import os

from django.test import TestCase, override_settings
from rest_framework.test import APIClient

from app.expenses.models import Category, Subcategory


TEST_TOKEN = "test-token-123"


@override_settings()
class APITestCase(TestCase):
	def setUp(self):
		os.environ["API_TOKEN"] = TEST_TOKEN
		self.client = APIClient()
		self.category = Category.objects.create(name="Survival", order=1)
		self.subcategory = Subcategory.objects.create(
			name="Food", order=1, category=self.category
		)
		self.other_sub = Subcategory.objects.create(
			name="Other", order=99, category=self.category
		)

	def tearDown(self):
		if "API_TOKEN" in os.environ:
			del os.environ["API_TOKEN"]

	def auth_headers(self):
		return {"HTTP_AUTHORIZATION": f"Bearer {TEST_TOKEN}"}

	# --- Authentication ---

	def test_no_token_returns_403(self):
		response = self.client.get("/api/categories/")
		self.assertEqual(response.status_code, 403)

	def test_invalid_token_returns_403(self):
		response = self.client.get(
			"/api/categories/", HTTP_AUTHORIZATION="Bearer wrong-token"
		)
		self.assertEqual(response.status_code, 403)

	def test_valid_token_returns_200(self):
		response = self.client.get("/api/categories/", **self.auth_headers())
		self.assertEqual(response.status_code, 200)

	# --- Root ---

	def test_root_returns_links(self):
		response = self.client.get("/api/", **self.auth_headers())
		self.assertEqual(response.status_code, 200)
		data = response.json()
		self.assertEqual(data["type"], "Success")
		self.assertIn("categories", data["_links"])
		self.assertIn("expenses", data["_links"])

	# --- Categories ---

	def test_get_categories(self):
		response = self.client.get("/api/categories/", **self.auth_headers())
		self.assertEqual(response.status_code, 200)
		data = response.json()
		self.assertEqual(data["type"], "Success")
		self.assertEqual(len(data["data"]), 1)
		self.assertEqual(data["data"][0]["name"], "Survival")
		self.assertIn("subcategories", data["data"][0])
		self.assertEqual(len(data["data"][0]["subcategories"]), 2)
		self.assertIn("_links", data)

	# --- Subcategories ---

	def test_get_subcategories(self):
		response = self.client.get(
			f"/api/categories/{self.category.id}/subcategories/",
			**self.auth_headers(),
		)
		self.assertEqual(response.status_code, 200)
		data = response.json()
		self.assertEqual(data["type"], "Success")
		self.assertEqual(len(data["data"]), 2)
		self.assertIn("_links", data)

	def test_get_subcategories_invalid_category(self):
		response = self.client.get(
			"/api/categories/9999/subcategories/",
			**self.auth_headers(),
		)
		self.assertEqual(response.status_code, 404)
		data = response.json()
		self.assertEqual(data["type"], "ResourceError")

	# --- Expenses ---

	def test_create_expense(self):
		response = self.client.post(
			"/api/expenses/",
			{
				"concept": "Groceries",
				"amount": "42.50",
				"category": self.category.id,
				"subcategory": self.subcategory.id,
			},
			format="json",
			**self.auth_headers(),
		)
		self.assertEqual(response.status_code, 201)
		data = response.json()
		self.assertEqual(data["type"], "Success")
		self.assertEqual(data["data"]["concept"], "Groceries")
		self.assertEqual(data["data"]["amount"], "42.50")
		self.assertIn("_links", data)

	def test_create_expense_missing_fields(self):
		response = self.client.post(
			"/api/expenses/",
			{"concept": "Test"},
			format="json",
			**self.auth_headers(),
		)
		self.assertEqual(response.status_code, 400)
		data = response.json()
		self.assertEqual(data["type"], "ParametersError")
		self.assertTrue(len(data["errors"]) > 0)

	def test_create_expense_mismatched_subcategory(self):
		other_cat = Category.objects.create(name="Culture", order=2)
		other_sub = Subcategory.objects.create(
			name="Books", order=1, category=other_cat
		)
		response = self.client.post(
			"/api/expenses/",
			{
				"concept": "Wrong combo",
				"amount": "10.00",
				"category": self.category.id,
				"subcategory": other_sub.id,
			},
			format="json",
			**self.auth_headers(),
		)
		self.assertEqual(response.status_code, 400)
		data = response.json()
		self.assertEqual(data["type"], "ParametersError")

	def test_create_expense_invalid_amount(self):
		response = self.client.post(
			"/api/expenses/",
			{
				"concept": "Test",
				"amount": "not-a-number",
				"category": self.category.id,
				"subcategory": self.subcategory.id,
			},
			format="json",
			**self.auth_headers(),
		)
		self.assertEqual(response.status_code, 400)

	def test_expenses_get_not_allowed(self):
		response = self.client.get("/api/expenses/", **self.auth_headers())
		self.assertEqual(response.status_code, 405)