from typing import Literal

from langchain.tools import tool
from pydantic import BaseModel, Field


class TicketSummaryInput(BaseModel):
    """Input fields for a support-ticket summary."""

    title: str = Field(description="Short title from the support queue")
    priority: Literal["low", "normal", "high"] = Field(
        default="normal",
        description="Escalation priority for the routing summary",
    )
    requester: str = Field(description="Name or team that opened the ticket")


@tool(
    "summarize_ticket",
    args_schema=TicketSummaryInput,
    description="Create a routing summary for a support ticket.",
)
def summarize_ticket(
    title: str,
    requester: str,
    priority: str = "normal",
) -> str:
    return f"[{priority}] {title} - requester: {requester}"


schema = summarize_ticket.tool_call_schema.model_json_schema()
print(f"Tool name: {summarize_ticket.name}")
print(f"Required inputs: {', '.join(schema['required'])}")
print(
    "Priority choices: "
    + ", ".join(schema["properties"]["priority"]["enum"])
)

result = summarize_ticket.invoke(
    {
        "title": "Database backup failed",
        "priority": "high",
        "requester": "Platform Operations",
    }
)
print(f"Tool result: {result}")