from django.test import TestCase
from modules.task_management.serializers import TaskSerializer
from rest_framework.exceptions import ValidationError
from django.contrib.auth import get_user_model
from modules.task_management.models import Task
from modules.fleet.models import Vehicle, WorkOrder


class TaskSerializerTests(TestCase):
    def setUp(self):
        User = get_user_model()
        self.user = User.objects.create_user(username="task-user-base", email="task-user-base@example.test", password="pass")
        self.vehicle = Vehicle.objects.create(registration_number="ZG-TSK-01", asset_type='crane')

    def test_validate_title_too_short_raises(self):
        serializer = TaskSerializer(data={"title": "ab", "description": "", "status": "aktivan", "vehicle": str(self.vehicle.id)})
        with self.assertRaises(ValidationError):
            serializer.is_valid(raise_exception=True)

    def test_validate_title_ok(self):
        serializer = TaskSerializer(data={"title": "Valid title", "description": "", "status": "aktivan", "vehicle": str(self.vehicle.id)})
        assert serializer.is_valid(), serializer.errors

    def test_cannot_close_without_work_order(self):
        serializer = TaskSerializer(data={"title": "Task 1", "description": "", "status": "neaktivan", "vehicle": str(self.vehicle.id)})
        with self.assertRaises(ValidationError):
            serializer.is_valid(raise_exception=True)

    def test_can_close_with_work_order(self):
        work_order = WorkOrder.objects.create(vehicle=self.vehicle, creator=self.user, purpose='defektaza')
        task = Task.objects.create(title="Task 2", description="", status="servis", assigned_to=self.user, vehicle=self.vehicle)

        serializer = TaskSerializer(instance=task, data={"status": "neaktivan", "work_order": str(work_order.id)}, partial=True)
        assert serializer.is_valid(), serializer.errors

    def test_cannot_mark_finished_without_work_order(self):
        serializer = TaskSerializer(data={"title": "Task 3", "description": "", "status": "zavrsen", "vehicle": str(self.vehicle.id)})
        with self.assertRaises(ValidationError):
            serializer.is_valid(raise_exception=True)

    def test_can_mark_finished_with_work_order(self):
        work_order = WorkOrder.objects.create(vehicle=self.vehicle, creator=self.user, purpose='kontrola')
        task = Task.objects.create(title="Task 4", description="", status="servis", assigned_to=self.user, vehicle=self.vehicle)

        serializer = TaskSerializer(instance=task, data={"status": "zavrsen", "work_order": str(work_order.id)}, partial=True)
        assert serializer.is_valid(), serializer.errors

    def test_scheduled_date_is_optional_on_create(self):
        serializer = TaskSerializer(data={"title": "Task planned", "status": "aktivan", "vehicle": str(self.vehicle.id)})
        assert serializer.is_valid(), serializer.errors
        assert 'scheduled_date' not in serializer.errors

    def test_scheduled_date_is_included_in_serialized_output(self):
        import datetime
        task = Task.objects.create(
            title="Task with date",
            assigned_to=self.user,
            vehicle=self.vehicle,
            scheduled_date=datetime.date(2026, 9, 1),
        )
        serializer = TaskSerializer(instance=task)
        assert 'scheduled_date' in serializer.data
        assert str(serializer.data['scheduled_date']) == '2026-09-01'

    def test_scheduled_date_can_be_null_in_serialized_output(self):
        task = Task.objects.create(title="Task no date", assigned_to=self.user, vehicle=self.vehicle)
        serializer = TaskSerializer(instance=task)
        assert serializer.data['scheduled_date'] is None

    def test_scheduled_date_accepts_valid_date(self):
        serializer = TaskSerializer(
            data={"title": "Task mit datum", "status": "aktivan",
                  "vehicle": str(self.vehicle.id), "scheduled_date": "2026-12-25"}
        )
        assert serializer.is_valid(), serializer.errors

    def test_scheduled_date_rejects_invalid_date_string(self):
        serializer = TaskSerializer(
            data={"title": "Task bad date", "status": "aktivan",
                  "vehicle": str(self.vehicle.id), "scheduled_date": "not-a-date"}
        )
        assert not serializer.is_valid()
        assert 'scheduled_date' in serializer.errors