from __future__ import absolute_import

import warnings
from importlib import import_module

from django import forms
from django.contrib.auth.tokens import PasswordResetTokenGenerator
from django.contrib.sites.shortcuts import get_current_site
from django.core import exceptions, validators
from django.urls import reverse
from django.utils.translation import gettext, gettext_lazy as _, pgettext

from ..utils import (
    build_absolute_uri,
    get_username_max_length,
    set_form_field_order,
)
from . import app_settings
from .adapter import get_adapter
from .app_settings import AuthenticationMethod
from .models import EmailAddress
from .utils import (
    filter_users_by_email,
    get_user_model,
    perform_login,
    setup_user_email,
    sync_user_email_addresses,
    url_str_to_user_pk,
    user_email,
    user_pk_to_url_str,
    user_username,
)


class EmailAwarePasswordResetTokenGenerator(PasswordResetTokenGenerator):

    def _make_hash_value(self, user, timestamp):
        ret = super(
            EmailAwarePasswordResetTokenGenerator, self)._make_hash_value(
                user, timestamp)
        sync_user_email_addresses(user)
        emails = set([user.email] if user.email else [])
        emails.update(
            EmailAddress.objects
            .filter(user=user)
            .values_list('email', flat=True))
        ret += '|'.join(sorted(emails))
        return ret


default_token_generator = EmailAwarePasswordResetTokenGenerator()


class PasswordVerificationMixin(object):
    def clean(self):
        cleaned_data = super(PasswordVerificationMixin, self).clean()
        password1 = cleaned_data.get('password1')
        password2 = cleaned_data.get('password2')
        if (password1 and password2) and password1 != password2:
            self.add_error(
                'password2', _("You must type the same password each time.")
            )
        return cleaned_data


class PasswordField(forms.CharField):

    def __init__(self, *args, **kwargs):
        render_value = kwargs.pop('render_value',
                                  app_settings.PASSWORD_INPUT_RENDER_VALUE)
        kwargs['widget'] = forms.PasswordInput(render_value=render_value)
        super(PasswordField, self).__init__(*args, **kwargs)


class SetPasswordField(PasswordField):

    def __init__(self, *args, **kwargs):
        super(SetPasswordField, self).__init__(*args, **kwargs)
        self.user = None

    def clean(self, value):
        value = super(SetPasswordField, self).clean(value)
        value = get_adapter().clean_password(value, user=self.user)
        return value


class LoginForm(forms.Form):

    password = PasswordField(label=_("Password"))
    remember = forms.BooleanField(label=_("Remember Me"),
                                  required=False)

    user = None
    error_messages = {
        'account_inactive':
        _("This account is currently inactive."),

        'email_password_mismatch':
        _("The e-mail address and/or password you specified are not correct."),

        'username_password_mismatch':
        _("The username and/or password you specified are not correct."),
    }

    def __init__(self, *args, **kwargs):
        self.request = kwargs.pop('request', None)
        super(LoginForm, self).__init__(*args, **kwargs)
        if app_settings.AUTHENTICATION_METHOD == AuthenticationMethod.EMAIL:
            login_widget = forms.TextInput(attrs={'type': 'email',
                                                  'autofocus': 'autofocus'})
            login_field = forms.EmailField(label=_("E-mail"),
                                           widget=login_widget)
        elif app_settings.AUTHENTICATION_METHOD \
                == AuthenticationMethod.USERNAME:
            login_widget = forms.TextInput(attrs={'autofocus': 'autofocus'})
            login_field = forms.CharField(
                label=_("Username"),
                widget=login_widget,
                max_length=get_username_max_length())
        else:
            assert app_settings.AUTHENTICATION_METHOD \
                == AuthenticationMethod.USERNAME_EMAIL
            login_widget = forms.TextInput(attrs={'autofocus': 'autofocus'})
            login_field = forms.CharField(label=pgettext("field label",
                                                         "Login"),
                                          widget=login_widget)
        self.fields["login"] = login_field
        set_form_field_order(self, ["login", "password", "remember"])
        if app_settings.SESSION_REMEMBER is not None:
            del self.fields['remember']

    def user_credentials(self):
        """
        Provides the credentials required to authenticate the user for
        login.
        """
        credentials = {}
        login = self.cleaned_data["login"]
        if app_settings.AUTHENTICATION_METHOD == AuthenticationMethod.EMAIL:
            credentials["email"] = login
        elif (
                app_settings.AUTHENTICATION_METHOD ==
                AuthenticationMethod.USERNAME):
            credentials["username"] = login
        else:
            if self._is_login_email(login):
                credentials["email"] = login
            credentials["username"] = login
        credentials["password"] = self.cleaned_data["password"]
        return credentials

