from django.test import TestCase
from django.urls import reverse
from rest_framework.test import APIClient
from rest_framework import status
from django.contrib.auth import get_user_model
from tenants.models import Tenant
from .models import Project, Task

User = get_user_model()

class ProjectTaskTests(TestCase):
    def setUp(self):
        self.client_a = APIClient()
        self.client_b = APIClient()
        
        self.tenant_a = Tenant.objects.create(name='Tenant A', subdomain='tenant-a')
        self.tenant_b = Tenant.objects.create(name='Tenant B', subdomain='tenant-b')

        self.teacher_a = User.objects.create_user(username='teacher_a', password='pw', role='teacher', tenant=self.tenant_a)
        self.student_a = User.objects.create_user(username='student_a', password='pw', role='student', tenant=self.tenant_a)
        self.teacher_b = User.objects.create_user(username='teacher_b', password='pw', role='teacher', tenant=self.tenant_b)

        # Login clients
        response_a = self.client_a.post(reverse('token_obtain_pair'), {'username': 'teacher_a', 'password': 'pw'})
        self.client_a.credentials(HTTP_AUTHORIZATION='Bearer ' + response_a.data['access'], HTTP_X_TENANT_ID=str(self.tenant_a.id))

        response_b = self.client_b.post(reverse('token_obtain_pair'), {'username': 'teacher_b', 'password': 'pw'})
        self.client_b.credentials(HTTP_AUTHORIZATION='Bearer ' + response_b.data['access'], HTTP_X_TENANT_ID=str(self.tenant_b.id))

        self.client_student = APIClient()
        response_stud = self.client_student.post(reverse('token_obtain_pair'), {'username': 'student_a', 'password': 'pw'})
        self.client_student.credentials(HTTP_AUTHORIZATION='Bearer ' + response_stud.data['access'], HTTP_X_TENANT_ID=str(self.tenant_a.id))

    def test_project_crud(self):
        # Create
        url = reverse('project-list')
        data = {'name': 'Project Alpha', 'description': 'Test project'}
        response = self.client_a.post(url, data, format='json')
        self.assertEqual(response.status_code, status.HTTP_201_CREATED)
        self.assertEqual(Project.objects.count(), 1)
        project_id = response.data['id']

        # List
        response = self.client_a.get(url)
        self.assertEqual(response.data['count'], 1)
        self.assertEqual(len(response.data['results']), 1)

        # Update
        detail_url = reverse('project-detail', kwargs={'pk': project_id})
        response = self.client_a.put(detail_url, {'name': 'Project Alpha Updated'}, format='json')
        self.assertEqual(response.status_code, status.HTTP_200_OK)
        self.assertEqual(response.data['name'], 'Project Alpha Updated')

        # Tenant Isolation - B should not see A's projects
        response = self.client_b.get(url)
        self.assertEqual(response.data['count'], 0)

        # Role Based - Student can read, but not create
        response = self.client_student.get(url)
        self.assertEqual(response.status_code, status.HTTP_200_OK)
        self.assertEqual(response.data['count'], 1)

        response = self.client_student.post(url, data, format='json')
        self.assertEqual(response.status_code, status.HTTP_403_FORBIDDEN)

    def test_task_crud(self):
        project = Project.objects.create(name='Proj A', tenant=self.tenant_a, created_by=self.teacher_a)
        
        # Create Task
        url = reverse('project-tasks-list', kwargs={'project_pk': project.id})
        data = {'title': 'Backend Auth', 'description': 'JWT Setup', 'status': 'todo', 'priority': 'high'}
        response = self.client_a.post(url, data, format='json')
        
        self.assertEqual(response.status_code, status.HTTP_201_CREATED)
        task_id = response.data['id']

        # Update Task Assignment
        detail_url = reverse('project-tasks-detail', kwargs={'project_pk': project.id, 'pk': task_id})
        response = self.client_a.patch(detail_url, {'assigned_to_id': self.student_a.id}, format='json')
        self.assertEqual(response.status_code, status.HTTP_200_OK)
        
        task = Task.objects.get(id=task_id)
        self.assertEqual(task.assigned_to, self.student_a)