from typing import Optional

from sqlalchemy.exc import IntegrityError

from app.email_utils import (
    get_email_domain_part,
    send_cannot_create_directory_alias,
    send_cannot_create_domain_alias,
    email_belongs_to_alias_domains,
)
from app.errors import AliasInTrashError
from app.extensions import db
from app.log import LOG
from app.models import (
    Alias,
    CustomDomain,
    Directory,
    User,
    DeletedAlias,
    DomainDeletedAlias,
    AliasMailbox,
)


def try_auto_create(address: str) -> Optional[Alias]:
    """Try to auto-create the alias using directory or catch-all domain
    """
    alias = try_auto_create_catch_all_domain(address)
    if not alias:
        alias = try_auto_create_directory(address)

    return alias


def try_auto_create_directory(address: str) -> Optional[Alias]:
    """
    Try to create an alias with directory
    """
    # check if alias belongs to a directory, ie having directory/anything@EMAIL_DOMAIN format
    if email_belongs_to_alias_domains(address):
        # if there's no directory separator in the alias, no way to auto-create it
        if "/" not in address and "+" not in address and "#" not in address:
            return None

        # alias contains one of the 3 special directory separator: "/", "+" or "#"
        if "/" in address:
            sep = "/"
        elif "+" in address:
            sep = "+"
        else:
            sep = "#"

        directory_name = address[: address.find(sep)]
        LOG.d("directory_name %s", directory_name)

        directory = Directory.get_by(name=directory_name)
        if not directory:
            return None

        dir_user: User = directory.user

        if not dir_user.can_create_new_alias():
            send_cannot_create_directory_alias(dir_user, address, directory_name)
            return None

        try:
            LOG.d("create alias %s for directory %s", address, directory)

            mailboxes = directory.mailboxes

            alias = Alias.create(
                email=address,
                user_id=directory.user_id,
                directory_id=directory.id,
                mailbox_id=mailboxes[0].id,
            )
            db.session.flush()
            for i in range(1, len(mailboxes)):
                AliasMailbox.create(
                    alias_id=alias.id, mailbox_id=mailboxes[i].id,
                )

            db.session.commit()
            return alias
        except AliasInTrashError:
            LOG.warning(
                "Alias %s was deleted before, cannot auto-create using directory %s, user %s",
                address,
                directory_name,
                dir_user,
            )
            return None


def try_auto_create_catch_all_domain(address: str) -> Optional[Alias]:
    """Try to create an alias with catch-all domain"""

    # try to create alias on-the-fly with custom-domain catch-all feature
    # check if alias is custom-domain alias and if the custom-domain has catch-all enabled
    alias_domain = get_email_domain_part(address)
    custom_domain = CustomDomain.get_by(domain=alias_domain)

    if not custom_domain:
        return None

    # custom_domain exists
    if not custom_domain.catch_all:
        return None

    # custom_domain has catch-all enabled
    domain_user: User = custom_domain.user

    if not domain_user.can_create_new_alias():
        send_cannot_create_domain_alias(domain_user, address, alias_domain)
        return None

    try:
        LOG.d("create alias %s for domain %s", address, custom_domain)
        alias = Alias.create(
            email=address,
            user_id=custom_domain.user_id,
            custom_domain_id=custom_domain.id,
            automatic_creation=True,
            mailbox_id=domain_user.default_mailbox_id,
        )
        db.session.commit()
        return alias
    except AliasInTrashError:
        LOG.warning(
            "Alias %s was deleted before, cannot auto-create using domain catch-all %s, user %s",
            address,
            custom_domain,
            domain_user,
        )
        return None


def delete_alias(alias: Alias, user: User):
    Alias.delete(alias.id)
    db.session.commit()

    # save deleted alias to either global or domain trash
    if alias.custom_domain_id:
        try:
            DomainDeletedAlias.create(
                user_id=user.id, email=alias.email, domain_id=alias.custom_domain_id
            )
            db.session.commit()
        except IntegrityError:
            LOG.error(
                "alias %s domain %s has been added before to DeletedAlias",
                alias.email,
                alias.custom_domain_id,
            )
            db.session.rollback()
    else:
        try:
            DeletedAlias.create(email=alias.email)
            db.session.commit()
        except IntegrityError:
            LOG.error("alias %s has been added before to DeletedAlias", alias.email)
            db.session.rollback()