from datetime import timedelta

import pytest
from django.utils import timezone
from rest_framework import serializers

from accounts.models import InviteCode, InviteCodeUsage, User
from accounts.serializers import RegisterSerializer


def registration_data(code="VALID-CODE", username="math_user"):
    return {
        "invite_code": code,
        "username": username,
        "password": "StrongPass_2026",
        "nickname": "数学少年",
        "track": User.Track.STANDARD,
    }


@pytest.mark.django_db
def test_register_serializer_有效邀请码创建用户并原子消费():
    invite = InviteCode.objects.create(code="VALID-CODE", max_uses=1)
    serializer = RegisterSerializer(
        data=registration_data(),
        context={"ip_address": "127.0.0.1"},
    )

    assert serializer.is_valid(), serializer.errors
    user = serializer.save()

    invite.refresh_from_db()
    assert invite.used_count == 1
    assert user.check_password("StrongPass_2026")
    usage = InviteCodeUsage.objects.get(user=user)
    assert usage.invite_code == invite
    assert usage.ip_address == "127.0.0.1"


@pytest.mark.django_db
def test_register_serializer_过期邀请码拒绝创建用户():
    InviteCode.objects.create(
        code="EXPIRED",
        max_uses=1,
        expires_at=timezone.now() - timedelta(seconds=1),
    )
    serializer = RegisterSerializer(data=registration_data(code="EXPIRED"))

    assert serializer.is_valid(), serializer.errors
    with pytest.raises(serializers.ValidationError, match="已过期或已用完"):
        serializer.save()
    assert User.objects.count() == 0


@pytest.mark.django_db
def test_register_serializer_用户名大小写重复时校验失败():
    User.objects.create_user(
        username="Math_User",
        password="StrongPass_2026",
        nickname="已有用户",
    )
    serializer = RegisterSerializer(data=registration_data(username="math_user"))

    assert not serializer.is_valid()
    assert "用户名已存在" in str(serializer.errors["username"])


@pytest.mark.django_db
def test_register_serializer_游客迁移字段类型错误时拒绝():
    InviteCode.objects.create(code="VALID-CODE", max_uses=1)
    data = registration_data()
    data["visitor_data"] = {"favorites": None}
    serializer = RegisterSerializer(data=data)

    assert not serializer.is_valid()
    assert "favorites 必须是数组" in str(serializer.errors["visitor_data"])