from django.contrib.auth.decorators import login_required
from django.core.exceptions import ObjectDoesNotExist, PermissionDenied
from django.shortcuts import render, redirect, get_object_or_404
from django.contrib.auth import authenticate, login, logout
from django.contrib.auth import update_session_auth_hash
from django.http import HttpResponse, Http404
from django.contrib import messages
from core.utils.mail_service import send_forget_password_email
from core.utils.utils import generate_qr_code, link_scraper
from django.utils import timezone
from datetime import timedelta
import psutil

from core.models import (
    UserAccount,
    Subscription,
    PanelConnection,
    ResetPassword,
)
from core.forms import (
    UserCreationForm,
    AdminUserCreationForm,
    AdminUserEditForm,
    UserEditForm,
    UserPasswordChangeForm,
    UserEmailChangeForm,
    SubscriptionForm,
    SubscriptionEditForm,
    AdminConnectionCreationForm
)

from core.utils.link_detail_api_service import get_user_info, connection_test, get_all_online_users

from GateKeeper.settings import EMAIL_ACTIVE, CUSTOM_APP_NAME


# util functions

def is_admin_or_moderator(user):
    return user.account_type in ('admin', 'moderator')


def is_allowed_to_edit(user, target_user):
    return user.account_type == 'admin' or \
        (user.account_type == 'moderator' and target_user.account_type == 'user') or \
        (user.account_type == 'moderator' and target_user.username == user.username) or \
        target_user.username == user.username


def is_allowed_to_delete(user, target_user):
    return user.account_type == 'admin' or \
        (user.account_type == 'moderator' and target_user.account_type == 'user') or \
        (user.account_type == 'moderator' and target_user.username == user.username)


def has_permission(request, user):
    return (
            request.user.account_type == 'admin' or
            (request.user.account_type == 'moderator' and user.account_type == 'user') or
            (request.user.account_type == 'moderator' and user.username == request.user.username) or
            user.username == request.user.username
    )


def redirect_based_on_user_type(user):
    if is_admin_or_moderator(user):
        return redirect('panel-admin')
    else:
        return redirect('user-view-links', username=user.username)


def handle_form_errors(request, form):
    for field, errors in form.errors.items():
        for error in errors:
            messages.error(request, f'Error in {field}: {error}')


def get_subscription_links(user):
    try:
        links = Subscription.objects.filter(assigned_to=user)
        return links.filter(is_active=True)
    except ObjectDoesNotExist:
        return None


def handle_object_does_not_exist(request):
    messages.error(request, 'No subscription links were located.')
    raise Http404("No subscription links were located.")


# view methods


def index(request) -> HttpResponse:
    if request.user.is_authenticated:
        return redirect_based_on_user_type(request.user)
    return redirect('sign-in')


def user_sign_in(request) -> HttpResponse:
    if request.user.is_authenticated:
        return redirect_based_on_user_type(request.user)

    context = {
        'custom_app_name': CUSTOM_APP_NAME,
        'page_title': ['Sign In'],
        'EMAIL_ACTIVE': EMAIL_ACTIVE,
    }
    if request.method == 'POST':
        email = request.POST.get('email')
        password = request.POST.get('password')

        try:
            user = UserAccount.objects.get(email=email)
            user_auth = authenticate(request, username=user.username, password=password)

            if user_auth is not None:
                login(request, user_auth)
                user.last_login_ip = request.META.get('REMOTE_ADDR')
                user.save()

                if user.account_type in ('admin', 'moderator'):
                    return redirect('panel-admin')
                return redirect('user-view-links', username=user.username)

        except ObjectDoesNotExist:
            messages.error(request, 'Invalid email or password')

    if 'logout' in request.GET and request.GET['logout'] == '1':
        messages.success(request, 'You have successfully logged out.')

