from datetime import date

from django.contrib.auth import get_user_model
from django.test import TestCase

from tasks.models import Task

User = get_user_model()


class CustomRecurrenceTests(TestCase):
    """Tests for Task.calculate_next_due_date() with custom RRULE patterns."""

    def setUp(self):
        self.user = User.objects.create_user(
            username='testuser',
            email='testuser@example.com',
            password='testpass123',
        )

    def make_task(self, **kwargs):
        defaults = {
            'user': self.user,
            'title': 'Test task',
            'recurrence': 'custom',
        }
        defaults.update(kwargs)
        return Task.objects.create(**defaults)

    def test_every_wednesday(self):
        # 2026-01-07 is a Wednesday
        task = self.make_task(due_date=date(2026, 1, 7), recurrence_rule='FREQ=WEEKLY;BYDAY=WE')
        self.assertEqual(task.calculate_next_due_date(), date(2026, 1, 14))

    def test_every_other_wednesday(self):
        task = self.make_task(due_date=date(2026, 1, 7), recurrence_rule='FREQ=WEEKLY;INTERVAL=2;BYDAY=WE')
        self.assertEqual(task.calculate_next_due_date(), date(2026, 1, 21))

    def test_every_second_tuesday(self):
        # 2026-01-13 is the second Tuesday of January 2026
        task = self.make_task(due_date=date(2026, 1, 13), recurrence_rule='FREQ=MONTHLY;BYDAY=2TU')
        self.assertEqual(task.calculate_next_due_date(), date(2026, 2, 10))

    def test_every_15th(self):
        task = self.make_task(due_date=date(2026, 1, 15), recurrence_rule='FREQ=MONTHLY;BYMONTHDAY=15')
        self.assertEqual(task.calculate_next_due_date(), date(2026, 2, 15))

    def test_respects_recurrence_end_date(self):
        task = self.make_task(
            due_date=date(2026, 1, 7),
            recurrence_rule='FREQ=WEEKLY;BYDAY=WE',
            recurrence_end_date=date(2026, 1, 10),
        )
        self.assertIsNone(task.calculate_next_due_date())

    def test_malformed_rule_returns_none(self):
        task = self.make_task(due_date=date(2026, 1, 7), recurrence_rule='not a valid rrule')
        self.assertIsNone(task.calculate_next_due_date())

    def test_create_next_recurrence(self):
        task = self.make_task(due_date=date(2026, 1, 15), recurrence_rule='FREQ=MONTHLY;BYMONTHDAY=15')
        new_task = task.create_next_recurrence()
        self.assertIsNotNone(new_task)
        self.assertEqual(new_task.due_date, date(2026, 2, 15))
        self.assertEqual(new_task.recurrence_rule, 'FREQ=MONTHLY;BYMONTHDAY=15')
        self.assertEqual(new_task.status, 'pending')

    def test_parsed_custom_recurrence_weekly(self):
        task = self.make_task(recurrence_rule='FREQ=WEEKLY;INTERVAL=2;BYDAY=WE')
        parsed = task.parsed_custom_recurrence
        self.assertEqual(parsed['freq'], 'weekly')
        self.assertEqual(parsed['interval'], 2)
        self.assertEqual(parsed['byweekday'], ['WE'])

    def test_parsed_custom_recurrence_monthly_nth(self):
        task = self.make_task(recurrence_rule='FREQ=MONTHLY;BYDAY=2TU')
        parsed = task.parsed_custom_recurrence
        self.assertEqual(parsed['freq'], 'monthly')
        self.assertEqual(parsed['monthly_mode'], 'nth')
        self.assertEqual(parsed['nth_ordinal'], 2)
        self.assertEqual(parsed['nth_weekday'], 'TU')

    def test_parsed_custom_recurrence_blank(self):
        task = self.make_task(recurrence_rule='')
        parsed = task.parsed_custom_recurrence
        self.assertIsNone(parsed['freq'])
        self.assertEqual(parsed['byweekday'], [])