from pydantic import BaseModel, Field

# Default instruction sent to the vision model when the agent does not provide a
# more specific question. Kept in Chinese to match the product's primary locale.
DEFAULT_VISION_PROMPT = "请仔细观察这张图片,尽可能详细、准确地描述其中的全部内容,包括文字、图表、物体、场景与布局等关键信息。"


class VisionConfig(BaseModel):
    """Configuration for image recognition (识图).

    When ``model_name`` names a model from ``models[]``, the lead agent's
    ``view_image`` tool delegates image understanding to that dedicated model
    and returns a text description — so a text-only chat model can still "see"
    uploaded images. When ``model_name`` is unset, vision falls back to the main
    chat model, which only works when that model has ``supports_vision: true``.
    """

    model_name: str | None = Field(
        default=None,
        description="Name of the model (from models[]) used for image recognition. When unset, falls back to the main chat model if it supports vision.",
    )
    prompt: str = Field(
        default=DEFAULT_VISION_PROMPT,
        description="Default instruction for the vision model when no per-call question is given.",
    )
    max_tokens: int | None = Field(
        default=None,
        description="Optional override for the vision model's max output tokens; falls back to the model's own config when unset.",
    )