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




class UserCreate(BaseModel):
    email: EmailStr
    name: str = Field(..., min_length=1, max_length=100)
    password: str = Field(..., min_length=8)
    
    @field_validator('name')
    def validate_name(cls, v):
        if not v.strip():
            raise ValueError('Name cannot be empty or just whitespace')
        return v.strip()
    
    @field_validator('password')
    def validate_password(cls, v):
        if not validate_password_strength(v):
            raise ValueError(
                'Password must be at least 8 characters long and contain '
                'at least one uppercase letter, one lowercase letter, '
                'one digit'
            )
        return v


class Token(BaseModel):
    access_token: str
    token_type: str = "bearer"
    expires_in: int
    email: EmailStr
    name: str


class LogoutResponse(BaseModel):
    message: str


class MessageResponse(BaseModel):
    message: str


class EmailVerificationRequest(BaseModel):
    email: EmailStr


class UserPublic(BaseModel):
    id: str
    email: EmailStr
    name: str
    created_at: datetime

    model_config = {
        "json_encoders": {
            datetime: lambda v: v.isoformat()
        }
    }

def validate_password_strength(password: str) -> bool:
    """Validate password meets security requirements"""
    if len(password) < 8:
        return False
    if not re.search(r"[A-Z]", password):
        return False
    if not re.search(r"[a-z]", password):
        return False
    if not re.search(r"[0-9]", password):
        return False
    return True

class UserQuery(BaseModel):
    query:str
    thread_id: Optional[str] = None  
    create_new_thread: Optional[bool] = False

class SourceItem(BaseModel):
    document_id: str
    filename: str
    chunk_index: Optional[int] = None
    score: Optional[float] = None

class ChatResponse(BaseModel):
    result: str
    thread_id: str
    user_id: str
    is_new_thread: bool
    sources: list[SourceItem] = Field(default_factory=list)

class ThreadItem(BaseModel):
    thread_id: str
    title: str
    created_at: Optional[datetime] = None

class ThreadsResponse(BaseModel):
    threads: list[ThreadItem]
    total: int

class MessageContent(BaseModel):
    query: Optional[str] = None
    messages: list[Any] = Field(default_factory=list)
    
    @field_validator("messages", mode="before")
    @classmethod
    def normalize_messages(cls, v):
        """Always coerce a bare string into a single-element list."""
        if isinstance(v, str):
            return [v]
        if v is None:
            return []
        return v      

class ThreadMessagesResponse(BaseModel):
    thread_id: str
    messages: MessageContent


class DocumentItem(BaseModel):
    document_id: str
    filename: str
    content_type: str
    status: str
    chunk_count: int = 0
    created_at: datetime
    updated_at: datetime
    error_message: Optional[str] = None


class DocumentListResponse(BaseModel):
    documents: list[DocumentItem]
    total: int


class DocumentUploadResponse(BaseModel):
    message: str
    document: DocumentItem


class DocumentDeleteResponse(BaseModel):
    message: str
    document_id: str