    return render(request, 'login/sign-in.html', context)


def user_sign_up(request) -> HttpResponse:
    if request.user.is_authenticated:
        return redirect_based_on_user_type(request.user)

    if request.method == 'POST':
        form = UserCreationForm(request.POST)
        if form.is_valid():
            user_form = form.save(commit=False)
            user_form.account_type = 'user'
            user_form.first_name = user_form.first_name.capitalize()
            user_form.last_name = user_form.last_name.capitalize()
            user_form.email = user_form.email.lower()
            user_form.username = user_form.username.lower()
            user_form.save()

            messages.success(request, 'Congratulations on creating your account!')
            return redirect('sign-in')

    context = {
        'custom_app_name': CUSTOM_APP_NAME,
        'page_title': ['Sign Up'],
    }
    form = UserCreationForm()
    context['form'] = form
    return render(request, 'login/sign-up.html', context)


def user_sign_out(request) -> HttpResponse:
    logout(request)
    return redirect('sign-in')


def user_forget_password(request) -> HttpResponse:
    if request.user.is_authenticated:
        return redirect_based_on_user_type(request.user)
    if not EMAIL_ACTIVE:
        raise PermissionDenied

    context = {
        'custom_app_name': CUSTOM_APP_NAME,
        'page_title': ['Forget Password'],
    }

    if request.method == 'POST':
        try:
            user = UserAccount.objects.get(email=request.POST.get("email"))

            reset_password = ResetPassword.objects.create(
                user=user,
            )
            reset_password.save()

            send_forget_password_email(request, user, reset_password.key_token)
            messages.success(
                request, 'Your password reset instructions have been sent to your email. Check your inbox now.'
            )

        except ObjectDoesNotExist:
            messages.error(request, 'Invalid email')

    return render(request, 'login/forget-password.html', context)


def user_reset_password(request, reset_key) -> HttpResponse:
    if request.user.is_authenticated:
        return redirect_based_on_user_type(request.user)
    if not EMAIL_ACTIVE:
        raise PermissionDenied

    context = {
        'custom_app_name': CUSTOM_APP_NAME,
        'page_title': ['Reset Password'],
        "reset_key": reset_key,
    }

    reset_password = ResetPassword.objects.get(key_token=reset_key)

    if request.method == 'POST':
        try:
            user = UserAccount.objects.get(id=reset_password.user.id)
            password = request.POST.get('password')
            password2 = request.POST.get('confirm-password')

            if password == password2:
                user.set_password(password)
                user.save()

                reset_password.delete()

                user = authenticate(request, username=user.username, password=password)
                if user is not None:
                    login(request, user)
                    return redirect_based_on_user_type(user)

        except ObjectDoesNotExist:
            messages.error(request, 'Could not change perform the password reset!')

    return render(request, 'login/reset-password.html', context)


@login_required(login_url='/auth/sign-in')
def panel_admin(request) -> HttpResponse:
    if is_admin_or_moderator(request.user):
        context = {
            'custom_app_name': CUSTOM_APP_NAME,
            'request': request,
            'page_title': ['User Management', 'Overview'],
        }

        try:
            last_24_h = timezone.now() - timedelta(days=1)
            last_week = timezone.now() - timedelta(days=7)
            users = UserAccount.objects

            context['last_24_h_active_users_count'] = len(users.filter(last_login__gte=last_24_h))
            context['last_week_active_users_count'] = len(users.filter(last_login__gte=last_week))
            context['overall_active_users_count'] = len(users.filter(last_login__isnull=False))
            context['panel_online_users'] = get_all_online_users()
        except UserAccount.DoesNotExist:
            pass
        context["cpu_percent"] = psutil.cpu_percent(interval=1)
        context["ram_percent"] = psutil.virtual_memory().percent

        return render(request, 'panel/pages/overview.html', context)
    return redirect('panel-user', username=request.user.username)


