import re
from datetime import datetime
from email.headerregistry import Address

from django.contrib.auth.models import UserManager
from django.utils.timezone import now as timezone_now

from zerver.lib.i18n import get_default_language_for_new_user
from zerver.lib.onboarding_steps import copy_onboarding_steps
from zerver.lib.timezone import canonicalize_timezone
from zerver.lib.upload import copy_avatar
from zerver.models import (
    Realm,
    RealmUserDefault,
    Recipient,
    Stream,
    Subscription,
    UserBaseSettings,
    UserProfile,
)
from zerver.models.realms import get_fake_email_domain


def copy_default_settings(
    settings_source: UserProfile | RealmUserDefault, target_profile: UserProfile
) -> None:
    # Important note: Code run from here to configure the user's
    # settings should not send events, as that would cause clients
    # to throw an exception (we haven't sent the realm_user/add event
    # yet, so that event will include the updated details of target_profile).
    #
    # Note that this function will do at least one save() on target_profile.
    for settings_name in UserBaseSettings.property_types:
        if settings_name in ["default_language", "enable_login_emails"] and isinstance(
            settings_source, RealmUserDefault
        ):
            continue

        if settings_name == "email_address_visibility":
            # For email_address_visibility, the value selected in registration form
            # is preferred over the realm-level default value and value of source
            # profile.
            continue
        value = getattr(settings_source, settings_name)
        setattr(target_profile, settings_name, value)

    if isinstance(settings_source, RealmUserDefault):
        target_profile.save()
        return

    target_profile.full_name = settings_source.full_name
    target_profile.timezone = canonicalize_timezone(settings_source.timezone)
    target_profile.save()

    if settings_source.avatar_source == UserProfile.AVATAR_FROM_USER:
        from zerver.actions.user_settings import do_change_avatar_fields

        copy_avatar(settings_source, target_profile)
        do_change_avatar_fields(
            target_profile,
            UserProfile.AVATAR_FROM_USER,
            skip_notify=True,
            acting_user=target_profile,
        )

    copy_onboarding_steps(settings_source, target_profile)


def get_dummy_email_address_for_display_regex(realm: Realm) -> str:
    """
    Returns a regex that matches the format of dummy email addresses we
    generate for the .email of users with limit email_address_visibility.

    The reason we need a regex is that we want something that we can use both
    for generating the dummy email addresses and recognizing them together with extraction
    of the user ID.
    """

    # We can't directly have (\d+) in the username passed to Address, because it gets
    # mutated by the underlying logic for escaping special characters.
    # So we use a trick by using $ as a placeholder which will be preserved, and then
    # replace it with (\d+) to obtain our intended regex.
    address_template = Address(username="user$", domain=get_fake_email_domain(realm.host)).addr_spec
    regex = re.escape(address_template).replace(r"\$", r"(\d+)", 1)
    return regex


def get_display_email_address(user_profile: UserProfile) -> str:
    if not user_profile.email_address_is_realm_public():
        # The format of the dummy email address created here needs to stay consistent
        # with get_dummy_email_address_for_display_regex.
        return Address(
            username=f"user{user_profile.id}", domain=get_fake_email_domain(user_profile.realm.host)
        ).addr_spec
    return user_profile.delivery_email


# create_user_profile is based on Django's User.objects.create_user,
# except that we don't save to the database so it can used in
# bulk_creates
#
# Only use this for bulk_create -- for normal usage one should use
# create_user (below) which will also make the Subscription and
# Recipient objects
def create_user_profile(
    realm: Realm,
    email: str,
    password: str | None,
    active: bool,
    bot_type: int | None,
    full_name: str,
    bot_owner: UserProfile | None,
    is_mirror_dummy: bool,
    tos_version: str | None,
    timezone: str,
    default_language: str,
    force_id: int | None = None,
    force_date_joined: datetime | None = None,
    *,
    email_address_visibility: int,
) -> UserProfile:
    if force_date_joined is None:
        date_joined = timezone_now()
    else:
        date_joined = force_date_joined

    email = UserManager.normalize_email(email)

    extra_kwargs = {}
    if force_id is not None:
        extra_kwargs["id"] = force_id

