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

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.request import REQ, has_request_variables
from zerver.lib.response import json_error, json_success
from zerver.lib.webhooks.common import check_send_webhook_message, \
    validate_extract_webhook_http_header, UnexpectedWebhookEventType
from zerver.lib.webhooks.git import TOPIC_WITH_BRANCH_TEMPLATE, \
    TOPIC_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_TOPIC_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}.')
BITBUCKET_REPO_UPDATED_CHANGED = ('{actor} changed the {change} of the **{repo_name}**'
                                  ' repo from **{old}** to **{new}**\n')
BITBUCKET_REPO_UPDATED_ADDED = '{actor} changed the {change} of the **{repo_name}** repo to **{new}**\n'

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

@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'),
                           branches: Optional[str]=REQ(default=None),
                           user_specified_topic: Optional[str]=REQ("topic", default=None)) -> HttpResponse:
    type = get_type(request, payload)
    if type == 'push':
        # 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()

    subject = get_subject_based_on_type(payload, type)
    body_function = get_body_based_on_type(type)
    if 'include_title' in signature(body_function).parameters:
        body = body_function(
            payload,
            include_title=user_specified_topic is not None
        )
    else:
        body = body_function(payload)

    if type != 'push':
        check_send_webhook_message(request, user_profile, subject, body)
    else:
        for b, s in zip(body, subject):
            check_send_webhook_message(request, user_profile, s, b)

    return json_success()

def get_subject_for_branch_specified_events(payload: Dict[str, Any],
                                            branch_name: Optional[str]=None) -> str:
    return TOPIC_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_TOPIC_TEMPLATE.format(repository_name=get_repository_name(payload['repository']))

def get_subject_based_on_type(payload: Dict[str, Any], type: str) -> Any:
    if type.startswith('pull_request'):
        return TOPIC_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 TOPIC_WITH_PR_OR_ISSUE_INFO_TEMPLATE.format(
            repo=get_repository_name(payload['repository']),
            type='Issue',
            id=payload['issue']['id'],
            title=payload['issue']['title']
        )
    if type == 'push':
        return get_push_subjects(payload)
    return get_subject(payload)

def get_type(request: HttpRequest, payload: Dict[str, Any]) -> str:
    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_{}'
        # Note that we only need the HTTP header to determine pullrequest events.
        # We rely on the payload itself to determine the other ones.
        event_key = validate_extract_webhook_http_header(request, "X_EVENT_KEY", "BitBucket")
        action = re.match('pullrequest:(?P<action>.*)$', event_key)
        if action:
            action_group = action.group('action')
            if action_group in PULL_REQUEST_SUPPORTED_ACTIONS:
                return pull_request_template.format(action_group)
    else:
        event_key = validate_extract_webhook_http_header(request, "X_EVENT_KEY", "BitBucket")
        if event_key == 'repo:updated':
            return event_key

    raise UnexpectedWebhookEventType('BitBucket2', event_key)

def get_body_based_on_type(type: str) -> Any:
    fn = GET_SINGLE_MESSAGE_BODY_DEPENDING_ON_TYPE_MAPPER.get(type)
    return fn

def get_push_bodies(payload: Dict[str, Any]) -> List[str]:
    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))
        # if change['new'] is None, that means a branch was deleted
        elif change.get('new') is None:
            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]) -> str:
    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]) -> str:
    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]) -> str:
    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]) -> str:
    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]) -> str:
    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_api_url = payload['commit_status']['links']['commit']['href']
    commit_id = commit_api_url.split('/')[-1]

    commit_info = "[{short_commit_id}]({repo_url}/commits/{commit_id})".format(
        repo_url=get_repository_url(payload['repository']),
        short_commit_id=commit_id[:7],
        commit_id=commit_id
    )

    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],
                             include_title: Optional[bool]=False) -> str:
    action = '[commented]({}) on'.format(payload['comment']['links']['html']['href'])
    return get_issue_action_body(payload, action, include_title)

def get_issue_action_body(payload: Dict[str, Any], action: str,
                          include_title: Optional[bool]=False) -> str:
    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,
        title=issue['title'] if include_title else None
    )

def get_pull_request_action_body(payload: Dict[str, Any], action: str,
                                 include_title: Optional[bool]=False) -> str:
    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'),
        title=pull_request['title'] if include_title else None
    )

def get_pull_request_created_or_updated_body(payload: Dict[str, Any], action: str,
                                             include_title: Optional[bool]=False) -> str:
    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,
        title=pull_request['title'] if include_title else None
    )

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

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

def get_pull_request_comment_action_body(
        payload: Dict[str, Any], action: str,
        include_title: Optional[bool]=False
) -> str:
    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'],
        title=payload['pullrequest']['title'] if include_title else None
    )

def get_push_tag_body(payload: Dict[str, Any], change: Dict[str, Any]) -> str:
    if change.get('created'):
        tag = change['new']
        action = 'pushed'  # type: Optional[str]
    elif change.get('closed'):
        tag = change['old']
        action = 'removed'

    return get_push_tag_event_message(
        get_user_username(payload),
        tag.get('name'),
        tag_url=tag['links']['html'].get('href'),
        action=action
    )

def get_repo_updated_body(payload: Dict[str, Any]) -> str:
    changes = ['website', 'name', 'links', 'language', 'full_name', 'description']
    body = ""
    repo_name = payload['repository']['name']
    actor = payload['actor']['username']

    for change in changes:
        new = payload['changes'][change]['new']
        old = payload['changes'][change]['old']
        if change == 'full_name':
            change = 'full name'
        if new and old:
            message = BITBUCKET_REPO_UPDATED_CHANGED.format(
                actor=actor, change=change, repo_name=repo_name,
                old=old, new=new
            )
            body += message
        elif new and not old:
            message = BITBUCKET_REPO_UPDATED_ADDED.format(
                actor=actor, change=change, repo_name=repo_name, new=new
            )
            body += message

    return body

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'),
    'push': get_push_bodies,
    'repo:updated': get_repo_updated_body,
}