@login_required(login_url='/auth/sign-in')
def panel_admin_user_list(request) -> HttpResponse:
    if request.user.account_type in ('admin', 'moderator'):
        context = {
            'custom_app_name': CUSTOM_APP_NAME,
            'request': request,
            'page_title': ['User Management', 'User List'],
        }

        page_ordering = request.GET.get('order', '-id')

        if request.user.account_type == 'admin':
            users = UserAccount.objects.all().order_by(f'{page_ordering}')
        else:
            users = UserAccount.objects.filter(account_type='user').order_by(f'{page_ordering}')

        if request.method == 'POST':
            form = AdminUserCreationForm(request.POST)
            if form.is_valid():
                user = form.save(commit=False)
                user.email = user.email.lower()
                user.username = user.username.lower()
                form.save()

                add_user_form = AdminUserCreationForm()
                context['add_user_form'] = add_user_form
                context['users'] = users
                return render(request, 'panel/pages/users-list.html', context)

        add_user_form = AdminUserCreationForm()
        context['add_user_form'] = add_user_form
        context['users'] = users

        return render(request, 'panel/pages/users-list.html', context)

    raise PermissionDenied


@login_required(login_url='/auth/sign-in')
def panel_admin_edit_user(request, username: str) -> HttpResponse:
    if request.user.account_type in ['admin', 'moderator']:

        context = {
            'custom_app_name': CUSTOM_APP_NAME,
            'request': request,
            'page_title': ['User Management', 'User List', 'Edit User'],
        }

        user = get_object_or_404(UserAccount, username=username)

        if request.method == 'POST':
            form = AdminUserEditForm(request.POST, instance=user)
            if form.is_valid():
                user_form = form.save(commit=False)
                user_form.email = user_form.email.lower() \
                    if user_form.email != "" else user_form.email
                user_form.username = user_form.username.lower() \
                    if user_form.username != "" else user_form.username
                user_form.first_name = user_form.first_name.capitalize() \
                    if user_form.first_name != "" else user_form.first_name
                user_form.last_name = user_form.last_name.capitalize() \
                    if user_form.last_name != "" else user_form.last_name
                user_form.save()

                messages.success(request, 'User was successfully updated!')
                return redirect('panel-admin-user-lists')

        form = AdminUserEditForm(instance=user)
        context['form'] = form
        return render(request, 'panel/pages/admin-edit-user.html', context)

    messages.error(request, 'Action Not Allowed')
    return redirect('panel-user', username=request.user.username)


@login_required(login_url='/auth/sign-in')
def panel_admin_create_link(request, username: str) -> HttpResponse:
    if request.user.account_type in ['admin', 'moderator']:

        context = {
            'custom_app_name': CUSTOM_APP_NAME,
            'request': request,
            'page_title': ['User Management', 'User List', 'Create Link'],
        }

        user = get_object_or_404(UserAccount, username=username)

        if request.method == 'POST':
            form = SubscriptionForm(request.POST)
            if form.is_valid():
                link_form = form.save(commit=False)
                link_form.created_by = request.user
                link_form.assigned_to = user
                link_form.expose = False
                link_form.save()

                messages.success(
                    request, f'Link was successfully assigned to {user.first_name} {user.last_name} [{user.username}].'
                )
                return redirect('panel-admin-user-lists')

        form = SubscriptionForm()
        context['form'] = form
        context['user'] = user
        return render(request, 'panel/pages/admin-create-link.html', context)

    messages.error(request, 'Action Not Allowed')
    return redirect('panel-user', username=request.user.username)


@login_required(login_url='/auth/sign-in')
def panel_admin_edit_link(request, shorten_uuid_link: str) -> HttpResponse:
    if is_admin_or_moderator(request.user):

        context = {
            'custom_app_name': CUSTOM_APP_NAME,
            'request': request,
            'page_title': ['User Management', 'User List', 'Edit Link'],
        }

        link = get_object_or_404(Subscription, subscription_uuid=shorten_uuid_link)

        if request.method == 'POST':
            form = SubscriptionEditForm(request.POST, instance=link)
            if form.is_valid():
                link_instance = form.save(commit=False)
                link_instance.save()

                messages.success(
                    request,
                    f'Link with the id [{link.subscription_uuid}] was successfully updated.'
                )
                return redirect('user-view-links', username=link.assigned_to.username)

        form = SubscriptionEditForm(instance=link)
        context['form'] = form
        context['user'] = link.assigned_to
        return render(request, 'panel/pages/admin-edit-link.html', context)

    messages.error(request, 'Action Not Allowed')
    return redirect('panel-user', username=request.user.username)