    def clean_login(self):
        login = self.cleaned_data['login']
        return login.strip()

    def _is_login_email(self, login):
        try:
            validators.validate_email(login)
            ret = True
        except exceptions.ValidationError:
            ret = False
        return ret

    def clean(self):
        super(LoginForm, self).clean()
        if self._errors:
            return
        credentials = self.user_credentials()
        user = get_adapter(self.request).authenticate(
            self.request,
            **credentials)
        if user:
            self.user = user
        else:
            auth_method = app_settings.AUTHENTICATION_METHOD
            if auth_method == app_settings.AuthenticationMethod.USERNAME_EMAIL:
                login = self.cleaned_data['login']
                if self._is_login_email(login):
                    auth_method = app_settings.AuthenticationMethod.EMAIL
                else:
                    auth_method = app_settings.AuthenticationMethod.USERNAME
            raise forms.ValidationError(
                self.error_messages['%s_password_mismatch' % auth_method])
        return self.cleaned_data

    def login(self, request, redirect_url=None):
        ret = perform_login(request, self.user,
                            email_verification=app_settings.EMAIL_VERIFICATION,
                            redirect_url=redirect_url)
        remember = app_settings.SESSION_REMEMBER
        if remember is None:
            remember = self.cleaned_data['remember']
        if remember:
            request.session.set_expiry(app_settings.SESSION_COOKIE_AGE)
        else:
            request.session.set_expiry(0)
        return ret


class _DummyCustomSignupForm(forms.Form):

    def signup(self, request, user):
        """
        Invoked at signup time to complete the signup of the user.
        """
        pass


def _base_signup_form_class():
    """
    Currently, we inherit from the custom form, if any. This is all
    not very elegant, though it serves a purpose:

    - There are two signup forms: one for local accounts, and one for
      social accounts
    - Both share a common base (BaseSignupForm)

    - Given the above, how to put in a custom signup form? Which form
      would your custom form derive from, the local or the social one?
    """
    if not app_settings.SIGNUP_FORM_CLASS:
        return _DummyCustomSignupForm
    try:
        fc_module, fc_classname = app_settings.SIGNUP_FORM_CLASS.rsplit('.', 1)
    except ValueError:
        raise exceptions.ImproperlyConfigured('%s does not point to a form'
                                              ' class'
                                              % app_settings.SIGNUP_FORM_CLASS)
    try:
        mod = import_module(fc_module)
    except ImportError as e:
        raise exceptions.ImproperlyConfigured('Error importing form class %s:'
                                              ' "%s"' % (fc_module, e))
    try:
        fc_class = getattr(mod, fc_classname)
    except AttributeError:
        raise exceptions.ImproperlyConfigured('Module "%s" does not define a'
                                              ' "%s" class' % (fc_module,
                                                               fc_classname))
    if not hasattr(fc_class, 'signup'):
        if hasattr(fc_class, 'save'):
            warnings.warn("The custom signup form must offer"
                          " a `def signup(self, request, user)` method",
                          DeprecationWarning)
        else:
            raise exceptions.ImproperlyConfigured(
                'The custom signup form must implement a "signup" method')
    return fc_class


class BaseSignupForm(_base_signup_form_class()):
    username = forms.CharField(label=_("Username"),
                               min_length=app_settings.USERNAME_MIN_LENGTH,
                               widget=forms.TextInput(
                                   attrs={'autofocus': 'autofocus'}))
    email = forms.EmailField(widget=forms.TextInput(
        attrs={'type': 'email'}))

    def __init__(self, *args, **kwargs):
        email_required = kwargs.pop('email_required',
                                    app_settings.EMAIL_REQUIRED)
        self.username_required = kwargs.pop('username_required',
                                            app_settings.USERNAME_REQUIRED)
        super(BaseSignupForm, self).__init__(*args, **kwargs)
        username_field = self.fields['username']
        username_field.max_length = get_username_max_length()
        username_field.validators.append(
            validators.MaxLengthValidator(username_field.max_length))
        username_field.widget.attrs['maxlength'] = str(
            username_field.max_length)

