from typing import Any, Dict, Mapping, Optional
from urllib.parse import urljoin

from django.conf import settings
from django.http import HttpRequest
from django.utils.html import escape
from django.utils.safestring import SafeString
from django.utils.translation import get_language

from version import (
    LATEST_MAJOR_VERSION,
    LATEST_RELEASE_ANNOUNCEMENT,
    LATEST_RELEASE_VERSION,
    ZULIP_VERSION,
)
from zerver.lib.exceptions import InvalidSubdomainError
from zerver.lib.realm_description import get_realm_rendered_description, get_realm_text_description
from zerver.lib.realm_icon import get_realm_icon_url
from zerver.lib.request import RequestNotes
from zerver.lib.send_email import FromAddress
from zerver.lib.subdomains import get_subdomain, is_root_domain_available
from zerver.models import Realm, UserProfile, get_realm
from zproject.backends import (
    AUTH_BACKEND_NAME_MAP,
    auth_enabled_helper,
    get_external_method_dicts,
    password_auth_enabled,
    require_email_format_usernames,
)
from zproject.config import get_config

DEFAULT_PAGE_PARAMS: Mapping[str, Any] = {
    "development_environment": settings.DEVELOPMENT,
}


def common_context(user: UserProfile) -> Dict[str, Any]:
    """Common context used for things like outgoing emails that don't
    have a request.
    """
    return {
        "realm_uri": user.realm.uri,
        "realm_name": user.realm.name,
        "root_domain_url": settings.ROOT_DOMAIN_URI,
        "external_url_scheme": settings.EXTERNAL_URI_SCHEME,
        "external_host": settings.EXTERNAL_HOST,
        "user_name": user.full_name,
        "corporate_enabled": settings.CORPORATE_ENABLED,
    }


def get_realm_from_request(request: HttpRequest) -> Optional[Realm]:
    request_notes = RequestNotes.get_notes(request)
    if request.user.is_authenticated:
        return request.user.realm
    if not request_notes.has_fetched_realm:
        # We cache the realm object from this function on the request data,
        # so that functions that call get_realm_from_request don't
        # need to do duplicate queries on the same realm while
        # processing a single request.
        subdomain = get_subdomain(request)
        request_notes = RequestNotes.get_notes(request)
        try:
            request_notes.realm = get_realm(subdomain)
        except Realm.DoesNotExist:
            request_notes.realm = None
        request_notes.has_fetched_realm = True
    return request_notes.realm


def get_valid_realm_from_request(request: HttpRequest) -> Realm:
    realm = get_realm_from_request(request)
    if realm is None:
        raise InvalidSubdomainError
    return realm


def get_apps_page_url() -> str:
    if settings.CORPORATE_ENABLED:
        return "/apps/"
    return "https://zulip.com/apps/"


def is_isolated_page(request: HttpRequest) -> bool:
    """Accept a GET param `?nav=no` to render an isolated, navless page."""
    return request.GET.get("nav") == "no"


def zulip_default_context(request: HttpRequest) -> Dict[str, Any]:
    """Context available to all Zulip Jinja2 templates that have a request
    passed in.  Designed to provide the long list of variables at the
    bottom of this function in a wide range of situations: logged-in
    or logged-out, subdomains or not, etc.

    The main variable in the below is whether we know what realm the
    user is trying to interact with.
    """
    realm = get_realm_from_request(request)

    if realm is None:
        realm_uri = settings.ROOT_DOMAIN_URI
        realm_name = None
        realm_icon = None
    else:
        realm_uri = realm.uri
        realm_name = realm.name
        realm_icon = get_realm_icon_url(realm)

    register_link_disabled = settings.REGISTER_LINK_DISABLED
    login_link_disabled = settings.LOGIN_LINK_DISABLED
    find_team_link_disabled = settings.FIND_TEAM_LINK_DISABLED
    allow_search_engine_indexing = False

    if (
        settings.ROOT_DOMAIN_LANDING_PAGE
        and get_subdomain(request) == Realm.SUBDOMAIN_FOR_ROOT_DOMAIN
    ):
        register_link_disabled = True
        login_link_disabled = True
        find_team_link_disabled = False
        allow_search_engine_indexing = True

    apps_page_web = settings.ROOT_DOMAIN_URI + "/accounts/go/"

    if settings.DEVELOPMENT:
        secrets_path = "zproject/dev-secrets.conf"
        settings_path = "zproject/dev_settings.py"
        settings_comments_path = "zproject/prod_settings_template.py"
    else:
        secrets_path = "/etc/zulip/zulip-secrets.conf"
        settings_path = "/etc/zulip/settings.py"
        settings_comments_path = "/etc/zulip/settings.py"