@login_required(login_url='/auth/sign-in')
def panel_admin_delete_link(request, shorten_uuid_link: str) -> HttpResponse:
    if is_admin_or_moderator(request.user):

        link = get_object_or_404(Subscription, subscription_uuid=shorten_uuid_link)

        if is_allowed_to_delete(request.user, link.assigned_to):
            link.delete()
            return redirect('user-view-links', username=link.assigned_to.username)

    raise PermissionDenied


@login_required(login_url='/auth/sign-in')
def panel_admin_delete_user(request, username: str) -> HttpResponse:
    if is_admin_or_moderator(request.user):

        user = UserAccount.objects.get(username=username)

        if is_allowed_to_edit(request.user, user):
            user.delete()
            return redirect('panel-admin-user-lists')

    raise PermissionDenied


@login_required(login_url='/auth/sign-in')
def panel_admin_setting_panel_connection(request) -> HttpResponse:
    if request.user.account_type == 'admin':
        context = {
            'custom_app_name': CUSTOM_APP_NAME,
            'request': request,
            'page_title': ['Panel Setting', 'Panel Connection'],
        }

        if request.method == 'POST':
            form = AdminConnectionCreationForm(request.POST)
            if form.is_valid():
                connection_form = form.save(commit=False)
                connection_form.url = connection_form.url.rstrip('/')
                if connection_form.panel_name != PanelConnection.panel_marzban:

                    session_panel_cookie, is_panel_active = connection_test(
                        connection_form.username,
                        connection_form.password,
                        connection_form.url,
                    )
                    if is_panel_active:
                        connection_form.is_active = True
                        connection_form.session_cookie = session_panel_cookie
                    else:
                        connection_form.is_active = False
                connection_form.save()

        panel_connections = PanelConnection.objects.all()
        context['panel_connections'] = panel_connections

        context['connection_creation_form'] = AdminConnectionCreationForm()

        return render(request, 'panel/pages/admin-setting-panel-connection.html', context)

    return redirect('panel-user', username=request.user.username)


@login_required(login_url='/auth/sign-in')
def panel_admin_setting_panel_edit_connection(request, connection_id: int) -> HttpResponse:
    if request.user.account_type == 'admin':
        context = {
            'custom_app_name': CUSTOM_APP_NAME,
            'request': request,
            'page_title': ['Panel Setting', 'Edit Connection'],
        }
        panel_connection = get_object_or_404(PanelConnection, id=connection_id)

        if request.method == 'POST':
            form = AdminConnectionCreationForm(request.POST, instance=panel_connection)
            if form.is_valid():
                connection_form = form.save(commit=False)
                connection_form.url = connection_form.url.rstrip('/')
                if connection_form.panel_name != PanelConnection.panel_marzban:
                    session_panel_cookie, is_panel_active = connection_test(
                        connection_form.username,
                        connection_form.password,
                        connection_form.url,
                    )
                    if is_panel_active:
                        connection_form.is_active = True
                        connection_form.session_cookie = session_panel_cookie
                    else:
                        connection_form.is_active = False

                connection_form.save()
                return redirect('panel-admin-setting-panel-connection')

        connection_form = AdminConnectionCreationForm(instance=panel_connection)
        context['panel_connection'] = panel_connection
        context['connection_form'] = connection_form

        return render(request, 'panel/pages/admin-setting-panel-edit-connection.html', context)

