from __future__ import annotations

from typing import Any

from fastapi import APIRouter, Request, Response

from app.a2a.agent_card import build_agent_card
from app.a2a.models import A2ARpcError, A2ARpcRequest, A2ARpcResponse
from app.config import get_settings

settings = get_settings()

router = APIRouter(tags=["a2a"])


@router.get("/.well-known/agent-card.json")
def get_agent_card(request: Request, response: Response) -> dict[str, Any]:
    response.headers["A2A-Version"] = "1.0"
    return build_agent_card(settings=settings, request=request)


@router.post("/a2a/rpc", response_model=A2ARpcResponse)
def a2a_rpc(payload: A2ARpcRequest, response: Response) -> A2ARpcResponse:
    response.headers["A2A-Version"] = "1.0"
    if payload.jsonrpc != "2.0":
        return _error_response(
            request_id=payload.id,
            code=-32600,
            message="Invalid Request: jsonrpc must be '2.0'.",
        )

    if payload.method in {"ping", "health.ping", "health/ping"}:
        return A2ARpcResponse(
            id=payload.id,
            result={"status": "ok", "agent": settings.a2a_agent_name},
        )

    return _error_response(
        request_id=payload.id,
        code=-32601,
        message=f"Method '{payload.method}' is not implemented yet.",
    )


def _error_response(request_id: str | int | None, code: int, message: str) -> A2ARpcResponse:
    return A2ARpcResponse(
        id=request_id,
        error=A2ARpcError(code=code, message=message),
    )