from datetime import datetime
from pydantic import BaseModel, Field


class ConversationCreate(BaseModel):
    title: str | None = Field(default=None, max_length=200)
    subject: str = ""
    grade: str = ""


class ConversationRename(BaseModel):
    title: str = Field(..., min_length=1, max_length=200)
    pinned: bool | None = None


class ChatSend(BaseModel):
    content: str = Field(..., min_length=1, max_length=4000)
    subject: str = ""
    grade: str = ""


class MessageOut(BaseModel):
    id: int
    role: str
    content: str
    created_at: datetime | None = None

    model_config = {"from_attributes": True}


class ConversationOut(BaseModel):
    id: int
    title: str
    subject: str = ""
    grade: str = ""
    pinned: bool = False
    created_at: datetime | None = None
    updated_at: datetime | None = None
    messages: list[MessageOut] = Field(default_factory=list)

    model_config = {"from_attributes": True}