    raise PermissionDenied


@login_required(login_url='/auth/sign-in')
def panel_admin_setting_panel_deleted_connection(request, connection_id: int) -> HttpResponse:
    if request.user.account_type == 'admin':
        panel_connection = get_object_or_404(PanelConnection, id=connection_id)
        panel_connection.delete()
        return redirect('panel-admin-setting-panel-connection')

    raise PermissionDenied


@login_required(login_url='/auth/sign-in')
def panel_user_profile_overview(request, username: str) -> HttpResponse:
    context = {
        'request': request,
    }

    if request.user.username == username or is_admin_or_moderator(request.user):
        user = get_object_or_404(UserAccount, username=username)
        context['page_title'] = ['Users', 'Profile', 'User Profile']
        context['custom_app_name'] = CUSTOM_APP_NAME
        context['user'] = user
        context['form'] = UserEditForm(instance=user)
        context['email_change_form'] = UserEmailChangeForm(instance=user)
        context['password_reset_form'] = UserPasswordChangeForm(user)

        return render(request, 'panel/pages/user-profile.html', context)

    return redirect('sign-in')


@login_required(login_url='/auth/sign-in')
def panel_user_edit(request, username: str) -> HttpResponse:
    user = get_object_or_404(UserAccount, username=username)

    if request.method == 'POST':
        form = UserEditForm(request.POST, instance=user)
        if form.is_valid():
            if has_permission(request, user):
                user_form = form.save(commit=False)
                user_form.username = user_form.username.lower() \
                    if user_form.username != "" else user_form.username
                user_form.first_name = user_form.first_name.capitalize() \
                    if user_form.first_name != "" else user_form.first_name
                user_form.last_name = user_form.last_name.capitalize() \
                    if user_form.last_name != "" else user_form.last_name
                user_form.save()
                messages.success(request, 'Your Profile was successfully updated!')

                return redirect('panel-user-profile', username=user_form.username)
        else:
            handle_form_errors(request, form)

        return redirect('panel-user-profile', username=username)

    messages.error(request, 'Action Not Allowed')
    return redirect('panel-user-profile', username=username)


@login_required(login_url='/auth/sign-in')
def panel_user_change_email(request, username):
    user = get_object_or_404(UserAccount, username=username)

    if request.method == 'POST':
        form = UserEmailChangeForm(request.POST, instance=user)

        if form.is_valid():
            if request.user.account_type == 'admin' or \
                    (request.user.account_type == 'moderator' and user.account_type == 'user') or \
                    (request.user.account_type == 'moderator' and user.username == request.user.username) or \
                    user.username == request.user.username:
                form.save()
                update_session_auth_hash(request, user)
                messages.success(request, 'Your E-mail was successfully updated!')
        else:
            handle_form_errors(request, form)

        return redirect('panel-user-profile', username=username)

    messages.error(request, 'Action Not Allowed')
    return redirect('panel-user-profile', username=username)


@login_required(login_url='/auth/sign-in')
def panel_user_reset_password(request, username: str) -> HttpResponse:
    user = get_object_or_404(UserAccount, username=username)

    if request.method == 'POST':
        form = UserPasswordChangeForm(user, request.POST)

        if form.is_valid() and user.check_password(form.cleaned_data['old_password']):
            if (
                    request.user.account_type == 'admin' or
                    (request.user.account_type == 'moderator' and user.account_type == 'user') or
                    (request.user.account_type == 'moderator' and user.username == request.user.username) or
                    user.username == request.user.username
            ):
                form.save()
                update_session_auth_hash(request, user)
                messages.success(request, 'Your password was successfully updated!')
        else:
            handle_form_errors(request, form)

        return redirect('panel-user-profile', username=username)

    messages.error(request, 'Action Not Allowed')
    return redirect('panel-user-profile', username=username)