    user_profile = UserProfile(
        is_staff=False,
        is_active=active,
        full_name=full_name,
        last_login=date_joined,
        date_joined=date_joined,
        realm=realm,
        is_bot=bool(bot_type),
        bot_type=bot_type,
        bot_owner=bot_owner,
        is_mirror_dummy=is_mirror_dummy,
        tos_version=tos_version,
        timezone=timezone,
        default_language=default_language,
        delivery_email=email,
        email_address_visibility=email_address_visibility,
        **extra_kwargs,
    )
    if bot_type or not active:
        password = None
    if user_profile.email_address_is_realm_public():
        # If emails are visible to everyone, we can set this here and save a DB query
        user_profile.email = get_display_email_address(user_profile)
    user_profile.set_password(password)
    return user_profile


def create_user(
    email: str,
    password: str | None,
    realm: Realm,
    full_name: str,
    active: bool = True,
    role: int | None = None,
    bot_type: int | None = None,
    bot_owner: UserProfile | None = None,
    tos_version: str | None = None,
    timezone: str = "",
    avatar_source: str = UserProfile.AVATAR_FROM_GRAVATAR,
    is_mirror_dummy: bool = False,
    default_language: str | None = None,
    default_sending_stream: Stream | None = None,
    default_events_register_stream: Stream | None = None,
    default_all_public_streams: bool | None = None,
    source_profile: UserProfile | None = None,
    force_id: int | None = None,
    force_date_joined: datetime | None = None,
    create_personal_recipient: bool = True,
    enable_marketing_emails: bool | None = None,
    email_address_visibility: int | None = None,
) -> UserProfile:
    realm_user_default = RealmUserDefault.objects.get(realm=realm)
    if bot_type is None:
        if email_address_visibility is not None:
            user_email_address_visibility = email_address_visibility
        else:
            user_email_address_visibility = realm_user_default.email_address_visibility
    else:
        # There is no privacy motivation for limiting access to bot email addresses,
        # so we hardcode them to EMAIL_ADDRESS_VISIBILITY_EVERYONE.
        user_email_address_visibility = UserProfile.EMAIL_ADDRESS_VISIBILITY_EVERYONE

    # Users created via the API or LDAP/SAML syncing code paths will
    # usually not have a default_language value, and should fall back
    # to the realm default.
    if default_language is None:
        default_language = get_default_language_for_new_user(realm, request=None)

    user_profile = create_user_profile(
        realm,
        email,
        password,
        active,
        bot_type,
        full_name,
        bot_owner,
        is_mirror_dummy,
        tos_version,
        timezone,
        default_language,
        force_id=force_id,
        force_date_joined=force_date_joined,
        email_address_visibility=user_email_address_visibility,
    )
    user_profile.avatar_source = avatar_source
    user_profile.timezone = timezone
    user_profile.default_sending_stream = default_sending_stream
    user_profile.default_events_register_stream = default_events_register_stream
    if role is not None:
        user_profile.role = role
    # Allow the ORM default to be used if not provided
    if default_all_public_streams is not None:
        user_profile.default_all_public_streams = default_all_public_streams
    # If a source profile was specified, we copy settings from that
    # user.  Note that this is positioned in a way that overrides
    # other arguments passed in, which is correct for most defaults
    # like time zone where the source profile likely has a better value
    # than the guess. As we decide on details like avatars and full
    # names for this feature, we may want to move it.
    if source_profile is not None:
        # copy_default_settings saves the attribute values so a secondary
        # save is not required.
        copy_default_settings(source_profile, user_profile)
    elif bot_type is None:
        copy_default_settings(realm_user_default, user_profile)
    else:
        # This will be executed only for bots.
        user_profile.save()

    if bot_type is None and enable_marketing_emails is not None:
        user_profile.enable_marketing_emails = enable_marketing_emails
        user_profile.save(update_fields=["enable_marketing_emails"])

    if not user_profile.email_address_is_realm_public():
        # With restricted access to email addresses, we can't generate
        # the fake email addresses we use for display purposes without
        # a User ID, which isn't generated until the .save() above.
        user_profile.email = get_display_email_address(user_profile)
        user_profile.save(update_fields=["email"])

    if not create_personal_recipient:
        return user_profile

    recipient = Recipient.objects.create(type_id=user_profile.id, type=Recipient.PERSONAL)
    user_profile.recipient = recipient
    user_profile.save(update_fields=["recipient"])

    Subscription.objects.create(
        user_profile=user_profile, recipient=recipient, is_user_active=user_profile.is_active
    )
    return user_profile