from django.shortcuts import render, redirect, get_object_or_404
from django.contrib.auth.decorators import login_required, user_passes_test
from django.contrib.auth.mixins import LoginRequiredMixin, UserPassesTestMixin
from django.contrib import messages
from django.views.generic import (
    ListView, DetailView, CreateView, UpdateView, DeleteView
)
from django.urls import reverse_lazy
from django.contrib.auth import update_session_auth_hash
from django.contrib.auth.forms import PasswordChangeForm
from django.db.models import Q

from .models import CustomUser, UserGroup
from .forms import CustomUserForm, UserGroupForm

def is_admin_or_manager(user):
    """Check if user is admin or manager"""
    return user.user_type in ['admin', 'manager']

def is_admin(user):
    """Check if user is admin"""
    return user.user_type == 'admin'

class ProfileView(LoginRequiredMixin, DetailView):
    """User profile view"""
    model = CustomUser
    template_name = 'users/profile.html'
    context_object_name = 'user_profile'
    
    def get_object(self):
        return self.request.user

class ProfileEditView(LoginRequiredMixin, UpdateView):
    """Edit user profile"""
    model = CustomUser
    template_name = 'users/profile_edit.html'
    fields = ['first_name', 'last_name', 'email', 'phone', 'department', 'profile_picture']
    success_url = reverse_lazy('users:profile')
    
    def get_object(self):
        return self.request.user
    
    def form_valid(self, form):
        messages.success(self.request, 'Profile updated successfully!')
        return super().form_valid(form)

class ChangePasswordView(LoginRequiredMixin, UpdateView):
    """Change user password"""
    model = CustomUser
    template_name = 'users/change_password.html'
    success_url = reverse_lazy('users:profile')
    
    def get_object(self):
        return self.request.user
    
    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context['form'] = PasswordChangeForm(self.request.user)
        return context
    
    def post(self, request, *args, **kwargs):
        form = PasswordChangeForm(request.user, request.POST)
        if form.is_valid():
            user = form.save()
            update_session_auth_hash(request, user)
            messages.success(request, 'Password changed successfully!')
            return redirect('users:profile')
        else:
            messages.error(request, 'Please correct the errors below.')
            return self.render_to_response(self.get_context_data(form=form))

class UserListView(LoginRequiredMixin, UserPassesTestMixin, ListView):
    """List all users (admin/manager only)"""
    model = CustomUser
    template_name = 'users/user_list.html'
    context_object_name = 'users'
    paginate_by = 20
    
    def test_func(self):
        return is_admin_or_manager(self.request.user)
    
    def get_queryset(self):
        queryset = CustomUser.objects.all().order_by('username')
        search_query = self.request.GET.get('search', '')
        if search_query:
            queryset = queryset.filter(
                Q(username__icontains=search_query) |
                Q(first_name__icontains=search_query) |
                Q(last_name__icontains=search_query) |
                Q(email__icontains=search_query) |
                Q(employee_id__icontains=search_query)
            )
        return queryset

class UserDetailView(LoginRequiredMixin, UserPassesTestMixin, DetailView):
    """User detail view (admin/manager only)"""
    model = CustomUser
    template_name = 'users/user_detail.html'
    context_object_name = 'user_detail'
    
    def test_func(self):
        return is_admin_or_manager(self.request.user)

class UserCreateView(LoginRequiredMixin, UserPassesTestMixin, CreateView):
    """Create new user (admin/manager only)"""
    model = CustomUser
    form_class = CustomUserForm
    template_name = 'users/user_form.html'
    success_url = reverse_lazy('users:user_list')
    
    def test_func(self):
        return is_admin_or_manager(self.request.user)
    
    def form_valid(self, form):
        messages.success(self.request, 'User created successfully!')
        return super().form_valid(form)

class UserEditView(LoginRequiredMixin, UserPassesTestMixin, UpdateView):
    """Edit user (admin/manager only)"""
    model = CustomUser
    form_class = CustomUserForm
    template_name = 'users/user_form.html'
    success_url = reverse_lazy('users:user_list')
    
    def test_func(self):
        return is_admin_or_manager(self.request.user)
    
    def form_valid(self, form):
        messages.success(self.request, 'User updated successfully!')
        return super().form_valid(form)

class GroupListView(LoginRequiredMixin, UserPassesTestMixin, ListView):
    """List all user groups (admin/manager only)"""
    model = UserGroup
    template_name = 'users/group_list.html'
    context_object_name = 'groups'
    paginate_by = 20
    
    def test_func(self):
        return is_admin_or_manager(self.request.user)

class GroupDetailView(LoginRequiredMixin, UserPassesTestMixin, DetailView):
    """User group detail view (admin/manager only)"""
    model = UserGroup
    template_name = 'users/group_detail.html'
    context_object_name = 'group_detail'
    
    def test_func(self):
        return is_admin_or_manager(self.request.user)

class GroupCreateView(LoginRequiredMixin, UserPassesTestMixin, CreateView):
    """Create new user group (admin/manager only)"""
    model = UserGroup
    form_class = UserGroupForm
    template_name = 'users/group_form.html'
    success_url = reverse_lazy('users:group_list')
    
    def test_func(self):
        return is_admin_or_manager(self.request.user)
    
    def form_valid(self, form):
        messages.success(self.request, 'User group created successfully!')
        return super().form_valid(form)