@login_required(login_url='/auth/sign-in')
def user_view_links(request, username: str) -> HttpResponse:
    context = {
        'custom_app_name': CUSTOM_APP_NAME,
        'page_title': ['Link Control', 'View Links'],
        'request': request,
    }
    user = get_object_or_404(UserAccount, username=username)
    if request.user.username == username or \
            (request.user.account_type == 'moderator' and user.account_type == 'user') or \
            request.user.account_type == 'admin':
        try:
            links = Subscription.objects.filter(assigned_to=user)
            context['links'] = links.filter(is_active=True)
            context['exposed_links'] = links.filter(is_active=True, expose=True)
            context['restricted_links'] = links.filter(is_active=True, expose=False)
        except ObjectDoesNotExist:
            messages.error(request, 'No subscription links were located.')

        return render(request, 'panel/pages/user-view-links.html', context)

    raise Http404("No subscription links were located.")


@login_required(login_url='/auth/sign-in')
def user_view_single_link(request, shorten_uuid_link) -> HttpResponse:
    context = {
        'custom_app_name': CUSTOM_APP_NAME,
        'page_title': ['Link Control', 'View Links'],
        'request': request,
    }
    try:
        link = Subscription.objects.get(subscription_uuid=shorten_uuid_link)
        if request.user.username == link.assigned_to.username or \
                (request.user.account_type == 'moderator' and link.assigned_to.account_type == 'user') or \
                request.user.account_type == 'admin':
            context['link'] = link
            context['scheme_host'] = request.scheme + '://' + request.get_host()

            if not link.panel_connection:
                qrcode_data = generate_qr_code(
                    link.subscription_link
                )
                context['qrcode'] = qrcode_data

            elif link.panel_connection.panel_name == PanelConnection.panel_marzban:
                context['link_details'] = get_user_info(link)
                qrcode_data = generate_qr_code(
                    f'{context.get("scheme_host")}/panel/user/user-link/show/{link.subscription_uuid}'
                )
                context['qrcode'] = qrcode_data

            else:
                context['link_details'] = get_user_info(link)
                qrcode_data = generate_qr_code(
                    link.subscription_link
                )
                context['qrcode'] = qrcode_data

            return render(request, 'panel/pages/user-view-link-activation.html', context)

    except ObjectDoesNotExist:
        handle_object_does_not_exist(request)


@login_required(login_url='/auth/sign-in')
def user_view_single_link_expose(request, shorten_uuid_link) -> HttpResponse:
    try:
        link = Subscription.objects.get(subscription_uuid=shorten_uuid_link)
        if request.user.username == link.assigned_to.username or \
                (request.user.account_type == 'moderator' and link.assigned_to.account_type == 'user') or \
                request.user.account_type == 'admin':
            link.expose = True
            link.save()

            return redirect('user_link_page', shorten_uuid_link=shorten_uuid_link)

    except ObjectDoesNotExist:
        handle_object_does_not_exist(request)


@login_required(login_url='/auth/sign-in')
def user_view_single_link_restrict(request, shorten_uuid_link) -> HttpResponse:
    try:
        link = Subscription.objects.get(subscription_uuid=shorten_uuid_link)
        if request.user.username == link.assigned_to.username or \
                (request.user.account_type == 'moderator' and link.assigned_to.account_type == 'user') or \
                request.user.account_type == 'admin':
            link.expose = False
            link.save()

            return redirect('user_link_page', shorten_uuid_link=shorten_uuid_link)

    except ObjectDoesNotExist:
        handle_object_does_not_exist(request)


def user_view_single_link_show(request, shorten_uuid_link) -> HttpResponse:
    user_ip = request.META['REMOTE_ADDR']

    try:
        link = Subscription.objects.get(subscription_uuid=shorten_uuid_link)

        if link.expose or link.assigned_to.last_login_ip == user_ip:

            link.use_count += 1
            link.save()

            if link.panel_connection:
                if link.panel_connection.panel_name == PanelConnection.panel_marzban:
                    return HttpResponse(link_scraper(link.subscription_link))
            else:
                return HttpResponse(link.subscription_link)
        else:
            raise Http404("No subscription link were located.")

    except ObjectDoesNotExist:
        handle_object_does_not_exist(request)