"""Tests for the 18+ age gate on user registration."""

from datetime import date, timedelta

import pytest
from fastapi.testclient import TestClient

from app.main import app
from app.routers.auth import calculate_age, MIN_AGE, RegisterRequest


class TestCalculateAge:
    """Unit tests for the calculate_age helper."""

    def test_exactly_18(self):
        today = date(2026, 6, 15)
        dob = today.replace(year=today.year - 18)
        assert calculate_age(dob, today=today) == 18

    def test_just_turned_18(self):
        today = date(2026, 6, 15)
        dob = today.replace(year=today.year - 18) - timedelta(days=1)
        assert calculate_age(dob, today=today) == 18

    def test_one_day_short_of_18(self):
        today = date(2026, 6, 15)
        dob = today.replace(year=today.year - 18) + timedelta(days=1)
        assert calculate_age(dob, today=today) == 17

    def test_leap_day_birthday_before(self):
        assert calculate_age(date(2000, 2, 29), today=date(2024, 2, 28)) == 23

    def test_leap_day_birthday_after(self):
        assert calculate_age(date(2000, 2, 29), today=date(2024, 3, 1)) == 24


class TestRegisterRequestDob:
    def test_dob_parsed_from_iso_string(self):
        req = RegisterRequest(username="u", email="u@example.com", password="p",
                              date_of_birth="1990-01-01")
        assert req.date_of_birth == date(1990, 1, 1)

    def test_dob_required(self):
        with pytest.raises(Exception):
            RegisterRequest(username="u", email="u@example.com", password="p")

    def test_bad_dob_string_rejected(self):
        with pytest.raises(Exception):
            RegisterRequest(username="u", email="u@example.com", password="p",
                            date_of_birth="not-a-date")


class TestRegisterAgeGate:
    """End-to-end: the /register endpoint computes age from the DOB."""

    def _dob_for_age(self, years: int) -> str:
        return (date.today().replace(year=date.today().year - years)).isoformat()

    def test_adult_accepted(self):
        client = TestClient(app)
        r = client.post("/api/auth/register", json={
            "username": "gate_adult", "email": "gate_adult@e.com",
            "password": "secret123", "date_of_birth": self._dob_for_age(25),
        })
        assert r.status_code == 201, r.text

    def test_minor_rejected(self):
        client = TestClient(app)
        r = client.post("/api/auth/register", json={
            "username": "gate_minor", "email": "gate_minor@e.com",
            "password": "secret123", "date_of_birth": self._dob_for_age(15),
        })
        assert r.status_code == 403
        assert str(MIN_AGE) in r.json()["detail"]

    def test_exactly_18_accepted(self):
        client = TestClient(app)
        r = client.post("/api/auth/register", json={
            "username": "gate_18", "email": "gate_18@e.com",
            "password": "secret123",
            "date_of_birth": (date.today().replace(year=date.today().year - 18) - timedelta(days=1)).isoformat(),
        })
        assert r.status_code == 201, r.text

    def test_future_dob_rejected(self):
        client = TestClient(app)
        r = client.post("/api/auth/register", json={
            "username": "gate_future", "email": "gate_future@e.com",
            "password": "secret123", "date_of_birth": "2999-01-01",
        })
        assert r.status_code == 400

    def test_dob_is_stored(self):
        client = TestClient(app)
        dob = self._dob_for_age(30)
        reg = client.post("/api/auth/register", json={
            "username": "gate_stored", "email": "gate_stored@e.com",
            "password": "secret123", "date_of_birth": dob,
        })
        assert reg.status_code == 201
        me = client.get("/api/auth/me", headers={
            "Authorization": f"Bearer {reg.json()['access_token']}"
        })
        assert me.json()["date_of_birth"] == dob