"""
用户相关 Schema

定义用户数据的验证和序列化规则。
"""

import re
from datetime import datetime
from typing import Annotated

from pydantic import EmailStr, Field, field_validator

from app.core.config import settings
from app.schemas.base import BaseSchema


# 用户名正则：字母开头，只允许字母、数字、下划线
USERNAME_PATTERN = re.compile(r"^[a-zA-Z][a-zA-Z0-9_]*$")


class UserBase(BaseSchema):
    """用户基础字段"""

    username: Annotated[
        str,
        Field(
            min_length=settings.username_min_length,
            max_length=settings.username_max_length,
            description="用户名（字母开头，只允许字母、数字、下划线）",
            examples=["john_doe"],
        ),
    ]
    email: Annotated[
        EmailStr | None,
        Field(
            default=None,
            description="邮箱地址",
            examples=["user@example.com"],
        ),
    ]
    nickname: Annotated[
        str | None,
        Field(
            default=None,
            max_length=64,
            description="昵称",
            examples=["John"],
        ),
    ]

    @field_validator("username")
    @classmethod
    def validate_username(cls, v: str) -> str:
        """验证用户名格式"""
        if not USERNAME_PATTERN.match(v):
            raise ValueError("用户名必须以字母开头，只能包含字母、数字和下划线")
        return v.lower()  # 统一转小写


class UserCreate(UserBase):
    """用户注册请求"""

    password: Annotated[
        str,
        Field(
            min_length=settings.password_min_length,
            max_length=settings.password_max_length,
            description="密码",
            examples=["SecurePass123"],
        ),
    ]

    @field_validator("password")
    @classmethod
    def validate_password(cls, v: str) -> str:
        """验证密码强度"""
        errors: list[str] = []

        if settings.password_require_uppercase and not re.search(r"[A-Z]", v):
            errors.append("至少包含一个大写字母")

        if settings.password_require_lowercase and not re.search(r"[a-z]", v):
            errors.append("至少包含一个小写字母")

        if settings.password_require_digit and not re.search(r"\d", v):
            errors.append("至少包含一个数字")

        if settings.password_require_special and not re.search(r"[!@#$%^&*(),.?\":{}|<>]", v):
            errors.append("至少包含一个特殊字符")

        if errors:
            raise ValueError("密码强度不足：" + "；".join(errors))

        return v


class UserUpdate(BaseSchema):
    """用户信息更新请求"""

    nickname: Annotated[
        str | None,
        Field(
            default=None,
            max_length=64,
            description="昵称",
        ),
    ]
    email: Annotated[
        EmailStr | None,
        Field(
            default=None,
            description="邮箱地址",
        ),
    ]
    avatar_url: Annotated[
        str | None,
        Field(
            default=None,
            max_length=512,
            description="头像 URL",
        ),
    ]
    bio: Annotated[
        str | None,
        Field(
            default=None,
            max_length=500,
            description="个人简介",
        ),
    ]


class UserResponse(BaseSchema):
    """用户信息响应"""

    id: str
    username: str
    email: str | None
    nickname: str | None
    avatar_url: str | None
    bio: str | None
    is_active: bool
    created_at: datetime
    last_login_at: datetime | None


class UserProfileResponse(BaseSchema):
    """用户公开资料响应（不包含敏感信息）"""

    id: str
    username: str
    nickname: str | None
    avatar_url: str | None
    bio: str | None
    created_at: datetime