    # Used to remove links to Zulip docs and landing page from footer of self-hosted pages.
    corporate_enabled = settings.CORPORATE_ENABLED

    support_email = FromAddress.SUPPORT
    support_email_html_tag = SafeString(
        f'<a href="mailto:{escape(support_email)}">{escape(support_email)}</a>'
    )

    default_page_params: Dict[str, Any] = {
        **DEFAULT_PAGE_PARAMS,
        "server_sentry_dsn": settings.SENTRY_FRONTEND_DSN,
        "request_language": get_language(),
    }
    if settings.SENTRY_FRONTEND_DSN is not None:
        if realm is not None:
            default_page_params["realm_sentry_key"] = realm.string_id
        default_page_params["server_sentry_environment"] = get_config(
            "machine", "deploy_type", "development"
        )
        default_page_params["server_sentry_sample_rate"] = settings.SENTRY_FRONTEND_SAMPLE_RATE
        default_page_params["server_sentry_trace_rate"] = settings.SENTRY_FRONTEND_TRACE_RATE

    context = {
        "root_domain_landing_page": settings.ROOT_DOMAIN_LANDING_PAGE,
        "custom_logo_url": settings.CUSTOM_LOGO_URL,
        "register_link_disabled": register_link_disabled,
        "login_link_disabled": login_link_disabled,
        "terms_of_service": settings.TERMS_OF_SERVICE_VERSION is not None,
        "login_url": settings.HOME_NOT_LOGGED_IN,
        "only_sso": settings.ONLY_SSO,
        "external_host": settings.EXTERNAL_HOST,
        "external_url_scheme": settings.EXTERNAL_URI_SCHEME,
        "realm_uri": realm_uri,
        "realm_name": realm_name,
        "realm_icon": realm_icon,
        "root_domain_url": settings.ROOT_DOMAIN_URI,
        "apps_page_url": get_apps_page_url(),
        "apps_page_web": apps_page_web,
        "open_realm_creation": settings.OPEN_REALM_CREATION,
        "development_environment": settings.DEVELOPMENT,
        "support_email": support_email,
        "support_email_html_tag": support_email_html_tag,
        "find_team_link_disabled": find_team_link_disabled,
        "password_min_length": settings.PASSWORD_MIN_LENGTH,
        "password_min_guesses": settings.PASSWORD_MIN_GUESSES,
        "zulip_version": ZULIP_VERSION,
        "user_is_authenticated": request.user.is_authenticated,
        "settings_path": settings_path,
        "secrets_path": secrets_path,
        "settings_comments_path": settings_comments_path,
        "platform": RequestNotes.get_notes(request).client_name,
        "allow_search_engine_indexing": allow_search_engine_indexing,
        "landing_page_navbar_message": settings.LANDING_PAGE_NAVBAR_MESSAGE,
        "is_isolated_page": is_isolated_page(request),
        "default_page_params": default_page_params,
        "corporate_enabled": corporate_enabled,
    }

    context["PAGE_METADATA_URL"] = f"{realm_uri}{request.path}"
    if realm is not None and realm.icon_source == realm.ICON_UPLOADED:
        context["PAGE_METADATA_IMAGE"] = urljoin(realm_uri, realm_icon)

    return context


def login_context(request: HttpRequest) -> Dict[str, Any]:
    realm = get_realm_from_request(request)

    if realm is None:
        realm_description = None
        realm_invite_required = False
        realm_web_public_access_enabled = False
    else:
        realm_description = get_realm_rendered_description(realm)
        realm_invite_required = realm.invite_required
        # We offer web-public access only if the realm has actual web
        # public streams configured, in addition to having it enabled.
        realm_web_public_access_enabled = realm.allow_web_public_streams_access()

    context: Dict[str, Any] = {
        "realm_invite_required": realm_invite_required,
        "realm_description": realm_description,
        "require_email_format_usernames": require_email_format_usernames(realm),
        "password_auth_enabled": password_auth_enabled(realm),
        "two_factor_authentication_enabled": settings.TWO_FACTOR_AUTHENTICATION_ENABLED,
        "realm_web_public_access_enabled": realm_web_public_access_enabled,
    }

    if realm is not None and realm.description:
        context["PAGE_TITLE"] = realm.name
        context["PAGE_DESCRIPTION"] = get_realm_text_description(realm)

    # Add the keys for our standard authentication backends.
    no_auth_enabled = True
    for auth_backend_name in AUTH_BACKEND_NAME_MAP:
        name_lower = auth_backend_name.lower()
        key = f"{name_lower}_auth_enabled"
        is_enabled = auth_enabled_helper([auth_backend_name], realm)
        context[key] = is_enabled
        if is_enabled:
            no_auth_enabled = False

    context["external_authentication_methods"] = get_external_method_dicts(realm)
    context["no_auth_enabled"] = no_auth_enabled

    # Include another copy of external_authentication_methods in page_params for use
    # by the desktop client. We expand it with IDs of the <button> elements corresponding
    # to the authentication methods.
    context["page_params"] = dict(
        external_authentication_methods=get_external_method_dicts(realm),
    )
    for auth_dict in context["page_params"]["external_authentication_methods"]:
        auth_dict["button_id_suffix"] = "auth_button_{}".format(auth_dict["name"])

    return context


def latest_info_context() -> Dict[str, str]:
    context = {
        "latest_release_version": LATEST_RELEASE_VERSION,
        "latest_major_version": LATEST_MAJOR_VERSION,
        "latest_release_announcement": LATEST_RELEASE_ANNOUNCEMENT,
    }
    return context


def get_realm_create_form_context() -> Dict[str, Any]:
    context = {
        "MAX_REALM_NAME_LENGTH": str(Realm.MAX_REALM_NAME_LENGTH),
        "MAX_REALM_SUBDOMAIN_LENGTH": str(Realm.MAX_REALM_SUBDOMAIN_LENGTH),
        "root_domain_available": is_root_domain_available(),
        "sorted_realm_types": sorted(Realm.ORG_TYPES.values(), key=lambda d: d["display_order"]),
    }
    return context