from pydantic import Field, NonNegativeFloat, NonNegativeInt, PositiveFloat
from pydantic_settings import BaseSettings


class AgentBackendConfig(BaseSettings):
    """
    Configuration settings for the Agent backend runtime integration.
    """

    AGENT_BACKEND_BASE_URL: str | None = Field(
        description="Base URL for the Dify Agent backend service.",
        default=None,
    )

    AGENT_BACKEND_API_TOKEN: str | None = Field(
        description="Bearer token for authenticating with the Agent backend control-plane API.",
        default=None,
    )

    AGENT_BACKEND_USE_FAKE: bool = Field(
        description="Use the deterministic in-process fake Agent backend client.",
        default=False,
    )

    AGENT_BACKEND_FAKE_SCENARIO: str = Field(
        description="Scenario used by the fake Agent backend client.",
        default="success",
    )

    AGENT_BACKEND_STREAM_READ_TIMEOUT_SECONDS: PositiveFloat = Field(
        description="Read timeout for one Agent backend SSE connection.",
        default=30,
    )

    AGENT_BACKEND_STREAM_MAX_RECONNECTS: NonNegativeInt = Field(
        description="Maximum Agent backend SSE reconnects before failing the run.",
        default=3,
    )

    AGENT_BACKEND_HOME_SNAPSHOT_TIMEOUT_SECONDS: PositiveFloat = Field(
        description=(
            "Client timeout for Agent backend calls that may carry a Home Snapshot transfer: "
            "snapshot capture and delete, and Execution Binding creation that restores one. "
        ),
        default=45.0,
    )

    AGENT_BACKEND_BINDING_FILE_DOWNLOAD_TIMEOUT_SECONDS: PositiveFloat = Field(
        description="Client timeout for converting a Binding file to a ToolFile through the Agent backend.",
        default=240,
    )

    AGENT_SHELL_ENABLED: bool = Field(
        description=(
            "Inject the Home, Workspace, Sandbox, and Shell runtime layers into Agent runs. "
            "Requires Dify Agent to have a deployment-selected runtime backend."
        ),
        default=True,
    )

    AGENT_APP_TEXT_DELTA_DEBOUNCE_SECONDS: NonNegativeFloat = Field(
        description=(
            "Buffer Agent App assistant text deltas for up to this many seconds before "
            "publishing SSE chunks. Set to 0 to publish each delta immediately."
        ),
        default=0.5,
    )