get_pull_request_comment_created_action_body(payload: Dict[str, Any]) -> Text:
    action = '[commented]({})'.format(payload['comment']['links']['html']['href'])
    return get_pull_request_comment_action_body(payload, action)

def get_pull_request_deleted_or_updated_comment_action_body(payload: Dict[str, Any], action: Text) -> Text:
    action = "{} a [comment]({})".format(action, payload['comment']['links']['html']['href'])
    return get_pull_request_comment_action_body(payload, action)

def get_pull_request_comment_action_body(payload: Dict[str, Any], action: str) -> Text:
    action += ' on'
    return get_pull_request_event_message(
        get_user_username(payload),
        action,
        payload['pullrequest']['links']['html']['href'],
        payload['pullrequest']['id'],
        message=payload['comment']['content']['raw']
    )

def get_push_tag_body(payload: Dict[str, Any], change: Dict[str, Any]) -> Text:
    if change.get('created'):
        tag = change['new']
        action = 'pushed'  # type: Optional[Text]
    elif change.get('closed'):
        tag = change['old']
        action = 'removed'
    else:
        tag = change['new']
        action = None
    return get_push_tag_event_message(
        get_user_username(payload),
        tag.get('name'),
        tag_url=tag['links']['html'].get('href'),
        action=action
    )

def get_pull_request_title(pullrequest_payload: Dict[str, Any]) -> str:
    return pullrequest_payload['title']

def get_pull_request_url(pullrequest_payload: Dict[str, Any]) -> str:
    return pullrequest_payload['links']['html']['href']

def get_repository_url(repository_payload: Dict[str, Any]) -> str:
    return repository_payload['links']['html']['href']

def get_repository_name(repository_payload: Dict[str, Any]) -> str:
    return repository_payload['name']

def get_repository_full_name(repository_payload: Dict[str, Any]) -> str:
    return repository_payload['full_name']

def get_user_display_name(payload: Dict[str, Any]) -> str:
    return payload['actor']['display_name']

def get_user_username(payload: Dict[str, Any]) -> str:
    return payload['actor']['username']

def get_branch_name_for_push_event(payload: Dict[str, Any]) -> Optional[str]:
    change = payload['push']['changes'][-1]
    potential_tag = (change['new'] or change['old'] or {}).get('type')
    if potential_tag == 'tag':
        return None
    else:
        return (change['new'] or change['old']).get('name')

GET_SINGLE_MESSAGE_BODY_DEPENDING_ON_TYPE_MAPPER = {
    'fork': get_fork_body,
    'commit_comment': get_commit_comment_body,
    'change_commit_status': get_commit_status_changed_body,
    'issue_updated': partial(get_issue_action_body, action='updated'),
    'issue_created': partial(get_issue_action_body, action='created'),
    'issue_commented': get_issue_commented_body,
    'pull_request_created': partial(get_pull_request_created_or_updated_body, action='created'),
    'pull_request_updated': partial(get_pull_request_created_or_updated_body, action='updated'),
    'pull_request_approved': partial(get_pull_request_action_body, action='approved'),
    'pull_request_unapproved': partial(get_pull_request_action_body, action='unapproved'),
    'pull_request_fulfilled': partial(get_pull_request_action_body, action='merged'),
    'pull_request_rejected': partial(get_pull_request_action_body, action='rejected'),
    'pull_request_comment_created': get_pull_request_comment_created_action_body,
    'pull_request_comment_updated': partial(get_pull_request_deleted_or_updated_comment_action_body,
                                            action='updated'),
    'pull_request_comment_deleted': partial(get_pull_request_deleted_or_updated_comment_action_body,
                                            action='deleted')
}