"""Additional question category assignments: counts, filters, validation and migration."""
import io
import os
import unittest
from datetime import datetime
from pathlib import Path
from unittest.mock import patch

import test_quiz_builder as fixtures
from alembic import command
from alembic.config import Config
from alembic.script import ScriptDirectory
from app.models.question import Question
from app.models.question_category import QuestionCategoryLink


class MultiCategoryTests(unittest.TestCase):
    def setUp(self):
        self.bank = fixtures.BuilderTests()
        self.bank.setUp()
        self.client = self.bank.client

    def tearDown(self):
        self.bank.tearDown()

    def test_additional_categories_update_counts_filters_and_bank_rows(self):
        self.bank.user = self.bank.mod  # Question management is moderator-only.
        question = self.bank.db.get(Question, 3)
        self.assertEqual(question.question_category_id, 3)
        response = self.client.patch('/questions/3', json={'additional_category_ids': [4, 2]})
        self.assertEqual(response.status_code, 200, response.text)
        self.assertEqual(response.json()['question_category_id'], 3)
        self.bank.user = self.bank.owner  # Viewing counts stays open to learners.
        cats = {cat['id']: cat['question_count'] for cat in self.client.get('/question-categories/').json()}
        self.assertEqual(cats[4], 1)  # Was an empty category; now includes the linked question.
        self.assertEqual(cats[2], 4)  # Questions 2, 4 and 5, plus the additional link on question 3.
        self.assertEqual(cats[1], 5)  # Question 3 was already counted through its primary (descendant of 1).
        self.assertEqual(self.client.get('/questions/builder/count', params={'category_ids': [4]}).json()['count'], 1)
        self.assertEqual(self.client.get('/questions/builder/count', params={'category_ids': [2]}).json()['count'], 4)
        bank = self.client.get('/questions/bank', params={'category_ids': '4'}).json()
        self.assertEqual([row['id'] for row in bank['questions']], [3])
        self.assertEqual(set(bank['questions'][0]['category_ids']), {2, 3, 4})
        self.assertEqual(self.client.get('/questions/bank/ids', params={'category_ids': '4'}).json(), [3])
        # Category quiz creation counts extra-linked questions too.
        created = self.client.post('/question-categories/4/create-quiz', params={'title': 'Linked quiz', 'mode': 'learning'})
        self.assertEqual(created.status_code, 200, created.text)
        # A removed question is not reachable through its category either.
        self.bank.db.get(Question, 3).deleted_at = datetime(2026, 1, 1)
        self.bank.db.commit()
        self.assertEqual(self.client.get('/questions/builder/count', params={'category_ids': [4]}).json()['count'], 0)

    def test_additional_categories_replace_validate_and_ignore_primary(self):
        self.bank.user = self.bank.mod
        self.assertEqual(self.client.patch('/questions/3', json={'additional_category_ids': [999]}).status_code, 400)
        self.assertEqual(self.client.patch('/questions/3', json={'question_category_id': 999}).status_code, 400)
        self.assertEqual(self.client.patch('/questions/3', json={'additional_category_ids': [3, 4, 4]}).status_code, 200)
        links = {link.category_id for link in self.bank.db.query(QuestionCategoryLink).filter_by(question_id=3)}
        self.assertEqual(links, {4})  # Primary is ignored; duplicates collapsed.
        self.assertEqual(self.client.patch('/questions/3', json={'additional_category_ids': []}).status_code, 200)
        self.assertEqual(self.bank.db.query(QuestionCategoryLink).filter_by(question_id=3).count(), 0)
        self.bank.user = self.bank.peer
        self.assertEqual(self.client.patch('/questions/3', json={'additional_category_ids': [4]}).status_code, 403)  # Learners cannot edit.

    def test_offline_migration_creates_link_table(self):
        output = io.StringIO()
        config = Config(output_buffer=output)
        config.set_main_option('script_location', str(Path(__file__).resolve().parents[1] / 'alembic'))
        scripts = ScriptDirectory.from_config(config)
        self.assertEqual(len(scripts.get_heads()), 1)
        self.assertEqual(scripts.get_revision('h1c2d3e4f506').down_revision, 'g4b7e2f5a903')
        with patch.dict(os.environ, {'DATABASE_URL': 'postgresql://unused@127.0.0.1/offline_only'}):
            command.upgrade(config, 'g4b7e2f5a903:h1c2d3e4f506', sql=True)
            sql = output.getvalue()
            self.assertIn('CREATE TABLE IF NOT EXISTS question_category_links', sql)
            self.assertIn('UNIQUE (question_id, category_id)', sql)
            output.seek(0)
            output.truncate()
            command.downgrade(config, 'h1c2d3e4f506:g4b7e2f5a903', sql=True)
            self.assertIn('DROP TABLE IF EXISTS question_category_links', output.getvalue())


if __name__ == '__main__':
    unittest.main()