from datetime import datetime
from typing import Optional
from pydantic import BaseModel, EmailStr, Field, field_validator, model_validator, ConfigDict
import re

class UserBase(BaseModel):
    username: str = Field(..., min_length=3, max_length=50)
    email: EmailStr

    @field_validator('username')
    @classmethod
    def validate_username(cls, v: str) -> str:
        if not re.match(r'^[a-zA-Z0-9_-]+$', v):
            raise ValueError('Username must contain only alphanumeric characters, underscores, and dashes')
        return v

class UserCreate(UserBase):
    password: str = Field(..., min_length=8, max_length=128)

    @field_validator('password')
    @classmethod
    def validate_password_strength(cls, v: str) -> str:
        if not re.search(r'[A-Z]', v):
            raise ValueError('Password must contain at least one uppercase letter')
        if not re.search(r'[a-z]', v):
            raise ValueError('Password must contain at least one lowercase letter')
        if not re.search(r'\d', v):
            raise ValueError('Password must contain at least one digit')
        return v

class User(UserBase):
    id: int
    is_active: bool
    is_superuser: bool
    created_at: datetime

    model_config = ConfigDict(from_attributes=True)

class UserCreateByAdmin(UserBase):
    password: str = Field(..., min_length=8, max_length=128)
    is_superuser: bool = False

    @field_validator('password')
    @classmethod
    def validate_password_strength(cls, v: str) -> str:
        if not re.search(r'[A-Z]', v):
            raise ValueError('Password must contain at least one uppercase letter')
        if not re.search(r'[a-z]', v):
            raise ValueError('Password must contain at least one lowercase letter')
        if not re.search(r'\d', v):
            raise ValueError('Password must contain at least one digit')
        return v

class UserUpdate(BaseModel):
    username: Optional[str] = Field(None, min_length=3, max_length=50)
    email: Optional[EmailStr] = None
    password: Optional[str] = Field(None, min_length=8, max_length=128)
    is_active: Optional[bool] = None
    is_superuser: Optional[bool] = None

    @field_validator('username')
    @classmethod
    def validate_username(cls, v: Optional[str]) -> Optional[str]:
        if v is not None and not re.match(r'^[a-zA-Z0-9_-]+$', v):
            raise ValueError('Username must contain only alphanumeric characters, underscores, and dashes')
        return v

    @field_validator('password')
    @classmethod
    def validate_password_strength(cls, v: Optional[str]) -> Optional[str]:
        if v is not None:
            if not re.search(r'[A-Z]', v):
                raise ValueError('Password must contain at least one uppercase letter')
            if not re.search(r'[a-z]', v):
                raise ValueError('Password must contain at least one lowercase letter')
            if not re.search(r'\d', v):
                raise ValueError('Password must contain at least one digit')
        return v

class UserListResponse(BaseModel):
    users: list[User]
    total: int
    skip: int
    limit: int

class Token(BaseModel):
    access_token: str
    token_type: str

class TokenData(BaseModel):
    username: Optional[str] = None

class PasswordChange(BaseModel):
    current_password: str = Field(..., min_length=1)
    new_password: str = Field(..., min_length=8, max_length=128)
    confirm_password: str = Field(..., min_length=8, max_length=128)

    @field_validator('new_password')
    @classmethod
    def validate_password_strength(cls, v: str) -> str:
        if not re.search(r'[A-Z]', v):
            raise ValueError('Password must contain at least one uppercase letter')
        if not re.search(r'[a-z]', v):
            raise ValueError('Password must contain at least one lowercase letter')
        if not re.search(r'\d', v):
            raise ValueError('Password must contain at least one digit')
        return v

    @model_validator(mode='after')
    def passwords_match(self) -> 'PasswordChange':
        if self.new_password != self.confirm_password:
            raise ValueError('Passwords do not match')
        return self

class AliyunKeyUpdate(BaseModel):
    api_key: str = Field(..., min_length=1, max_length=500)

class AliyunKeyVerifyResponse(BaseModel):
    valid: bool
    message: str

class UserPreferences(BaseModel):
    default_backend: str = Field(default="aliyun", pattern="^(local|aliyun)$")
    onboarding_completed: bool = Field(default=False)

class UserPreferencesResponse(BaseModel):
    default_backend: str = Field(default="aliyun", pattern="^(local|aliyun)$")
    onboarding_completed: bool = Field(default=False)
    available_backends: list[str] = Field(default=["aliyun"])

class SystemSettingsUpdate(BaseModel):
    local_model_enabled: bool

class SystemSettingsResponse(BaseModel):
    local_model_enabled: bool