from datetime import datetime
from typing import Literal

from pydantic import BaseModel, field_validator

from app.schemas.chat import ChatMessage, ChatResponse


class QueueRequest(BaseModel):
    messages: list[ChatMessage]
    max_tokens: int = 2048
    temperature: float = 0.0
    response_format: Literal["json", "text"] = "text"
    priority: Literal["high", "normal", "low"] = "normal"

    @field_validator("messages")
    @classmethod
    def messages_not_empty(cls, v: list) -> list:
        if not v:
            raise ValueError("messages must not be empty")
        return v


class JobStatus(BaseModel):
    id: str
    status: str
    priority: str
    position: int | None = None  # number of jobs ahead; None when not pending
    created_at: datetime
    started_at: datetime | None = None
    finished_at: datetime | None = None
    result: ChatResponse | None = None
    error: str | None = None


class QueueStatus(BaseModel):
    running: bool
    paused: bool
    queue_size: int
    current_job_id: str | None = None