        default_field_order = [
            'username',
            'email',
            'email2',  # ignored when not present
            'password1',
            'password2',  # ignored when not present
        ]
        if app_settings.SIGNUP_EMAIL_ENTER_TWICE:
            self.fields["email2"] = forms.EmailField(
                label=_("E-mail (again)"),
                widget=forms.TextInput(
                    attrs={
                        'type': 'email'
                    }
                )
            )
        if email_required:
            self.fields['email'].label = gettext("E-mail")
            self.fields['email'].required = True
        else:
            self.fields['email'].label = gettext("E-mail (optional)")
            self.fields['email'].required = False
            self.fields['email'].widget.is_required = False
            if self.username_required:
                default_field_order = [
                    'username',
                    'email',
                    'email2',  # ignored when not present
                    'password1',
                    'password2',  # ignored when not present
                ]

        if not self.username_required:
            del self.fields["username"]

        set_form_field_order(
            self,
            getattr(self, 'field_order', None) or default_field_order)

    def clean_username(self):
        value = self.cleaned_data["username"]
        value = get_adapter().clean_username(value)
        return value

    def clean_email(self):
        value = self.cleaned_data['email']
        value = get_adapter().clean_email(value)
        if value and app_settings.UNIQUE_EMAIL:
            value = self.validate_unique_email(value)
        return value

    def validate_unique_email(self, value):
        return get_adapter().validate_unique_email(value)

    def clean(self):
        cleaned_data = super(BaseSignupForm, self).clean()
        if app_settings.SIGNUP_EMAIL_ENTER_TWICE:
            email = cleaned_data.get('email')
            email2 = cleaned_data.get('email2')
            if (email and email2) and email != email2:
                self.add_error(
                    'email2', _("You must type the same email each time.")
                )
        return cleaned_data

    def custom_signup(self, request, user):
        custom_form = super(BaseSignupForm, self)
        if hasattr(custom_form, 'signup') and callable(custom_form.signup):
            custom_form.signup(request, user)
        else:
            warnings.warn("The custom signup form must offer"
                          " a `def signup(self, request, user)` method",
                          DeprecationWarning)
            # Historically, it was called .save, but this is confusing
            # in case of ModelForm
            custom_form.save(user)


class SignupForm(BaseSignupForm):
    def __init__(self, *args, **kwargs):
        super(SignupForm, self).__init__(*args, **kwargs)
        self.fields['password1'] = PasswordField(label=_("Password"))
        if app_settings.SIGNUP_PASSWORD_ENTER_TWICE:
            self.fields['password2'] = PasswordField(
                label=_("Password (again)"))

        if hasattr(self, 'field_order'):
            set_form_field_order(self, self.field_order)

    def clean(self):
        super(SignupForm, self).clean()

        # `password` cannot be of type `SetPasswordField`, as we don't
        # have a `User` yet. So, let's populate a dummy user to be used
        # for password validaton.
        dummy_user = get_user_model()
        user_username(dummy_user, self.cleaned_data.get("username"))
        user_email(dummy_user, self.cleaned_data.get("email"))
        password = self.cleaned_data.get('password1')
        if password:
            try:
                get_adapter().clean_password(
                    password,
                    user=dummy_user)
            except forms.ValidationError as e:
                self.add_error('password1', e)

        if app_settings.SIGNUP_PASSWORD_ENTER_TWICE \
                and "password1" in self.cleaned_data \
                and "password2" in self.cleaned_data:
            if self.cleaned_data["password1"] \
                    != self.cleaned_data["password2"]:
                self.add_error(
                    'password2',
                    _("You must type the same password each time."))
        return self.cleaned_data

    def save(self, request):
        adapter = get_adapter(request)
        user = adapter.new_user(request)
        adapter.save_user(request, user, self)
        self.custom_signup(request, user)
        # TODO: Move into adapter `save_user` ?
        setup_user_email(request, user, [])
        return user


class UserForm(forms.Form):

    def __init__(self, user=None, *args, **kwargs):
        self.user = user
        super(UserForm, self).__init__(*args, **kwargs)


class AddEmailForm(UserForm):

    email = forms.EmailField(
        label=_("E-mail"),
        required=True,
        widget=forms.TextInput(
            attrs={"type": "email",
                   "size": "30"}))

    def clean_email(self):
        value = self.cleaned_data["email"]
        value = get_adapter().clean_email(value)
        errors = {
            "this_account": _("This e-mail address is already associated"
                              " with this account."),
            "different_account": _("This e-mail address is already associated"
                                   " with another account."),
        }
        users = filter_users_by_email(value)
        on_this_account = [u for u in users if u.pk == self.user.pk]
        on_diff_account = [u for u in users if u.pk != self.user.pk]

        if on_this_account:
            raise forms.ValidationError(errors["this_account"])
        if on_diff_account and app_settings.UNIQUE_EMAIL:
            raise forms.ValidationError(errors["different_account"])
        return value

    def save(self, request):
        return EmailAddress.objects.add_email(request,
                                              self.user,
                                              self.cleaned_data["email"],
                                              confirm=True)


class ChangePasswordForm(PasswordVerificationMixin, UserForm):

    oldpassword = PasswordField(label=_("Current Password"))
    password1 = SetPasswordField(label=_("New Password"))
    password2 = PasswordField(label=_("New Password (again)"))

    def __init__(self, *args, **kwargs):
        super(ChangePasswordForm, self).__init__(*args, **kwargs)
        self.fields['password1'].user = self.user

    def clean_oldpassword(self):
        if not self.user.check_password(self.cleaned_data.get("oldpassword")):
            raise forms.ValidationError(_("Please type your current"
                                          " password."))
        return self.cleaned_data["oldpassword"]

    def save(self):
        get_adapter().set_password(self.user, self.cleaned_data["password1"])


class SetPasswordForm(PasswordVerificationMixin, UserForm):

    password1 = SetPasswordField(label=_("Password"))
    password2 = PasswordField(label=_("Password (again)"))

    def __init__(self, *args, **kwargs):
        super(SetPasswordForm, self).__init__(*args, **kwargs)
        self.fields['password1'].user = self.user

    def save(self):
        get_adapter().set_password(self.user, self.cleaned_data["password1"])


class ResetPasswordForm(forms.Form):

    email = forms.EmailField(
        label=_("E-mail"),
        required=True,
        widget=forms.TextInput(attrs={
            "type": "email",
            "size": "30",
        })
    )

    def clean_email(self):
        email = self.cleaned_data["email"]
        email = get_adapter().clean_email(email)
        self.users = filter_users_by_email(email, is_active=True)
        if not self.users:
            raise forms.ValidationError(_("The e-mail address is not assigned"
                                          " to any user account"))
        return self.cleaned_data["email"]

    def save(self, request, **kwargs):
        current_site = get_current_site(request)
        email = self.cleaned_data["email"]
        token_generator = kwargs.get("token_generator",
                                     default_token_generator)

        for user in self.users:

            temp_key = token_generator.make_token(user)

            # save it to the password reset model
            # password_reset = PasswordReset(user=user, temp_key=temp_key)
            # password_reset.save()

            # send the password reset email
            path = reverse("account_reset_password_from_key",
                           kwargs=dict(uidb36=user_pk_to_url_str(user),
                                       key=temp_key))
            url = build_absolute_uri(
                request, path)

            context = {"current_site": current_site,
                       "user": user,
                       "password_reset_url": url,
                       "request": request}

            if app_settings.AUTHENTICATION_METHOD \
                    != AuthenticationMethod.EMAIL:
                context['username'] = user_username(user)
            get_adapter(request).send_mail(
                'account/email/password_reset_key',
                email,
                context)
        return self.cleaned_data["email"]


class ResetPasswordKeyForm(PasswordVerificationMixin, forms.Form):

    password1 = SetPasswordField(label=_("New Password"))
    password2 = PasswordField(label=_("New Password (again)"))

    def __init__(self, *args, **kwargs):
        self.user = kwargs.pop("user", None)
        self.temp_key = kwargs.pop("temp_key", None)
        super(ResetPasswordKeyForm, self).__init__(*args, **kwargs)
        self.fields['password1'].user = self.user

    def save(self):
        get_adapter().set_password(self.user, self.cleaned_data["password1"])


class UserTokenForm(forms.Form):

    uidb36 = forms.CharField()
    key = forms.CharField()

    reset_user = None
    token_generator = default_token_generator

    error_messages = {
        'token_invalid': _('The password reset token was invalid.'),
    }

    def _get_user(self, uidb36):
        User = get_user_model()
        try:
            pk = url_str_to_user_pk(uidb36)
            return User.objects.get(pk=pk)
        except (ValueError, User.DoesNotExist):
            return None

    def clean(self):
        cleaned_data = super(UserTokenForm, self).clean()

        uidb36 = cleaned_data.get('uidb36', None)
        key = cleaned_data.get('key', None)

        if not key:
            raise forms.ValidationError(self.error_messages['token_invalid'])

        self.reset_user = self._get_user(uidb36)
        if (self.reset_user is None or
                not self.token_generator.check_token(self.reset_user, key)):
            raise forms.ValidationError(self.error_messages['token_invalid'])

        return cleaned_data